Inhibition of neurogenic inflammation by the amazonian herbal medicine Sangre de grado

This study was designed to determine if the Amazonian medicinal sangre de g rado, confers benefit by suppressing the activation of sensory afferent ner ves. Methods: (i) vasorelaxation of rat mesenteric arteries in response to calcitonin gene-related peptide; (ii) rat paw edema in response to protease -activating peptide receptor 2-activating peptide; (iii) rat paw hyperalges ia in response to low-dose protease-activating peptide receptor 2-activatin g peptide or prostaglandin E-2; (iv) gastric hyperemia in response luminal. capsaicin; (v) a clinical trial of a sangre de grado balm in pest control workers. The parent botanical was fractionated for evaluation of potential active components. In preconstricted rat mesenteric arteries, highly dilute d sangre de grado (1:10,000) caused a shift to the right of the calcitonin gene-related peptide dose-response curve (p<0.01). Paw edema in response to protease-activating peptide receptor 2-activating peptide (500 <mu>g) was reduced by as single topical administration sangre de grado balm (1% concen tration, p<0.01) for at least 6 h. Hyperalgesia induced by either low-dose protease-activating peptide receptor 2-activating peptide (50 <mu>g) or pro staglandin E-2 was prevented by sangre de grado balm. A fraction possessing analgesic and capsaicin antagonistic properties was isolated and high-perf ormance liquid chromatography and gas chromatography mass spectrometry anal ysis indicated that it was a proanthocyandin oligomer. In pest control work ers, sangre de grado balm (Zangrado) was preferred over placebo, for the re lief of itching, pain, discomfort, edema, and redness in response to wasps, fire ants, mosquitoes, bees, cuts, abrasions, and plant reactions. Subject s reported relief within minutes. We conclude that sangre de grado is a pot ent inhibitor of sensory afferent nerve mechanisms and supports its ethnome dical use for disorders characterized by neurogenic inflammation.