Inhibitory Effects of Selected Medicinal Plants on Bacterial Growth of Methicillin-Resistant Staphylococcus aureus
1
Department of Biomedical Engineering, College of Health Science, Gachon University, Incheon 21936, Korea
2
Department of Health Sciences & Technology, Gachon Advanced Institute for Health Sciences & Technology, Gachon University, Incheon 21999, Korea
*
Author to whom correspondence should be addressed.
†
These authors contributed equally to this work.
Molecules 2022, 27(22), 7780; https://doi.org/10.3390/molecules27227780
Submission received: 31 October 2022
/
Revised: 7 November 2022
/
Accepted: 9 November 2022
/
Published: 11 November 2022
(This article belongs to the Special Issue Plant Extracts: Biological and Pharmacological Activity—the Second Edition)
Abstract
:Methicillin-resistant Staphylococcus aureus (MRSA) is a serious threat to global public health due to its capacity of tolerate conventional antibiotics. Medicinal plants are traditionally used to treat infectious diseases caused by bacterial pathogens. In the present study, 16 medicinal plants were screened for antibacterial activities to preselect more effective species. Ethanol extracts of selected medicinal plants (Caesalpinia sappan L., Glycyrrhiza uralensis Fisch., Sanguisorba officinalis L., and Uncaria gambir Roxb) were partitioned successively with different solvents (n-hexane, chloroform, ethyl acetate, 1-butanol, and water). Disc diffusion assay and broth microdilution were performed to evaluate the antibacterial activities of plant extracts and fractions against Staphylococcus aureus strains. Furthermore, the cytotoxicity of the extracts and fractions was determined against the human hepatoma (HepG2) and human lung carcinoma (A549) cell lines using a trypan blue exclusion method. A few extracts and fractions showed significant inhibitory effects on the bacterial growth of all tested strains, including multidrug-resistance (MDR) clinical isolates. The ethyl acetate fraction of C. sappan had the most potent effects with minimum inhibitory/bactericidal concentrations (MIC/MBC) of 31.2/62.5 μg/mL and showed low cytotoxicity with over 90% cell viability in both cells. Our results suggest that medicinal plants have considerable potential as alternatives to conventional antibiotics.
1. Introduction
Methicillin-resistant Staphylococcus aureus (MRSA) is a prevalent pathogen that causes severe infections in both the healthcare and community settings [1]. MRSA infections have emerged as a global public health burden, substantially increasing morbidity and mortality rates. In hospital settings, Asian countries have reported more MRSA prevalence than countries in Europe [2,3]. The prevalence of MRSA in some Asian countries is particularly high. For example, 73% of clinical isolates in South Korea were identified as MRSA according to reports of a regional resistance surveillance program in 2011 [4,5].
MRSA shows resistance to beta-lactam antibiotics such as penicillin, cephalosporin, and carbapenem and, over time, has become resistant to a few other antibiotic classes including fluoroquinolone, macrolide, aminoglycoside, and clindamycin [6,7]. MRSA infections are difficult to treat due to the capacity of tolerate conventional antibiotics [3]. Thus, new antibiotic agents with different mechanisms of action are urgently needed to control MRSA infections. In fact, the World Health Organization (WHO) has classified MRSA as a high-priority pathogen for the development of novel antibiotics [8].
To search for effective alternatives of antibiotics to treat bacterial infections, plant resources have shown great potential. The use of medicinal plants is still being considered a conventional treatment for diseases or syndromes worldwide [9,10]. Medicinal values of plants are derived from various bioactive compounds such as alkaloids, flavonoids, phenolic compounds, steroids, tannins, terpenoids, and other secondary metabolites [10]. Plant-derived compounds possess low-cost, less toxicity, fewer side effects, and lower propensity of resistance development [11,12]. Owing to these unique properties, medicinal plants are considered attractive alternatives to synthetic chemical antibiotics [13]. Screening of medicinal plants is a key to the research and development of potential antibiotic agents for therapeutic use [14].
Individual bioactive compounds in plant extracts might have little efficacy because they often act in combination with other compounds to control microbial infections [15]. The present study aimed to evaluate antibacterial activities of medicinal plants using plant extracts and fractions of extracts. A total of 16 medicinal plants were screened for antibacterial activities using a broth microdilution method. The inhibitory effects of extracts and fractions from selected medicinal plants on bacterial growth of S. aureus strains including MRSA clinical isolates were then investigated. To evaluate the cytotoxicity of extracts and fractions against HepG2 and A549 cell lines, we performed a cell viability assay.
2. Results and Discussion
In the present study, we confirmed the antibacterial activities of plant extracts and fractions from medicinal plants. To preselect the more effective species, antibacterial activities of ethanol extracts from 16 medicinal plants were evaluated with a broth microdilution method (Figure S1). Four medicinal plants were selected based on their inhibitory effects on bacterial growth of S. aureus strains. Information on these 16 species of medicinal plants is presented in Table 1.
Ethanol extracts of medicinal plants were prepared and partitioned according to the above process (Figure 1). Extraction yields using ethanol for 16 medicinal plants are shown in Table 1. The highest extraction yield was obtained from S. baicalensis (62.37%), followed by that from U. gambir (61.84%). Water and butanol fractions showed higher average yields at 15.40% and 9.95%, respectively, than ethyl acetate fractions (6.80%) and chloroform fractions (3.39%). Hexane fractions had the lowest average yield, at 0.56%. As the polarity of fraction solvents increased, more compounds or polar compounds with a higher mass were extracted from plants. These results are in line with previous studies showing that compounds in plant extracts are predominantly of intermediate and high polarity [16,17].
The inhibitory effects of selected medicinal plants were tested by antibacterial bioassays. Two reference strains (MSSA and MRSA) and two clinical isolates (MRSA and MDRSA) of S. aureus were used in these assays, showing different antibiotic resistance patterns (Table 2 and Figure S2). Thus, bioactive extracts with a novel mechanism of action could be confirmed. MDR was defined as being resistant to at least three different antibiotic classes [18].
Antibacterial activities of extracts and fractions were assessed by disc diffusion method. The diameter of a clear zone was measured and recorded. The results are shown in Table 3 and Table 4. All S. aureus strains were extremely susceptible to rifampicin. Distilled water exhibited no antibacterial activity. Antibacterial activities showed the following order from high to low: C. sappan, U. gambir, G. uralensis, and S. officinalis extracts (Figure S3). C. sappan extract showed a remarkable antibacterial activity with much wider inhibition zones (23.27–25.53 mm) at a concentration of 40 mg/mL and even at a lower concentration of 2.5 mg/mL. In contrast, S. officinalis extracts showed no antibacterial activities at concentrations below 20 mg/mL. We confirmed that the susceptibilities of each bacterial strain to different extracts of selected medicinal plants showed no significant differences (Figure 2). In other words, plant extracts might possess different mechanisms of action compared to conventional antibiotics. Thus, they could be active against bacterial strains regardless of their resistance [19,20].
