Comparative anti-hyperglycemic potentials of medicinal plants.

Validation of the ethnobotanical use of the leaves of Artemisia vulgaris Linn. (Compositae), Eucalyptus tereticornis Sm. (Myrtaceae), Solanum nigrum Linn. (Solanaceae), and Vitex negundo Linn. (Verbenaceae); stems of Nopalea cochinellifera (Linn.) Salm-Dyck (Cactaceae); roots of Imperata cylindrica Beauv. (Gramineae); dried bark of Syzygium cumini (Linn.) Skeels (Myrtaceae) as anti-diabetic agents using the oral glucose tolerance test showed that only the bark of Syzygium cumini and the leaves of Vitex negundo and Eucalyptus tereticornis exhibited anti-hyperglycemic activities when fed simultaneously with glucose. At the same dosages of 5 mg/20 g mouse, Syzygium cumini-treated mice showed a significant decrease in blood glucose levels (BGLs) at 30 min (alpha=0.10) and from 45 min onwards at alpha=0.05. Vitex negundo exhibited greater anti-hyperglycemic activity than Eucalyptus tereticornis. Both showed a significant decrease in BGLs at 60 min but at alpha=0.05 for Vitex negundo and at alpha=0.07 for Eucalyptus tereticornis. There was no significant lowering in BGLs for Imperata cylindrica and Solanum nigrum while there was even an increase in BGLs for Nopalea cochinellifera and Artemisia vulgaris.