Composition and Antimicrobial Activity of the Essential Oil fromMentha spicataL. subsp.Spicata

Current status, technology, regulation and future perspectives of essential oils usage in the food and drink industry

Nowadays, essential oils (EOs) have a wide use in many applications such as in food, cosmetics, pharmaceutical and animal feed products. Consumers' preferences concerning healthier and safer foodstuffs lead to an increased demand for natural products, in replacement of synthetic substances, used as preservatives, flavourings etc. EOs, besides being safe, are promising alternatives as natural food additives, and much research has been carried out on their antioxidant and antimicrobial activity. The initial purpose of this review is to discuss conventional and 'green' extraction techniques along with their basic mechanism for the isolation of EOs from aromatic plants. This review aims to provide a broad overview of the current knowledge about the chemical constitution of EOs while considering the existence of different chemotypes, since bioactivity is attributed to the chemical composition - qualitative and quantitative - of EOs. Although the food industry primarily uses EOs as flavourings, an overview on recent applications of EOs in food systems and active packaging is provided. EOs exhibit poor solubility in water, oxidation susceptibility, negative organoleptic effect and volatility, restricting their use. Encapsulation techniques have been proven to be one of the best approaches to preserve the biological activities of EOs and minimize their effects on food sensory qualities. Herein, different encapsulation techniques and their basic mechanism for loading EOs are discussed. EOs are highly accepted by consumers, who are often under the misconception that 'natural' means safe. This is, however, an oversimplification, and the possible toxicity of EOs should be taken into consideration. Thus, in the final section of the current review, the focus is on current EU legislation, safety assessment and sensory evaluation of EOs. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Plant Essential Oils as a Tool in the Control of Bovine Mastitis: An Update

Bovine mastitis is a major concern for the dairy cattle community worldwide. Mastitis, subclinical or clinical, can be caused by contagious or environmental pathogens. Costs related to mastitis include direct and indirect losses, leading to global annual losses of USD 35 billion. The primary treatment of mastitis is represented by antibiotics, even if that results in the presence of residues in milk. The overuse and misuse of antibiotics in livestock is contributing to the development of antimicrobial resistance (AMR), resulting in a limited resolution of mastitis treatments, as well as a serious threat for public health. Novel alternatives, like the use of plant essential oils (EOs), are needed to replace antibiotic therapy when facing multidrug-resistant bacteria. This review aims to provide an updated overview of the in vitro and in vivo studies available on EOs and their main components as an antibacterial treatment against a variety of mastitis causing pathogens. There are many in vitro studies, but only several in vivo. Given the promising results of treatments with EOs, further clinical trials are needed.

Separation and Qualitative Study of Mentha asiatica Boriss. Essential Oil Components by prep-GC, GC-QTOF-MS, NMR and Prediction of Bioactive Compounds

In order to understand the material basis of wild Mentha asiatica Boris. in Xinjiang, the chemical constituents of essential oil extracted from aerial parts of this plant were studied. A total 52 components were detected and 45 compounds were identified. First of all, the essential oil was separated by silica gel column chromatography, and divided into several parts according to the results of thin layer chromatography. Eight fractions were obtained, and then each fragment was preliminarily screened for antibacterial activity. It was found that all eight fragments had certain antibacterial activity in different level. Then the fractions were subjected to preparative gas chromatography (prep-GC) for further isolation. Ten compounds were identified by ¹³ C-NMR, ¹ H-NMR and gas chromatography-quadrupole time of flight-Mass spectrometry (GC-QTOF-MS). They are sabinene, limonene and β-caryophyllene, (1R*,3S*,5R*)-sabinyl acetate, piperitone oxide, rotundifolone, thymol, piperitone, 4-hydroxypiperiditone, cedrol. After screened by bioautography, 4-hydroxypiperone and thymol were showed best antibacterial activity. The inhibitory effects of the two isolated compounds on Candida albicans and their related mechanisms were studied. The results showed that, 4-hydroxypiperone and thymol significantly reduced ergosterol content on the surface of Candida albicans cell membrane in a dose-dependent manner. This work has accumulated experience for the development and utilization of Xinjiang characteristic medicinal plant resources and new drug research and development, and provided scientific basis and support for the later research and development of Mentha asiatica Boris.

