Evaluation for antidiabetic activity in selected medicinal plants used in Malaysian traditional medicine for the treatment of diabetes

Aqueous extracts of three medicinal plants used in Malaysian traditional medicine for the treatment of diabetes were investigated. The nuts of Areca cathecu, leaves of Lagerstroemia speciosa and Ficus deltoidea were each extracted by boiling in distilled water. The aqueous extracts were filtered and the filtrates were then spray dried. Their biological evaluation was conducted to determine their blood glucose lowering effect in normoglycaemic and alloxan-induced diabetic rats. Commercially available antidiabetic drug, glybenclamide was used as positive control. Toxicity of the extracts was carried out using the brine shrimp lethality assay and in vivo acute toxicity test in rats. Aqueous extracts of all the plants studied showed significant reduction in blood glucose level up to 50% in rats over a period of 3 to 4 weeks. The largest reduction in blood glucose levels was exhibited by the aqueous extracts of the Lagestroemia speciosa, followed by the Ficus deltoidea and Areca cathecu. There was no evidence of toxicity of the extracts against the brine shrimp (up to 4,000 μg/ml) and in rats (up to 0.2% body weight). (Author)