Effect of Costus spiralis (Jacq.) Roscoe Leaves, Methanolic Extract and Guaijaverin on Blood Glucose and Lipid Levels in a Type II Diabetic Rat Model.

This study aimed to isolate and identify flavonoids with hypoglycemic activity in Costus spiralis leaves. The methanolic extract (ME) was rich in flavonoids, while the powdered leaves (PL) contained considerable amounts of macro- and microelements. Oral acute treatment of streptozotocin (STZ)-induced diabetic rats for 18 h with the C. spiralis PL, ME and isolated guaijaverin (GUA) lowered glycemia, improved oral glucose tolerance and inhibited liver lipid peroxidation. GUA and ME lowered plasma levels of low-density and non-high density lipoproteins; GUA also lowered total cholesterol levels. PL, ME and GUA did not significantly alter the plasma levels of triglycerides, high-density lipoproteins, very low-density lipoproteins, creatinine and aspartate transaminase, and the total protein levels in the kidney and liver tissues. Therefore, C. spiralis leaves are promising raw materials and rich sources of bioactive flavonoids for the development of novel antidiabetic drugs due to their hypoglycemic, antidyslipidemic and antioxidant actions.

Genetic structure and chemical diversity in natural populations of Uncaria guianensis (Aubl.) J.F.Gmel. (Rubiaceae).

Uncaria guianensis is native to the Amazon and is used traditionally as an anti-inflammatory. Natural populations of the species have declined markedly in recent times because of strong anthropic pressure brought about by deforestation and indiscriminate collection. The aim of the present study was to assess the genetic and chemical diversity among eight natural populations of U. guianensis located in the Brazilian states of Acre, Amapá and Amazonas. A set of four primer combinations was employed in sequence-related amplified polymorphism (SRAP) amplifications of leaf DNA, and the fragments were analyzed in an LI-COR model 4300 DNA Analyzer. Genetic variability within the populations (81%) was substantially greater than that detected between them (19%). The highest percentage of polymorphic loci (90.21%) and the largest genetic variability were observed in the population located in Mazagão, Amapá. Genetic differentiation between populations was high (Fst = 0.188) and the studied populations formed three distinct genetic groups (K = 3). The population located in Assis Brasil, Acre, presented the highest average content of the mitraphylline (0.60 mg/g dry weight,). However, mitraphylline and isomitraphylline not detected in most individuals in the studied populations, and it is questionable whether they should be considered as chemical markers of the species. The genetic data confirm the urgent need for conservation programs for U. guianensis, and for further studies aimed at ascertaining the genetic basis and heritability of alkaloid accumulation.

Genetic diversity and chemical variability of Lippia spp. (Verbenaceae).

BACKGROUND: The genus Lippia comprises 150 species, most of which have interesting medicinal properties. Lippia sidoides (syn. L. origanoides) exhibits strong antimicrobial activity and is included in the phytotherapy program implemented by the Brazilian Ministry of Health. Since species of Lippia are morphologically very similar, conventional taxonomic methods are sometimes insufficient for the unambiguous identification of plant material that is required for the production of certified phytomedicines. Therefore, genetic and chemical analysis with chemotype identification will contribute to a better characterization of Lippia species. METHODS: Amplified Length Polymorphism and Internal Transcribed Spacer molecular markers were applied to determine the plants' genetic variability, and the chemical variability of Lippia spp. was determined by essential oil composition. RESULTS: Amplified Length Polymorphism markers were efficient in demonstrating the intra and inter-specific genetic variability of the genus and in separating the species L. alba, L. lupulina and L. origanoides into distinct groups. Phylogenetic analysis using Amplified Length Polymorphism and markers produced similar results and confirmed that L. alba and L. lupulina shared a common ancestor that differ from L. origanoides. Carvacrol, endo-fenchol and thymol were the most relevant chemical descriptors. CONCLUSION: Based on the phylogenetic analysis it is proposed that L. grata should be grouped within L. origanoides due to its significant genetic similarity. Although Amplified Length Polymorphism and Internal Transcribed Spacer markers enabled the differentiation of individuals, the genotype selection for the production of certified phytomedicines must also consider the chemotype classification that reflects their real medicinal properties.

