Schinus terebinthifolius leaf extract causes midgut damage, interfering with survival and development of Aedes aegypti larvae

In this study, a leaf extract from Schinus terebinthifolius was evaluated for effects on survival, development, and midgut of A. aegypti fourth instar larvae (L4), as well as for toxic effect on Artemia salina. Leaf extract was obtained using 0.15 M NaCl and evaluated for phytochemical composition and lectin activity. Early L4 larvae were incubated with the extract (0.3–1.35%, w/v) for 8 days, in presence or absence of food. Polymeric proanthocyanidins, hydrolysable tannins, heterosid and aglycone flavonoids, cinnamic acid derivatives, traces of steroids, and lectin activity were detected in the extract, which killed the larvae at an LC50 of 0.62% (unfed larvae) and 1.03% (fed larvae). Further, the larvae incubated with the extract reacted by eliminating the gut content. No larvae reached the pupal stage in treatments at concentrations between 0.5% and 1.35%, while in the control (fed larvae), 61.7% of individuals emerged as adults. The extract (1.0%) promoted intense disorganization of larval midgut epithelium, including deformation and hypertrophy of cells, disruption of microvilli, and vacuolization of cytoplasms, affecting digestive, enteroendocrine, regenerative, and proliferating cells. In addition, cells with fragmented DNA were observed. Separation of extract components by solid phase extraction revealed that cinnamic acid derivatives and flavonoids are involved in larvicidal effect of the extract, being the first most efficient in a short time after larvae treatment. The lectin present in the extract was isolated, but did not show deleterious effects on larvae. The extract and cinnamic acid derivatives were toxic to A. salina nauplii, while the flavonoids showed low toxicity. S. terebinthifolius leaf extract caused damage to the midgut of A. aegypti larvae, interfering with survival and development. The larvicidal effect of the extract can be attributed to cinnamic acid derivatives and flavonoids. The data obtained using A. salina indicates that caution should be used when employing this extract as a larvicidal agent

Phospholipase A2 of harpalycina 2 activity, an isoflavone isolated of Harpalyce brasiliana Benth.

