Casearia sylvestris Sw., popularly known in Brazil as 'guaçatonga', has been used as antitumor, antiseptic, antiulcer, local anaesthetic and healer in folk medicine. Snakebite envenomation by Bothrops jararacussu (Bjssu) constitutes a relevant public health hazard capable of inducing serious local damage in victims. This study examined the pharmacological action of apolar and polar C. sylvestris leaf extracts in reverting the neuromuscular blockade and myonecrosis, which is induced by Bjssu venom and its major toxin bothropstoxin-I on the mouse phrenic nerve-diaphragm preparations. The polar methanol extract (ME) was by far the most efficacious. ME not only prevented myonecrosis and abolished the blockade, but also increased ACh release. Such facilitation in neuromuscular transmission was observed with ME alone, but was accentuated in preparations incubated with ME plus venom or toxin. This established synergy opens an interesting point of investigation because the venom or toxin in contact with ME changes from a blocking to a facilitating effect. It is suggested that rutin, known to have potent antioxidant properties, and one of the components present in the ME, could have a role in the observed effects. Since commercial rutin did not reproduce the ME effects, it is likely that a rutin-containing phytocomplex is neutralizing the bothropic envenoming effects.

Abstract:The hydroalcoholic extract of Casearia gossypiosperma Briquet (Flacourtiaceae) was standardized for the first time through quality control procedures including pharmacognostic methods, fingerprint chromatograms, defined amounts of marker substances and physicochemical characteristics. The pharmacological activity of C. gossypiosperma (Cg) hydroalcoholic extract was assayed by a traditional in vitro test, which involved irreversible neuromuscular blockade induced by Bothrops jararacussu (Bjssu) venom (60 μg/mL) in mouse phrenic nerve-diaphragm preparations. Bjssu venom blocked muscle activity for 26 (± 2.0) minutes (n = 6). Cg extract (0.1 mg/mL) induced changes on the baseline muscle activity without impairing the muscle function and inhibited 87.6% (± 1.8) (n = 6) of the Bjssu venom-induced blockade. Both flavonoids (0.624 g%) and polyphenols (4.63 g%) from the extract were spectrophotometrically quantified. Therefore, the present study confirms the antibothropic activity of Cg extract, supporting the ethnomedical use of Casearia sp. in the treatment of snakebite victims.Key words: antibothropic extract, Bothrops jararacussu, Casearia gossypiosperma Briquet, snake venoms. pharmacologically assessed for the first time. Original PaPer The Journal of Venomous Animals and Toxins including Tropical DiseasesIn vivo myotoxic effects and in vitro irreversible neuromuscular blockade effects of crude venom from the snake Bothrops jararacussu are well known pharmacological methods used to study drugs showing antivenom properties (29,30). Thus, the aim of the present study was to verify the capability of Casearia gossypiosperma hydroalcoholic extract to neutralize the neuromuscular blockade induced by Bothrops jararacussu venom. MATERIALS AND METHODS Plant Material and ExtractionLeaves from an adult C. gossypiosperma Briquet (Cg) tree were collected from the herbarium at the Higher School of Agriculture Luiz de Queiroz (ESALQ) of the University of São Paulo, Piracicaba, São Paulo, Brazil, in January 2006; the species was previously identified in 1988 (protocol IAC 38115). Cg leaves were dried at 35°C to 40°C for 24 hours. The dried leaves were then powdered, ground in a mill, macerated (200 g, during five days) in 2 L of 70% ethanol and the suspension was percolated (under protection against light) at 20 drops/minute, resulting in a 10% (m/v) hydroalcoholic extract. Quality Control Assays of the Medicinal Plants Ash and humidity testsTo observe elementary physical and chemical characteristics, Cg powder was subjected to ash and humidity tests (31). Briefly, 100 g of the specimen powder were placed in six calibrated melting pots, which were warmed until total carbonization of the powders. The melting pots were kept at 650°C and the ashes were then weighed. Results are expressed as grams of ashes/100 g of sample. The humidity test was performed by placing 1 g of specimen powder in six calibrated porcelain capsules, which were heated at 105ºC during four hours and then weighed. Thin Layer Chromatography (TLC)Aliquots...