Gallic acid anti-myotoxic activity and mechanism of action, a snake venom phospholipase A2 toxin inhibitor, isolated from the medicinal plant Anacardium humile.

Snakebite envenoming is the cause of an ongoing health crisis in several regions of the world, particularly in tropical and neotropical countries. This scenario creates an urgent necessity for new practical solutions to address the limitations of current therapies. The current study investigated the isolation, phytochemical characterization, and myotoxicity inhibition mechanism of gallic acid (GA), a myotoxin inhibitor obtained from Anacardium humile. The identification and isolation of GA was achieved by employing analytical chromatographic separation, which exhibited a compound with retention time and nuclear magnetic resonance spectra compatible with GA's commercial standard and data from the literature. GA alone was able to inhibit the myotoxic activity induced by the crude venom of Bothrops jararacussu and its two main myotoxins, BthTX-I and BthTX-II. Circular dichroism (CD), fluorescence spectroscopy (FS), dynamic light scattering (DLS), and interaction studies by molecular docking suggested that GA forms a complex with BthTX-I and II. Surface plasmon resonance (SPR) kinetics assays showed that GA has a high affinity for BthTX-I with a KD of 9.146 × 10-7 M. Taken together, the two-state reaction mode of GA binding to BthTX-I, and CD, FS and DLS assays, suggest that GA is able to induce oligomerization and secondary structure changes for BthTX-I and -II. GA and other tannins have been shown to be effective inhibitors of snake venoms' toxic effects, and herein we demonstrated GA's ability to bind to and inhibit a snake venom PLA2, thus proposing a new mechanism of PLA2 inhibition, and presenting more evidence of GA's potential as an antivenom compound.

Metabolite profile and consumer sensory acceptability of meat from lean Nellore and Angus × Nellore crossbreed cattle fed soybean oil.

Thirty each Nellore (NEL) and crossbred Angus × Nellore (AxN) were used to evaluate the effect of feeding soybean oil (SBO) and breed on meat sensory acceptability and its relation to muscle metabolite profiles. Cattle were fed for 133 d on two different diets: 1) basal feedlot diet (CON) and 2) CON diet with 3.5% added SBO. No interactions between diet and genetic group were detected for any traits measured. Meat from animals fed SBO diet had lower overall liking, flavor, tenderness and juiciness scores compared to meat from animals fed CON diet. The four most important compounds differing between animals fed CON and SBO diets were betaine, glycerol, fumarate, and carnosine, suggesting that metabolic pathways such as glycerolipid metabolism; glycine, serine and threonine metabolism; glutamine and glutamate metabolism; valine, leucine and isoleucine biosynthesis; and alanine, aspartate and glutamate metabolism were affected by diets. Nellore beef had a higher overall liking and meat flavor scores than AxN beef. The four most important compounds differing between breeds were glycine, glucose, alanine, and carnosine, which may indicate that metabolic pathways such as glutathione metabolism; primary bile acid biosynthesis; alanine, aspartate and glutamate metabolism; and valine, leucine and isoleucine biosynthesis were affected by genetic groups. Meat carnosine, inosine monophosphate, glutamate, betaine, glycerol and creatinine levels were correlated with sensory acceptability scores. Meat metabolite profiles and sensory acceptability were differentially impacted by diet and breed.

Effects of n-3 and n-6 feeding sources on the quality and lipid oxidation of meat from feedlot-finished Bos indicus steers.

This study was conducted to evaluate the fatty acid profile, sensory properties and lipid oxidation of meat on retail display (RD) from Nellore steers (n = 96) fed diets containing soybean (SOY), sunflower (SUN), or linseed (LIN) oil or a control diet (CON). After slaughtering, samples of the Longissimus muscle were collected for sensory properties (1 day), fatty acid composition (1 day) and oxidation stability (3 days under RDC) evaluations. No differences in total lipids, cholesterol, TBARS, and total SFAs, MUFAs, PUFAs, and PUFA/SFA were observed. However, meat from animals fed vegetable oil had more CLA than that of the CON samples. The flavour, juiciness and overall acceptability were affected by the treatments (P < 0.05), but no consistent effect of a specific oil source was observed. Meat colour was not affected by diets or days under RD, and 7-ketocholesterol was not detected in any sample. The oil sources used in this work were not effective in consistently changing meat properties.

Biodiversity as a source of bioactive compounds against snakebites.

Snakebites are a frequently neglected public health issue in tropical and subtropical countries. According to the World Health Organization, 5 million people are bitten annually including up to 2.5 million envenomations. Treatment with antivenom serum remains the only specific therapy for snakebite envenomation. However, it is heterologous and therefore liable to cause adverse reactions, such as early anaphylactic, pyrogenic and delayed reactions. In order to develop alternatives to the current therapy, researchers have been looking for natural products and plant extracts with antimyotoxic, anti-hemorrhagic and anti-inflammatory properties. Especially due to the role the physiopathological processes triggered by snake toxins, play in paralysis, bleeding disorders, kidney failure and tissue damage. Considering the fact that studies involving snake toxins and specific inhibitors, particularly on a molecular level, are the main key to understand neutralization mechanisms and to propose models or prototypes for an alternative therapy, this article presents efforts made by the scientific community in order to produce validated data regarding 87 compounds and plant extracts obtained from 79 species. These plants, which belong to 63 genera and 40 families, have been used by traditional medicine as alternatives or complements to the current serum therapy.

