Using HPLC and multivariate analyses to investigate variations in the polyphenolic compounds as well as antioxidant and antiglycative activities of some Lamiaceae species native to Iran

Abstract

The Lamiaceae family is a major source of species among medicinal plants that are highly valued for their antioxidant properties and multiple pharmaceutical uses in folk medicine. Satureja, Origanum, and Dracocephalum are some of the major genera belonging to the Lamiaceae family. The present study used seven Iranian endemic species of the Lamiaceae family, viz. one from each of S. hortensis, S. bachtiarica, S. sahendica, and D. kotschyi species as well as three ecotypes from O. vulgare and compared them in terms of their antioxidant activities. S. hortensis exhibited the highest total phenolic (266.82 mg Tannic acid/g DW) and total flavonoid (22.63 mg Quercetin/g DW) contents with the highest antioxidant activity (IC50 = 95.52 μg/mL), while the least activity was recorded for the aqueous extract of Origanum. High performance liquid chromatography (HPLC) was also performed to determine the major polyphenols. Rosmarinic acid was identified as the predominant phenolic compound in all the studied Lamiaceae species. Three Satureja species richer in phenolics and flavonoids with a substantial antioxidant activity were also selected to investigate their antiglycation properties. For comparison, the antiglycative activity was also assessed in bovine serum albumin/methylglyoxal system. The highest and lowest anti-glycative activities were recorded for S. hortensis and S. sahendica, respectively. Finally, S. hortensis was found to produce the highest amounts of such polyphenols as rosmarinic, syringic, caffeic, and ferulic acids basically considered to be the main phenolic acids responsible for the antioxidant and anti-glycative activities of the plant extracts.