Demonstration of anti-bradykinin compounds in callus cultures of Mandevilla velutina

Calluses from stems and leaves of Mandevilla velutina were grown in culture for 30,45 and 60 days. Thin-layer chromatography of ethyl acetate extracts of calluses from stems of M. velutina revealed the presence of 6 compounds. Two of them had RF values identical to those of the anti-bradykinin (BK) compounds MV8609 and MV8610 previously isolated from the natural plant. The ethyl acetate extract (20 to 80 microng/ml) from stem callus culture antagonized in a concentration-dependent and reversible manner contractions caused by BK (0.1-100 nM) in the isolated rat uterus. The extracts obtained from calluses cultured for 30,45 and 60 days were about 79-, 63-and 31-fold more potent, respectively, in antagonizing BK than the crude extract obtained from the rhizome of the plant

Blockade of the bradykinin-evoked diphasic response of isolated rat duodenum by the crude extract of and compounds obtained from Mandevilla velutina

The influence of an aqueous/ethanolic extract of M. velutina (CE) and of two compound (MV 8608 and MV 8612) purified from the plant on BK-, Ad- and K+ -induced responses of the rat duodenum was analyzed in vitro. In preparations precontracted with Ca2+, the CE (1 and 2 mg/ml) markedly inhibited BK -induced relaxation in a dose-dependent manner but was less effective against Ad-induced relaxation. The CE (0.5 mg/ml) also antagonized BK -induced relaxation and contraction of strips bathed in normal medium. The two compounds from M. velutina (10 and 20 microng/ml) also promoted a dose-dependent blockade of both responses to BK, only slightly depressing the response to K+