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.

ABSTRACT. 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.

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