Costus spiralis (Jacq.) Roscoe: A Novel Source of Flavones with α-Glycosidase Inhibitory Activity.

Costus spiralis, a plant used in traditional Brazilian medicine for the treatment of complications in diabetes, was investigated. Assay of hexane, ethyl acetate, methanol, and aqueous fractions obtained by partition of a crude methanol extract of dried leaves of C. spiralis revealed that AGI activity was confined to the ethyl acetate fraction. Purification of this fraction yielded schaftoside and isoschaftoside. The AGI activities of the two flavones were lower than, but comparable with, that of the anti-diabetic drug acarbose. In contrast, the IC50 value of the ethyl acetate fraction was 1.95-, 2.34-, and 2.22-fold higher than those of acarbose, schaftoside, and isoschaftoside, respectively. The results demonstrate for the first time that schaftoside and isoschaftoside are responsible, in part, for the AGI activity of C. spiralis. Our study suggests that further investigations into C. spiralis may lead to the discovery of additional compounds with antihyperglycemic activity.

Thymus vulgaris L. essential oil and its main component thymol: Anthelmintic effects against Haemonchus contortus from sheep.

Haemonchus contortus is an important gastrointestinal parasite on sheep farms in tropical regions. The resistance of the parasite against most anthelmintic drugs represents a great economic problem to sheep farming and is a major challenge that needs to be overcome. The searches for new anthelmintic agents that act on different stages of the parasite's life cycle are necessary for the development of new therapeutic options. The aim of this study was to evaluate the in vitro and in vivo anthelmintic activity of Thymus vulgaris essential oil against H. contortus and of its main component, the monoterpene thymol. Despite the relative ineffectiveness of the oil in the in vivo test, which may be corrected in the future after technical improvements to increase the oil's bioavailability, the in vitro results validated the popular use of T. vulgaris oil as an anthelmintic agent, at least against H. contortus. In fact, both the essential oil and thymol, which accounts for 50.22% of the oil composition, were effective against the three main stages of H. contortus. The oil and thymol were able to inhibit egg hatching by 96.4-100%, larval development by 90.8-100%, and larval motility by 97-100%. Similar to the positive control (levamisole 20mg/mL), the oil and thymol completely inhibited the motility of H. contortus adults within the first 8h of the experiment. Since thymol reproduces the anthelmintic effects of the oil and because it is the main component of the oil, it is reasonable to assume that thymol is the most important compound responsible for the anthelmintic effect of T. vulgaris. These results are of ethnopharmacological importance and may contribute to the development of new drugs and even herbal medicines, increasing treatment options for the farm breeding.

Evaluation of anticandidal and antioxidant activities of phenolic compounds from Pyrostegia venusta (Ker Gawl.) Miers.

We have investigated the in vitro anticandidal and antioxidant activities of phenolic compounds from Pyrostegia venusta flower extracts. We used the HPLC technique to purify the flavonoid (quercetin-3-O-α-l-rhamnopyranosyl-(1→6)-ß-d-galactopyranoside) and two phenylpropanoid glycosides (verbascoside and isoverbascoside); we evaluated the antimicrobial activity of the extracts against Candida strains (Candidaalbicans; Candidakrusei ATCC 6258; and the clinical isolate strains of Candida sp. C. albicans, C. krusei, Candidatropicalis, Candidaparapsilosis, and Candidaguilhermondii). The P. venusta flower extracts displayed antimicrobial and antioxidant activities. The semi-purified fraction of the P. venusta flower extract and the phenylpropanoid glycoside verbascoside exhibited activity similar to that of amphotericin B, which denoted that they are potentially applicable as natural antioxidant and anticandidal agents in the pharmaceutical industries.