The chemistry and sensory characteristics of new herbal tea-based kombuchas

Kombucha is a black tea-based, non-alcoholic beverage fermented by yeast and bacteria are known for its refreshing scent and taste and presents biological characteristics, namely antioxidant, antimicrobial and anti-inflammatory activity. The present study compared traditional kombucha prepared with black tea and green tea to kombuchas produced with several alternative substrates, including white tea, chrysanthemum, honeysuckle, and mint infusions. Throughout the fermentation process, liquid and gas chromatography analyzed sugars, ethanol, organic acids, and volatile compounds. Sugar consumption was substrate-dependent, with mint kombucha having the highest amount of residual sugar and honeysuckle having the lowest. Forty-six volatile organic compounds were detected, including alcohols, esters, acids, aldehydes, ketones, and other compounds. Twenty-two compounds were produced during the fermentation and identified in all kombuchas; some of these compounds represented fruity and floral aromas. Another 24 compounds were substrate specific. Notably, the herb-based kombuchas (chrysanthemum, honeysuckle, and mint) contained several compounds absent in the tea-based kombuchas and are associated with minty, cooling, and refreshing aromas. Mint and green tea kombucha attained the highest and lowest overall sensorial acceptance ratings, respectively. This study demonstrated herbal substrates' suitability to prepare kombucha gastronomically with volatile compound and flavor profiles distinct from tea-based kombuchas. PRACTICAL APPLICATION: The kombucha beverage is a low-caloric functional drink that is increasingly popular around the world. While it is traditionally produced with black or green tea, this paper explores its production based on other herbal and floral infusions. The kombucha analogs presented in this paper can provide consumers with healthy alternatives for sugary soft drinks while also offering a broader range of flavors.

Antifungal activity of essential oil from Mentha spicata L. and Mentha pulegium L. growing wild in Sardinia island (Italy)

This study aims to evaluate the antifungal activity of Mentha spicata L. and Mentha pulegium L. from Sardinia and to assess their efficacy on virulence factors for Candida albicans, particularly on the inhibition of the germ tube formation. The major compounds of the essential oils were carvone (62.9%) for M. spicata and pulegone (86.2%) for M. pulegium. The essential oil from M. spicata showed a more preeminent effect against Cryptococcus neoformans and the dermatophytes Trichophyton rubrum and T. verrucosum (0.32 μL/mL). Both oils were very effective in inhibiting C. albicans germ tube formation, at doses well below their MIC (0.16 μL/mL).

Effects of clove (Syzygium aromaticum) oil on quail growth, carcass traits, blood components, meat quality, and intestinal microbiota

To provide a safe growth promoter, the present study has investigated the effects of different levels of cold-pressed clove oil (CCPO) on growth performance, carcass traits, blood biochemistry, and intestinal microbial population of growing Japanese quails. A total of 300 quails (1-wk old) were randomly divided into 3 treatment groups: control basal diet, basal diet +0.75 mL oil/kg diet, and basal diet +1.5 mL oil/kg diet. Quails fed with 1.5 mL clove oil/kg diet showed a 3.43% improvement in live body weight vs. control group. Similar trend was observed for daily body weight gain. Feed intake gradually increased (P < 0.01) with an increase in clove oil level. The best feed conversion rate was reported for the control group, followed by the group treated with 1.5 mL CCPO/kg diet during the whole period (1 to 6 wk of age). Total globulin differed significantly in 1.5 mL CCPO/kg diet group. Antioxidant enzyme activities, lipid profile, and reduced glutathione concentrations significantly improved in a dose-dependent manner. Blood urea nitrogen, creatinine, malondialdehyde, 8-hydroxy-2΄-deoxyguanosine, and protein carbonyl levels significantly decreased in quails supplemented with 1.5 mL CCPO/kg diet vs. control group. Serum levels of insulin-like growth factor-1, insulin, growth hormone, and thyroxine significantly increased in quails supplemented with 1.5 mL CCPO/kg diet vs. control group. The intestinal bacterial population, coliforms, Escherichia coli, and Salmonella spp. in the ileal content were lower (P < 0.05) in groups treated with oil (1.5 mL/kg) vs. control group. Thus, dietary supplementation with antimicrobial CCPO (1.5 mL/kg diet) could enhance growth performance, improve health status, and reduce intestinal pathogens in Japanese quails.

