Evaluation of the cytotoxic and mutagenic potential of three ginkgolic acids.

Ginkgolic acids (GAs) are alkylphenols which can be found in the fruits and leaves of Ginkgo biloba L. (Ginkgoaceae) used in herbal teas, drugs and food supplements. Standardized leaf extracts of G. biloba are widely used in the therapy of cognitive decline including Alzheimer's diseases. However, GAs are known to have cytotoxic and allergenic potential and are suspected to possess genotoxic properties. Therefore, we examined in this study the cytotoxicity and mutagenicity of three major GAs with different alkyl or alkenyl groups (13:0, 15:1, 17:1). Cytotoxicity was assessed in male Chinese hamster lung fibroblasts (V79 cells) using the resazurin reduction assay. The substances showed concentration dependent cytotoxic effects after 24h of incubation at concentrations of 50µM and higher. Mutagenicity was determined by using the Ames fluctuation assay in different Salmonella typhimurium strains (TA97a, TA98, TA100 and TA102) with and without exogenous metabolic activation (S9 mix). Furthermore, we analyzed the mutagenic potency of the three major GAs in V79 cells by performing the hypoxanthine phosphoribosyl transferase (HPRT) assay which detects gene mutations at the HPRT locus. None of the mutagenic assays showed any increase in mutagenicity above background. Therefore, these data provide evidence that the GAs tested have some cytotoxic potency but are not mutagenic. Thus, our findings contribute to the risk assessment of preparations containing plant extracts from G. biloba.

Efeito do extrato de ginkgobiloba (EGb) sobre a toxicidade sistêmica e órgãos do sistema reprodutor masculino de ratos Wistar adultos / Effect of ginkgobiloba extract (EGb) on systemic toxicity and organs of the male reproductive system of adult Wistar rats

O Extrato de Ginkgobiloba (EGb) é um dos fitoterápicos mais consumidos no mundo. Entretanto ainda há escassez de ensaios toxicológicos em animais e o risco à exposição humana principalmente pelos compostos alquilfenóis, representados pelos ácidos ginkgólicos, que podem causar quadros alérgicos e serem compostos mutagênicos e carcinogênicos. O presente trabalho teve o objetivo de avaliar a toxicidade sistêmica do EGb. Oitenta ratos Wistar de três meses de idade foram tratados com água destilada (Grupo Controle) e extrato aquoso de Ginkgobilobanas seguintes doses: 3,5 (EGb 3,5); 7,0 (EGb 7,0) e 14,0mg/kg (EGb 14,0) uma vez ao dia, por 56 dias consecutivos. Foram avaliados semanalmente, o peso dos animais (g) e a estimativa de consumo diário de ração (g). Indícios de sinais de toxicidade sistêmica como perda de peso, piloereção, diarreia, cromodacriorreia, estereotipias, alterações da atividade locomotora e comportamentais e mortes também foram monitorados. Após anestesia, o sangue dos animais foi coletado para avaliação de hemograma completo e dosagem bioquímica de ureia, creatinina e alanina aminotransferase (ALT). Após a eutanásia, os animais foram submetidos à necropsia e os testículos esquerdo e direito, epidídimo esquerdo, vesícula seminal repleta, próstata ventral, rins esquerdo e direito, fígado e baço foram removidos e pesados em balança de precisão. Durante todo o procedimento experimental não foram observados nos animais sinais clínicos de toxicidade sistêmica e mortes. Houve diferenças estatísticas da estimativa de consumo de ração na sexta semana e oitava semanas de avaliação, embora sem diferença no peso corporal. Não houve diferença no peso dos órgãos e na análise bioquímica sérica. Na avaliação hematológica dos animais, houve diferença estatística significativa na hemoglobinometria em que o grupo EGb 14,0 apresentou-se estatisticamente superior ao grupo EGb 3,5.A concentração de hemoglobina globular média também apresentou diferença estatística significativa, em que o EGb 3,5 apresentou médias inferiores aos grupos EGb 7,0 e EGb 14,0 e o grupo controle apresentou média inferior ao grupo EGb 14,0. Sugere-se que o EGb no presente trabalho, e com as doses utilizadas, não causou toxicidade sistêmica e nem provocou alterações em órgãos de ratos Wistar.

The Ginkgobiloba Extract (EGb) is one of the most commonly consumed herbal in the world. However there are still few toxicity tests on animals and the risk of human exposure mainly by alkyl compounds, represented by acids, which can cause allergies and are mutagenic and carcinogenic compounds. This study had the objective of evaluate the systemic toxicity of EGb. Eighty Wistar rats, three months of age were treated with distilled water (Control Group) and aqueous extract Ginkgobilobanas following doses: 3.5 (EGb 3.5); 7.0 (EGb 7.0) and 14,0mg / kg (14.0 EGb) once a day for consecutive 56 days. Were evaluated weekly animal weight (g) and the estimated daily intake (g). Evidence of systemic signs of toxicity such as weight loss, piloerection, diarrhea, stereotypies and behavioral changes in motor activity and deaths were also monitored. After anesthesia, the animals were collected for evaluation of complete blood count and biochemical analysis of urea, creatinine and alanine aminotransferase (ALT). After euthanasia, the animals were autopsied and the left and right testis, left epididymis, seminal vesicle filled, ventral prostate, left and right kidneys, liver and spleen were removed and weighed on a precision scale. Throughout the experimental procedure were not observed in animals clinical signs of systemic toxicity and deaths. Were no statistical differences in the estimate of feed intake in the sixth week and eighth week evaluation, although no difference in body weight. There were no differences in organ weight and serum biochemical analysis. Hematological evaluation of the animals, there was a statistically significant difference in Hemoglobinometry where 14.0 EGb group was statistically higher than the EGb group 3,5. A mean corpuscular hemoglobin concentration also showed a statistically significant difference in the EGb 3 5 showed an average lower than 7.0 and EGb groups EGb 14.0 and the control group showed less than 14.0 EGb group. It is suggested that EGb in this work, and the doses used, did not cause systemic toxicity nor caused changes in organs of Wistar rats.