In vitro assessment of antimicrobial activity of Pothomorphe umbellata extracts against Enterococcus faecalis.

BACKGROUND: Due to the complex anatomy of the root canal system, biomechanical preparation is not able to completely eliminate all microorganisms present in the endodontic infections, making it necessary the use of an intracanal medication. AIM: The aim of this study was to assess the antimicrobial activity of an intracanal medication containing the ethyl-acetate fraction of Pothomorphe umbellata against Enterococcus faecalis. MATERIALS AND METHODS: Fifty seven human maxillary canine teeth were used, of which 54 were infected with E. faecalis every 72 h, for 28 days, and cultured for 24 h. Contaminated teeth were randomly separated into three groups (n = 18) and treated as follows: Group I - calcium hydroxide-based medication; Group II - P. umbellata-based medication; Group III - contaminated teeth without medication. Three teeth were used as negative control. After 7, 14 and 28 days of treatment, six teeth from each group were assessed for the level of microbial growth after each period of treatment. RESULTS: The intracanal medication containing P. umbellata was effective against E. faecalis after 7, 14, and 28 days of treatment without statistically significant difference in comparison to calcium hydroxide treatment (Kruskal-Wallis test, P > 0.05). CONCLUSION: Ethyl-acetate fraction of P. umbellate was efficient against E. faecalis, making this phytotherapy a viable option for endodontic treatment.

Chemical composition and antifungal activity of the essential oils of Schinus weinmannifolius collected in the spring and winter.

Reports on the chemical and pharmacological profile of the essential oil of Schinus weinmannifolius do not exist, although other Schinus species have been widely investigated for their biological activities. This work aimed to evaluate the chemical composition and antimicrobial activity of the essential oil of S. weinmannifolius collected in the spring and winter. The essential oils were extracted by hydrodistillation, analyzed by GC/MS and submitted to microdilution tests, to determine the minimum inhibitory concentration. The oils displayed different chemical composition and antimicrobial action. Bicyclogermacrene and limonene predominated in the oils extracted in the winter and spring, respectively, whereas only the latter oil exhibited antifungal activity.

Evaluation of the Hypoglycemic Properties of Anacardium humile Aqueous Extract.

The antihyperglycemic effects of several plant extracts and herbal formulations which are used as antidiabetic formulations have been described and confirmed to date. The main objective of this work was to evaluate the hypoglycemic activity of the aqueous extract of Anacardium humile. Although the treatment of diabetic animals with A. humile did not alter body weight significantly, a reduction of the other evaluated parameters was observed. Animals treated with A. humile did not show variation of insulin levels, possibly triggered by a mechanism of blood glucose reduction. Levels of ALT (alanine aminotransferase) decreased in treated animals, suggesting a protective effect on liver. Levels of cholesterol were also reduced, indicating the efficacy of the extract in reestablishing the balance of nutrients. Moreover, a kidney protection may have been achieved due to the partial reestablishment of blood glucose homeostasis, while no nephrotoxicity could be detected for A. humile. The obtained results demonstrate the effectiveness of A. humile extracts in the treatment of alloxan-induced diabetic rats. Therefore, A. humile aqueous extract, popularly known and used by diabetic patients, induced an improvement in the biochemical parameters evaluated during and following treatment of diabetic rats. Thus, a better characterization of the medicinal potential of this plant will be able to provide a better understanding of its mechanisms of action in these pathological processes.

Anti-snake venom activities of extracts and fractions from callus cultures of Sapindus saponaria.

