Special Issue "Antioxidant and Protective Effects of Plant Extracts"

A special issue of Antioxidants (ISSN 2076-3921). This special issue belongs to the section "Extraction and Industrial Applications of Antioxidants".

Deadline for manuscript submissions: 29 February 2024 | Viewed by 3742

Special Issue Editors

Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, Viale delle Scienze, Parco d’Orleans II, Bldg. 17, 90123 Palermo, Italy
Interests: natural product drug discovery; phytochemistry; liquid chromatography; essential oils; gas chromatography–mass spectrometry; solid phase extraction; high-performance liquid chromatography
Department of Biology, University of Naples Federico II, 80126 Naples, Italy
Interests: plant natural products; secondary metabolites; antibacterial activity; antioxidant activity; antitumoral activity; microscopy; protection against environmental stresses
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Medicinal plants, aromatic and wild herbs, in their different parts (roots, stems, stems, flowers, seeds, etc.) have been used since ancient times not only as flavoring additives and food preservatives, but the active ingredients contained therein are also the cornerstones of traditional medicine and ethnomedicine. Over the years, volatile compounds such as the terpenoids of essential oils; or secondary non-volatile metabolites extractable from the different parts, such as flavonoids, limonoids, triterpenoids, alkaloids, and polyphenols, have shown different antioxidant, protective, antimicrobial, antiproliferative, and anti-inflammatory effects. The growing concern about antibiotic resistance, as well as the skepticism of the world population towards the use of synthetic substances within the food supply chain and the growing attention towards the use of secondary metabolites to achieve a good lifestyle, have increasingly strengthened the importance of scientific opinion towards natural products. Based on countless scientific research, plant extracts such as essential oils or non-volatile extracts could help in terms of reducing microbial effects, ensuring safety, preserving food products, protecting against foreign agents such as metals, and exerting an antioxidant effect on human health. Therefore, the purpose of this Special Issue is to provide readers with a wide range of innovative scientific articles or original reviews, highlighting developments with respect to the past, and to stress biological and chemical advances in the application of plant extracts and essential oils as antioxidants and protective agents.

Dr. Natale Badalamenti
Dr. Adriana Basile
Guest Editors

Manuscript Submission Information

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Keywords

  • essential oils
  • plant and food extracts
  • antioxidant
  • anti-inflammatory
  • antimicrobial
  • protective effects
  • antiproliferative

Published Papers (4 papers)

