Agnes B. Alimboyoguen

Hypoglycaemic effects of tea extracts and ent-kaurenoic acid from Smallanthus sonchifolius

Hypoglycaemic activity was observed in normoglycaemic mice orally administered with the aqueous Smallanthus sonchifolius leaf tea extract, alloxan-induced diabetic mice orally administered with ent-kaurenoic acid (1), and normoglycaemic mice intraperitoneally administered with 1 from S. sonchifolius leaves. A single dose administration of 50 mg kg−1 BW yacon leaf tea extract demonstrated immediate but relatively short hypoglycaemic activity, with significant effects observed during 1–2 h. Similarly, administration with 100 mg kg−1 BW yacon leaf tea extract obtained by heavy stirring in hot water demonstrated a more potent activity compared to the positive control at 1.5–2.0 h. Oral administration of 1 did not affect the blood glucose level of the alloxan-induced diabetic mice, but a single intraperitonial injection of 10 mg kg−1 BW in normoglycaemic mice had consistent percent blood glucose reduction persisting from 1 to 2 h observation periods.

Angio-Suppressive Effect of Sterols from Ardisia Pyramidalis (Cav.) Pers.

Spinasterol (1) and spinasteryl acetate (2) from the leaves of Ardisia pyramidalis (Cav.) Pers. (Myrsinaceae) were tested on duck chorioallantoic membrane (CAM) vascularity assay. The petechial to severe hemorrhaging, hyperemia, and the formation of ghost vessels were observed in CAMs treated with compounds 1 and 2. Both sterols have effectively suppressed blood vessel branching and inter-capillary elongation. High degree of vonWillebrand factor expression was observed in these CAMs treated with 1 and 2. This is further confirmed by the absence of the epithelial membrane antigen in all samples tested, suggesting that the main mechanism of angio-suppression is related to the action of von Willebrand factor which modulates other angiogenic factors. Spinasterol was found to be most effective in reducing the branch point formation and inter capillary distance with very minimal incidence of mortality, thus suggesting its potential as a source of phytopharmaceuticals.