Neutralization of the neuromuscular activity of bothropstoxin-i, a myotoxin from Bothrops jararacussu snake venom, by a hydroalcoholic extract of Casearia sylvestris Sw. (guaçatonga)

Y Oshima-Franco,A C O Cintra,G B Leite,C M V Alves,N Andréo Filho,L Rodrigues-Simioni,M G Silva,M Gerenutti

doi:10.1590/s1678-91992005000400007

Y Oshima-Franco, A C O Cintra + Show 6 more

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https://doi.org/10.1590/s1678-91992005000400007

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Abstract

Numerous plants are used as snakebite antidotes in Brazilian folk medicine, including Casearia sylvestris Swartz, popularly known as guaçatonga. In this study, we examined the action of a hydroalcoholic extract from C. sylvestris on the neuromuscular blockade caused by bothropstoxin-I (BthTX-I), a myotoxin from Bothrops jararacussu venom, in mouse isolated phrenic nerve-diaphragm (PND) preparations. Aqueous (8 and 12 mg/ml, n=4 and 5, respectively) and hydroalcoholic (12 mg/ml, n=12) extracts of the leaves of C. sylvestris caused facilitation in PND preparations followed by partial neuromuscular blockade. BthTX-I (20 µg/ml, n=4) caused 50% paralysis after 65±15 min (mean ± S.E.M). Preincubation (30 min at 37° C) of BthTX-I (20 µg/ml, n=4) with a concentration of the hydroalcoholic extract (4 mg/ml) that had no neuromuscular activity, such as the control (n=5), prevented the neuromuscular blockade caused by the toxin. This protection may be mediated by compounds such as flavonoids and phenols identified by thin-layer chromatography and colorimetric assays.

Highlights

The standard treatment for snakebites in humans is the administration of antivenom [5]
We examined the action of a hydroalcoholic extract from C. sylvestris on the neuromuscular blockade caused by bothropstoxin-I (BthTX-I), a myotoxin from Bothrops jararacussu venom, in mouse isolated phrenic nerve-diaphragm (PND) preparations
We examined the neuromuscular activity of aqueous and hydroalcoholic extracts of C. sylvestris, and assessed the activity of the hydroalcoholic extract to neutralize the neuromuscular blockade caused by BthTX-I, a myotoxin from Bothrops jararacussu venom, that causes muscle damage [12, 24] and blockade of directly and indirectly evoked contractions in mouse phrenic nerve-diaphragm preparations [11]

Summary

Introduction

The standard treatment for snakebites in humans is the administration of antivenom [5]. In Trinidad, the standard treatment for snakebites and scorpion stings in dogs involves the use of steroids, antibiotics, and the enzyme ananase (from the pineapple Ananas comosus). This enzyme, the administration of which must occur within 2 hours of the bite [15], reduces the inflammatory response and helps to degrade necrotic tissue. (Flacourtiaceae), popularly known as guaçatonga, grows wild throughout the tropics, where it adapts to forests and plains [28] This plant is widely used in folk medicine as an antiseptic, wound healer, topical anesthetic, and antitumor, anti-ulcer and anti-snakebite agent [1, 2, 3, 14]. We examined the neuromuscular activity of aqueous and hydroalcoholic extracts of C. sylvestris, and assessed the activity of the hydroalcoholic extract to neutralize the neuromuscular blockade caused by BthTX-I, a myotoxin from Bothrops jararacussu venom, that causes muscle damage [12, 24] and blockade of directly and indirectly evoked contractions in mouse phrenic nerve-diaphragm preparations [11]

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