Disc diffusion assays were also performed using fractions of selected medicinal plants at a concentration of 10 mg/mL. According to results presented in Figure S4, hexane and chloroform fractions only showed inhibition zones for G. uralensis. Ethyl acetate fractions showed more potent activities than other fractions. Butanol fractions showed antibacterial activities against C. sappan and U. gambir. In contrast, water fractions of all plant species and S. officinalis fractions showed no antibacterial activities. The ethyl acetate fraction of C. sappan resulted in the largest clear zones with diameters of 23.10–23.83 mm. The butanol fraction of C. sappan also showed significant activities with diameters of 16.40–17.77 mm for clear zones. These results are considered to be due to different classes of phytochemicals extracted by different solvents and plant materials. Compounds extracted from medicinal plants are mainly dependent on the type of solvent used in the extraction process. For example, polar solvents are used for extracting phenolic compounds, their glycosides, and saponins, whereas non-polar solvents are used to extract fatty acids and steroids [21,22]. On the other hand, although water fraction simultaneously had the highest yields, they showed poor inhibitory effects. These results suggest that massive amounts of compounds might be present in more polar fractions. However, not all compounds show antibacterial activities [23].
Antimicrobial mechanisms of plant extracts are not clearly understood yet. Meanwhile, we confirmed that inhibition zones of plant extracts were dependent on their concentrations and fraction solvents. Our results showed that ethanol extracts of G. uralensis, S. officinalis, and U. gambir had an equal MIC value of 250 μg/mL by the broth microdilution method (Table 5). However, differences in inhibition zones of extracts were observed (Table 3). This could be caused by difficulty in diffusion through agar of G. uralensis and S. officinalis extracts because the major active compounds of these extracts possessed high MWs. The diameter of the clear zone measured by the disc diffusion method is dependent on the degree of diffusion of the active substance. Previous studies have reported that the degree of diffusion is affected by the MW and polarity of compounds [23,24]. The above limitation of the disc diffusion method might have caused differences in the antimicrobial activity between different types of extracts. Disc diffusion method could be inappropriate for testing antimicrobial activities of plant extracts due to factors that might adversely affect the accuracy of results [24,25]. Thus, we determined MIC values to accurately compare the effectiveness of different plant extracts.
It is widely considered that extracts having MIC values below 8 mg/mL possess some antimicrobial activities, while extracts with MIC values below 1 mg/mL exhibit remarkable antimicrobial activities [7]. According to results presented in Figure S1, half of tested extracts showed remarkable antibacterial activities. Especially, four ethanol extracts (C. sappan, G. uralensis, S. officinalis, and U. gambir) exhibited more significant activities with lower MIC values (Table 5). The ethanol extract of C. sappan showed the best activity with MIC values of 62.5 μg/mL for all tested strains. Among various fractions, hexane, chloroform, and water fractions showed little activity. However, hexane and chloroform fractions of G. uralensis inhibited the bacterial growth of S. aureus, with MIC values of 62.5 and 31.2 μg/mL, respectively. MIC values of ethyl acetate fractions were determined as follows: C. sappan (31.2 μg/mL), G. uralensis (125 μg/mL), S. officinalis (500 μg/mL), and U. gambir (62.5 μg/mL). The MIC values of butanol fractions were C. sappan (62.5–125 μg/mL), S. officinalis (250 μg/mL), and U. gambir (125 μg/mL). The butanol and water fractions of G. uralensis showed little activity. A previous study has reported that the chloroform fraction of G. uralensis has 2.5-fold higher antimicrobial activity than the hexane fraction, with an MIC value of 0.1 mg/mL against MRSA strains, whereas the butanol and aqueous fractions exhibit no antibacterial activity [26]. Furthermore, prominent antibacterial activity was observed for extracts and fractions from C. sappan. Brazilin, one of the major active compounds in C. sappan, has been reported to show noteworthy antibacterial activity against antibiotic-resistant bacteria, including MRSA [27].
The MBC/MIC ratio determines whether extracts and fractions are bactericidal or bacteriostatic. The results are interpreted as bactericidal for MBC/MIC ≤ 4 or bacteriostatic for MBC/MIC > 4 [28]. The MBC/MIC ratio is shown in Table 5 and Figure 3. Ethanol extracts and water fractions of S. officinalis revealed bacteriostatic activities. Other extracts and fractions showed bactericidal activities. These results indicated that extracts and fractions of selected medicinal plants might act as potent bactericidal agents. Bactericidal agents are preferred over bacteriostatic agents clinically because killing bacteria is considered to be more effective for controlling infections than inhibiting bacterial growth [29].
To elucidate the inhibitory effects of extracts and fractions, a bacterial growth curve was determined toward MRSA 33,591 and CI-2. As shown in Figure 4, ethanol extracts of selected medicinal plants had significant bacterial growth inhibition with a wide range of concentrations. All tested bacteria showed dose-dependent growth inhibition. The time-lag with 31.2 μg/mL of C. sappan extract reaching to the exponential phase was changed from 8 h to 10 h compared to BHI broth (control). However, our results demonstrated that fractions showed much stronger inhibitory effects than ethanol extracts. The ethyl acetate fraction of C. sappan and chlorform fraction of G. uralensis extended the lag phase by 2 h and 4 h at a concentration of 15.6 μg/mL, respectively (Figure 5).
The cytotoxicity of extracts and fractions was determined using the trypan blue exclusion method. Trypan blue is a negatively charged dye and only stains non-viable cells in blue [30]. HepG2 and A549 cells were treated with MIC concentrations of extracts and fractions for 24 h. The number of viable cells was counted, and cell viability was calculated with the percentage of living cells and dead cells. As shown in Table 6, ethanol extract and ethyl acetate fraction of C. sappan had low cytotoxicity (>90% cell viability) at concentrations of 62.5 and 31.2 μg/mL, whereas other extracts and fractions showed mild cytotoxicity (60–90% cell viability) [31]. Cell viability increased at lower doses, and both cell lines showed a slight difference in the viability between different fraction solvents and plant materials but with no significant differences. These results suggest that plant extracts may be relative efficient and safe for therapeutic use. However, normal cell lines were not used in the present study and further studies are needed to demonstrate the safety of plant extracts. It is critically important to note that in vivo efficacy and toxicity of plant extracts may not reflect in vitro properties due to other pharmacokinetic and pharmacodynamic factors [32].
3. Materials and Methods
3.1. Plant materials
A total of 16 species of medicinal plants (Areca catechu L., Caesalpinia sappan L., Cinnamomum loureirii Nees., Curcuma aromatica Salisb., Euphorbia humifusa Wild., Glechoma grandis (A. Gray) Kuprian., Glycyrrhiza uralensis Fisch., Lonicera japonica Thunb, Morus alba L., Phellinus linteus, Polygonum tinctorium Ait., Quercus salicina Blume, Sanguisorba officinalis L., Scutellaria baicalensis Georgi., Sophora flavescens Ait., and Uncaria gambir Roxb.) were purchased from Samhong Medicinal Herb Market (Seoul, Korea).
