Alpha-glucosidase inhibitory and antiplasmodial properties of terpenoids from the leaves of Buddleja saligna Willd.

In our continuing search for biologically active natural product(s) of plant origin,Buddleja saligna, a South African medicinal plant, was screened in line with its traditional use for antidiabetic (yeast alpha glucosidase inhibitory) and antiplasmodial (against a chloroquine sensitive strain ofPlasmodium falciparum(NF54)) activities. The hexane fraction showed the most promising activity with regards to its antidiabetic (IC50 = 260 ± 0.112 µg/ml) and antiplasmodial (IC50 = 8.5 ± 1.6 µg/ml) activities. Using activity guided fractionation three known terpenoids (betulonic acid, betulone and spinasterol) were isolated from this species for the first time. The compounds displayed varying levels of biological activities (antidiabetic: 27.31 µg/ml ≥ IC50 ≥ 5.6 µg/ml; antiplasmodial: 14 µg/ml ≥ IC50 ≥ 2 µg/ml) with very minimal toxicity. [ABSTRACT FROM AUTHOR]