Antioxidant, genotoxic, antigenotoxic, and antineoplastic activities of apitoxin produced by Apis mellifera in Northeast, Brazil / Atividades antioxidantes, genotóxicas, antigenotóxicas e antineoplásicas da apitoxina produzida por Apis mellifera no Nordeste do Brasil

ABSTRACT: The objective was to evaluate the in vitro antioxidant, genotoxic, antigenotoxic, and antineoplastic activities of apitoxin produced by the bee Apis mellifera. The antioxidant activity of the apitoxin solution was evaluated using the DPPH (2,2-diphenyl-1-picrilhydrazyl) method. Genotoxic potential of apitoxin was analyzed by comparing the mean DNA damage indices (idDNA) of L929 strain fibroblasts exposed to hydrogen peroxide (H2O2 - genotoxic substance), distilled water, or apitoxin. The antigenotoxic effect of apitoxin was analyzed by assessing the percentage decrease in H2O2-induced genotoxicity in L929 fibroblasts co-treated with three concentrations of the aqueous apitoxin solution and subjected to comet assay. In vitro antineoplastic activity in human tumor cell lines of prostate adenocarcinoma (PC3), hepatocellular carcinoma (HEPGE2), melanoma (MAD-MB435), and astrocytoma (SNB19), were verified by MTT [3- (4) bromide colorimetric method, 5-dimethylthiazol-2-yl) -2,5-diphenyltetrazolium]. Apitoxin had no genotoxic effect on L929 cells at concentrations of 30, 10, and 5 µg/mL after 24 hours of exposure. This effect was only evident at 50 µg/mL. Apitoxin promoted a significant reduction in DNA damage index (idDNA) at all concentrations tested. At 30 µg/mL, apitoxin attenuated the genotoxic effects induced by H2O2. Apitoxin also demonstrated in vitro antineoplastic potential, since the cytotoxic effect was observed at concentrations of 50 µg/mL and 25 µg/mL, with significant reduction in viability percentage of PC3 tumor cell lines, HEPGE2, MAD-MB435, and SNB19. The high antioxidant activity associated with the absence of genotoxic effect and the genoprotective and antineoplastic effect demonstrated by apitoxin here provide indications of apitoxin's therapeutic potential.

RESUMO: O objetivo deste estudo foi avaliar as atividades antioxidantes, genotóxicas, antigenotóxicas e antineoplásicas in vitro da apitoxina produzida pela abelha Apis mellifera. A atividade antioxidante da solução da apitoxina foi avaliada pelo método DPPH (2,2-difenil-1-picrilhidrazil). O potencial genotóxico da apitoxina foi analisado através dos índices médios de dano ao DNA (idDNA) dos fibroblastos da linhagem L929 expostos à peróxido de hidrogênio (H2O2 - substância genotóxica), água destilada ou apitoxina. O efeito antigenotóxico da apitoxina foi analisado através da avaliação da diminuição percentual na genotoxicidade induzida por H2O2 nos fibroblastos L929 co-tratados com três concentrações da solução aquosa de apitoxina e submetidos ao ensaio cometa. A atividade antineoplásica in vitro em linhagens celulares tumorais humanas de adenocarcinoma da próstata (PC3), carcinoma hepatocelular (HEPGE2), melanoma (MAD-MB435) e astrocitoma (SNB19), foram verificadas pelo método colorimétrico do brometo de MTT [3- (4), 5-dimetiltiazol -2-il) -2,5-difeniltetrazólio]. A apitoxina não teve efeito genotóxico nas células L929 nas concentrações de 30, 10 e 5 µg / mL após 24 horas de exposição. Este efeito foi apenas evidente a 50 µg / mL. A apitoxina promoveu uma redução significativa no índice de danos ao DNA (idDNA) em todas as concentrações testadas. A 30 µg / mL, a apitoxina atenuou os efeitos genotóxicos induzidos por H2O2. A apitoxina também demonstrou potencial antineoplásico in vitro, uma vez que o efeito citotóxico foi observado em concentrações de 50 µg / mL e 25 µg / mL, com redução significativa na porcentagem de viabilidade das linhagens celulares de PC3, HEPGE2, MAD-MB435 e SNB19. A alta atividade antioxidante associada à ausência de efeito genotóxico e o efeito genoprotetor e antineoplásico demonstrado pela apitoxina aqui fornecem indicações do potencial terapêutico da apitoxina.