As fosfolipases A2 secretÃrias (sPLA2, EC 3.1.1.4) hidrolisam a ligaÃÃo Ãster sn-2 dos fosfolipÃdios, liberando Ãcidos graxos e lisofosfolipÃdios. A expressÃo destas enzimas esta elevada em diversas condiÃÃes patolÃgicas como, artrite reumatÃide, sepse, aterosclerose e cÃncer. AlÃm disto, as sPLA2s sÃo os principais componentes tÃxicos dos venenos de algumas serpentes, sendo os principais responsÃveis pelo dano tecidual local. A harpalicina 2 Ã uma isoflavona isolada das folhas de Harpalyce brasiliana Benth., uma raiz-de-cobra utilizada na medicina popular do Nordeste para tratar envenenamentos por serpentes e condiÃÃes inflamatÃrias. O objetivo deste trabalho foi avaliar o efeito da harpalicina 2 nas atividades enzimÃtica, edematogÃnica e miotÃxica de sPLA2s isoladas dos venenos de Bothrops pirajai (PrTX-III), Crotalus durissus terrificus (Cdt F15), Apis mellifera (Apis) e Naja naja (Naja). AlÃm disso, o efeito sobre agregaÃÃo plaquetÃria induzida pela piratoxina-III (PrTX-III) em decorrÃncia do tratamento com a harpalicina 2 tambÃm foi avaliado. A harpalicina 2 inibiu todas as sPLA2s testadas, com percentuais de inibiÃÃo de 58,7, 78,8, 87,7 e 88,1 % para PrTX-III, Cdt F15, Apis e Naja, respectivamente. A primeira fase da atividade edematogÃnica induzida pela administraÃÃo das sPLA2s tambÃm foi inibida pela harpalicina 2, assim como a miotoxicidade. Quando avaliada especificamente sobre a PrTX-III, em comparaÃÃo com os inibidores padrÃo, Ãcido aristolÃchico (Aris Ac) e brometo de p-bromofenacila (p-BPB), a IC50 da harpalicina 2 sobre a atividade enzimÃtica foi de 11,34 Â 0,28 μg/mL. AlteraÃÃes conformacionais como um leve desenovelamento e a transiÃÃo da forma dimÃrica para monomÃrica tambÃm foram observadas apÃs o tratamento com a harpalicina 2, sem contudo alterar a massa da proteÃna. Nos experimentos de agregaÃÃo plaquetÃria, a harpalicina 2 incubada previamente com a PrTX-III inibiu a agregaÃÃo quando comparada a proteÃna nÃo tratada. O efeito inibitÃrio do Ãcido aristolÃchico e do p-BPB foram menores do que os da harpalicina 2, que tambÃm inibiu a agregaÃÃo induzida pelo Ãcido araquidÃnico. Os resultados de docking, obtidos utilizando as estruturas cristalogrÃficas das sPLA2s oriundas do Protein Data Bank, revelaram uma tendÃncia entre os valores dos GOLD scores e os percentuais de inibiÃÃo da atividade enzimÃtica e de agregaÃÃo plaquetÃria, apontando a formaÃÃo de ligaÃÃes de hidrogÃnio entre a harpalicina 2 e resÃduos importantes do sÃtio ativo das sPLA2s, como a histidina-48. Em conclusÃo, estes resultados mostraram o efeito inibitÃrio da harpalicina 2 sobre as atividades enzimÃticas e tÃxicas das sPLA2s, corroborando, em parte, o uso da H. brasiliana na medicina popular.Secretory phospholipases A2 (sPLA2, EC 3.1.1.4) hydrolyses the sn-2 ester bond of phospholipids, releasing fatty acids and lysophospholipids. The expression of these enzymes is found to be elevated in many pathological conditions, such as rheumatoid arthritis, sepsis, atherosclerosis, and cancer. Moreover, sPLA2s are the main toxic components of some snake venoms, being the mainly responsible for the local tissue damage. Harpalycin 2 is an isoflavona isolated from the leaves of Harpalyce brasiliana Benth., a snakeroot used in folk medicine to treat snake bites and inflammation in Northeast of Brazil. The aim of this study was evaluate the effect of harpalycin 2 in the enzymatic, edematogenic, and myotoxic activities of sPLA2s isolated from Bothrops pirajai (PrTX-III), Crotalus durissus terrificus (Cdt F15), Apis mellifera (Apis), and Naja naja (Naja) venoms. Futher, the effect on the platelet aggregation induced by PrTX-III as a result of the treatment with harpalycin 2 was also evaluated. Harpalycin 2 inhibited all sPLA2s tested, with inhibition percentages of 58.7, 78.8, 87.7, and 88.1 % for PrTX-III, Cdt F15, Apis, and Naja, respectively. The early phase of the edema induced by sPLA2s administration was also inhibited by harpalycin 2, as well as the myotoxicity. When assayed specifically with the PrTX-III, in comparison with two standard sPLA2 inhibitor, aristolochic acid (Aris Ac) and p-bromophenacyl bromide (p-BPB), the IC50 of harpalycin 2 on the enzymatic activity was 11.34 Â 0.28 μg/mL. Conformational changes as a slightly unfolding and the transition from the dimeric to the monomeric form were also observed after treatment with the harpalycin 2, with no changes in the molecular mass of the protein. In the platelet aggregation assays, the harpalycin 2 incubated with the PrTX-III inhibited the aggregation when compared to the untreated protein. The inhibitory effect of Aris Ac and p-BPB were lower than that of harpalycin 2, which also inhibited the aggregation induced by arachidonic acid. The docking results, using the crystallographic structures of the sPLA2s taken from the Protein Data Bank, showed a trend between the GOLD scores and the percentages of catalytic activity and platelet aggregation inhibition, showing the formation of hydrogen bonds between harpalycin 2 and important residues in the active site of the sPLA2s, as His48. In conclusion, these results showed the inhibitory effect of harpalycin 2 on the enzymatic and toxic activities of sPLA2s, corroborating, at least in part, the use of H. brasiliana in folk medicine