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.

Chemotherapeutic potential of two gallic acid derivative compounds from leaves of Casearia sylvestris Sw (Flacourtiaceae).

Casearia sylvestris is a plant used in the treatment of several diseases, including cancer. Studies have shown that C. sylvestris presents an interesting antitumoral potential, due to the presence of casearins and some sesquiterpens with antitumoral activity. In this work, we tested the potential chemotherapeutic of two gallic acid-derived compounds isolated from C. sylvestris leaves: isobutyl gallate-3,5-dimethyl ether (IGDE) and methyl gallate-3,5-dimethyl ether (MGDE). We utilized two tumoral models: Ehrlich ascites tumor cells (EAT)/BALB/c mice and Lewis lung cancer cells (LLC1)/C57bl/6 mice. MGDE and IGDE increased the survival of mice inoculated with EAT cells and decreased the tumor volume in the LLC1 model, compared to control groups. Both compounds presented similar and low in vitro cytotoxicity against Ehrlich ascites tumor cells and did not present any significant toxicity against Lewis lung cancer cells. Since the direct in vitro activity against Ehrlich tumor and Lewis lung cancer cells was low, we investigated the effects of MGDE or IGDE treatment on the activity of total natural killer cells from Ehrlich ascites tumor-bearing mice, as a possible explanation for the mechanisms of these compounds in vivo. MGDE and IGDE improved NK cell cytotoxicity against Ehrlich ascites cells. As expected, tumor growth in non-treated mice markedly suppressed NK cell cytolysis while, IGDE completely reversed this effect, when mice were treated with 0.5 mg/kg dosages of these compounds for 4 days. The pharmacokinetic studies showed that IGDE remains in the organism for a long period of time, possibly explaining the higher compound efficiency.

Isolation and characterization of ellagic acid derivatives isolated from Casearia sylvestris SW aqueous extract with anti-PLA(2) activity.

The Casearia sylvestris SW (Flacourtiaceae) is utilized in folk medicine (Brazil and all Latin American) to treat several pathologic processes as inflammation, cancer, microbial infection and snake bites. Studies showed that C. sylvestris aqueous extract can inhibit many toxic effects caused by snake venoms (or caused by phospholipase A(2) isolated) from different species, mainly of Bothrops genus. Inhibition of enzymatic and myotoxic activities, decrease of edema formation and increase of the survival rate of rats injected with lethal doses of bothropic venoms are some toxic effects inhibited by C. sylvestris. In this study, four ellagic acid derivatives from aqueous extracts of C. sylvestris were isolated, characterized, and tested against effects from both total venom and PLA(2) (Asp 49 BthTX-II) from the venom of Bothrops jararacussu. The isolated compounds were as follows: ellagic acid (A), 3'-O-methyl ellagic acid (B), 3,3'-di-O-methyl ellagic acid (C), 3-O-methyl-3',4'-methylenedioxy ellagic acid (D). The inhibition constant values (Ki) for enzymatic activity, as well the IC(50) values found in the edematogenic and myotoxic activities, indicate that the ellagic acid is the best inhibitor of these activities, while compounds C and D are the substances with lowest capacity on inhibiting these same effects. Our results show that the presence of hydroxyls at position 3 or 3' (compounds A and B) increases the capacity of these derivatives on inhibiting these toxic effects. However, the presence of methoxyl groups at position 3 or 3' reduced, but did not completely inhibit the capacity of compounds C and D on inhibiting all the toxic effects studied.

Chemotherapeutic potential of the volatile oils from Zanthoxylum rhoifolium Lam leaves.

In this work, the anti-tumor properties of the volatile oil from Zanthoxylum rhoifolium Lam leaves and some terpenes (alpha-humulene, beta-caryophyllene, alpha-pinene and beta-pinene) were investigated in vitro and in vivo using the Ehrlich ascites tumor model. Treatment of Ehrlich ascites tumor-bearing mice with 20 mg/kg of the volatile oil and beta-caryophyllene for 4 days has significantly increased survival, whereas administration of alpha-humulene, alpha-pinene and beta-pinene were ineffective in affording protection. Volatile oil and beta-caryophyllene exhibited little direct activity against Ehrlich tumor cells in vitro, while alpha-humulene, alpha-pinene and beta-pinene did not such activity. Investigation of the effects of the volatile oil (and terpenes) treatment on total natural killer cells (NK cell) activity from tumor-bearing mice as a possible mechanism of these compounds in vivo revealed that volatile oil and beta-caryophyllene significantly improved NK cell cytotoxicity against YAC-1, a Moloney virus-induced mouse T-cell lymphoma of A/SN origin and Ehrlich ascites cells. As expected, tumor growth in non-treated mice markedly suppressed NK cell cytolysis while the volatile oil and beta-caryophyllene reversed this effect when mice were treated with 20-mg/kg dosages of these compounds for 4 days. Summing up, volatile oil exhibits anti-tumor efficacy and significative immunomodulatory action in vivo, which may be related to beta-caryophyllene associated to the synergism of other natural compounds presented in volatile oil from Z. rhoifolium Lam leaves.