Effects of ginkgo biloba extract on learning and memory and protection of hippocampal neurons in rats with vascular dementia / 中华行为医学与脑科学杂志

Objective To investigate the effects of ginkgo biloba extracts ( EGb761) on learning and memory and the protective effect on hippocampal neurons in rats with vascular dementia (VD). Meth-ods Ninety rats were randomly divided into sham-operated group,model group and EGb761-treated group, with 30 rats in each group. Rats in each group were examined at 15 days,1 month and 2 months,with 10 rats in each time point. VD model was established by bilateral carotid artery occlusion combinding with injection of sodium nitroprusside. Morris water maze test was used to detect the learning and memory function of rats. The expression of glial fibrillary acidic protein (GFAP) was observed by immunofluorescence. Western-blot was used to detect the protein expression of P-glycoprotein ( P-GP ), excitatory amino acid transporters 2 ( EAAT2),caspase-3 and cleaved caspase-3. RT-PCR was used to detect the mRNA expression of P-GP and EAAT2 in the hippocampus of rats in each group. Results Compared with sham-operated group,the escape latency (EL) was significantly prolonged at each time point in model group ( sham-operated group:15 days (15. 52±3. 23) s,1 month ( 14. 21 ± 2. 62) s,2 months ( 15. 37 ± 1. 66) s;model group:15 days ( 30. 35 ± 2. 30)s,1 month(40. 78± 3. 55) s, 2 months( 33. 88± 1. 47) s; all P<0. 01). The EL of EGb761-treated group was significantly shorter than that of the model group(EGb761-treated group:15 days(25. 69±2. 44)s, 1 month(20. 78±1. 72)s,2 months(18. 23±1. 67)s,all P<0. 01). Immunofluorescence showed that the ex-pression of GFAP in EGb761-treated group was lower than that of the model group (P<0. 01). Western blot showed that cleaved caspase-3 protein expression in EGb761-treated group at each time point was significant-ly lower than that in the model group (P<0. 01). Western-blot and RT-PCR results showed that the protein and mRNA expression of P-GP and EAAT2 in EGb761-treated group at 15 day and 1 month time points were significant increased than those in the model group (P<0. 01). At 2 month time point,which were lower than those in the model group (P<0. 01). Conclusion EGb761 can improve the learning and memory ability of VD rats,and regulate the protein and mRNA expression of P-GP and EAAT2 in hippocampus of VD rats at different time points (up-regulated in 1 month and down-regulated in 2 month),and down-regulate the ex-pression of cleaved caspase-3 and GFAP at different time points,thereby delaying the brain damage of VD rats and protecting neurons.

The effects of the standardized extracts of Ginkgo biloba on steroidogenesis pathways and aromatase activity in H295R human adrenocortical carcinoma cells

OBJECTIVES: Aromatase inhibitors that block estrogen synthesis are a proven first-line hormonal therapy for postmenopausal breast cancer. Although it is known that standardized extract of Ginkgo biloba (EGb761) induces anti-carcinogenic effects like the aromatase inhibitors, the effects of EGb761 on steroidogenesis have not been studied yet. Therefore, the effects of EGb761 on steroidogenesis and aromatase activity was studied using a H295R cell model, which was a good in vitro model to predict effects on human adrenal steroidogenesis. METHODS: Cortisol, aldosterone, testosterone, and 17β-estradiol were evaluated in the H295R cells by competitive enzyme-linked immunospecific assay after exposure to EGb761. Real-time polymerase chain reaction were performed to evaluate effects on critical genes in steroid hormone production, specifically cytochrome P450 (CYP11/17/19/21) and the hydroxysteroid dehydrogenases (3β-HSD2 and 17β-HSD1/4). Finally, aromatase activities were measured with a tritiated water-release assay and by western blotting analysis. RESULTS: H295R cells exposed to EGb761 (10 and 100 μg/mL) showed a significant decrease in 17β-estradiol and testosterone, but no change in aldosterone or cortisol. Genes (CYP19 and 17β-HSD1) related to the estrogen steroidogenesis were significantly decreased by EGb761. EGb761 treatment of H295R cells resulted in a significant decrease of aromatase activity as measured by the direct and indirect assays. The coding sequence/ Exon PII of CYP19 gene transcript and protein level of CYP19 were significantly decreased by EGb761. CONCLUSIONS: These results suggest that EGb761 could regulate steroidogenesis-related genes such as CYP19 and 17β-HSD1, and lead to a decrease in 17β-estradiol and testosterone. The present study provides good information on potential therapeutic effects of EGb761 on estrogen dependent breast cancer.

Development in New Dosage Forms of Active Components from Ginkgo Biloba Extracts / 中国药师

The main active components in Ginkgo biloba extracts were Ginkgo biloba flavonoids and lactone compounds. This pa-per reviewed on the kinds and pharmacological effects of the active ingredients in Ginkgo biloba extracts, and focused on four aspects including controlled-release preparations, solubilized solid preparations, nanoparticle formulations and time- and site-specific formula-tions to introduce the development in the new dosage forms of Ginkgo biloba flavonoids and lactone compounds.

Technology Optimization and Identification of Ginkgo Biloba Extracts-hydroxyprop-?-cyclodextrin(GBE-HP-?-CD) Inclusion Compounds / 中国药房

OBJECTIVE:To optimize the preparation technology of Ginkgo biloba extracts-hydroxyprop-?-cyclodextrin(GBE-HP-?-CD) inclusion compounds and to identify this inclusion compound.METHODS:The optimum preparation condition was studied by orthogonal test with encapsulation rate as the index of evaluation.The inclusion compounds were prepared with solution-agitating technique.The inclusion compounds were identified by phase solubility diagra-m,differential scanning calorimetry(DSC) and infrared spectroscopy methods,respectively.RESULTS:The optimum inclusion condition was as follows:the ratio of GBE to HP-?-CD=1.5∶1;agitating time=6 h;inclusion temperature=50 ℃.CONCLUSION:It has been preliminarily proved that it is possible for Ginkgo biloba extracts and hydroxyprop-?-cyclodextrin to be made into inclusion compounds.HP-?-CD has satisfactory solublization on Ginkgo biloba extracts.