Activity of cabenegrin A-II in biochemical, hematological and pressure effects induced by bothrops jararacussu snake venom in rats.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgicoO uso de plantas medicinais no tratamento de picadas de serpentes à amplamente difundido nas culturas populares ao redor do mundo. Esta prÃtica pode ser Ãtil no tratamento primÃrio de vÃtimas de acidentes ofÃdicos, principalmente em Ãreas onde o soro antiveneno nÃo està prontamente disponÃvel. Os pterocarpanos, especialmente as cabenegrinas A-I e A-II, tiveram sua atividade antiofÃdica comprovada em diversos modelos experimentais. Esta dissertaÃÃo objetivou estabelecer uma metodologia para estudos das alteraÃÃes bioquÃmicas e hematolÃgicas induzidas pelo veneno de B. jararacussu em ratos e verificar o efeito da cabenegrina A-II nestas alteraÃÃes, alÃm de verificar o efeito da cabenegrina A-II nas alteraÃÃes pressÃricas induzidas pelo veneno. Foram analisados parÃmetros indicativos da funÃÃo renal (creatinina, urÃia e Ãcido Ãrico), da funÃÃo hepÃtica (AST e ALT), de dano muscular (CK), alÃm de glicose, eletrÃlitos e hemograma. As alteraÃÃes bioquÃmicas e hematolÃgicas induzidas pelo veneno variaram conforme a via de administraÃÃo, variaÃÃes estas relacionadas à amplitude de absorÃÃo do veneno. Neste estudo, a via intramuscular foi escolhida para os estudos com a cabenegrina A-II. Neste modelo experimental, a cabenegrina A-II foi capaz de reverter à maioria dos efeitos bioquÃmicos e hematolÃgicos produzidos pela administraÃÃo do veneno de B. jararacussu, apontando para uma melhora considerÃvel da funÃÃo renal e hepÃtica dos animais, bem como um dano muscular menos pronunciado. Nas alteraÃÃes pressÃricas causadas pelo veneno de B. jararacussu, a cabenegrina A-II bloqueou o efeito hipotensor do veneno, um indicativo de inibiÃÃo enzimÃtica promovida por este pterocarpano prenilado. Estes dados, acrescentados a estudos prÃvios realizados com essas substÃncias, as colocam como uma alternativa de protÃtipos na busca de novos agentes antiveneno.Medicinal plants against snakebite are widespread used in folk medicine in the world. This practice may be useful as a first treatment of snakebite victims, mainly in places where antivenom immunotherapy is not promptly available. Pterocarpans, especially the cabenegrins A-I and A-II, had their antiophidic activity proved by several experimental models. This work aimed to fix one efficient methodology to study biochemical and hematological alterations induced by Bothrops jararacussu venom in rats and verify the effects of cabenegrin A-II in these alterations, besides studying the effects of cabenegrin A-II in pressure changes induced by this venom. Indicatives parameters for renal function (creatinin, urea and uric acid), hepatic function (AST and ALT) and muscle injury (CK), besides glucose, electrolytes and hemogram were analyzed. Biochemical and hematological changes varied according the way of administration of the venom, variations related to the rate of absorption of the venom. In this case, intramuscular way was chosen to study the effects of cabenegrin A-II, where cabenegrin A-II was able to block the major part of biochemical and hematological effects induced by B. jararacussu venom, showing an improve in renal and hepatic function and less muscle injury than control group. On pressure changes induced by B. jararacussu venom, cabenegrin A-II blocked the hypotensive effect of the venom, indicating enzymatic inhibition promoted by this prenylated pterocarpan. These data, added to previous studies with this class, indicate prenylated pterocarpans as lead compounds in research of new antivenom drugs

Synthesis and biological evaluation of thiazole derivatives as LbSOD inhibitors

Leishmaniasis is considered as one of the major neglected tropical diseases due to its magnitude and wide geographic distribution. Leishmania braziliensis, responsible for cutaneous leishmaniasis, is the most prevalent species in Brazil. Superoxide dismutase (SOD) belongs to the antioxidant pathway of the parasites and human host. Despite the differences between SOD of Leishmania braziliensis and human make this enzyme a promising target for drug development efforts. No medicinal chemistry effort has been made to identify LbSOD inhibitors. Herein, we show that thermal shift assays (TSA) and fluorescent protein-labeled assays (FPLA) can be employed as primary and secondary screens to achieve this goal. Moreover, we show that thiazole derivatives bind to LbSOD with micromolar affinity

Quercetin As An Inhibitor Of Snake Venom Secretory Phospholipase A2.

As polyphenolic compounds isolated from plants extracts, flavonoids have been applied to various pharmaceutical uses in recent decades due to their anti-inflammatory, cancer preventive, and cardiovascular protective activities. In this study, we evaluated the effects of the flavonoid quercetin on Crotalus durissus terrificus secretory phospholipase A2 (sPLA2), an important protein involved in the release of arachidonic acid from phospholipid membranes. The protein was chemically modified by treatment with quercetin, which resulted in modifications in the secondary structure as evidenced through circular dichroism. In addition, quercetin was able to inhibit the enzymatic activity and some pharmacological activities of sPLA2, including its antibacterial activity, its ability to induce platelet aggregation, and its myotoxicity by approximately 40%, but was not able to reduce the inflammatory and neurotoxic activities of sPLA2. These results suggest the existence of two pharmacological sites in the protein, one that is correlated with the enzymatic site and another that is distinct from it. We also performed molecular docking to better understand the possible interactions between quercetin and sPLA2. Our docking data showed the existence of hydrogen-bonded, polar interactions and hydrophobic interactions, suggesting that other flavonoids with similar structures could bind to sPLA2. Further research is warranted to investigate the potential use of flavonoids as sPLA2 inhibitors.1899-1

