Evaluation of Betulin Mutagenicity by Salmonella/Microsome Test

Purpose: Betulin is a pentacyclic triterpene found in the outer barks of innumerous plants. This secondary metabolite is easily isolated from plants with the major interest in converting it to betulinic acid, which pharmacological properties were much more exploited than betulin. But, investments in the own betulin have been grown since no chemical step is necessary. In this study we focused the precursor betulin in order to evaluate its mutagenicity by Salmonella/microsome assay (Ames test). Methods: The Ames test was carried out using a commercial betulin exposed to Salmonella typhimurium strains TA98, TA100, TA102, and TA97a, in experiments with (+S9) and without (-S9) metabolic activation. Results: Betulin was unable to increase the number of revertants (+S9 and -S9 metabolic activation) showing the absence of any mutagenic effect by Ames test.Conclusion: This study allowed attribute safety to betulin being important for exploiting its pharmacological uses

Effects of Vochysia haenkeana extract on the neuromuscular blockade induced by Bothrops jararaca venom on chick biventer cervicis preparation in vitro

Vochysia haenkeana extract (Vh-E) was assessed against the neuromuscular blockade induced by Bothrops jararaca venom on chick biventer cervicis (BC) preparation. Pre- and post-venom incubation treatments (Pre-vit and Post-vit) were analysed here. Contractures ACh (110 µM) and KCl (20 mM) were evoked before and after addition of venom without stimulation. Vh-E (600 µg/mL) under Pre-vit was more efficient to neutralize the neuromuscular blockade by venom (40 µg/mL) [72.5±4.6% (venom) vs. 45.2±14% (Vh-E) of blockade, p<0.05, n=4]. Vh-E (600 µg/mL) did not cause significant changes under Post-vit [72.5±4.6% (venom) vs. 63.4±8.2% (Vh-E) of blockade, n=4]. The Pre-vit inhibited the blockade of the contracture to ACh (106±17% of response; n=4) while the Post-vit was able to attenuate the effect of the venom on this contracture (55±5% of response; n=4); related to those contractures to KCl both of treatments with Vh-E attenuated the blocker effect of the venom (62.5±7.7% and 55±5% of response for Pre-vit and Post-vit, respectively; n=4). In conclusion, Vh-E neutralizes partially the neuromuscular blockade in Pre-vit, an effect that can be related to preserved function of “extrinsic” post-synaptic receptors, by measured contractures in response to ACh. The myotoxicity of the venom was significantly reduced by Vh-E in both, Pre-vit and Post-vit, by measured contractures in response to KCl

Neutralising ability of <i>Terminalia fagifolia</i> extract (Combretaceae) against the <i>in vitro</i> neuromuscular effects of <i>Bothrops jararacussu</i> venom

<p>The ability of <i>Terminalia fagifolia</i> hydroalcoholic extract (<i>Tf</i>-HE) to neutralise the paralysis and myotoxicity induced by <i>Bothrops jararacussu</i> venom was assayed using mouse phrenic nerve-diaphragm (PND) preparation and two varieties of chick biventer cervicis (BC) preparations. <i>Tf</i>-HE 100 μg/mL and 500 μg/mL were tested against 40 and 200 μg of venom/mL in PND and BC preparations, respectively, using pre- and post-venom incubation treatments. The effects of <i>Tf</i>-HE against the myotoxicity caused by venom were evaluated via histological analysis (PND) and creatine kinase (CK) release (BC). <i>Tf</i>-HE was able to reverse the venom paralysis in both preparation types. The contractures to exogenous ACh in BC preparations showed that <i>Tf</i>-HE may act on extrinsic, preserving those intrinsic postsynaptic receptors. There was a positive correlation between CK and morphological changes. The high non-hemolytic saponin content can explain the <i>Tf</i>-HE efficacy against the toxic effects of <i>B. jararacussu</i> venom in vertebrate neuromuscular preparations.</p

New pharmacological insights of <i>Galactia glaucescens</i>

<p><i>Galactia glaucescens</i> leaves are popularly used against snakebites in Brazil. The hydroethanolic extract from aerial parts of <i>G. glaucescens</i> (HEGg) was assayed against the neurotoxicity and myotoxicity induced by <i>Bothrops jararacussu</i> venom. A traditional myographic technique was applied for neurotoxicity and the resulting muscles were treated routinely by light microscopy analysis for myotoxicity. Additionally, the antimicrobial potential of HEGg was evaluated against <i>Staphylococcus aureus</i>, <i>Escherichia coli</i> and <i>Pseudomonas aeruginosa</i> strains, as well as Rutin was isolated for the first time in this specie using chromatographic and spectroscopic methods and its antiophidian property was assessed. HEGg totally prevents the neurotoxicity and myotoxicity effects caused by <i>B. jararacussu</i>, but did not show any antimicrobial effect. Concluding, HEGg and Rutin were able to counteract the toxic effects of the venom and confirmed the antiophidian potential, but not antimicrobial, of <i>G. glaucescens</i> as an alternative for neutralization of <i>B. jararacussu</i> venom.</p