The red seaweed Plocamium brasilienseshows anti-snake venom toxic effects

Abstract

Background: Snakebite is considered a neglected tropical disease by the World Health Organization. In Brazil, about 70% of the envenomation cases are caused byBothropssnakes. Its venom may provoke hemorrhage, pain, necrosis, hemolysis, renal or cardiac failure and even death in victims. Since commercial antivenom does not efficiently neutralize the local toxic effects of venoms, natural products have been tested in order to provide alternative or complementary treatment to serum therapy. Therefore, the present study aimed to evaluate the ability of the seaweedPlocamium brasilienseand its active derivatives to neutralize hemorrhagic, edematogenic, hemolytic, coagulant and proteolytic activities ofB. jararacavenom.Methods: Specimens ofP. brasiliensewere collected in Rio de Janeiro state, Brazil, dried and submitted to oil extraction using four solvents of increasing polarities, n-hexane (HEX), dichloromethane (DCM), ethyl acetate (ETA) and hydroalcoholic solution (HYD). The solvents were evaporated, yielding HEX, DCM, ETA and HYD extracts. Further, all extracts were dissolved in dimethylsulfoxide. In addition, two monoterpenes (8-bromo-3,4,7-trichloro-3,7-dimethyl-1E, 5E-octadiene and 1,8-dibromo-3,4,7-trichloro-3,7-dimethyl-1E, 5E-octadiene) and a cholesterol fraction were isolated from the extract ofP. brasilienseprepared in hexane. Algal samples were incubated for 30 minutes withB. jararacavenom, and then tested for lethality; hemorrhagic, edematogenic, hemolytic, coagulant and proteolytic effects.Results: Most of the algal extracts inhibited the toxic effects with different potencies. The DCM extract was the most effective, since it inhibited all types of toxic activity. On the other hand, the HYD extract failed to inhibit any effect. Moreover, the isolated products inhibited proteolysis and protected mice from hemorrhage in 30% of the cases, whereas 8-bromo-3,4,7-trichloro-3,7-dimethyl-1E, 5E-octadiene inhibited 100% and 20% of the hemorrhagic and proteolytic activities, respectively. None of the algal products were toxic to mice.Conclusion: Seaweeds may be a promising source of inhibitors against toxic effects caused byB. jararacaenvenomation, which may contribute to antivenom treatment.