Research

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22 pages, 1234 KiB

Open AccessArticle

Phytochemical Variability, In Vitro and In Vivo Biological Investigations, and In Silico Antibacterial Mechanisms of Mentha piperita Essential Oils Collected from Two Different Regions in Morocco

by Samiah Hamad Al-Mijalli, Nidal Naceiri Mrabti, Hayat Ouassou, Ryan A. Sheikh, Emad M. Abdallah, Hamza Assaggaf, Saad Bakrim, Mohammed Merae Alshahrani, Ahmed Abdullah Al Awadh, Ahmed Qasem, Ammar Attar, Learn-Han Lee, Abdelhakim Bouyahya, Khang Wen Goh, Long Chiau Ming and Hanae Naceiri Mrabti

Foods 2022, 11(21), 3466; https://doi.org/10.3390/foods11213466 - 01 Nov 2022

Cited by 7 | Viewed by 2210

Abstract

The objective of this work is to explore the phytochemical profile of Mentha piperita essential oils (MPEO) collected from two different Moroccan regions using gas chromatography-mass spectrophotometer (GC-MS) and to investigate their antioxidant, anti-inflammatory, antidiabetic and, antimicrobial effects using in vivo and in [...] Read more.

The objective of this work is to explore the phytochemical profile of Mentha piperita essential oils (MPEO) collected from two different Moroccan regions using gas chromatography-mass spectrophotometer (GC-MS) and to investigate their antioxidant, anti-inflammatory, antidiabetic and, antimicrobial effects using in vivo and in vitro assays. The chemical constituent of MPEO from the Azrou zone is dominated by carvone (70.25%), while MPEO from the Ouazzane zone is rich in Menthol (43.32%) and Menthone (29.4%). MPEO from Ouezzane showed higher antioxidant activity than EO from Azrou. Nevertheless, EO from Ouezzane considerably inhibited 5-Lipoxygenase (IC₅₀ = 11.64 ± 0.02 µg/mL) compared to EO from Azro (IC₅₀ = 23.84 ± 0.03 µg/mL). Both EOs from Azrou and Ouazzane inhibited the α-amylase activity in vitro, with IC₅₀ values of 131.62 ± 0.01 µg/mL and 91.64 ± 0.03 µg/mL, respectively. The EOs were also tested for minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The discdiffusion test revealed that MPEOs from both regions have significant antibacterial efficacy, and MPEOs from the north region showed the highest effect. The gram-positive bacteria were the most susceptible organisms. The MIC concentrations were in the range of 0.05 to 6.25 mg/mL, and the MBC concentrations were within 0.05–25.0 mg/mL. The MBC/MIC index indicated that MPEO has strong bactericidal effects. Full article

(This article belongs to the Special Issue Antimicrobial, Antiviral and Antioxidant Potential of Extracts from Natural Product)

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18 pages, 540 KiB

Open AccessArticle

Biological Activity of Extracts from Aromatic Plants as Control Agents against Spoilage Molds Isolated from Sheep Cheese

by Nuria Muñoz-Tebar, Emilio J. González-Navarro, Teresa María López-Díaz, Jesús A. Santos, Gonzalo Ortiz de Elguea-Culebras, M. Mercedes García-Martínez, Ana Molina, Manuel Carmona and María Isabel Berruga

Foods 2021, 10(7), 1576; https://doi.org/10.3390/foods10071576 - 07 Jul 2021

Cited by 7 | Viewed by 2945

Abstract

The aim of this work was to assess the antifungal and antioxidant activity of essential oils and ethanolic extracts from distilled solid by-products from aromatic plants (Artemisia dracunculus, Hyssopus officinalis, Lavandula stoechas, Origanum vulgare and [...] Read more.

The aim of this work was to assess the antifungal and antioxidant activity of essential oils and ethanolic extracts from distilled solid by-products from aromatic plants (Artemisia dracunculus, Hyssopus officinalis, Lavandula stoechas, Origanum vulgare and Satureja montana) against 14 fungi strains isolated from sheep cheese and identified at species level using DNA barcoding based on β-tubulin sequence analysis. In addition, capacity of fungi to produce ochratoxin A, patulin, cyclopiazonic acid and sterigmatocystin was analyzed. Of the isolates, 85.7% belonged to Penicillium (P. commune/biforme, P. crustosum) and 14.3% to Aspergillus (A. puulaauensis and A. jensenii), the first time that these Aspergillus species have been found in sheep’s cheese. All P. commune isolates were producers of cyclopiazonic acid, and the two Aspergillus strains produced sterigmatocystin, but the others did not produce any tested mycotoxin. Among the essential oils tested, oregano, savory and tarragon had a significant antifungal activity against all the isolated strains, but no ethanolic extract showed antifungal activity. By contrast, ethanolic extracts showed great potential as antioxidants. The identification of new molds in cheese will help the dairy industry to know more about those molds affecting the sector, and the use of aromatic plants in the control of fungal spoilage could be a suitable alternative to chemical preservatives used in the agri-food industry. Full article

