Phytochemical Screening, Antioxidant Activity and α‐Glucosidase Inhibitability of Bauhinia x blakeana Dunn Leaf and Flower Extracts from Vietnam

Abstract

Bauhinia x blakeana Dunn is traditionally used as vegetables, medicinal herbs to treat diseases, and ornamental trees. The current study was performed to evaluate the phytochemicals, total phenolic (TPC) and total flavonoid (TFC) contents, antioxidant activity, and α‐glucosidase inhibitability of Bx blakeana leaf and flower from Vietnam. Qualitative phytochemical analysis showed positive results for carbohydrates, organic acids, carotenoids, steroids, cardiac glycosides, triterpenoids, saponins, flavonoids, and tannins. The TPC and TFC obtained from Bx blakeana leaf were 99.81 ± 0.94 (mg GAE/g E) and 114.93 ± 1.06 (mg RE/g E), respectively, whereas they were 40.45 ± 0.50 (mg GAE/g E) and 59.61 ± 0.85 (mg RE/g E) from Bx blakeana flower. The DPPH radical scavenging capacity assay of the crude ethanolic extracts of Bx blakeana leaf (IC50 = 266.52 ± 1.03 μg/mL; R2 = 0.9864) and flower (IC50 > 1000 μg/mL) was determined. The leaf and flower extracts showed significant αglucosidase inhibitory activity with IC50 values of 61.88 ± 0.19 μg/mL (R2 = 0.9838), 190.79 ± 0.18 μg/mL (R2 = 0.9891), respectively. These results indicated that the extract of Bx blakeana leaf and flower can be a promising candidate for alternative drug or functional food discovery, and nutritional recommendations for the control of oxidative stress and diabetes.