The inhibitory potential of the condensed-tannin-rich fraction of Plathymenia reticulata Benth. (Fabaceae) against Bothrops atrox envenomation

• Published in: Journal of ethnopharmacology 2016-05, Vol.183 (NA), p.136-142
• Main Authors: de Moura, Valéria Mourão, da Silva, Wania Cristina Rodrigues, Raposo, Juliana D.A., Freitas-de-Sousa, Luciana A., Dos-Santos, Maria Cristina, de Oliveira, Ricardo Bezerra, Veras Mourão, Rosa Helena
• Format: Article
• Language: English
• Subjects: Animals; Anti-snakebite plants; Antivenins - chemistry; Antivenins - pharmacology; Bothrops; Brazil; Condensed tannins; Crotalid Venoms - antagonists & inhibitors; Edema - drug therapy; Edema - metabolism; Fabaceae; Fabaceae - chemistry; Hemorrhage - drug therapy; Hemorrhage - metabolism; Phospholipases - metabolism; Plant Extracts - chemistry; Plant Extracts - pharmacology; Plathymenia; Plathymenia reticulate; Proanthocyanidins - chemistry; Proanthocyanidins - pharmacology; Snake Bites - drug therapy; Snakebite envenomation
• ISSN: 0378-8741; 1872-7573
• DOI: 10.1016/j.jep.2016.02.047

Ethnobotanical studies have shown that Plathymenia reticulata Benth. (Fabaceae) has been widely used in cases of snake envenomation, particularly in Northern Brazil. In light of this, the aim of this study was to evaluate the inhibitory potential of the condensed-tannin-rich fraction obtained from the bark of P. reticulata against the main biological activities induced by Bothrops atrox venom (BaV). The chemical composition of the aqueous extract of P. reticulata (AEPr) was first investigated by thin-layer chromatography (TLC) and the extract was then fractionated by column chromatography on Sephadex LH-20. This yielded five main fractions (Pr1, Pr2, Pr3, Pr4 and Pr5), which were analyzed by colorimetry to determine their concentrations of total phenolics, total tannins and condensed tannins and to assess their potential for blocking the phospholipase activity of BaV. The Pr5 fraction was defined as the fraction rich in condensed tannins (CTPr), and its inhibitory potential against the activities of the venom was evaluated. CTPr was evaluated in different in vivo and in vitro experimental protocols. The in vivo protocols consisted of (1) pre-incubation (venom:CTPr, w/w), (2) pre-treatment (orally administered) and (3) post-treatment (orally administered) to evaluate the effect on the hemorrhagic and edematogenic activities of BaV; in the in vitro protocol the effect on phospholipase and coagulant activity using pre-incubation in both tests was evaluated. There was statistically significant inhibition (p