α-amylase and α-glucosidase antidiabetic potential of ten essential oils from Calophyllum inophyllum Linn

Diabetes mellitus (DM) is a multifactorial metabolic disorder which is of public health concern. Therapeutic intervention using reliable, affordable and non-toxic natural sources is crucial. Aim of the study: This research was designed to evaluate the α-amylase and α-glucosidase inhibitory activities of ten essential oils from Calophyllum inophyllum Linn. The study is part of our local sourcing for natural promising leads to ameliorating diabetes mellitus globally. Materials and methods: Essential oils from ten parts of C. inophyllum Linn were extracted by hydro-distillation using all-glass Clevenger-type apparatus. The percentage yields (w/v) were between 0.219 and 0.506 %. A plot of percentage inhibition versus concentration (mg/mL) of essential oils gave the IC50 values for each essential oil using non-linear regression analysis in reference to acarbose a standard anti-diabetic drug. Results: The following IC50 values (mg/mL) were obtained in the determination of α-amylase inhibition: [(Leaf, 0.043±0.05); (Leaf-stalk, 0.044±0.02); (Flower, 0.045±0.05); (Seed, 0.042±0.03); (Pod, 0.040±0.05); (Peel, 0.047±0.09); (Stem wood, 0.047±0.02); (Stem bark, 0.049±0.05); (Root wood, 0.048±0.05) and (Root bark, 0.046±0.04)] compared to acarbose (0.034±0.02). While α-glucosidase assay gave the following IC50 values (mg/mL): [(Leaf, 0.044±0.02); (Leaf-stalk, 0.043±0.03); (Flower, 0.044±0.04); (Seed, 0.048±0.02); (Pod, 0.038±0.04); (Peel, 0.048±0.03); (Stem wood, 0.048±0.04); (Stem bark, 0.048±0.02); (Root wood, 0.047±0.04) and (Root bark, 0.045±0.04)] with reference to acarbose (0.032±0.04). The high α-amylase and α-glucosidase inhibitory activity of pod essential oil in comparison with the reference drug must be due to the presence of some impact bioactive phyto-contituents in it. Conclusion: C. inophyllum Linn has been considered a fundamental source of potent anti-diabetic drugs which could be useful in the management of postprandial hyperglycemia.