Cyclooxygenase inhibiting and anti-bacterial activities of South African Erythrina species

Aqueous, ethanolic and ethyl acetate extracts of the bark and leaves of fiv e South African Erythrina species Erythrina caffra, Erythrina humeana, Eryt hrina latissima, Erythrina lysistemon and Erythrina zeyheri were screened f or prostaglandin synthesis-inhibitory and anti-bacterial activity. The bark generally displayed higher activity than the leaves in both bioassays. The highest cyclooxygenase inhibiting activity and anti-bacterial activity was recorded for the ethanol and ethyl acetate bark extracts of E. caffra, E. latissima and E. lysistemon. An anti-bacterial compound, 4',5,7-trihydroxy- 6-prenylisoflavone, was isolated by bioassay-guided fractionation from bark of E. lysistemon. (C) 2001 Elsevier Science Ireland Ltd. All rights reserv ed.