Diterpenoids from the roots of Croton macrostachys.

Three novel diterpenoids have been isolated from the roots of Croton macrostachys. The structure and stereochemistry of the compounds have been unambiguously settled as neoclerodan-5,10-en-19,6beta;20,12-diolide, 3alpha, 19-dihydroxytrachylobane, and 3alpha,18,19-trihydroxytrachylobane from detailed spectroscopic evidence.

Some pharmacological properties of an aqueous extract of securinega virosa roots.

An aqueous extract of Securinega virosa is used by traditional healers in Tanga (northeastern Tanzania) as an aphrodisiac and in the treatment of impotence, which is one of the manifestations of diabetes mellitus. An aqueous extract of the roots at doses of 0.1,0.2, 0.4 and 1.0 g/kg body weight lowered the area under the oral glucose tolerance curve (OGTT) in normal albino rabbits by 0.3 (P >0.05), 7.85, 11.0 and 9.6% (P =0.05), respectively. Chlorpropamide (0.1 g/kg body weight) had a greater effect on blood glucose and lowered area under the OGTT curve by 16.3%. The extract, at a dose of 0.4 g/kg body weight, had no effect on fasting blood glucose (FBG) when compared to controls given distilled water (P >0.05), except at 4 h, when the FBG for treated animals was higher. The LD 50 (95% confidence interval) determined by intraperitoneal administration of the extract to white albino mice was 0.30 (0.20-0.50) g/kg body weight. We conclude that the aqueous extract of Securinega virosa roots lowered the area under the OGTT curve dose-dependently at doses between 0.1 and 1.0 g/kg body weight. It did not lower blood glucose below fasting levels both in the fed and fasted state. More work is required to determine the toxic characteristics of the extract and the utility of the observed activity in the management of diabetes mellitus in humans.

Facilitation of retinal function recovery by coumarin derivatives.

Ischemic retinopathy is a difficult disease to treat, although numerous drugs have been tried in the clinics. Coumarin was one of those tried as an anti-coagulant with a marginal efficacy. In this study, 15 coumarin derivatives were studied on the b-wave recovery in electroretinogram which is an indicator of the functional recovery of retina after ischemic insult. It was found that when positions 6, 7 and 8 were occupied by various functional groups, the b-wave recovery could be markedly enhanced. On the other hand, single occupation of position 3 with any functional group would cause damaging effects to the anti-ischemic activity. It is concluded that some coumarin derivatives with two or all of these positions at 6, 7 and 8 occupied by certain functional groups could result in useful drugs for the treatment of ischemic retinopathy.