Hepatoprotective and antineoplastic potencial of red propolis produced by the bees Apis mellifera in the semiarid of Rio Grande do Norte, Brazil / Potencial hepatoprotetor e antineoplásico da própolis vermelha produzida pela abelha Apis mellifera no semiárido do Rio Grande do Norte, Brasil

The objective of this study was to evaluate the hepatoprotective effect of the honey bee Apis mellifera ethanolic extract of the red propolis, obtained in four municipalities of the Rio Grande do Norte semi-arid region, through an in vitro evaluation of the antineoplastic potential in human hepatic carcinoma (HepG2) and normal cell lines (L929), and from the comet assay in hepatic cell lines (ZF-L hepatocytes) to evaluate the genoprotective potential of the extract. The hepatoprotective effect was also evaluated in vivo by the induction of chronic experimental hepatic lesions in rodents (Rattus norvegicus Berkenhout, 1769), Wistar line, by intraperitoneal administration of thioacetamide (TAA) at the dose of 0.2g/kg. The animals were distributed in the following experimental groups: G1 (control), G2 (treated with 500mg/kg ethanolic extract of propolis), G3 (treated with 500mg/kg of ethanolic extract and TAA) and G4 (treated with TAA). All rats were submitted to serum biochemical, macroscopic, histological and stereological biochemical exams of the liver. It was verified the genoprotective effect of red propolis since the mean damages promoted to DNA in cells tested with the extract were significantly lower than the mean of the positive control damage (hydrogen peroxide). The red propolis extract did not present cytotoxic activity to the tumor cells of human liver cancer, as well as to normal ones. The absence of cytotoxicity in normal cells may indicate safety in the use of the propolis extract. The results of the serum biochemical evaluation showed that the serum levels of the aminotransferase enzymes (AST) did not differ significantly between G1, G2 and G3 when compared to each other. G4 showed significant increase in levels compared to the other groups, indicating that the administration of the extract did not cause liver toxicity, as well as exerted hepatoprotective effect against the hepatic damage induced by TAA. The G3 and G4 animals developed cirrhosis, but in G3 the livers were characterized by the presence of small regenerative nodules and level with the surface of the organ, whereas in G4 the livers showed large regenerative nodules. The livers of the G1 and G2 animals presented normal histological appearance, whereas the livers of the G3 animals showed regenerative nodules surrounded by thin septa of connective tissue, and in G4 the regenerative nodules were surrounded by thick septa fibrous connective tissue. The analysis of the hepatic tissues by means of stereology showed that there was no statistical difference between the percentage of hepatocytes, sinusoids, and collagens in G1 and G2. In G3 the percentage of hepatocytes, sinusoids, and collagen did not differ significantly from the other groups. It was concluded that the ethanolic extract of the red propolis exerted a hepatoprotective effect, because it promoted in vitro reduction of the damage to the DNA of liver cells, antineoplastic activity in human hepatocellular carcinoma cell line (HepG2) and did not exert cytotoxic effect in normal cells or was able to reduce liver enzyme activity and the severity of cirrhosis induced by TAA in vivo.(AU)

Este estudo objetivou avaliar o efeito hepatoprotetor do extrato etanólico da própolis vermelha da abelha Apis mellifera, obtido em quatro municípios do semiárido do Rio Grande do Norte, mediante avaliação in vitro do potencial antineoplásico em linhagens de células de carcinoma hepático humano (HepG2) e em linhagens de células normais (L929), além do ensaio cometa em linhagens de células hepáticas (hepatócitos ZF-L) para avaliar o potencial genoprotetor do extrato. O efeito hepatoprotetor também foi avaliado in vivo através da indução de lesões hepática experimental crônica em roedores da espécie Rattus norvegicus (Berkenhout, 1769), linhagem Wistar, pela administração intraperitoneal de tioacetamida (TAA) na dose de 0,2g/kg. Os animais foram distribuídos nos seguintes grupos experimentais: G1 (controle), G2 (tratados com 500mg/kg de extrato etanólico da própolis), G3 (tratados com 500mg/kg de extrato etanólico e TAA) e G4 (tratados com TAA). Todos os ratos foram submetidos aos exames bioquímico sérico, anatomopatológico macroscópico, histológico e esteriológico do fígado. Foi constatado o efeito genoprotetor da própolis vermelha uma vez que as médias dos danos promovidos ao DNA em células testadas com o extrato foram significativamente inferiores à média dos danos do controle positivo (peróxido de hidrogênio). O extrato da própolis vermelha não apresentou atividade citotóxica para células tumorais de câncer de fígado humano, bem como para normais. A ausência de citotoxicidade em células normais, tal como constatado, pode indicar segurança no uso do extrato da própolis. Os resultados da avaliação bioquímica sérica demonstraram que os níveis séricos das enzimas aminotransferase (AST) não diferiram significativamente entre G1, G2 e G3, quando comparadas entre si. No G4 houve aumento significativo dos níveis em relação aos demais grupos, indicando que a administração do extrato não causou toxicidade hepática, bem como exerceu efeito hepatoprotetor frente ao dano hepático induzido pela TAA. Os animais dos G3 e G4 desenvolveram cirrose, porém no G3 os fígados caracterizaram-se pela presença de pequenos nódulos regenerativos e nivelados com a superfície do órgão, enquanto que no G4 os fígados apresentaram grandes nódulos regenerativos. Os fígados dos animais G1 e G2 apresentaram aspecto histológico normal, enquanto que os fígados dos animais do G3 apresentaram nódulos regenerativos circundados por finos septos de tecido conjuntivo, e nos do G4 os nódulos regenerativos foram circundados por espessos septos de tecido conjuntivo fibroso. A análise dos tecidos hepáticos por meio de estereologia mostrou que não houve diferença estatística entre o percentual de hepatócitos, sinusoides e colágenos nos G1 e G2. No G3 o percentual de hepatócitos, sinusoides e colágeno não diferiu significativamente dos demais grupos. Concluiu-se que o extrato etanólico da própolis vermelha exerceu efeito genoprotetor, por promover in vitro redução do dano ao DNA de células hepáticas, atividade antineoplásica em linhagem celular de carcinoma hepatocelular humano (HepG2) e não exerceu efeito citotóxico em células normais ou efeito hepatoprotetor in vivo com diminuição da gravidade da cirrose induzida por TAA.(AU)