(This article belongs to the Special Issue Antimicrobial, Antiviral and Antioxidant Potential of Extracts from Natural Product)

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12 pages, 3534 KiB

Open AccessArticle

Alginate-Assisted Lemongrass (Cymbopogon nardus) Essential Oil Dispersions for Antifungal Activity

by Martina Cofelice, Giuseppe Cinelli, Francesco Lopez, Tiziana Di Renzo, Raffaele Coppola and Anna Reale

Foods 2021, 10(7), 1528; https://doi.org/10.3390/foods10071528 - 02 Jul 2021

Cited by 20 | Viewed by 3770

Abstract

The use of natural compounds as food preservatives is becoming increasingly popular as it is perceived positively by consumers. Among these substances, essential oils have attracted great interest owing to their antioxidant and antimicrobial properties. However, several challenges impair the use of essential [...] Read more.

The use of natural compounds as food preservatives is becoming increasingly popular as it is perceived positively by consumers. Among these substances, essential oils have attracted great interest owing to their antioxidant and antimicrobial properties. However, several challenges impair the use of essential oils in food products, such as their degradation or loss during food processing and storage, the strong aroma, even at low concentrations, which may negatively affect the sensory characteristics of food. In this context, the development of nanoformulations able to stabilize essential oils may represent a smart solution to this issue. The aim of the study was to evaluate the efficiency of alginate-based nanoformulations enriched with lemongrass (Cymbopogon nardus) essential oil (LEO) and Tween 80 against several fungi namely Penicillium expansus, Aspergillus niger and Rhizopus spp. Firstly, the flow behavior of systems at different concentrations of alginate (1%, 2% and 3% w/w) were studied. Then, emulsion-based nanoformulations at different concentrations of lemongrass essential oil in the range of 0–2% w/w were stabilized by a fixed amount of Tween 80, characterized and tested for their antifungal activity. Our results showed that the best nanoformulation able to inhibit Rhizopus spp., Penicillium expansum and Aspergillus niger, for at least 10 days, was constituted by 1% alginate/1.5% LEO/1% Tween 80. Hence, the incorporation of essential oil into nanoformulation systems may represent a valid alternative to overcome the disadvantages that limit the commercial application of essential oils. Full article

(This article belongs to the Special Issue Antimicrobial, Antiviral and Antioxidant Potential of Extracts from Natural Product)

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12 pages, 952 KiB

Open AccessCommunication

Potential In Vitro Inhibition of Selected Plant Extracts against SARS-CoV-2 Chymotripsin-Like Protease (3CL^Pro) Activity

by Carla Guijarro-Real, Mariola Plazas, Adrián Rodríguez-Burruezo, Jaime Prohens and Ana Fita

Foods 2021, 10(7), 1503; https://doi.org/10.3390/foods10071503 - 29 Jun 2021

Cited by 26 | Viewed by 10637

Abstract

Antiviral treatments inhibiting Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) replication may represent a strategy complementary to vaccination to fight the ongoing Coronavirus disease 19 (COVID-19) pandemic. Molecules or extracts inhibiting the SARS-CoV-2 chymotripsin-like protease (3CL^Pro) could contribute to reducing or [...] Read more.

Antiviral treatments inhibiting Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) replication may represent a strategy complementary to vaccination to fight the ongoing Coronavirus disease 19 (COVID-19) pandemic. Molecules or extracts inhibiting the SARS-CoV-2 chymotripsin-like protease (3CL^Pro) could contribute to reducing or suppressing SARS-CoV-2 replication. Using a targeted approach, we identified 17 plant products that are included in current and traditional cuisines as promising inhibitors of SARS-CoV-2 3CL^Pro activity. Methanolic extracts were evaluated in vitro for inhibition of SARS-CoV-2 3CL^Pro activity using a quenched fluorescence resonance energy transfer (FRET) assay. Extracts from turmeric (Curcuma longa) rhizomes, mustard (Brassica nigra) seeds, and wall rocket (Diplotaxis erucoides subsp. erucoides) at 500 µg mL⁻¹ displayed significant inhibition of the 3CL^Pro activity, resulting in residual protease activities of 0.0%, 9.4%, and 14.9%, respectively. Using different extract concentrations, an IC₅₀ value of 15.74 µg mL⁻¹ was calculated for turmeric extract. Commercial curcumin inhibited the 3CL^Pro activity, but did not fully account for the inhibitory effect of turmeric rhizomes extracts, suggesting that other components of the turmeric extract must also play a main role in inhibiting the 3CL^Pro activity. Sinigrin, a major glucosinolate present in mustard seeds and wall rocket, did not have relevant 3CL^Pro inhibitory activity; however, its hydrolysis product allyl isothiocyanate had an IC₅₀ value of 41.43 µg mL⁻¹. The current study identifies plant extracts and molecules that can be of interest in the search for treatments against COVID-19, acting as a basis for future chemical, in vivo, and clinical trials. Full article

