The Genus Hyssopus: Traditional Use, Phytochemicals and Pharmacological Properties

According to modern concepts, the genus Hyssopus L. includes seven plant species (Hyssopus ambiguus (Trautv.) Iljin ex Prochorov. & Lebel; Hyssopus cuspidatus Boriss; Hyssopus latilabiatus C.Y.Wu & H.W. Li; Hyssopus macranthus Boriss.; Hyssopus officinalis L.; Hyssopus seravschanicus (Dubj.) Pazij; Hyssopus subulifolius (Rech.f.) Rech.f.). The plants are rich in various groups of biologically active substances with a wide spectrum of pharmacological action. This review presents a modern comprehensive overview of the botanical research, extraction methods, chemical composition and pharmacological activity of plants of the genus Hyssopus L. As a result of the review, it was established that the chemical composition of plant extracts of the genus Hyssopus L. depends on various factors (place of growth, weather conditions, chemotypes, extraction methods, etc.). For the further use of the plants, the extraction methods and low-molecular metabolites isolated from them (mono- and sesquiterpenoids, flavonoids, alkaloids, etc.) are discussed. The data from the review provide an assessment of the relevance.

Potential of Essential Oils in the Control of Listeria monocytogenes

Listeria monocytogenes is a foodborne pathogen, the causative agent of listeriosis. Infections typically occur through consumption of foods, such as meats, fisheries, milk, vegetables, and fruits. Today, chemical preservatives are used in foods; however, due to their effects on human health, attention is increasingly turning to natural decontamination practices. One option is the application of essential oils (EOs) with antibacterial features, since EOs are considered by many authorities as being safe. In this review, we aimed to summarize the results of recent research focusing on EOs with antilisterial activity. We review different methods via which the antilisterial effect and the antimicrobial mode of action of EOs or their compounds can be investigated. In the second part of the review, results of those studies from the last 10 years are summarized, in which EOs with antilisterial effects were applied in and on different food matrices. This section only included those studies in which EOs or their pure compounds were tested alone, without combining them with any additional physical or chemical procedure or additive. Tests were performed at different temperatures and, in certain cases, by applying different coating materials. Although certain coatings can enhance the antilisterial effect of an EO, the most effective way is to mix the EO into the food matrix. In conclusion, the application of EOs is justified in the food industry as food preservatives and could help to eliminate this zoonotic bacterium from the food chain.

An Overview of Herbal Nutraceuticals, Their Extraction, Formulation, Therapeutic Effects and Potential Toxicity

Herbal nutraceuticals are foods derived from plants and/or their derivatives, such as oils, roots, seeds, berries, or flowers, that support wellness and combat acute and chronic ailments induced by unhealthful dietary habits. The current review enlists various traditional as well as unexplored herbs including angelica, burnet, caraway, laurel, parsley, yarrow, and zedoary, which are rich sources of bioactive components, such as aloesin, angelicin, trans-anethole, and cholesteric-7-en-3β-ol. The review further compares some of the extraction and purification techniques, namely, Soxhlet extraction, ultrasound assisted extraction, microwave assisted extraction, supercritical fluid extraction, accelerated solvent extraction, hydro-distillation extraction, ultra-high-pressure extraction, enzyme assisted extraction, pulsed electric field extraction, bio affinity chromatography, cell membrane chromatography, and ligand fishing. Herbal nutraceuticals can be purchased in varied formulations, such as capsules, pills, powders, liquids, and gels. Some of the formulations currently available on the market are discussed here. Further, the significance of herbal nutraceuticals in prevention and cure of diseases, such as diabetes, obesity, dementia, hypertension, and hypercholesterolemia; and as immunomodulators and antimicrobial agents has been discussed. Noteworthy, the inappropriate use of these herbal nutraceuticals can lead to hepatotoxicity, pulmonary toxicity, cytotoxicity, carcinogenicity, nephrotoxicity, hematotoxicity, and cardiac toxicity. Hence, this review concludes with a discussion of various regulatory aspects undertaken by the government agencies in order to minimize the adverse effects associated with herbal nutraceuticals.