Cuban flora species as a potential source of DNA protective compounds / Especies de la flora cubana cómo fuente potencial de compuestos protectores del DNA

Environmental exposure to genotoxic agents represents a major health concern for modern society. DNA damage could lead to mutations, which accumulative effect is closely related to degenerative and lethal diseases, such as cancer. Because of their structural and chemical diversity natural products play a fundamental role in pharmaceutical sciences for novel drug discovery. The present review article focuses on pre-clinical studies done with some species from Cuban flora that have been tested with positive antigenotoxic properties against different genotoxins. Special emphasis regarding molecular mechanisms suggested, from antioxidant activity to DNA repair modulation, a critical discussion of the state of art and the perspectives in the use of these plants as a new and promising strategy for genoprotection in the 21st Century are included.

La exposición ambiental a agentes genotóxicos representa un problema de salud significativo en la sociedad actual. El daño al ADN puede generar mutaciones, cuyo efecto acumulativo se encuentra estrechamente relacionado con enfermedades degenerativas y letales como el cáncer. Debido a su diversidad estructural y química los productos naturales juegan un papel fundamental en las ciencias farmacéuticas en el descubrimiento de nuevas drogas. El presente artículo de revisión puntualiza estudios pre-clínicos realizados con determinadas especies de la flora cubana que han sido estudiadas con una respuesta antioxidante positiva frente a diferentes genotoxinas. Se enfatizan especialmente los mecanismos moleculares sugeridos, desde actividad antioxidante hasta modulación de la reparación del ADN, así como una discusión crítica del estado del arte y las perspectivas en el empleo de estas plantas como una estrategia nueva y prometedora para la genoprotección en el siglo 21.

Antioxidant capacity and genoprotective effect of ethanol fruit extract from Detarium microcarpum Guill. and Perr. (Caesalpiniaceae)

Objective To evidence the ability of ethanol fruit extract from Detarium microcarpum (D. microcarpum) to preserve DNA integrity against oxidative genomic damage. Methods Ethanol extract from D. microcarpum fruit pulp was analyzed for its antioxidant capacity using ferric reducing antioxidant power, 2,2-diphenyl-1-picrylhydrazyl, 2,2′-azinobis-3-ethyl-ethylbenzothiazoline-6-sulphonate, superoxide anion, deoxyribose degradation and lipid peroxidation models. The genoprotective activity was assessed ex vivo by comet assay, on liver cells of NMRI female mice using cyclophosphamide (CP) as genotoxic agent. Results Ethanol extract from D. microcarpum fruit pulp exhibited interesting antioxidant activity in 2,2-diphenyl-1-picrylhydrazyl, deoxyribose degradation and lipid peroxidation assays. The extract did not present any genotoxic effect but protected DNA against CP-induced damages with a dose-dependent manner. The genoprotective effect observed was related to the antioxidant molecules of the fruit that scavenged the hydroxyl radical (generated by the metabolism of CP) as well as the peroxyl and alkoxyl radicals issued from lipid peroxidation. Other mechanisms such as inactivation of CP metabolism to genotoxic end products, induction of the expression of antioxidant and DNA repair enzymes have been discussed. Conclusions Our results suggest that the wild edible fruit from D. microcarpum could be beneficial on consumer's health by its antioxidant and genoprotective effects, particularly during chemotherapies exhibiting genotoxic effects like CP in cancer treatment.

Antioxidant potential and oxidative DNA damage preventive activity of unexplored endemic species of Curcuma.

Free radical scavenging activity, ferrous ion chelating capacity, reducing power and genoprotective effect of the aqueous leaf extracts of four unexplored endemic Curcuma spp. (C. vamana, C. neilgherrensis, C. mutabilis, C. haritha) were found to be dose-dependent and were highest in C. vamana. DNA protection property of the extracts was evaluated against H2O2/UV-induced oxidative damage. DNA-methyl green displacement assay showed that these extracts were free of DNA intercalating compounds. Further, hemolysis assay also showed that the extracts were non-toxic to human erythrocytes. The results highlight C. vamana as a promising source for herbal preparations possessing high antioxidant potential and genoprotective activity.