(This article belongs to the Special Issue Antimicrobial, Antiviral and Antioxidant Potential of Extracts from Natural Product)

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12 pages, 949 KiB

Open AccessArticle

Antimicrobial Activity of Myrtus communis L. and Rosmarinus officinalis L. Essential Oils against Listeria monocytogenes in Cheese

by Cristina Saraiva, Ana Catarina Silva, Juan García-Díez, Beniamino Cenci-Goga, Luca Grispoldi, Aníbal Filipe Silva and José Manuel Almeida

Foods 2021, 10(5), 1106; https://doi.org/10.3390/foods10051106 - 17 May 2021

Cited by 19 | Viewed by 2716

Abstract

Listeria monocytogenes has been referred to as a concern microorganism in cheese making due to its ability to survive and grow in a wide range of environmental conditions, such as refrigeration temperatures, low pH and high salt concentration at the end of the [...] Read more.

Listeria monocytogenes has been referred to as a concern microorganism in cheese making due to its ability to survive and grow in a wide range of environmental conditions, such as refrigeration temperatures, low pH and high salt concentration at the end of the production process. Since cheese may be a potential hazard for consumers, especially high-risk consumers (e.g., pregnant, young children, the elderly, people with medical conditions), efforts of the dairy industry have been aimed at investigating new conservation techniques based on natural additives to meet consumers’ demands on less processed foods without compromising the food safety. Thus, the aim of this study was to evaluate the efficacy of Myrtus communis L. (myrtle) and Rosmarinus officinalis L. (rosemary) essential oils (EO) against Listeria monocytogenes ATCC 679 spiked in sheep cheese before ripening. After the cheesemaking process, the samples were stored at 8 °C for 2 h, 1 d, 3 d, 14 d and 28 d. The composition of EO was identified by gas chromatography-mass spectrometry (GC-MS) analysis. Constituents such as 1,8-cineole, limonene, methyl-eugenol, α-pinene, α-terpineol, α-terpinolene and β-pinene were present in both EO, accounting for 44.61% and 39.76% from the total of chemical compounds identified for myrtle and rosemary EO, respectively. According to the chemical classification, both EO were mainly composed of monoterpenes. Minimum inhibitory concentration (MIC) against L. monocytogenes was obtained at 31.25 μL/mL to myrtle EO and at 0.40 μL/mL to rosemary EO. Then, cheeses were inoculated with L. monocytogenes (Ca. 6 log CFU/mL) and EO was added at MIC value. The addition of rosemary and myrtle EO displayed lower counts of L. monocytogenes (p < 0.01) (about 1–2 log CFU/g) during the ripening period compared to control samples. Ripening only influences (p < 0.001) the growth of L. monocytogenes in control samples. Since rosemary and myrtle EO do not exert any negative impact on the growth of native microflora (p > 0.05), their use as natural antimicrobial additives in cheese demonstrated a potential for dairy processors to assure safety against L. monocytogenes. Full article

(This article belongs to the Special Issue Antimicrobial, Antiviral and Antioxidant Potential of Extracts from Natural Product)

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14 pages, 2415 KiB

Open AccessArticle

Relationships between Structure and Antioxidant Capacity and Activity of Glycosylated Flavonols

by Zhengcao Xiao, Liangliang He, Xiaohui Hou, Jianping Wei, Xiaoyu Ma, Zihan Gao, Yahong Yuan, Jianbo Xiao, Pengmin Li and Tianli Yue

Foods 2021, 10(4), 849; https://doi.org/10.3390/foods10040849 - 14 Apr 2021

Cited by 30 | Viewed by 2474

Abstract

The antioxidant capacity (AC) and antioxidant activity (AA) of three flavonols (FLV), aglycones and their glycosylated derivatives were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays in various solvents. Findings confirmed that the glycosylation at the 3-position (3-glycosylation) always decreased the AC [...] Read more.

