In addition to the naturopathic medicines based on the antiseptic, anti-inflammatory, anticancer, or antioxidant properties of plant extracts that have been capitalized upon through the pharmaceutical industry, the increasing interest of the food industry in this area requires potent new materials capable of supporting this market. This study aimed to evaluate the in vitro amino acid contents and antioxidant activities of ethanolic extracts from sixteen plants. Our results show high accumulated amino acid contents, mainly of proline, glutamic, and aspartic acid. The most consistent values of essential amino acids were isolated from T. officinale, U. dioica, C. majus, A. annua, and M. spicata. The results of the 2,2-diphenyl-1-pycrylhydrazyl (DPPH) radical scavenging assay indicate that R. officinalis was the most potent antioxidant, followed by four other extracts (in decreasing order): T. serpyllum, C. monogyna, S. officinalis, and M. koenigii. The network and principal component analyses found four natural groupings between samples based on DPPH free radical scavenging activity content. Each plant extracts’ antioxidant action was discussed based on similar results found in the literature, and a lower capacity was observed for most species. An overall ranking of the analyzed plant species can be accomplished due to the range of experimental methods. The literature review revealed that these natural antioxidants represent the best side-effect-free alternatives to synthetic additives, especially in the food processing industry.

Aromatic plants are widely used in food preparation for aroma and fragrance, but they are also a good source of amino acids and fatty acids. Three indigenous species, Basil (Ocimum basilicum), mint (Mentha piperita) and sage (Salvia officinalis) which are traditionally used in medicine and food, were characterized and compared in terms of volatile extracts, amino acids, fatty acids contents and antioxidant activities. The gas chromatographic–mass spectrometry (GC–MS) method is a suitable technique for the characterization of the compounds of the herbs extracts. Antioxidant activity was measured using extracts ability to scavenge DPPH radicals. Linalool was found the major compound in basil, menthol in mint and α-thujone in sage. The dominant amino acids identified in the plants extracts were glutamic acid and aspartic acid in basil and mint, while proline was found in high concentration in sage and mint. The total free fatty acids (TFA) were highest in mint, followed by sage and basil. The essential omega 3 alpha-linolenic acid (ALA) was identified in all three extracts. All samples exhibited antioxidant activity, sage extract having the highest antioxidant activity.

In this study, chitosan (CH)/polyvinyl alcohol (PVA) hybrid nanofibers incorporating three distinct essential oils lemon, lime, and grapefruit were successfully obtained via the innovative electrospinning technique. Characteristics of the electrospinning polymeric mixture loaded with essential oils using variable ratios of CH/PVA were evaluated. The nanoencapsulation process of citrus essential oils was achieved with 47.67%–88.16% encapsulation efficiency. Notably, the thermal stability of the encapsulated essential oils experienced a significant enhancement after encapsulation. Scanning electron microscopy analysis revealed valuable insights, revealing that an increased amount of incorporated essential oil within the polymeric mixture solutions led to a reduction in the average fiber diameters. The resulting nanofibers demonstrated notable attributes such as antioxidant, tyrosinase inhibitory, and antibacterial activities. The present research demonstrates the ability of CH/PVA hybrid nanofibers obtained through an electrospinning process to preserve citrus essential oils properties quality and reveals a high potential application of nonencapsulated citrus essential oils in biomaterials, food packaging, and advanced cosmetic application.

A comparative study for analysis of essential oils obtained from plants grown in Transylvania, plants belonging to Apiaceae family, was achieved. Five types of plants seeds from Coriandrum sativum L. (coriander), Anethum graveolens L. (dill), Pimpinella anisum L. (anise), Carum carvi L. (caraway) and Foeniculum vulgare L. (fennel) were hydrodistilled to yield essential oils. The chemical composition of the obtained essential oils was determined; also the antioxidant, antimicrobial and tyrosinase inhibitory activities were investigated. The major constituent of coriander essential oil were linalool (73%), for dill (52.7%) and caraway (67.55%) was carvone and for anise (95.2%) and fennel (89.64%) was trans-anethole. The anise seeds essential oils provide the highest antioxidant activity while the coriander essential was the lowest. The fennel essential oils proved to be a potent tyrosinase inhibitor. All studied essential oils exhibited considerable antimicrobial activity, but coriander essential oil proved to have a very high antibacterial activity on gram-negative bacteria E. Coli and Klebsiella pneumonia.

A comparative study concerning the influence of geographic location and also the influence of enzyme-assisted extraction on the essential oils isolated from Transylvanian wild Thymus serpyllum was achieved. The collected Thymus serpyllum plants, from three different regions from Transilvania, were hydrodistilled to yield essential oils. The influence of enzymatic assisted extraction on the essential oils isolated from Thymus serpyllum was evaluated. All analyzed plants proved to belong to carvacrol chemotype class. The major constituents of wild Thymus serpyllum from these three regions were carvacrol (26.58%-47.62%), p-cymene (8.61%-18.97%), methylcarvacrol (8.81%-13.35%), thymol (1.6%-11.07%), gamma-terpinene (2.09%-7.55%), beta-bysabolene (3.42%-5.18%), caryophyllene (3.17%-4.83%). Using the enzymatic treatment, the percentage in composition of some components was modified and proved to have an improvement on antioxidant and antimicrobial properties. All studied essential oils exhibited considerable antioxidant and antimicrobial activity.