Quantitative analysis of flavonoids and phenolics extracted from Diplazium esculentum (Retz.) Sw. for their anti-hyperglycemic potential

Abstract

Background: Hyperglycemia arises from excessive blood glucose due to starch hydrolysis by α-amylase and α-glucosidase. Drugs like acarbose inhibit these enzymes to manage hyperglycemia, but long-term use poses risks. Fern species Diplazium esculentum metabolites show promise as acarbose alternatives. Methods: Sequential extraction of secondary metabolites from D. esculentum involved solvents in successive stages: hexane, ethyl acetate, and water. Subsequently, an assessment of phenolic and flavonoid concentrations within the ethyl acetate and aqueous extracts was conducted. Furthermore, the investigation encompassed the evaluation of % inhibition and IC50 values pertaining to the activities of α-amylase and α-glucosidase. Results: The findings indicated that the flavonoid concentrations in the ethyl acetate and aqueous extracts were 146.90 ± 27.20 µg quercetin equivalent per gram of fresh weight (eq./g FW) and 101.95 ± 40.62 µg quercetin eq./g FW, respectively. In terms of total phenolic content, the ethyl acetate extract contained 121.25 ± 8.29 µg of gallic acid eq./g FW, whereas the aqueous extract had 109.90 ± 7.22 µg gallic acid eq./g FW. The IC50 values demonstrated that the aqueous extract had moderate inhibitory effects on α-amylase with a value of 108.05 µg/mL, while acarbose exhibited very strong inhibition with a value of 3.12. Conclusion: Ferns are relatively ineffective in treating hyperglycemia.