Variability in Biological Activities of Satureja montana Subsp. montana and Subsp. variegata Based on Different Extraction Methods

Winter savory (Satureja montana L.) is a well-known spice and medicinal plant with a wide range of activities and applications. Two subspecies of S. montana, subsp. montana and subsp. variegata, were used for the preparation of seven different extracts: steam distillation (essential oil (EO) and hydrolate (HY)), subcritical water (SWE), ultrasound-assisted (UAE-MeOH and UAE-H₂O), and microwave-assisted (MAE-MeOH and MAE-H₂O) extraction. The obtained EOs, HYs, and extracts were used for an in vitro evaluation of the antioxidant activity (DPPH, ABTS, reducing power, and superoxide anion methods) and in vitro antimicrobial activity against Bacillus cereus, Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Salmonella Typhimurium, Saccharomyces cerevisiae, and Candida albicans. The antimicrobial screening was conducted using disk-diffusion assessment, minimal inhibitory concentration, time–kill kinetics modeling, and pharmacodynamic study of the biocide effect. The total phenolic content (TPC) was highest in EO, followed by SWE, MAE, and UAE, and the lowest was in HY. The highest antimicrobial activity shows EO and SWE for both varieties, while different UAE and MAE extracts have not exhibited antimicrobial activity. The natural antimicrobials in the S. montana extract samples obtained by green extraction methods, indicated the possibility of ecologically and economically better solutions for future in vivo application of the selected plant subspecies.

Chemical Composition, Antioxidant, and Antimicrobial Activity of Dracocephalum moldavica L. Essential Oil and Hydrolate

Steam distillation was used for the isolation of Dracocephalum moldavica L. (Moldavian dragonhead) essential oil (DMEO). This aromatic herbaceous plant is widespread across the Northern Hemisphere regions and has been utilized in health-improving studies and applications. In addition to the DMEO, the hydrolate (DMH), a byproduct of the distillation process, was also collected. The DMEO and DMH were analyzed and compared in terms of their chemical composition, as well as their in vitro biological activities. The main component in DMEO was geranyl acetate, while geranial was dominant in DMH. The DMEO demonstrated better antioxidant and antimicrobial activities compared with the DMH against Staphylococcus aureus, Escherichia coli, Salmonella Typhimurium, and Listeria monocytogenes, which represent sources of food-borne illness at the global level. The DMEO and DMH show promise as antioxidant and antimicrobial additives to various products.

Weather Conditions Influence on Lavandin Essential Oil and Hydrolate Quality

Lavandula sp. essential oil and hydrolate are commercially valuable in various industry branches with the potential for wide-ranging applications. This study aimed to evaluate the quality of these products obtained from L. x intermedia cv. ‘Budrovka’ for the first time cultivated on Fruška Gora Mt. (Serbia) during three successive seasons (2019, 2020, and 2021). Essential oil extraction was obtained by steam distillation, and the composition and influence of weather conditions were also assessed, using flowering tops. The obtained essential oils and hydrolates were analysed by gas chromatography with a flame ionization detector (GC-FID) and gas chromatography coupled to mass spectrometry (GC-MS). A linear regression model was developed to predict L. x intermedia cv. ‘Budrovka’ essential oil volatile compound content and hydrolate composition during three years, according to temperature and precipitation data, and the appropriate regression coefficients were calculated, while the correlation analysis was employed to analyse the correlations in hydrolate and essential oil compounds. To completely describe the structure of the research data that would present a better insight into the similarities and differences among the diverse L. x intermedia cv. ‘Budrovka’ samples, the PCA was used. The most dominant in L. intermedia cv. ‘Budrovka’ essential oil and hydrolate were oxygenated monoterpenes: linalool, 1,8-cineole, borneol, linalyl acetate, and terpinene-4-ol. It is established that the temperature was positively correlated with all essential oil and hydrolate compounds. The precipitations were positively correlated with the main compounds (linalool, 1,8-cineole, and borneol), while the other compounds’ content negatively correlated to precipitation. The results indicated that Fruška Gora Mt. has suitable agro-ecological requirements for cultivating Lavandula sp. and providing satisfactory essential oil and hydrolate.

