Comparative study of the antidiabetic potential of twig extracts and compounds from two different locations in Malaysia.

L. (Rubiaceae) is an edible plant distributed in Asian countries including Malaysia. Fresh leaves have been traditionally used as a remedy for indigestion and diarrhea. Several phytochemical studies of the leaves have been documented, but there are few reports on twigs. This study investigates the enzyme inhibition of twig extracts and compound isolated from them. In addition, molecular docking of scopoletin was investigated. Plants were obtained from two locations in Malaysia, Johor (PFJ) and Pahang (PFP). Hexane, chloroform and methanol extracts along with isolated compound (scopoletin) were evaluated for their enzyme inhibition activities (10,000-0.000016 µg/mL). The separation and identification of bio-active compounds were carried out using column chromatography and spectroscopic techniques, respectively. molecular docking of scopoletin with receptors (α-amylase and α-glucosidase) was carried out using AutoDock 4.2. The IC values of α-amylase and α-glucosidase inhibition activity of PFJ chloroform extract were 9.60 and 245.6 µg/mL, respectively. PFP chloroform extract exhibited α-amylase and α-glucosidase inhibition activity (IC = 14.83 and 257.2 µg/mL, respectively). The α-amylase and α-glucosidase inhibitory activity of scopoletin from both locations had IC values of 0.052 and 0.057 µM, respectively. Separation of PFJ chloroform extract afforded scopoletin (), stigmasterol () and γ-sitosterol () and the PFP chloroform extract yielded (), (), () and ergost-5-en-3-ol (). Scopoletin was isolated from this species for the first time. calculations gave a binding energy between scopoletin and α-amylase of -6.03 kcal/mol.