3.2. Preparation and Fractionation of Plant Extracts
Plant materials were blended to powder using a home grinder and soaked in 70% ethanol with shaking (110 rpm) for 24 h. The ratio of plant materials to solvent was 1:10 (w/v). Crude extracts were centrifuged with 3000× g rpm for 30 min. Supernatants were collected and concentrated using a rotary evaporator WEV-1001V (Daihan Scientific Co., Wonju, Korea) in vacuum at 50 °C. The concentrated residue was dissolved in 10% dimethyl sulfoxide (DMSO; Sigma Chemical Co., St. Louis, MO, USA) and finally filtered through a Whatman filter paper No. 2 (Whatman, Kent, UK) to obtain ethanol extracts.
For the preparation of fractions, ethanol extracts were suspended in distilled water and partitioned successively with different solvents (n-hexane, chloroform, ethyl acetate, and 1-butanol) (Sigma Chemical Co., St. Louis, MO, USA) in the order of increasing polarity. Each layer was prepared following the above process. All prepared samples were collected into conical tubes and stored in a refrigerator at 4 °C until further use. The percentage of extraction yield was calculated with the following equation: extraction yield (%) = (dry weight of extract/dry weight of plant material) × 100.
3.3. Bacteria Culture
Antibacterial activities of samples were evaluated against standard strains of S. aureus together with MRSA clinical isolates. Standard reference strains (S. aureus ATCC 29,213; MRSA ATCC 33,591) were purchased from American Type Culture Collection (ATCC; Manassas, VA, USA). MRSA clinical isolates were originally isolated from clinical specimens and identified in Gachon University Gil Medical Center (Incheon, Korea) [1]. These isolates were preserved in a −80 °C freezer in 20% glycerol (v/v) until further use. Each bacterium was initially cultivated on brain heart infusion (BHI; Kisan Bio, Seoul, Korea) agar medium in the plate. Before assays, a single colony was picked from each plate and incubated in BHI broth with shaking (110 rpm) at 37 °C for 24 h.
3.4. Antibiotic Susceptibility Testing
Antibiotic susceptibility was tested using the Kirby–Bauer disc diffusion method with some modifications [33]. Susceptibilities to ten different antibiotic discs (ampicillin (10 µg), penicillin G (10 IU), kanamycin (30 µg), gentamicin (10 µg), streptomycin (10 µg), tetracycline (30 µg), erythromycin (15 µg), vancomycin (30 µg), chloramphenicol (30 µg), and methicillin (5 µg) (Liofilchem, Teramo, Italy)) were evaluated. Each bacterial suspension was adjusted to a turbidity of McFarland 0.5 and inoculated to BHI plates. After antibiotic discs were carefully placed on BHI plates, plates were incubated at 37 °C for 24 h. The diameter of a clear zone was measured and interpreted according to the manufacturer’s instructions based on CLSI guidelines.
3.5. Disc Diffusion Assay
Disc diffusion assay was performed to evaluate antibacterial activities following a previous study [34]. Briefly, each bacterial suspension (1 × 108 CFU/mL) was mixed well with 100 mL of fresh BHI medium containing 1.5% agar (w/v). The mixture consisting of bacterial suspension and BHI medium was poured onto Petri dishes. While solidifying the medium, 100 μL of each sample was loaded onto each paper-disc (8 mm/diameter). Rifampicin (30 µg) (Sigma Chemical Co., St. Louis, MO, USA) was used as a positive control. Loaded paper discs were gently placed onto plates. These plates were then incubated at 37 °C for 24 h. Diameters of clear zones were measured after incubation. The experiments were performed in triplicate.
3.6. Determination of Minimum Inhibitory Concentration (MIC)
Minimum inhibitory concentration (MIC) was determined using the broth microdilution method according to Bostanci et al. [35] with slight modifications. Briefly, 200 μL of the samples was inoculated to first wells of 96-well microplates and serially diluted two-fold (ranging from 2000 to 3.9 μg/mL). Then, 100 μL of each bacterial suspension (1 × 106 CFU/mL) was inoculated to wells. The total volume was 200 μL per well. Rifampicin was used as a positive control. The optical density (OD) was measured at 595 nm with a spectrophotometer (Multiskan FC; Thermo Fisher Scientific, Waltham, MA, USA). Microplates were incubated continuously for up to 18 h for monitoring inhibitory effects of samples on bacterial growth. MIC was defined as the lowest concentration that inhibited visible growth of bacteria.
3.7. Determination of Minimum Bactericidal Concentration (MBC)
To determine minimum bactericidal concentration (MBC), the broth microdilution assay was used and 50 μL of the samples was taken from the well that inhibited visible growth of bacteria. Samples were transferred to a new microplate, and 150 μL of BHI broth was added to each well. Plates were incubated for 18 h. MBC was defined as the lowest concentration that killed 99.9% of bacteria.
3.8. Cell Culture
Human hepatoma, HepG2 (KCLB 88,065) and human lung carcinoma, A549 (KCLB 10,185) cell lines were purchased from Korean Cell Line Bank (KCLB, Seoul, Korea). These cells were grown in monolayers in 25 cm2 flasks with 3 mL of Roswell Park Memorial Institute Medium (RPMI 1640; Gibco, Grand Island, NY, USA) supplemented with 10% fetal bovine serum (FBS; Gibco, Grand Island, NY, USA) and 1% penicillin and streptomycin (Sigma Chemical Co., St. Louis, MO, USA). They were cultured at 37 °C in a CO2 cell chamber (MMM Group, Planegg, Germany) with 5% CO2. Upon reaching 80–90% confluence, sub-cultured cells were dissociated with a trypsin-ethylenediaminetetraacetic acid (Trypsin-EDTA; Gibco, Grand Island, NY, USA) solution. After centrifugation, the cells were re-suspended with culture medium to 1 × 106 cells/mL and plated on 25 cm2 flasks. After 24 h incubation, logarithmic growth phase cells were used in the cell viability assay.
3.9. Cell Viability Assay
The cytotoxicity of samples was determined using the trypan blue exclusion method according to Ndlovu et al. [36] with slight modifications. The cells were seeded at a density of 5 × 104 cells/well in 24-well microplates and grown to attachment overnight. Subsequently, the cells were exposed to samples at their MIC concentrations. Each sample was diluted with RPMI 1640 and added to each well. Microplates were incubated at 37 °C with 5% CO2 for 24 h. After incubation, trypan blue solution (Sigma Chemical Co., St. Louis, MO, USA) was mixed with trypsinized cell suspensions in a ratio of 1: 1. Ten microliters of the mixture were deposited on a hemocytometer. After counting cells, the percentage of living cells and dead cells was calculated. The experiments were performed in duplicate.
