OBJECTIVETo explore the partial therapeutic mechanism of Ginkgo Biloba extract (GBE) in treating asthma.

METHODSFourteen SD rats were randomly divided into two groups, 7 rats were sensitized as the asthmatic model group and the others taken as the healthy control group. T lymphocytes were isolated from peripheral blood mononuclear cells (PBMCs) of the rats, and were cultured in vitro with Ginkgolide B (BN-52021 group) or Ginkgo Biloba extract 761 (EGb761 group) in different concentrations or without any of them (control group). T lymphocytes proliferation in groups were measured by using MTT assay and the effect of BN-52021 on T lymphocytes apoptosis was analyzed by flow cytometry at various times.

RESULTSCompared with the control group, BN-52021 could significantly inhibit the proliferation of T lymphocytes in both healthy and asthmatic rats in vitro (P <0. 05). The effects were enhanced as the concentration increasing and the time prolonging, the effects to the latter were higher than those to the former, showing significant difference between them ( P <0.05 ). However, the effect of EGb761 was varied with the concentrations. EGb761 could promote T lymphocytes proliferation at low concentration but inhibit it at high concentration, there was a significant difference as compared with that in the control group ( all P < 0. 05). The apoptotic rate of T lymphocytes rose as the concentration of BN-52021 increasing (P < 0. 01).

CONCLUSIONGBE has different effects on T lymphocytes proliferation since the different ingredients and the concentrations in vitro, and it also has different effects between healthy and asthmatic rats. Ginkgolide B is the main active ingredient among them, it can not only inhibit T lymphocytes proliferation but also increase the apoptotic rate.