Phenolic content and antioxidant activity of Etlingera dostseiana Naive, Demayo & Alejandro, 2020 (Zingiberaceae)

Abstract

The ginger species (Zingiberaceae family) have attract a lot of scientific attention because of their perceived beneficial effects on health. Despite this, for the numerous species of the family, scientific reports are quite scarce and warrant further analyses. The most of until now analyzed ginger species are allochthonous in the Philippines. Thus, this study was carried out to determine the total phenolic content and antioxidant activity of the ethanolic extracts of the leaves and rhizomes of Etlingera dostseiana Naive, Demayo & Alejandro, a Philippine endemic ginger species. Data recorded for total phenolic content (mg GAE/g dried sample) revealed that the leaves (15.44 ± 0.80) have a greater amount of phenolics than the rhizomes (0.59 ± 0.03). The total antioxidant activity (mg AAE/g dried sample) was also observed to be higher in leaves (14.24 ± 0.25) than in the rhizomes (0.91 ± 0.04), as well as the reducing power (mg GRPE/g dried sample) - 10.33 ± 1.13 in leaves versus 0.21 ± 0.06 in rhizomes. Based on the correlation analysis, a perfect positive linear relationship was observed among the total phenolic content, total antioxidant activity, and reducing power (r=1, p<0.001). These imply that the high contents of phenolic compounds contribute to the antioxidant activity of extracts of E. dostseiana. It can be regarded that E. dostseiana could be a candidate as a natural plant source of antioxidant compounds.