3.10. Statistical Analysis
Statistical analysis was performed using Microsoft Excel 2016 (Microsoft, Redmond, WA, USA) and SigmaPlot version 12.0 (Systat Software, San Jose, CA, USA). Average values were calculated as means and standard deviation (±SD). Statistical differences were assessed by analysis of variance (ANOVA). A p-value of less than 0.05 was considered statistically significant.
4. Conclusions
In the present study, we confirmed that ethanol extracts and fractions of medicinal plants had potent antibacterial activities against S. aureus strains, including MRSA clinical isolates. Among the tested samples selected with abilities to inhibit of S. aureus strains, the ethyl acetate fraction of C. sappan was the most effective. The fraction showed remarkable inhibitory effects on bacterial growth with MIC/MBC values of 31.2/62.5 μg/mL and exhibited low cytotoxicity with more than 90% survival rates on HepG2 and A549 cell lines, respectively. The chloroform fraction of G. uralensis also showed significant bacterial growth inhibition. The present study demonstrated a considerable potential of medicinal plants as alternatives to conventional antibiotics.
Supplementary Materials
The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/molecules27227780/s1, Figure S1: Screening of ethanol extracts from 16 medicinal plants for antibacterial activities by broth microdilution method. Figure S2: Antibiotic susceptibility testing for S. aureus strains. Figure S3: Antibacterial activities of ethanol extracts from selected medicinal plants by disc diffusion assay. Figure S4: Antibacterial activities of fractions from selected medicinal plants by disc diffusion assay.
Author Contributions
Conceptualization, Y.-J.H.; Formal analysis, I.-G.J.; Investigation, I.-G.J., J.-Y.J. and S.-H.Y.; Methodology, Y.-J.H., I.-G.J. and J.-Y.J.; Project administration, Y.-J.H. and I.-G.J.; Resources, Y.-J.H.; Supervision, Y.-J.H.; Validation, I.-G.J., J.-Y.J. and S.-H.Y.; Writing—original draft, Y.-J.H. and I.-G.J.; Writing—review and editing, Y.-J.H. and I.-G.J. All authors have read and agreed to the published version of the manuscript.
Funding
This study was supported by a grant from the RIS grant (No. 202103060001) at the Gachon University.
Institutional Review Board Statement
Not applicable.
Informed Consent Statement
Not applicable.
Data Availability Statement
Data supporting this study are available on request from the corresponding author.
Conflicts of Interest
The authors declare no conflict of interest.
References
- Mun, Y.S.; Hwang, Y.J. Novel spa and Multi-Locus Sequence Types (MLST) of Staphylococcus aureus Samples Isolated from Clinical Specimens in Korean. Antibiotics 2019, 8, 202. [Google Scholar] [CrossRef] [Green Version]
- Garoy, E.Y.; Gebreab, Y.B.; Achila, O.O.; Tekeste, D.G.; Kesete, R.; Ghirmay, R.; Kiflay, R.; Tesfu, T. Methicillin-Resistant Staphylococcus aureus (MRSA): Prevalence and Antimicrobial Sensitivity Pattern among Patients—A Multicenter Study in Asmara, Eritrea. Can. J. Infect. Dis. Med. Microbiol. 2019, 2019, 8321834. [Google Scholar] [CrossRef] [PubMed] [Green Version]
- Li, Y.; Lee, Y.; Seo, Y.; Hwang, Y. Relationship of multidrug-resistant gene and extended-spectrum carbapenem-resistance in Staphylococcus aureus. BIOCELL 2019, 43, 263–269. [Google Scholar] [CrossRef] [Green Version]
- Kim, H.J.; Choi, Q.; Kwon, G.C.; Koo, S.H. Molecular epidemiology and virulence factors of methicillin-resistant Staphylococcus aureus isolated from patients with bacteremia. J. Clin. Lab. Anal. 2020, 34, e23077. [Google Scholar] [CrossRef] [PubMed] [Green Version]
- Mendes, R.E.; Mendoza, M.; Singh, K.K.B.; Castanheira, M.; Bell, J.M.; Turnidge, J.D.; Lin, S.S.F.; Jones, R.N. Regional Resistance Surveillance Program Results for 12 Asia-Pacific Nations (2011). Antimicrob. Agents Chemother. 2013, 57, 5721–5726. [Google Scholar] [CrossRef] [PubMed] [Green Version]
- Masimen, M.A.A.; Harun, N.A.; Maulidiani, M.; Ismail, W.I.W. Overcoming Methicillin-Resistance Staphylococcus aureus (MRSA) Using Antimicrobial Peptides-Silver Nanoparticles. Antibiotics 2022, 11, 951. [Google Scholar] [CrossRef]
- Uc-Cachón, A.H.; Dzul-Beh, A.D.J.; Palma-Pech, G.A.; Jiménez-Delgadillo, B.; Flores-Guido, J.S.; Gracida-Osorno, C.; Molina-Salinas, G.M. Antibacterial and antibiofilm activities of Mayan medicinal plants against Methicillin-susceptible and -resistant strains of Staphylococcus aureus. J. Ethnopharmacol. 2021, 279, 114369. [Google Scholar] [CrossRef]
- World Health Organization. Global Priority List of Antibiotic-Resistant Bacteria to Guide Research, Discovery, and Development of New Antibiotics. 2017. Available online: https://www.who.int/news/item/27-02-2017-who-publishes-list-of-bacteria-for-which-new-antibiotics-are-urgently-needed (accessed on 12 October 2022).
