The leaves of Bauhinia holophylla, also known as "pata-de-vaca", have been traditionally used in Brazil to treat diabetes.[1] While the hypoglycemic activity of the extract is known, the active compounds are not yet identified. To this end, the active hydroalcoholic extract was fractionated by medium pressure liquid chromatography bioguided by an in vivo glucose tolerance test in diabetic mice.[2] This led to the identification of three non-cyanogenic cyanoglucoside derivatives (1-3) and a series of glycosylated flavonoids (5-11). One of the main leaves constituent, lithospermoside (3), exhibited strong hypoglycemic activity. NMR quantitation revealed that the hydroalcoholic extract contains 1.4% of lithospermoside and 3.4% of flavonoids. Surprisingly this NMR profiling also showed the presence of a high amount of pinitol (4) (12.5%), a cyclic polyol known to possess in vivo hypoglycemic activities. The glucose-lowering properties of the hydroalcoholic and traditional water infusion extracts of leaves of B. holophylla seems thus interestingly be the results of the cumulative/synergetic in vivo activities of three classes of unrelated compounds: glycosylated flavonoids (5-11), pinitol (4) and lithospermoside (3). These results support to some extent the traditional use of Bauhinia holophylla to treat diabetes.
References:
[1]. Oliveira F, Saito ML,. Braz J Pharmacog 1989; 2:170-196.
[2]. Andrikopoulos S, Blair AR, Deluca N, Fam BC, Proietto J. Am J Physiol-Endoc Med 2008; 295: E1323-E1332.