Safety Evaluation Of Ginkgo Biloba Extract

Based on the current reports from both domestic and foreign countries,Ginkgo Biloba Extract has extensive pharmacological actions,such as anti-bacterial,anti-viruses,anti-oxidant,enhance immunity,reduce lipid and so on.Ginkgo Biloba Extract has been widely used in medical care,food industry and daily chemical industry.The studies described here were performed to evaluate the preclinical toxicity of Ginkgo Biloba Extract,and hopefully that it can provide a theoretical basic for thr use of Ginkgo Biloba Extract in Veterinary domain.Acute toxicitu study of Ginkgo Biloba Extract following single oral administration in CD1 miceObjective:To evaluate the acute oral toxicity of Ginkgo Biloba Extract.Method: 25 CD1 mice per sex were placed on this study.The Ginkgo Biloba Extract was homogenized in 0.5% CMC-Na and yields a homogenous suspension for oral dosing at 20 mL/kg.After dosing,the mice were returned to the cage for further observation.No animal was found dead and no abnormal clinical observation was records with 14 days post dosing.Result:Based on the result of modified Karber’s method,the LD50 value of Ginkgo Biloba Extract following single oral administration in CD1 mice is 13 429 mg/kg with an approximate 95% confidence interval ranging from 12 228 mg/kg to 15 098 mg/kg.According to the classification table of chemical acute toxicity,Ginkgo Biloba Extract was classified as a no-toxic substance.Subchronic toxicity study of Ginkgo Biloba Extract following 30 consecutive days oral administration in SD ratsObjective: The purpose of this study was to determine the subchronic toxicity in SD rats for Ginkgo Biloba Extract.Method: Forty male and 40 female SD rats were randomly divided into 4 groups,and received the treatment of vehicle or Ginkgo Biloba Extract under different dosages for 30 consecutive days.The mortality,clinical observation,clinical pathology,gross necropsy and some other indexes were utilized as the important index for toxicology evaluation.Result: During the entire study period,no animal was found dead and no obvious clinical observations were observed.The study record generally indicated that the Ginkgo Biloba Extract treatment didn’t impair the appetite,bodyweight growth under the current dosage.Besides the urine analysis,no abnormality was found in all treatment groups for hematology,serum chemistry and coagulation test.No abnormality was found in all treatment groups for histopathology examination and organ index.In summary,following 30 consecutive days oral gavage of Ginkgo Biloba Extract at 4 000 mg/kg did not impair the animal health;the product is safe enough for clinical use of Ginkgo Biloba Extract.Ames test of Ginkgo Biloba ExtractObjective: This study was conducted to evaluate the test articles,Ginkgo Biloba Extract,for their ability to induce reverse mutations.Method: The assay was conducted in both the presence and absence of mammalian microsomal enzyme at the histidine locus in the genome of 5 strains of Salmonella typhimurium(TA97a,TA98,TA100,TA102,TA1535)with concurrent vehicle(acetone)and positive controls in duplicate using 6-well plates.Five concentrations ranging from 128 to 5000 mg/well were tested for the compound.Result: Results from the current study showed that Ginkgo Biloba Extract did not induce a positive increase in the mean number of revertants per well with these five strains of Salmonella typhimurium in the presence or absence of microsomal enzymes,and it is non-mutagenic.Micronucleus test of Ginkgo Biloba Extract in CD1 miceObjective: The purpose of this study was to conduct a micronucleus test in CD1 mice for Ginkgo Biloba Extract.Method: Thirty male and 30 female CD1 mice were randomly divided into 6 groups,and received the treatment of vehicle or Ginkgo Biloba Extract under three different dosages,a positive control,a negative control and a solvent control.At the end of the in-life study,try to make the bone marrow smears and examine the micronucleus of PCE.Result: Ginkgo Biloba Extract is nonmutagenic.