- Alibi, S.; Crespo, D.; Navas, J. Plant-Derivatives Small Molecules with Antibacterial Activity. Antibiotics 2021, 10, 231. [Google Scholar] [CrossRef]
- Archana, H.; Bose, V.G. Evaluation of phytoconstituents from selected medicinal plants and its synergistic antimicrobial activity. Chemosphere 2022, 287, 132276. [Google Scholar] [CrossRef]
- Panda, S.K.; Das, R.; Lavigne, R.; Luyten, W. Indian medicinal plant extracts to control multidrug-resistant S. aureus, including in biofilms. S. Afr. J. Bot. 2020, 128, 283–291. [Google Scholar] [CrossRef]
- George, B.; Abrahamse, H.; Hemmaragala, N.M. Caspase dependent apoptotic inhibition of melanoma and lung cancer cells by tropical Rubus extracts. Biomed. Pharmacother. 2016, 80, 193–199. [Google Scholar] [CrossRef]
- Duarte, A.E.; De Menezes, I.R.A.; Bezerra Morais Braga, M.F.; Leite, N.F.; Barros, L.M.; Waczuk, E.P.; Pessoa da Silva, M.A.; Boligon, A.; Teixeira Rocha, J.B.; Souza, D.O.; et al. Antimicrobial Activity and Modulatory Effect of Essential Oil from the Leaf of Rhaphiodon echinus (Nees & Mart) Schauer on Some Antimicrobial Drugs. Molecules 2016, 21, 743. [Google Scholar] [CrossRef] [Green Version]
- Guadie, A.; Dakone, D.; Unbushe, D.; Wang, A.; Xia, S. Antibacterial activity of selected medicinal plants used by traditional healers in Genta Meyche (Southern Ethiopia) for the treatment of gastrointestinal disorders. J. Herb. Med. 2020, 22, 100338. [Google Scholar] [CrossRef]
- Panda, S.K.; Mohanta, Y.K.; Padhi, L.; Park, Y.-H.; Mohanta, T.K.; Bae, H. Large Scale Screening of Ethnomedicinal Plants for Identification of Potential Antibacterial Compounds. Molecules 2016, 21, 293. [Google Scholar] [CrossRef] [PubMed]
- Famuyide, I.M.; Aro, A.O.; Fasina, F.O.; Eloff, J.N.; McGaw, L.J. Antibacterial activity and mode of action of acetone crude leaf extracts of under-investigated Syzygium and Eugenia (Myrtaceae) species on multidrug resistant porcine diarrhoeagenic Escherichia coli. BMC Vet. Res. 2019, 15, 162. [Google Scholar] [CrossRef] [Green Version]
- Obakiro, S.B.; Kiprop, A.; K’Owino, I.; Andima, M.; Owor, R.O.; Chacha, R.; Kigondu, E. Phytochemical, Cytotoxicity, and Antimycobacterial Activity Evaluation of Extracts and Compounds from the Stem Bark of Albizia coriaria Welw ex. Oliver. Evid.-Based Complement. Altern. Med. 2022, 2022, 7148511. [Google Scholar] [CrossRef]
- Foti, M.; Grasso, R.; Fisichella, V.; Mascetti, A.; Zafarana, M.A.; Colnaghi, M.; Grasso, M.; Spena, M.T. Analysis of Eurasian Stone curlew (Burhinus oedicnemus) microbial flora reveals the presence of multi-drug resistant pathogens in agro-pastoral areas of Sicily (Italy). Heliyon 2020, 6, e05401. [Google Scholar] [CrossRef]
- Bag, A.; Bhattacharyya, S.K.; Pal, N.K.; Chattopadhyay, R.R. In vitro antibacterial potential of Eugenia jambolana seed extracts against multidrug-resistant human bacterial pathogens. Microbiol. Res. 2012, 167, 352–357. [Google Scholar] [CrossRef]
- Álvarez-Martínez, F.; Barrajón-Catalán, E.; Herranz-López, M.; Micol, V. Antibacterial plant compounds, extracts and essential oils: An updated review on their effects and putative mechanisms of action. Phytomedicine 2021, 90, 153626. [Google Scholar] [CrossRef]
- De Zoysa, M.H.N.; Rathnayake, H.; Hewawasam, R.P.; Wijayaratne, W. Determination of In Vitro Antimicrobial Activity of Five Sri Lankan Medicinal Plants against Selected Human Pathogenic Bacteria. Int. J. Microbiol. 2019, 2019, 7431439. [Google Scholar] [CrossRef]
- Dirar, A.; Alsaadi, D.; Wada, M.; Mohamed, M.; Watanabe, T.; Devkota, H. Effects of extraction solvents on total phenolic and flavonoid contents and biological activities of extracts from Sudanese medicinal plants. S. Afr. J. Bot. 2019, 120, 261–267. [Google Scholar] [CrossRef]
- Arokiyaraj, S.; Bharanidharan, R.; Agastian, P.; Shin, H. Chemical composition, antioxidant activity and antibacterial mechanism of action from Marsilea minuta leaf hexane: Methanol extract. Chem. Cent. J. 2018, 12, 105–111. [Google Scholar] [CrossRef] [PubMed] [Green Version]
- Ren, L.; Hemar, Y.; Perera, C.O.; Lewis, G.; Krissansen, G.W.; Buchanan, P.K. Antibacterial and antioxidant activities of aqueous extracts of eight edible mushrooms. Bioact. Carbohydr. Diet. Fibre 2014, 3, 41–51. [Google Scholar] [CrossRef]
- Elshikh, M.; Ahmed, S.; Funston, S.; Dunlop, P.; McGaw, M.; Marchant, R.; Banat, I.M. Resazurin-based 96-well plate microdilution method for the determination of minimum inhibitory concentration of biosurfactants. Biotechnol. Lett. 2016, 38, 1015–1019. [Google Scholar] [CrossRef] [PubMed] [Green Version]
- Lee, J.W.; Ji, Y.J.; Yu, M.H.; Bo, M.H.; Seo, H.J.; Lee, S.P.; Lee, I.S. Antimicrobial effect and resistant regulation of Glycyrrhiza uralensis on methicillin-resistant Staphylococcus aureus. Nat. Prod. Res. 2009, 23, 101–111. [Google Scholar] [CrossRef]
- Pattananandecha, T.; Apichai, S.; Julsrigival, J.; Ogata, F.; Kawasaki, N.; Saenjum, C. Antibacterial Activity against Foodborne Pathogens and Inhibitory Effect on Anti-Inflammatory Mediators’ Production of Brazilin-Enriched Extract from Caesalpinia sappan Linn. Plants 2022, 11, 1698. [Google Scholar] [CrossRef]
- Mogana, R.; Adhikari, A.; Tzar, M.N.; Ramliza, R.; Wiart, C. Antibacterial activities of the extracts, fractions and isolated compounds from Canarium patentinervium Miq. against bacterial clinical isolates. BMC Complement. Med. Ther. 2020, 20, 55. [Google Scholar] [CrossRef] [Green Version]
- Rivas-Cáceres, R.R.; Stephano-Hornedo, J.L.; Lugo, J.; Vaca, R.; Del Aguila, P.; Yañez-Ocampo, G.; Mora-Herrera, M.E.; Díaz, L.M.C.; Cipriano-Salazar, M.; Alaba, P.A. Bactericidal effect of silver nanoparticles against propagation of Clavibacter michiganensis infection in Lycopersicon esculentum Mill. Microb. Pathog. 2018, 115, 358–362. [Google Scholar] [CrossRef]
- Nazir, S.; Rabbani, A.; Mehmood, K.; Maqbool, F.; Shah, G.M.; Khan, M.F.; Sajid, M. Antileishmanial activity and cytotoxicity of ZnO-based nano-formulations. Int. J. Nanomed. 2019, 14, 7809–7822. [Google Scholar] [CrossRef] [Green Version]
- Ramamoorthy, R.; Muthalagu, M.; Andra, S.; Ravichandran, B.; Narayanasamy, M. Investigation on antimicrobial, antioxidant and cytotoxicity properties of triple bark extract formulated using traditional medicinal plants. SN Appl. Sci. 2019, 1, 772. [Google Scholar] [CrossRef]
- Asong, J.A.; Amoo, S.O.; McGaw, L.J.; Nkadimeng, S.M.; Aremu, A.O.; Otang-Mbeng, W. Antimicrobial Activity, Antioxidant Potential, Cytotoxicity and Phytochemical Profiling of Four Plants Locally Used against Skin Diseases. Plants 2019, 8, 350. [Google Scholar] [CrossRef] [PubMed] [Green Version]
- Bauer, A.W.; Kirby, W.M.M.; Sherris, J.C.; Turck, M. Antibiotic susceptibility testing by a standardized single disk method. Am. J. Clin. Pathol. 1966, 36, 493–496. [Google Scholar] [CrossRef]
- Lee, Y.H.; Park, S.Y.; Hwang, Y.J.; Park, J.K. Molecular Weight Determination of Chitosan with Antibacterial Activity Using Matrix-Assisted Laser Desorption/Ionization-Time of Flight Mass Spectrometry Analysis. Macromol. Res. 2022, 30, 90–98. [Google Scholar] [CrossRef]
- Bostanci, M.T.; Bulbul, A.S.; Celik, I.S.; Kocabas, Y.Z.; Burhan, H.; Bayat, R.; Sen, F.; Zakariae, N.; Esmaeili, R.; Jafari, H.; et al. Investigation of antibacterial, antifungal, antibiofilm, antioxidant and anticancer properties of methanol extracts of Salvia marashica Ilcim, Celep & Dogan and Salvia caespitosa Montbret & Aucher ex Benth plants with medicinal importance. Chemosphere 2022, 288 Pt 2, 132602. [Google Scholar] [PubMed]
- Ndlovu, B.; De Kock, M.; Klaasen, J.; Rahiman, F. In Vitro Comparison of the Anti-Proliferative Effects of Galenia africana on Human Skin Cell Lines. Sci. Pharm. 2021, 89, 12. [Google Scholar] [CrossRef]
Figure 1.