Antinociceptive Effect of the Essential Oil Obtained from the Leaves of Croton cordiifolius Baill. (Euphorbiaceae) in Mice

Croton cordiifolius Baill. is a shrub known as “quebra-faca” and is used to treat inflammation, pain, wounds, and gastrointestinal disturbances in the semiarid region in the northeast of Brazil. In an ethnobotanical survey in the state of Pernambuco, “quebra-faca” use was cited in 33% of the interviews. Thus, we decided to evaluate the antinociceptive effects of the essential oil from C. cordiifolius (CcEO). Chemical analysis by gas chromatography-mass spectrometry revealed 1,8-cineole (25.09%) and α-phellandrene (15.43%) as major constituents. Antinociceptive activity was evaluated using murine models of chemically induced pain (writhing induced by acetic acid, formalin, capsaicin, and glutamate tests). Opioid and central nervous systems (CNS) involvement were also investigated. Regarding antinociceptive activity, CcEO (50 and 100 mg/kg) reduced the number of writhing responses induced by acetic acid and decreased the licking times in both phases of the formalin test. CcEO also was evaluated in capsaicin- and glutamate-induced nociception. While no effect was observed in the capsaicin test, CcEO (100 mg/kg) was effective in the glutamate test. Naloxone, an opioid antagonist, did not affect the antinociceptive activity of CcEO in writhing test. In conclusion, the antinociceptive effect of CcEO could be explained, at least in part, by inhibition of the glutamatergic system

Synthesis and Antimicrobial Activities of 5-Arylidene-thiazolidine-2,4-dione Derivatives

Antibiotic resistance is considered one of the world's major public health concerns. The main cause of bacterial resistance is the improper and repeated use of antibiotics. To alleviate this problem, new chemical substances against microorganisms are being synthesized and tested. Thiazolidines are compounds having many pharmacological activities including antimicrobial activities. For this purpose some thiazolidine derivatives substituted at position 5 in the thiazolidine nucleus were synthesized and tested against several microorganisms. Using a disc diffusion method, antimicrobial activity was verified against Gram-positive, Gram-negative, and alcohol acid resistant bacteria and yeast. The minimum inhibition concentrations (MIC) and minimum bactericidal concentrations (MBC) were determined. All derivatives showed antimicrobial activity mainly against Gram-positive bacteria, with MIC values ranging from 2 to 16 µg/mL

Antiophidic Solanidane Steroidal Alkaloids from Solanum campaniforme

Three new solanidane alkaloids bearing a 22,23-epoxy ring (1-3) and four known compounds were isolated from leaves of Solanum campaniforme. The structures were determined using spectroscopic techniques, including ID and 2D NMR, and HRESIMS experiments. The antiophidic activity of the alkaloids was tested against Bothrops pauloensis venom. Compounds 1-3 completely inhibited myotoxicity without inhibiting phospholipase A(2) activity of the venom, while hemorrhage and skin necrosis were significantly reduced in the presence of alkaloids 1 and 2.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Biological Evaluation of Arylsemicarbazone Derivatives as Potential Anticancer Agents

International audienceFourteen arylsemicarbazone derivatives were synthesized and evaluated in order to find agents with potential anticancer activity. Cytotoxic screening was performed against K562, HL-60, MOLT-4, HEp-2, NCI-H292, HT-29 and MCF-7 tumor cell lines. Compounds 3c and 4a were active against the tested cancer cell lines, being more cytotoxic for the HL-60 cell line with IC50 values of 13.08 μM and 11.38 μM, respectively. Regarding the protein kinase inhibition assay, 3c inhibited seven different kinases and 4a strongly inhibited the CK1δ/ε kinase. The studied kinases are involved in several cellular functions such as proliferation, migration, cell death and cell cycle progression. Additional analysis by flow cytometry revealed that 3c and 4a caused depolarization of the mitochondrial membrane, suggesting apoptosis mediated by the intrinsic pathway. Compound 3c induced arrest in G1 phase of the cell cycle on HL-60 cells, and in the annexin V assay approximately 50% of cells were in apoptosis at the highest concentration tested (26 μM). Compound 4a inhibited cell cycle by accumulation of abnormal postmitotic cells at G1 phase and induced DNA fragmentation at the highest concentration (22 μM)