Phytochemical screening, total phenolic, flavonoid contents, and antioxidant activities of four spices commonly used in Vietnamese traditional medicine

Abstract

The use of spices in Vietnamese folk medicine and culinary application is long-established and widespread. In this study, we preliminarily determined chemical composition and quantified antioxidant activity of leaf extracts of four typical spices herbs (Limnophila aromatica, Cosmos Caudatus Kunth, Limnophila rugosa (Roth) Merr and Elsholtzia ciliata (Thunb.) Hyland. The content of polyphenols and flavonoids was quantified by colorimetric method and antioxidant activity was determined based on the ability to scavenge free radicals by using DPPH and ABTS assay. Current results revealed the presence of triterpenoids, alkaloids, tannins, flavonoids, coumarins, saponins and reducing sugars in the herb extracts. L. aromatica showed highest total polyphenol and flavonoid content compared to those of other three species. Regarding antioxidant capacity, L. rugosa figures prominently among the four with IC50 measured at 137.30 ± 7.85 and 13.93 ± 0.82 µg/mL, respectively for DPPH and ABTS method.