Extraction and fractionation scheme for preparation of ethanol extracts and fractions.
Figure 2.
Inhibition zones of ethanol extracts (40 mg/mL) from selected medicinal plants against S. aureus strains. These results are represented the average diameter (mean ± SD) of triplicate tests, with p < 0.05 indicating statistical significance.
Figure 2.
Inhibition zones of ethanol extracts (40 mg/mL) from selected medicinal plants against S. aureus strains. These results are represented the average diameter (mean ± SD) of triplicate tests, with p < 0.05 indicating statistical significance.
Figure 3.
Antibacterial parameters of ethanol extracts and fractions from selected medicinal plants against MRSA strains.
Figure 3.
Antibacterial parameters of ethanol extracts and fractions from selected medicinal plants against MRSA strains.
Figure 4.
Influence of ethanol extracts from selected medicinal plants on bacterial growth of MRSA 33,591 and CI-2.
Figure 4.
Influence of ethanol extracts from selected medicinal plants on bacterial growth of MRSA 33,591 and CI-2.
Figure 5.
Influence of fractions from selected medicinal plants on bacterial growth of MRSA 33,591 and CI-2.
Figure 5.
Influence of fractions from selected medicinal plants on bacterial growth of MRSA 33,591 and CI-2.
Table 1.
List of medicinal plants used in the present study.
| Scientific Name | Common Name | Family | Parts Used | Origin | Extraction Yield (%) |
|---|---|---|---|---|---|
| Areca catechu L. | Areca nut | Arecaceae | Seeds | Indonesia | 17.62 |
| Caesalpinia sappan L. | Sappan wood | Leguminosae | Heartwoods | Indonesia | 10.47 |
| Curcuma aromatica Salisb. | Wild turmeric | Zingiberaceae | Roots | Indonesia | 19.65 |
| Cinnamomum loureiroi Nees. | Saigon cinnamon | Lauraceae | Barks | Vietnam | 11.48 |
| Euphorbia humifusa Wild. | Creeping euphorbia | Euphorbiaceae | Leaves and stems | Korea | 31.22 |
| Glechoma grandis (A. Gray) Kuprian. | Ground ivy | Lamiaceae | Leaves and stems | Korea | 35.16 |
| Glycyrrhiza uralensis Fisch. | Chinese liquorice | Fabaceae | Roots | China | 20.95 |
| Lonicera japonica Thunb. | Japanese honeysucke | Caprifoliaceae | Floral buds | China | 38.63 |
| Morus alba L. | White mulberry | Moraceae | Leaves | Korea | 20.25 |
| Phellinus linteus | Sanghuang | Hymenochaetaceae | Fruit bodies | China | 3.80 |
| Polygonum tinctorium Ait. | Chinese indigo | Polygonaceae | Leaves | China | 9.05 |
| Quercus salicina Blume | Japanese willow leaf oak | Fagaceae | Leaves | Korea | 31.92 |
| Sanguisorba officinalis L. | Greater burnet | Rosaceae | Roots | China | 23.84 |
| Scutellaria baicalensis Georgi. | Baikal skullcap | Lamiaceae | Roots | Korea | 62.37 |
| Sophora flavescens Ait. | shrubby sophora | Leguminosae | Roots | Korea | 29.70 |
| Uncaria gambir Roxb. | Gambir | Rubiaceae | Leaves and twigs | Indonesia | 61.84 |
Table 2.
Antibiotic resistance profiles of S. aureus strains used in the present study.
| Strains | Phenotype | Antibiotic Resistance Pattern |
|---|---|---|
| S. aureus ATCC 29,213 | MSSA | - |
| MRSA ATCC 33,591 | MRSA | Amp, Pen, Kan, Eryth, Strep, Tet, Gen, Chlo, Meth |
| CI-2 * | MDRSA | Amp, Pen, Kan, Eryth, Strep, Tet, Gen, Meth |
| CI-21 * | MRSA | Amp, Pen, Kan, Strep, Gen, Meth |
S. aureus: Staphylococcus aureus; CI: Clinical isolate; MSSA: Methicillin-susceptible Staphylococcus aureus; MRSA: Methicillin-resistant Staphylococcus aureus; MDRSA: Multidrug-resistant Staphylococcu aureus; Amp: ampicillin; Pen: Penicillin G; Kan: Kanamycin; Eryth: Erythromycin; Gen: Gentamycin; Tet: Tetracyclin; Strep: Streptomycin; Van: Vancomycin; Chlo: Chloramphenicol; Meth: methicillin. * Clinical isolates were isolated and identified in the previous study [1].
Table 3.
Antibacterial activities of ethanol extracts from selected medicinal plants against S. aureus strains.
Table 3.
