FLAVONOIDS AND ANTIOXIDANT ACTIVITY OF Calia secundilfora (Ort.) Yakovlev

Abstract

The possible extinction of some non-studied species such as Calia secundiflora might mean the loss of the knowledge about their metabolites with medicinal properties and agronomic interest. Th e phytochemical studies on C. secundiflora (Ort.) Yakovlev (Fabaceae) have been focused on its content of alkaloids, but its profile of flavonoids is still unknown. These plant metabolites have been associated to a natural antioxidant capacity which are beneficial for human health according to epidemiological studies. The objective of this research was to quantify the contents of phenolic compounds and flavonoids, as well as to identify the flavonoid structures in leaf and to evaluate their antioxidant potential. The antioxidant activity was evaluated by the DPPH (2,2-diphenyl-1-picrylhydrazyl) method in samples taken from Hidalgo State, México. The analysis by HPLC-MS allowed to the identify seven glycosides in the flavonols quercetin, isorhamnetin and kaempferol, which have not described previously for this species. The content of total phenolic compounds (8.31 ± 0.38 mg g^-1 of DM) was higher than that of flavonoids (3.08 ± 0.32 mg g^-1 of DM). These results explain the antioxidant activity (IC₅₀ = 88.54 ± 0.15; 109.44 ± 0.48 μg mL^-1) presented by the leaf extracts. The identification of these flavonoids may contribute to the chemotaxonomy of this genus.