The antioxidant activities and inhibitory effects on α-glucosidase and α-Amylase of ethanolic and aqueous extracts from various parts of Thai Caesalpinia sappan L.

Abstract

Caesalpinia sappan (CS) has been commonly used in beverage and folk medicine in China and ASEAN countries because of its various therapeutic properties. Only the heartwood has long been used in traditional medicines due to the presence of high concentration of brazilin (one of the most important bioactive compounds), whereas the other parts are limited in use. Thus, this work aimed to investigate ways of utilizing other parts of CS. This information is important for further use of other CS parts to promote zero waste and hence sustainable resource utilization. Herein, the crude ethanolic (CEE) and crude aqueous (CAE) extracts from twelve parts of CS were evaluated for their biological activities for the first time. Our work demonstrates that not only the heartwood, but also other parts of CS exhibit interesting biological activities. CAE from heartwood of branches exhibits the highest antioxidant activity, which is higher than that of the positive control, butylated hydroxytoluene. CEE from florets shows the highest inhibitory effect against α-Amylase, while CAE of barks shows better α-glucosidase inhibitory activity than the existing glucosidase inhibitor (acarbose). Molecular docking of brazilin (key bioactive compound) to both α-Amylase and glucosidase can also confirm the tight binding of brazilin to α-glucosidase.