CONTEXT: Sapindus saponaria L. (Sapindaceae) bark, root, and fruits are used as sedatives and to treat gastric ulcer and also demonstrate diuretic and expectorant effects. OBJECTIVE: The anti-snake venom properties of callus of S. saponaria are investigated here for the first time. MATERIALS AND METHODS: In vitro cultivated callus of Sapindus saponaria were lyophilized, and the extracts were prepared with different solvents, before submitting to phytochemical studies and evaluation of the anti-ophidian activity. Crude extracts were fractionated by liquid-liquid partition and the fractions were monitored by thin layer chromatography (TLC). Subsequently, anti-ophidian activities were analyzed toward Bothrops jararacussu Lacerda (Viperidae), B. moojeni Hoge (Viperidae), B. alternates Duméril (Viperidea) and Crotalus durissus terrificus Lineu (Viperidae) venoms and isolated myotoxins and phospholipase A(2) (PLA(2)). RESULTS: Fractions A1, A2 and the extract in MeOH:H(2)O (9:1) significantly inhibited the toxic and pharmacological activities induced by snake venoms and toxins, when compared to other extracts and fractions. The lethal, clotting, phospholipase, edema-inducing, hemorrhagic and myotoxic activities were partially inhibited by the different extracts and fractions. TLC profiles of the crude extracts (B and C) and fractions (A1 and A2) showed ß-sitosterol and stigmasterol as their main compounds. Stigmasterol exhibited inhibitory effects on enzymatic and myotoxic activities of PLA(2). DISCUSSION AND CONCLUSION: Sapindus saponaria extracts and fractions presented anti-ophidian activity and could be used as an adjuvant to serum therapy or for its supplementation, and in addition, as a rich source of potential inhibitors of enzymes involved in several pathophysiological human and animal diseases.

Protective effect of schizolobium parahyba flavonoids against snake venoms and isolated toxins.

Four compounds (isoquercitrin, myricetin-3-O-glucoside, catechin and gallocatechin) were isolated from lyophilized aqueous extract of Schizolobium parahyba leaves by chromatography on Sephadex LH-20, followed by semipreparative HPLC using a C-18 column, and identified by 1H and 13C NMR. The compounds were then, tested against hemorrhagic and fibrinogenolytic activities of Bothrops crude venoms and isolated metalloproteinases. The inhibitors neutralized the biological and enzymatic activities of Bothrops venoms and toxins isolated from B. jararacussu and B. neuwiedi venoms. The results showed that gallocatechin and myricetin-3-O-glucoside are good inhibitors of hemorrhagic and fibrinogenolytic activities of metalloproteinases, respectively. Gallocatechin also inhibited the myotoxic activity of both B. alternatus venom and BnSP-6 (Lys49 PhospholipaseA2 from B. neuwiedi). Circular dichroism and docking simulation studies were performed in order to investigate the possible interaction between BnSP-6 and gallocatechin. This is the first time these compounds and their anti-ophidian properties are reported for S. parahyba species. Forthcoming studies involving X-ray co-crystallization, will be of great importance for the development of new therapeutic agents for the treatment of ophidian accidents and for the better understanding of the structure/function relationship of venom toxins.

Bioactive chemical constituents and comparative antimicrobial activity of callus culture and adult plant extracts from Alternanthera tenella.

Crude extracts of a callus culture (two culture media) and adult plants (two collections) from Alternanthera tenella Colla (Amaranthaceae) were evaluated for their antibacterial and antifungal activity, in order to investigate the maintenance of antimicrobial activity of the extracts obtained from plants in vivo and in vitro. The antibacterial and antifungal activity was determined against thirty strains of microorganisms including Gram-positive and Gram-negative bacteria, yeasts and dermatophytes. Ethanolic and hexanic extracts of adult plants collected during the same period of the years 1997 and 2002 [Ribeirão Preto (SP), collections 1 and 2] and obtained from plant cell callus culture in two different hormonal media (AtT43 and AtT11) inhibited the growth of bacteria, yeasts and dermatophytes with inhibition halos between 6 and 20 mm. For the crude extracts of adult plants bioassay-guided fractionation, purification, and isolation were performed by chromatographic methods, and the structures of the isolated compounds were established by analysis of chemical and spectral evidences (UV, IR, NMR and ES-MS). Steroids, saponins and flavonoids (aglycones and C-glycosides) were isolated. The minimum inhibitory concentration (MIC) of the isolated compounds varied from 50 to 500 microg/mL.