Antibacterial activities of ethanol extracts from selected medicinal plants against S. aureus strains.
| Strains | Medicinal Plants | Diameter of the Clear Zone (mm) | ||||||
|---|---|---|---|---|---|---|---|---|
| Distilled Water | Rifampicin (30 μg) | Extract Concentration (mg/mL) | ||||||
| 40 | 20 | 10 | 5 | 2.5 | ||||
| S. aureus 29,213 | CS | - | 29.87 ± 0.09 | 25.40 ± 0.43 | 20.67 ± 0.24 | 17.27 ± 0.52 | 12.43 ± 0.33 | 9.77 ± 0.21 |
| GU | - | 29.87 ± 0.19 | 12.67 ± 0.24 | 10.00 ± 0.41 | 8.10 ± 0.08 | - | - | |
| SO | - | 30.00 ± 0.00 | 11.33 ± 0.24 | 8.80 ± 0.28 | - | - | - | |
| UG | - | 30.30 ± 0.51 | 14.90 ± 0.29 | 11.80 ± 0.24 | 9.17 ± 0.37 | - | - | |
| MRSA 33,591 | CS | - | 30.73 ± 0.57 | 25.53 ± 0.41 | 21.60 ± 0.43 | 18.07 ± 0.09 | 13.90 ± 0.65 | 10.73 ± 0.52 |
| GU | - | 30.67 ± 0.47 | 11.13 ± 0.19 | 9.73 ± 0.57 | 8.17 ± 0.09 | - | - | |
| SO | - | 30.67 ± 0.47 | 10.97 ± 0.12 | 10.20 ± 0.16 | - | - | - | |
| UG | - | 30.67 ± 0.62 | 15.40 ± 0.43 | 12.33 ± 0.47 | 9.13 ± 0.12 | - | - | |
| CI-2 | CS | - | 30.00 ± 0.00 | 25.00 ± 0.33 | 21.93 ± 0.74 | 18.07 ± 0.09 | 13.87 ± 0.41 | 11.13 ± 0.34 |
| GU | - | 29.67 ± 0.47 | 11.47 ± 0.41 | 9.60 ± 0.85 | 8.17 ± 0.08 | - | - | |
| SO | - | 29.67 ± 0.47 | 11.33 ± 0.34 | 9.87 ± 0.19 | - | - | - | |
| UG | - | 29.27 ± 0.90 | 16.07 ± 0.82 | 14.93 ± 0.82 | 10.00 ± 0.82 | - | - | |
| CI-21 | CS | - | 29.33 ± 0.47 | 23.27 ± 1.16 | 20.47 ± 0.34 | 17.50 ± 0.41 | 13.17 ± 0.24 | 9.87 ± 0.19 |
| GU | - | 29.83 ± 0.62 | 11.27 ± 0.38 | 9.60 ± 0.85 | 8.20 ± 0.16 | - | - | |
| SO | - | 29.33 ± 0.47 | 10.67 ± 0.47 | 9.67 ± 0.47 | - | - | - | |
| UG | - | 29.27 ± 0.90 | 14.60 ± 0.49 | 12.27 ± 0.38 | 9.93 ± 0.09 | - | - | |
S. aureus: Staphylococcus aureus; MRSA: Methicillin-resistant Staphylococcus aureus; CI: Clinical isolate; CS: Caesalpinia sappan L.; GU: Glycyrrhiza uralensis Fisch.; SO: Sanguisorba officinalis L.; UG: Uncaria gambir Roxb. These results are represented the average diameter (mean ± SD) of triplicate tests, with p < 0.05 indicating statistical significance.
Table 4.
Antibacterial activities of fractions from selected medicinal plants against S. aureus strains.
Table 4.
Antibacterial activities of fractions from selected medicinal plants against S. aureus strains.
| Strains | Medicinal Plants | Diameter of the Clear Zone (mm) | ||||||
|---|---|---|---|---|---|---|---|---|
| Distilled Water | Rifampicin (30 μg) | Fraction Concentration (10 mg/mL) | ||||||
| HEX | Chl | EtOAc | BuOH | Water | ||||
| S. aureus 29,213 | CS | - | 30.83 ± 0.24 | - | - | 23.23 ± 0.61 | 16.77 ± 0.95 | - |
| GU | - | 30.60 ± 0.43 | 8.67 ± 0.47 | 11.93 ± 0.33 | 10.70 ± 0.22 | - | - | |
| SO | - | 30.67 ± 0.47 | - | - | - | - | - | |
| UG | - | 30.43 ± 0.42 | - | - | 14.67 ± 1.09 | 10.00 ± 0.00 | - | |
| MRSA 33,591 | CS | - | 31.50 ± 0.41 | - | - | 23.10 ± 1.22 | 16.77 ± 0.21 | - |
| GU | - | 31.00 ± 0.00 | 8.33 ± 0.24 | 11.70 ± 0.79 | 10.93 ± 0.42 | - | - | |
| SO | - | 30.67 ± 0.47 | - | - | - | - | - | |
| UG | - | 30.83 ± 0.24 | - | - | 16.33 ± 1.09 | 9.93 ± 0.09 | - | |
| CI-2 | CS | - | 31.67 ± 0.24 | - | - | 23.83 ± 1.10 | 17.77 ± 0.92 | - |
| GU | - | 30.83 ± 0.24 | 8.67 ± 0.47 | 11.37 ± 0.49 | 10.57 ± 0.49 | - | - | |
| SO | - | 30.93 ± 0.09 | - | - | - | - | - | |
| UG | - | 31.43 ± 0.33 | - | - | 14.43 ± 0.66 | 10.27 ± 0.21 | - | |
| CI-21 | CS | - | 31.83 ± 0.24 | - | - | 23.33 ± 0.50 | 16.40 ± 0.83 | - |
| GU | - | 30.90 ± 0.29 | 8.77 ± 0.21 | 10.93 ± 0.09 | 10.23 ± 0.21 | - | - | |
| SO | - | 31.00 ± 0.00 | - | - | - | - | - | |
| UG | - | 31.33 ± 0.24 | - | - | 14.83 ± 1.68 | 9.83 ± 0.29 | - | |
S. aureus: Staphylococcus aureus; MRSA: Methicillin-resistant Staphylococcus aureus; CI: Clinical isolate; CS: Caesalpinia sappan L.; GU: Glycyrrhiza uralensis Fisch.; SO: Sanguisorba officinalis L.; UG: Uncaria gambir Roxb.; HEX: n-Hexane; Chl: Chloroform; EtOAc: Ethyl acetate; BuOH: 1-Butanol; Water: Distilled water. These results are represented the average diameter (mean ± SD) of triplicate tests, with p < 0.05 indicating statistical significance.
Table 5.
Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of ethanol extracts and fractions from selected medicinal plants against S. aureus strains.
Table 5.
Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of ethanol extracts and fractions from selected medicinal plants against S. aureus strains.
| Medicinal Plants | Extracts | Fractions | S. aureus 29,213 | MRSA 33,591 | CI-2 | CI-21 | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| MIC | MBC | MBC/MIC | MIC | MBC | MBC/MIC | MIC | MBC | MBC/MIC | MIC | MBC | MBC/MIC | |||
| CS | EtOH | 62.5 | 125 | 2 | 62.5 | 125 | 2 | 62.5 | 125 | 2 | 62.5 | 125 | 2 | |
| HEX | 2000 | >2000 | ND | 2000 | >2000 | ND | 2000 | >2000 | ND | 2000 | >2000 | ND | ||
| Chl | 1000 | 2000 | 2 | 1000 | 2000 | 2 | 1000 | 2000 | 2 | 1000 | 1000 | 1 | ||
| EtOAc | 31.2 | 62.5 | 2 | 31.2 | 62.5 | 2 | 31.2 | 62.5 | 2 | 31.2 | 62.5 | 2 | ||
| BuOH | 62.5 | 125 | 2 | 125 | 125 | 1 | 125 | 125 | 1 | 125 | 125 | 1 | ||
| Water | 1000 | 2000 | 2 | 1000 | 2000 | 2 | 1000 | 2000 | 2 | 1000 | 2000 | 2 | ||
| GU | EtOH | 250 | 500 | 2 | 250 | 500 | 2 | 250 | 500 | 2 | 250 | 500 | 2 | |
| HEX | 62.5 | 250 | 4 | 62.5 | 250 | 4 | 62.5 | 250 | 4 | 62.5 | 250 | 4 | ||
| Chl | 31.2 | 125 | 4 | 31.2 | 125 | 4 | 31.2 | 125 | 4 | 31.2 | 125 | 4 | ||
| EtOAc | 125 | 500 | 4 | 125 | 500 | 4 | 125 | 500 | 4 | 125 | 500 | 4 | ||
| BuOH | >2000 | ND | ND | >2000 | ND | ND | >2000 | ND | ND | >2000 | ND | ND | ||
| Water | >2000 | ND | ND | >2000 | ND | ND | >2000 | ND | ND | >2000 | ND | ND | ||
| SO | EtOH | 250 | 2000 | >4 | 250 | 2000 | >4 | 250 | 2000 | >4 | 250 | 2000 | >4 | |
| HEX | 1000 | >2000 | ND | 1000 | >2000 | ND | 1000 | >2000 | ND | 1000 | >2000 | ND | ||
| Chl | 1000 | >2000 | ND | 1000 | >2000 | ND | 1000 | >2000 | ND | 1000 | >2000 | ND | ||
| EtOAc | 500 | 1000 | 2 | 500 | 2000 | 4 | 500 | 2000 | 4 | 500 | 2000 | 4 | ||
| BuOH | 250 | 1000 | 4 | 250 | 1000 | 4 | 250 | 1000 | 4 | 250 | 1000 | 4 | ||
| Water | 250 | 2000 | >4 | 250 | 2000 | >4 | 250 | 2000 | >4 | 250 | 2000 | >4 | ||
| UG | EtOH | 250 | 500 | 2 | 250 | 500 | 2 | 250 | 500 | 2 | 250 | 500 | 2 | |
| HEX | >2000 | ND | ND | >2000 | ND | ND | >2000 | ND | ND | >2000 | ND | ND | ||
| Chl | 1000 | 1000 | 1 | 1000 | 2000 | 2 | 1000 | 2000 | 2 | 1000 | 2000 | 2 | ||
| EtOAc | 62.5 | 125 | 2 | 62.5 | 250 | 4 | 62.5 | 250 | 4 | 62.5 | 250 | 4 | ||
| BuOH | 125 | 250 | 2 | 125 | 250 | 2 | 125 | 250 | 2 | 125 | 250 | 2 | ||
| Water | 250 | 1000 | 4 | 250 | 1000 | 4 | 250 | 1000 | 4 | 250 | 1000 | 4 | ||
CS: Caesalpinia sappan L.; GU: Glycyrrhiza uralensis Fisch.; SO: Sanguisorba officinalis L.; UG: Uncaria gambir Roxb.; EtOH: Ethanol; HEX: n-Hexane; Chl: Chloroform; EtOAc: Ethyl acetate; BuOH: 1-Butanol; Water: Distilled water; S. aureus: Staphylococcus aureus; MRSA: Methicillin-resistant Staphylococcus aureus; CI: Clinical isolate; MIC: Minimum inhibitory concentration; MBC: Minimum bactericidal concentration; ND: No data. MIC and MBC values are presented as μg/mL.
Table 6.
Cytotoxicity of ethanol extracts and fractions from selected medicinal plants on HepG2 and A549 cell lines.
Table 6.
Cytotoxicity of ethanol extracts and fractions from selected medicinal plants on HepG2 and A549 cell lines.
| Medicinal Plants | Extracts/Fractions | Cell Viability (%) | |
|---|---|---|---|
| HepG2 | A549 | ||
| CS | EtOH | 90.15 ± 0.48 | 91.94 ± 1.24 |
| EtOAc | 90.75 ± 0.43 | 90.99 ± 0.50 | |
| GU | EtOH | 81.24 ± 0.58 | 83.05 ± 0.28 |
| Chl | 85.38 ± 2.62 | 87.94 ± 0.44 | |
| SO | EtOH | 81.30 ± 0.52 | 81.92 ± 1.07 |
| BuOH | 79.71 ± 0.30 | 80.64 ± 0.21 | |
| UG | EtOH | 82.05 ± 0.56 | 83.43 ± 0.57 |
| EtOAc | 85.45 ± 0.26 | 85.14 ± 0.29 | |
CS: Caesalpinia sappan L.; GU: Glycyrrhiza uralensis Fisch.; SO: Sanguisorba officinalis L.; UG: Uncaria gambir Roxb.; EtOH: Ethanol; Chl: Chloroform; EtOAc: Ethyl acetate; BuOH: 1-Butanol.
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Jung, I.-G.; Jeong, J.-Y.; Yum, S.-H.; Hwang, Y.-J. Inhibitory Effects of Selected Medicinal Plants on Bacterial Growth of Methicillin-Resistant Staphylococcus aureus. Molecules 2022, 27, 7780. https://doi.org/10.3390/molecules27227780
AMA Style
Jung I-G, Jeong J-Y, Yum S-H, Hwang Y-J. Inhibitory Effects of Selected Medicinal Plants on Bacterial Growth of Methicillin-Resistant Staphylococcus aureus. Molecules. 2022; 27(22):7780. https://doi.org/10.3390/molecules27227780
Chicago/Turabian StyleJung, In-Geun, Jae-Young Jeong, Seung-Hoon Yum, and You-Jin Hwang. 2022. "Inhibitory Effects of Selected Medicinal Plants on Bacterial Growth of Methicillin-Resistant Staphylococcus aureus" Molecules 27, no. 22: 7780. https://doi.org/10.3390/molecules27227780
