Characterization of Daboia russelii and Naja naja venom neutralizing ability of an undocumented indigenous medication in Sri Lanka

BACKGROUND: Indigenous medicinal practice in Sri Lanka talks about powerful compounds extracted from native plants for treating venomous snake bites which are hardly documented in literature but are used by the indigenous doctors for thousand years. OBJECTIVE: We screened the neutralizing ability of a herbal preparation practiced in indigenous medicine of Sri Lanka, consisting of Sansevieria cylindrica, Jatropha podagrica and Citrus aurantiifolia, for its ability to neutralize venom toxins of Naja naja (Common Cobra) and Daboia russelii (Russell's viper). MATERIALS AND METHODS: The venom toxicity was evaluated using a 5-day old chicken embryo model observing the pathophysiology and the mortality for six hours, in the presence or absence of the herbal preparation. The known toxin families to exist in snake venom, such as Phospholipase A(2), Snake venom Metalloprotease, were evaluated to understand the mechanism of venom neutralizing ability of the herbal preparation. RESULTS: The LD(50) of D. russelii venom, as measured using the 5-day old chicken embryo model, was 4.8 ± 0.865 ug (R(2) = 84.8%, P = 0.079). The pre-incubation of venom with the herbal preparation increased the LD(50) of D. russelii venom to 17.64 ± 1.35 μg (R(2) = 81.0%, P = 0.100), showing a clear neutralizing action of D. russelii venom toxicity by the herbal medicine. Whereas the pre-incubation of venom with the 1× venom neutralizing dose of commercially available polyvalent anti-venom serum shifted the LD(50) venom only up to 5.5 ± 1.35 μg (R(2) = 98.8%, P = 0.069). In the presence of the herbal preparation, Phospholipase A(2) activity of D. russelii venom was significantly reduced from 9.2 × 10(−3) mM min(−1) to 8.0 × 10(−3) mM min(−1) and that of N. naja from 2.92 × 10(−2) mM min(−1) to 0.188 × 10(−2) mM min(−1). Further, the pre-incubation of N. naja venom with the herbal preparation significantly reduced its Metalloprotease activity from 0.069 units min(−1) to 0.019 units min(−1). CONCLUSION: The herbal preparation shows a clear neutralizing action against the toxicities of D. russelii and N. naja venoms demonstrating the potential to be used as a plant based antidote for snake envenomation.