The antioxidant capacity (AC) and antioxidant activity (AA) of three flavonols (FLV), aglycones and their glycosylated derivatives were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays in various solvents. Findings confirmed that the glycosylation at the 3-position (3-glycosylation) always decreased the AC under most conditions due to substitution of the 3-position hydroxyl group and glycoside disruption in the molecular planarity. The 7-glycosylated derivatives did not have the above effects, thus generally exhibited ACs similar to their aglycones. Glycosylation decreased the AA of kaempferol and isorhamnetin for both assays in methanol, 3-glycosylation inhibited quercetin AA in the ABTS assay. In the DPPH assay, the AA of 3-glycosylated quercetin was significantly higher than quercetin. Using LC–MS/MS analysis, we found that quercetin and quercetin-7-glucoside underwent dimerization during the antioxidant reaction, potentially leading to a decline in AAs. However, 3-glycoside substitution may have hindered dimer formation, thereby allowing the FLVs to retain strong free radical scavenging abilities. Full article

(This article belongs to the Special Issue Antimicrobial, Antiviral and Antioxidant Potential of Extracts from Natural Product)

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19 pages, 1132 KiB

Open AccessArticle

Antioxidant Potential of Pine Needles: A Systematic Study on the Essential Oils and Extracts of 46 Species of the Genus Pinus

by Aikaterini Koutsaviti, Samer Toutoungy, Rouba Saliba, Sofia Loupassaki, Olga Tzakou, Vassilios Roussis and Efstathia Ioannou

Foods 2021, 10(1), 142; https://doi.org/10.3390/foods10010142 - 12 Jan 2021

Cited by 19 | Viewed by 3985

Abstract

The antioxidant activity of the essential oils, as well as of the organic and hydroethanolic extracts, of the fresh needles of 54 pine taxa was evaluated using the peroxy-oxalate and luminol chemiluminescence assays. Among all evaluated essential oils, P. canariensis and P. attenuata [...] Read more.

The antioxidant activity of the essential oils, as well as of the organic and hydroethanolic extracts, of the fresh needles of 54 pine taxa was evaluated using the peroxy-oxalate and luminol chemiluminescence assays. Among all evaluated essential oils, P. canariensis and P. attenuata displayed the highest levels of activity. P. contorta var. murrayana, followed by P. nigra var. caramanica, exhibited the highest antioxidant capacity among the organic extracts, while the most active hydroethanolic extract was that of P. nigra subsp. nigra. Based on the overall levels of activity, the latter taxon was selected for phytochemical analysis targeting the isolation of the bioactive constituents. As such, the organic extract of P. nigra subsp. nigra was subjected to chromatographic separations to yield 11 secondary metabolites (1−11) that were evaluated for their antioxidant activity. Nonetheless, the isolated compounds were found to be less active than the crude extract, thus suggesting the potential role of synergism. Full article

(This article belongs to the Special Issue Antimicrobial, Antiviral and Antioxidant Potential of Extracts from Natural Product)

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Review

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21 pages, 2911 KiB

Open AccessReview

A Systematic Review on the Antimicrobial Properties of Mediterranean Wild Edible Plants: We Still Know Too Little about Them, but What We Do Know Makes Persistent Investigation Worthwhile

by Giulia Cappelli and Francesca Mariani

Foods 2021, 10(9), 2217; https://doi.org/10.3390/foods10092217 - 18 Sep 2021

Cited by 3 | Viewed by 2962

Abstract

(1) Introduction: Bacterial resistance to antibiotics is estimated to be the cause of a major number of deaths by 2050 if we do not find strategies to slow down the rise of drug resistance. Reviews on Mediterranean wild edible plants (MWEPs) with antimicrobial [...] Read more.

(1) Introduction: Bacterial resistance to antibiotics is estimated to be the cause of a major number of deaths by 2050 if we do not find strategies to slow down the rise of drug resistance. Reviews on Mediterranean wild edible plants (MWEPs) with antimicrobial properties are scarce in the main databases (PubMed, Scopus, and WoS). Hence, we proceeded to conduct a new review of the studies on MWEPs. (2) Methods: We used ‘wild edible plant’ and ‘antimicrobial’ as keywords. Within this group, exclusion criteria were reviews, studies concerning non-Mediterranean plants or non-edible plants, studies on topics other than plants or containing no description of antimicrobial properties, or off-topic studies. (3) Results: Finally, out of the one hundred and ninety-two studies we had started with, we reviewed thirty-eight (19.8%) studies concerning the antimicrobial properties of seventy-four MWEPs species belonging to twenty-five Families. Fifty-seven (77%) species out of seventy-four proved to be antimicrobial, with a stringent threshold selection. (4) Conclusions: Studies are still very heterogeneous. We still know too little about MWEPs’ properties; however, what we already know strongly recommends carrying on investigation. Full article

(This article belongs to the Special Issue Antimicrobial, Antiviral and Antioxidant Potential of Extracts from Natural Product)

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