Abstract:
Decoctions prepared from the bark of Gmelina arborea have been employed in Sri Lankan traditional medicine as a remedy against diabetes mellitus. Encapsulation of bioactive secondary metabolites of G. arborea could enhance their therapeutic potential and provide controlled release. Amongst the different matrices available as options to encapsulate bioactive compounds, chitosan based nanoformulations have received favourable attention due to their advantageous biological properties such as biodegradability, biocompatibility and nontoxicity. Dried powdered stem-bark G. arborea (30 g) was separately extracted using deionized water, acetone, ethyl acetate, dichloromethane (400 mL each) under ultrasonication (40 kHz, 37 ⁰C, 30 min). The α-amylase inhibitory assay was conducted on each dried extract dissolved in buffer or DMSO, in triplicate. The total phenol content (TPC) and flavonoid content (TFC) were determined according to Folin Ciocalteu and aluminium chloride methods, respectively. The aqueous extract which showed the highest α-amylase inhibitory activity (IC50 0.19±0.04 mg/mL), TPC (12.97±0.12 mgGAE/g) and TFC (1.58±0.02 mgGAE/g) was subjected to nanoencapsulation.