Phototherapy promotes healing of chronic diabetic leg ulcers that failed to respond to other therapies.

OBJECTIVE: We tested the hypothesis that combined 660 and 890 nm LED phototherapy will promote healing of diabetic ulcers that failed to respond to other forms of treatment. RESEARCH DESIGN AND METHODS: A double-blind randomized placebo controlled design was used to study 23 diabetic leg ulcers in two groups of 14 patients. Group one ulcers were cleaned, dressed with 1% silver sulfadiazine cream and treated with "placebo" phototherapy (<1.0 J cm(-2)) twice per week, using a Dynatron Solaris 705(R) device. Group two ulcers were treated similarly but received 3 J cm(-2) dose. RESULTS: At each of 15, 30, 45, 60, 75, and 90 days of healing, mean ulcer granulation and healing rates were significantly higher for group two than the "placebo" group (P < 0.02). While "placebo" treated ulcers worsened during the initial 30 days, group two ulcers healed rapidly; achieving 56% more granulation and 79.2% faster healing by day 30, and maintaining similarly higher rates of granulation and healing over the "placebo" group all through. By day 90, 58.3% of group two ulcers had healed fully and 75% had achieved 90-100% healing. In contrast, only one "placebo" treated ulcer healed fully by day 90; no other ulcer attained > or =90% healing. CONCLUSION: Combined 660 and 890 nm light promotes rapid granulation and healing of diabetic ulcers that failed to respond to other forms of treatment.

The role of polar phytocomplexes on anticonvulsant effects of leaf extracts of Lippia alba (Mill.) N.E. Brown chemotypes.

OBJECTIVES: The purpose of the present work was to characterize the pharmacological profile of different L. alba chemotypes and to correlate the obtained data to the presence of chemical constituents detected by phytochemical analysis. METHODS: Essential oils from each L. alba chemotype (LP1-LP7) were characterized by gas chromatography-mass spectrometry (GC-MS) and extracted non-volatile compounds were analysed by HPLC and GC-MS. The anticonvulsant actions of the extracted compounds were studied in pentylenetetrazole-induced clonic seizures in mice and their effect on motor coordination was studied using the rota-rod test in rats. The synaptosomes and synaptic membranes of the rats were examined for the influence of LP3 chemotype extract on GABA uptake and binding experiments. KEY FINDINGS: Behavioural parameters encompassed by the pentylenetetrazole test indicated that 80% ethanolic extracts of LP1, LP3 and LP6 L. alba chemotypes were more effective as anticonvulsant agents. Neurochemical assays using synaptosomes and synaptic membranes showed that L. alba LP3 chemotype 80% ethanolic extract inhibited GABA uptake and GABA binding in a dose-dependent manner. HPLC analysis showed that LP1, LP3 and LP6 80% ethanolic extracts presented a similar profile of constituents, differing from those seen in LP2, LP4, LP5 and LP7 80% ethanolic extracts, which exhibited no anticonvulsant effect. GC-MS analysis indicated the occurrence of phenylpropanoids in methanolic fractions obtained from LP1, LP3 and LP6 80% ethanolic extracts and also the accumulation of inositol and flavonoids in hydroalcoholic fractions. CONCLUSIONS: Our results suggest that the anticonvulsant properties shown by L. alba might be correlated to the presence of a complex of non-volatile substances (phenylpropanoids, flavonoids and/or inositols), and also to the volatile terpenoids (beta-myrcene, citral, limonene and carvone), which have been previously validated as anticonvulsants.

Inhibition of snake venoms and phospholipases A(2) by extracts from native and genetically modified Eclipta alba: isolation of active coumestans.