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Research

16 pages, 1947 KiB  
Article
Chemical Composition of Salvia fruticosa Mill. Essential Oil and Its Protective Effects on Both Photosynthetic Damage and Oxidative Stress in Conocephalum conicum L. Induced by Environmental Heavy Metal Concentrations
Antioxidants 2023, 12(11), 1990; https://doi.org/10.3390/antiox12111990 - 11 Nov 2023
Viewed by 552
Abstract
The genus Salvia L., belonging to the Lamiaceae family, contains more than 900 species distributed in various parts of the world. It is a genus containing aromatic plants used both in the culinary field and above all in the cosmetic area to produce [...] Read more.
The genus Salvia L., belonging to the Lamiaceae family, contains more than 900 species distributed in various parts of the world. It is a genus containing aromatic plants used both in the culinary field and above all in the cosmetic area to produce several perfumes. Salvia fruticosa Mill., notoriously known as Greek Salvia, is a plant used since ancient times in traditional medicine, but today cultivated and used in various parts of Europe and Africa. Polar and apolar extracts of this plant confirmed the presence of several metabolites such as abietane and labdane diterpenoids, triterpenoids, steroids, and some flavonoids, causing interesting properties such as sedative, carminative, and antiseptic, while its essential oils (EOs) are mainly characterized by compounds such as 1,8-cineole and camphor. The aim of this work concerns the chemical analysis by GC and GC-MS, and the investigation of the biological properties, of the EO of S. fruticosa plants collected in eastern Sicily. The gas-chromatographic analysis confirmed the presence of 1,8-cineole (17.38%) and camphor (12.81%), but at the same time, also moderate amounts of α-terpineol (6.74%), β-myrcene (9.07%), camphene (8.66%), β-pinene (6.55%), and α-pinene (6.45%). To study the protective effect of EOs from S. fruticosa (both the total mixture and the individual compounds) on possible damage induced by heavy metals, an in vitro system was used in which a model organism, the liverwort Conocephalum conicum, was subjected to the effect of a mix of heavy metals (HM) prepared using values of concentrations actually measured in one of the most polluted watercourses of the Campania region, the Regi Lagni. Finally, the antioxidant response and the photosynthetic damage were examined. The exogenous application of the EO yields a resumption of the oxidative stress induced by HM, as demonstrated by the reduction in the Reactive Oxygen Species (ROS) content and by the increased activity of antioxidant enzyme catalase (CAT) and glutathione-S-transferase (GST). Furthermore, plants treated with HMs and EO showed a higher Fv/Fm (maximal quantum efficiency of PSII in the dark) with respect to HMs-only treated ones. These results clearly indicate the protective capacity of the EO of S. fruticosa against oxidative stress, which is achieved at least in part by modulating the redox state through the antioxidant pathway and on photosynthetic damage. Full article
(This article belongs to the Special Issue Antioxidant and Protective Effects of Plant Extracts)
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14 pages, 1774 KiB  
Article
LED Lights Influenced Phytochemical Contents and Biological Activities in Kale (Brassica oleracea L. var. acephala) Microgreens
Antioxidants 2023, 12(9), 1686; https://doi.org/10.3390/antiox12091686 - 29 Aug 2023
Viewed by 736
Abstract
Light-emitting diodes (LEDs) are regarded as an effective artificial light source for producing sprouts, microgreens, and baby leaves. Thus, this study aimed to investigate the influence of different LED lights (white, red, and blue) on the biosynthesis of secondary metabolites (glucosinolates, carotenoids, and [...] Read more.
Light-emitting diodes (LEDs) are regarded as an effective artificial light source for producing sprouts, microgreens, and baby leaves. Thus, this study aimed to investigate the influence of different LED lights (white, red, and blue) on the biosynthesis of secondary metabolites (glucosinolates, carotenoids, and phenolics) and the biological effects on kale microgreens. Microgreens irradiated with white LEDs showed higher levels of carotenoids, including lutein, 13-cis-β-carotene, α-carotene, β-carotene, and 9-cis-β-carotene, than those irradiated with red or blue LEDs. These findings were consistent with higher expression levels of carotenoid biosynthetic genes (BoPDS and BoZDS) in white-irradiated kale microgreens. Similarly, microgreens irradiated with white and blue LEDs showed slightly higher levels of glucosinolates, including glucoiberin, progoitrin, sinigrin, and glucobrassicanapin, than those irradiated with red LEDs. These results agree with the high expression levels of BoMYB28-2, BoMYB28-3, and BoMYB29 in white- and blue-irradiated kale microgreens. In contrast, kale microgreens irradiated with blue LEDs contained higher levels of phenolic compounds (gallic acid, catechin, ferulic acid, sinapic acid, and quercetin). According to the total phenolic content (TPC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) inhibition assays, the extracts of kale microgreens irradiated with blue LEDs had slightly higher antioxidant activities, and the DPPH inhibition percentage had a positive correlation with TPC in the microgreens. Furthermore, the extracts of kale microgreens irradiated with blue LEDs exhibited stronger antibacterial properties against normal pathogens and multidrug-resistant pathogens than those irradiated with white and red LEDs. These results indicate that white-LED lights are suitable for carotenoid production, whereas blue-LED lights are efficient in increasing the accumulation of phenolics and their biological activities in kale microgreens. Full article