Chemical composition, antioxidant, antimicrobial and Antiproliferative activities of essential oil of Mentha spicata L. (Lamiaceae) from Algerian Saharan atlas

BACKGROUND

Mentha spicata (M. spicata) is a member of Lamiaceae that spreads mainly in the temperate and sub-temperate zones of the world. It is considered as a rich source of essential oils, which is widely used in pharmaceutical industries and food production. The objectives of the current study were to evaluate chemical composition, antioxidant, antimicrobial and antiproliferative activities associated with the essential oil of M. spicata cultivated in Algerian Saharan Atlas.

METHODS

The aerial parts of M. spicata were subjected to hydrodistillation to produce the oil. Chemical identification of the oil composition was conducted by GC and GC-MS analyses. The antioxidant activity of the hydrodistilled oil was studied using DPPH, ABTS radical scavenging and ferric-reducing power assay. Antimicrobial potential was characterized against two microorganisms, signifying Gram positive, and Gram negative bacteria, and one Candida species. The microdilution method was employed to determine the minimum inhibitory concentration (MIC). The oil's antiproliferative effects against three human tumor cell lines were also investigated using the MTT assay, and the toxic doses that yielded 50% reduction of cell viability (LD50) were reported.

RESULTS

Chemical analysis of the essential oil composition revealed 44 unique compounds with oxygenated monoterpenes (67.2%), followed by monoterpene hydrocarbons (20.8%), as the most abundant chemical components. Essential oil of M. spicata demonstrated moderate antioxidant activities as well as moderate to weak antimicrobial activities with best susceptibility observed for Gram positive bacteria towards the oil. In addition, anticancer activities that are associated with the oil against three human cancer cell lines were observed with LD50 values of 324 μg/mL, 279 μg/mL, 975 μg/mL against T47D, HCT-116 and MCF-7 cell lines, respectively.

CONCLUSION

The results suggest that M. spicata essential oil may have potential value as a bioactive oil, for nutraceutical and medical applications, with its antioxidant, antimicrobial and antiproliferative activities.

Anti-proliferative effect and phytochemical analysis of Cymbopogon citratus extract

The antiproliferative and antioxidant potential of Cymbopogon citratus (Lemon grass) extracts were investigated. The extracts were isolated by solvent maceration method and thereafter subjected to antiproliferative activity test on five different cancer cells: human colon carcinoma (HCT-116), breast carcinoma (MCF-7 and MDA-MB 231), ovarian carcinoma (SKOV-3 and COAV), and a normal liver cell line (WRL 68). The cell viability was determined using MTT assay. The DPPH radical scavenging assay revealed a concentration dependent trend. A maximum percentage inhibition of 45% and an IC50 of 278  μg/mL were observed when aqueous extract was evaluated. In contrast, 48.3% and IC50 of 258.9  μg/mL were observed when 50% ethanolic extract was evaluated. Both extracts at concentration of 50 to 800  μg/mL showed appreciative metal chelating activity with IC50 value of 172.2 ± 31  μg/mL to 456.5 ± 30  μg/mL. Depending on extraction solvent content, extract obtained from 50% ethanolic solvent proved to be more potent on breast cancer MCF-7 cell line (IC50 = 68  μg/mL). On the other hand, 90% ethanolic extract showed a moderate potency on the ovarian cancer (COAV) and MCF-7 cells having an IC50 of 104.6  μg/mL each. These results suggested antiproliferative efficacy of C. citratus ethanolic extract against human cancer cell lines.