Detection and isolation of intestinal muscle relaxant substances from the root of Taverniera abyssinica A. Rich.

ETHNOPHARMACOLOGICAL RELEVANCE: In Ethiopian traditional medicine the root of Taverniera abyssinica A.Rich is known as a remedy for sudden gastrointestinal cramping and fever. In this study we have isolated and identified the bioactive principle of Taverniera abyssinica that exerts effects on isolated smooth muscle tissues of the rabbit duodenum and guinea-pig ileum. AIM OF THE STUDY: To isolate and purify the bioactive principle from the root of Taverniera abyssinica A.Rich by bioassay-guided fractionation, HPLC purification and masspectrometry, with further investigation of its bioactivity on isolated smooth muscle strips. MATERIALS AND METHODS: Roots of Taverniera abyssinica A.Rich extracted in 75% methanol/water were fractioned with a reverse phase column and then subjected to HPLC purification. Each fraction collected from the HPLC was tested for its bioactivity using electric field stimulation-evoked contractions of the rabbit duodenum and guinea-pig ileum. Finally, detailed structural analysis of the fraction displaying significant bioactivity was made by mass spectrometry. RESULTS: Through bioassay-guided fractionation and HPLC purification the bioactive fractions were identified. These were tested for bioactivity on isolated smooth muscle strips which showed about 80% inhibition of contractions evoked by electric field stimulation. These compounds were identified as formononetin, afrormosin and tectorigenin by using masspectrometry applying relevant standards for detection. CONCLUSION: The traditionally claimed smooth muscle-relaxing effect of the roots of Taverniera abyssinica A.Rich is essentially due the three isolated and purified the two isoflavones formononetin, afrormosin as well as the metoxyisoflavone tectorigenin, along with possibly other not yet purified bioactive substances, however with similar smooth muscle-relaxing properties.

Increased expired NO and roles of CO2 and endogenous NO after venous gas embolism in rabbits.

Venous gas embolism (VGE) is a feared complication in diving, aviation, surgery and trauma. We hypothesized that air emboli in the lung circulation might change expired nitric oxide (FeNO). A single intravenous infusion of air was given (100 mul kg(-1)) to three groups of anaesthetized mechanically ventilated rabbits: (A) one with intact NO production, (B) one with intact NO production and where end-tidal CO(2) was controlled, and (C) one with endogenous NO synthesis blockade (L: -NAME, 30 mg kg(-1)). Air infusions resulted in increased FeNO of the control group from 20 (4) [mean (SD)] ppb to a peak value of 39 (4) ppb within 5 min (P < 0.05), and FeNO was still significantly elevated [27 (2) ppb] after 20 min (P < 0.05). Parallel to the NO increase there were significant decreases in end-tidal CO(2 )(ETCO(2)) and mean arterial pressure and an increase in insufflation pressure. In group B, when CO(2) was supplemented after air infusion, NO was suppressed (P = 0.033), but was still significantly elevated compared with pre-infusion control (P < 0.05). In group C, all animals died within 40 min of air infusion whereas all animals in the other groups were still alive at this time point. We conclude that venous air embolization increases FeNO, and that a part of this effect is due to the concomitant decrease in ETCO(2). Furthermore, an intact NO production may be critical for the tolerance to VGE. Finally, FeNO might have a potential in the diagnosis and monitoring of pulmonary gas embolism.