We genetically modified Eclipta alba using Agrobacterium rhizogenes LBA 9402, with the aim of producing secondary metabolites with pharmacological properties against phospholipase A(2) and the myotoxic activities of snake venom. Extracts from in natura aerial parts and roots, both native and genetically modified (in vitro), were prepared and analysed by high-performance liquid chromatography. In natura materials showed the coumestan wedelolactone at higher concentration in the aerial parts, while demethylwedelolactone appeared at higher concentration in roots. Among the modified roots, clone 19 showed higher concentrations of these coumestans. Our results show that the in natura extracts of plants collected from Botucatu and Ribeirão Preto were efficient in inhibiting snake venom phospholipase A(2) activity. Regarding in vitro material, the best effect against Crotalus durissus terrificus venom was that of clone 19. Clone 19 and isolated coumestans (wedelolactone and demethylwedelolactone) inhibited the myotoxic activity induced by basic phospholipases A(2) isolated from the venoms of Crotalus durissus terrificus (CB) and Bothrops jararacussu (BthTX-I and II). The search for antivenom is justified by the need of finding active principles that are more efficient in neutralizing snake venoms and also as an attempt to complement serum therapy.

Guarana (Paullinia cupana var. sorbilis), an anciently consumed stimulant from the Amazon rain forest: the seeded-fruit transcriptome.

Guarana (Paullinia cupana var. sorbilis) is a plant native to the central Amazon basin. Roasted seed extracts have been used as medicinal beverages since pre-Colombian times, due to their reputation as stimulants, aphrodisiacs, tonics, as well as protectors of the gastrointestinal tract. Guarana plants are commercially cultivated exclusively in Brazil to supply the national carbonated soft-drink industry and natural product stores around the world. In this report, we describe and discuss the annotation of 15,387 ESTs from guarana seeded-fruits, highlighting sequences from the flavonoid and purine alkaloid pathways, and those related to biotic stress avoidance. This is the largest set of sequences registered for the Sapindaceae family.

Anti-inflammatory, analgesic and anti-oedematous effects of Lafoensia pacari extract and ellagic acid.

Lafoensia pacari St. Hil. (Lythraceae) is used in traditional medicine to treat inflammation. Previously, we demonstrated the anti-inflammatory effect that the ethanolic extract of L. pacari has in Toxocara canis infection (a model of systemic eosinophilia). In this study, we tested the anti-inflammatory activity of the same L. pacari extract in mice injected intraperitoneally with beta-glucan present in fraction 1 (F1) of the Histoplasma capsulatum cell wall (a model of acute eosinophilic inflammation). We also determined the anti-oedematous, analgesic and anti-pyretic effects of L. pacari extract in carrageenan-induced paw oedema, acetic acid writhing and LPS-induced fever, respectively. L. pacari extract significantly inhibited leucocyte recruitment into the peritoneal cavity induced by beta-glucan. In addition, the L. pacari extract presented significant analgesic, anti-oedematous and anti-pyretic effects. Bioassay-guided fractionation of the L. pacari extract in the F1 model led us to identify ellagic acid. As did the extract, ellagic acid presented anti-inflammatory, anti-oedematous and analgesic effects. However, ellagic acid had no anti-pyretic effect, suggesting that other compounds present in the plant stem are responsible for this effect. Nevertheless, our results demonstrate potential therapeutic effects of L. pacari extract and ellagic acid, providing new prospects for the development of drugs to treat pain, oedema and inflammation.

Antiophidian properties of the aqueous extract of Mikania glomerata.