(This article belongs to the Special Issue Antioxidant and Protective Effects of Plant Extracts)
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26 pages, 3017 KiB  
Article
Improvement in the Biosynthesis of Antioxidant-Active Metabolites in In Vitro Cultures of Isatis tinctoria (Brassicaceae) by Biotechnological Methods/Elicitation and Precursor Feeding
Antioxidants 2023, 12(5), 1111; https://doi.org/10.3390/antiox12051111 - 17 May 2023
Cited by 1 | Viewed by 893
Abstract
This study aimed to establish the in vitro shoot culture of Isatis tinctoria L. and its ability to produce antioxidant bioactive compounds. The Murashige and Skoog (MS) medium variants, containing different concentrations (0.1–2.0 mg/L) of benzylaminopurine (BAP) and 1-naphthaleneacetic acid (NAA) were tested. [...] Read more.
This study aimed to establish the in vitro shoot culture of Isatis tinctoria L. and its ability to produce antioxidant bioactive compounds. The Murashige and Skoog (MS) medium variants, containing different concentrations (0.1–2.0 mg/L) of benzylaminopurine (BAP) and 1-naphthaleneacetic acid (NAA) were tested. Their influence on the growth of biomass, accumulation of phenolic compounds, and antioxidant potential was evaluated. To improve the phenolic content, agitated cultures (MS 1.0/1.0 mg/L BAP/NAA) were treated with different elicitors, including the following: Methyl Jasmonate, CaCl2, AgNO3, and yeast, as well as with L-Phenylalanine and L-Tyrosine—precursors of phenolic metabolites. The total phenolic content (TPC) of hydroalcoholic extracts (MeOH 70%) obtained from the biomass grown in vitro was determined spectrophotometrically; phenolic acids and flavonoids were quantified by RP-HPLC. Moreover, the antioxidant potential of extracts was examined through the DPPH test, the reducing power, and the Fe2+ chelating assays. The biomass extracts obtained after 72 h of supplementation with Tyr (2 g/L), as well as after 120 and 168 h with Tyr (1 g/L), were found to be the richest in TPC (49.37 ± 0.93, 58.65 ± 0.91, and 60.36 ± 4.97 mg GAE/g extract, respectively). Whereas among the elicitors, the highest TPC achieved was with CaCl2 (20 and 50 mM 24 h), followed by MeJa (50 and 100 µM, 120 h). The HPLC of the extracts led to the identification of six flavonoids and nine phenolic acids, with vicenin-2, isovitexin, syringic, and caffeic acids being the most abundant compounds. Notably, the amount of all flavonoids and phenolic acids detected in the elicited/precursor feeding biomass was higher than that of the leaves of the parental plant. The best chelating activity was found with the extract of biomass fed with Tyrosine 2 g/L, 72 h (IC50 0.27 ± 0.01 mg/mL), the strongest radical scavenging (DPPH test) for the extract obtained from biomass elicited with CaCl2 50 mM, after 24 h of incubation (25.14 ± 0.35 mg Trolox equivalents (TE)/g extract). In conclusion, the in vitro shoot culture of I. tinctoria supplemented with Tyrosine, as well as MeJa and/or CaCl2, could represent a biotechnological source of compounds with antioxidant properties. Full article
(This article belongs to the Special Issue Antioxidant and Protective Effects of Plant Extracts)
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19 pages, 5092 KiB  
Article
Hydrogen Protection Boosts the Bioactivity of Chrysanthemum morifolium Extract in Preventing Palmitate-Induced Endothelial Dysfunction by Restoring MFN2 and Alleviating Oxidative Stress in HAEC Cells
Antioxidants 2023, 12(5), 1019; https://doi.org/10.3390/antiox12051019 - 28 Apr 2023
Viewed by 977
Abstract
As the most important natural antioxidants in plant extracts, polyphenols demonstrate versatile bioactivities and are susceptible to oxidation. The commonly used ultrasonic extraction often causes oxidation reactions involving the formation of free radicals. To minimize the oxidation effects during the ultrasonic extraction process, [...] Read more.
As the most important natural antioxidants in plant extracts, polyphenols demonstrate versatile bioactivities and are susceptible to oxidation. The commonly used ultrasonic extraction often causes oxidation reactions involving the formation of free radicals. To minimize the oxidation effects during the ultrasonic extraction process, we designed a hydrogen (H2)-protected ultrasonic extraction method and used it in Chrysanthemum morifolium extraction. Hydrogen-protected extraction improved the total antioxidant capacity, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, and polyphenol content of Chrysanthemum morifolium water extract (CME) compared with air and nitrogen (N2) conditions. We further investigated the protective effects and mechanisms of CME on palmitate (PA)-induced endothelial dysfunction in human aorta endothelial cells (HAECs). We found that hydrogen-protected CME (H2-CME) best-prevented impairment in nitric oxide (NO) production, endothelial NO synthase (eNOS) protein level, oxidative stress, and mitochondrial dysfunction. In addition, H2-CME prevented PA-induced endothelial dysfunction by restoring mitofusin-2 (MFN2) levels and maintaining redox balance. Full article
(This article belongs to the Special Issue Antioxidant and Protective Effects of Plant Extracts)
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