Comparative Study of the Essential Oil and Hydrosol Composition of Sweet Wormwood (Artemisia annua L.) from Serbia

The most abundant volatile compounds of sweet wormwood (Artemisia annua L.) essential oil were artemisia ketone (25.4 %) and trans-caryophyllene (10.2 %), followed by 1,8-cineole, camphor, germacrene D and β-selinene. The major volatile compounds in the hydrosol were camphor (25.1 %), 1,8-cineole (20.5 %) and artemisia ketone (10.7 %), followed by trans-pinocarveol and yomogi alcohol. Tested essential oil was rich in oxygenated monoterpenes and sesquiterpene hydrocarbons, while the former were identified as the major class of volatile compounds in the hydrosol, due to higher water solubility. Classification of all sweet wormwood chemotypes, according to essential oil composition, in available literature (17 studies and 61 accessions) could be done according to four chemotypes: artemisia ketone+artemisia alcohol (most abundant), artemisia ketone, camphor and nonspecific chemotype. According to this classification, essential oil of sweet wormwood from this study belongs to artemisia ketone (content varied between 22.1 and 55.8 %). Bearing in mind that hydrosols are a by-product of industrial production of essential oils, and the fact that sweet wormwood hydrosol has high contents of camphor, 1,8-cineole and artemisia ketone, there is a great potential for the use of this aromatic plant primary processing waste product as a water replacement in cosmetic industry, beverages flavoring, for food preservation, as well as in post-harvest pre-storage treatments in organic agriculture.

Volatile Compounds of Nepeta nuda L. from Rtanj Mountain (Serbia)

Unlike other studies that only determined the chemical composition of essential oils depending on their geographic origin, this research investigated the effect of weather conditions (temperature, precipitation, and insolation) on the chemical composition of Nepeta nuda L. essential oil. The collection of wild-growing N. nuda was carried out during three successive years, 2019, 2020, and 2021 at Rtanj Mountain (Serbia) on the same date (July 7th). Essential oil extraction from the plant was performed by hydro-distillation. After gas chromatographic-mass spectrometric analysis, a total of 102 volatile compounds were separated from N. nuda, during the observed period, 28 were unidentified, compromising between 5.0% and 8.7%, depending on the year. A multiple linear regression model was created, and statistical analyses were performed to provide knowledge about the prediction, feature profile, and the similarity in contents of active compounds of the N. nuda essential oil. The influence of temperature on the accumulation of the most abundant component, 1,8-cineole, was positive, while the impact of precipitation and insolation was negative. According to the cluster tree, there are four chemotypes of N. nuda essential oil: with nepetalactone, 1,8-cineole, mixed (nepetalactone+1,8-cineole+germacrene D), and nonspecific chemotypes. Bearing in mind that the biological activity of a raw material depends on the chemotype and environmental factors, this is a topic that deserves a more detailed approach. The N. nuda and its essential oil are promising materials with high biological potential, and these deserve further detailed investigation.

Encapsulation of Natural Bioactive Compounds by Electrospinning-Applications in Food Storage and Safety

Packaging is used to protect foods from environmental influences and microbial contamination to maintain the quality and safety of commercial food products, to avoid their spoilage and to extend their shelf life. In this respect, bioactive packaging is developing to additionally provides antibacterial and antioxidant activity with the same goals i.e., extending the shelf life while ensuring safety of the food products. New solutions are designed using natural antimicrobial and antioxidant agents such as essential oils, some polysaccharides, natural inorganic nanoparticles (nanoclays, oxides, metals as silver) incorporated/encapsulated into appropriate carriers in order to be used in food packaging. Electrospinning/electrospraying are receiving attention as encapsulation methods due to their cost-effectiveness, versatility and scalability. The electrospun nanofibers and electro-sprayed nanoparticles can preserve the functionality and protect the encapsulated bioactive compounds (BC). In this review are summarized recent results regarding applications of nanostructured suitable materials containing essential oils for food safety.