Aqueous extracts, prepared from dried or fresh roots, stems or leaves of Mikania glomerata, a plant found in Mata Atlântica in Southeastern Brazil, were able to efficiently neutralize different toxic, pharmacological, and enzymatic effects induced by venoms from Bothrops and Crotalus snakes. Phospholipase A(2) activity and the edema induced by Crotalus durissus terrificus venom were inhibited around 100 and approximately 40%, respectively, although this inhibition was only partial for Bothrops venoms. The hemorrhagic activity of Bothrops venoms (Bothrops altenatus, Bothrops moojeni, Bothrops neuwiedi, and Bothrops jararacussu) was significantly inhibited by this vegetal species, while the clotting activity of Crotalus durissus terrificus, Bothrops jararacussu, and Bothrops neuwiedi venoms was totally inhibited. Although, the mechanism of action of Mikania glomerata extract is still unknown, the finding that no visible change was detected in the electrophoretic pattern of snake venom after incubation with the extract excludes proteolytic degradation as a potential mechanism. Since the extract of Mikania glomerata significantly inhibited the studied snake venoms, it may be used as an alternative treatment to serumtherapy and, in addition, as a rich source of potential inhibitors of PLA(2)s, metalloproteases and serineproteases, enzymes involved in several physiopathological human and animal diseases.

Rosmarinic acid, a new snake venom phospholipase A2 inhibitor from Cordia verbenacea (Boraginaceae): antiserum action potentiation and molecular interaction.

Many plants are used in traditional medicine as active agents against various effects induced by snakebite. The methanolic extract from Cordia verbenacea (Cv) significantly inhibited paw edema induced by Bothrops jararacussu snake venom and by its main basic phospholipase A2 homologs, namely bothropstoxins I and II (BthTXs). The active component was isolated by chromatography on Sephadex LH-20 and by RP-HPLC on a C18 column and identified as rosmarinic acid (Cv-RA). Rosmarinic acid is an ester of caffeic acid and 3,4-dihydroxyphenyllactic acid [2-O-cafeoil-3-(3,4-di-hydroxy-phenyl)-R-lactic acid]. This is the first report of RA in the species C. verbenacea ('baleeira', 'whaler') and of its anti-inflammatory and antimyotoxic properties against snake venoms and isolated toxins. RA inhibited the edema and myotoxic activity induced by the basic PLA2s BthTX-I and BthTX-II. It was, however, less efficient to inhibit the PLA2 activity of BthTX-II and, still less, the PLA2 and edema-inducing activities of the acidic isoform BthA-I-PLA2 from the same venom, showing therefore a higher inhibitory activity upon basic PLA2s. RA also inhibited most of the myotoxic and partially the edema-inducing effects of both basic PLA2s, thus reinforcing the idea of dissociation between the catalytic and pharmacological domains. The pure compound potentiated the ability of the commercial equine polyvalent antivenom in neutralizing lethal and myotoxic effects of the crude venom and of isolated PLA2s in experimental models. CD data presented here suggest that, after binding, no significant conformation changes occur either in the Cv-RA or in the target PLA2. A possible model for the interaction of rosmarinic acid with Lys49-PLA2 BthTX-I is proposed.

Anticoagulant and antifibrinogenolytic properties of the aqueous extract from Bauhinia forficata against snake venoms.

The aqueous extract from aerial parts of Bauhinia forficata was able to neutralize the clotting activity induced by Bothrops and Crotalus crude venoms. The clotting time, upon human plasma, induced by B. moojeni venom was significantly prolonged. Clotting and fibrinogenolytic activities induced by isolated thrombin-like enzyme from Bothrops jararacussu were totally inhibited after incubation at different ratios. The extract was not able to neutralize the hemorrhagic activity induced by an Bothrops venoms, but it efficiently inhibited the edema induced by Crotalus durissus terrificus venom and isolated PLA2s. In addition, it did not inhibited the phospholipase A2 activity of Bothrops snake venoms. Interaction studies between Bauhinia forficata extract and snake venoms, when analyzed by SDS-PAGE, did not reveal any apparent degradation of the venom proteins. This extract is a promising source of natural inhibitors of serine-proteases involved in blood clotting disturbances induced by snake venoms.