Chemical Characterization and Biological Activities of Some Aromatic Plants in Aljouf, Saudi Arabia

Abstract

Importance: Natural food additives, especially antioxidants, are the future of food preservation industry as synthetic ones could have a long-term potential harm to human health, including toxicity and carcinogenicity. Results: The volatile constituents of fresh and dried Mentha suaveolens L in Saudi Arabia (Aljouf area) for the whole plant, leaves, and stems were extracted via maceration and analyzed using Gas Chromatography (GC) and Gas Chromatography/Mass Spectrometry (GC/MS). According to our knowledge, this study was unique for including all parts of the M. suaveolens L. The volatile constituents of fresh and dried M. suaveolens L for each part contained 125 compounds. Carvone was the main volatile constituent for fresh and dried M. suaveolens L for the whole plant (43.65% and 39%, respectively), leaves (64.31% and 53.45%, respectively), and stems (58.8% and 49%, respectively). The volatile constituents of M. suaveolens L belonged to the carvone chemotype because the volatile extracts were rich in carvone. Also, the analysis of non-volatile constituents of fresh and dried M. suaveolens L whole plant, leaves, and stems was performed by High-Performance Liquid Chromatography (HPLC). Rosmarinic acid was the main phenolic compound of fresh and dried M. suaveolens L for the whole plant (2223.3µg/g and 21191.9µg/g, respectively), leaves (28002.5µg/g and 15165.1µg/g, respectively), and stems (6558µg/g and 8378.4µg/g, respectively). All Mentha extracts showed strong antioxidant activity because it was rich in phenolic compounds. For the first time, a fungus (Penicillium glabrum) isolated from white cheese was inhibited by Mentha extracts. Leaves of fresh M. suaveolens L presented a higher antifungal activity compared with the other hexane extracts. In comparison, fresh M. suaveolens L stems showed higher antifungal activity than the other ethanolic extracts. Application aspects: This study indicates that M. suaveolens L could be used to manufacture unique natural antioxidants and a flavoring component. Although the observed biological activities of M. suaveolens L extracts were less than those recorded for synthetic antioxidants, they have the advantage of being safe and available as natural food additives in large and cost-effective quantities.