Purification And Pharmacodynamics Of Hypotensive Factor From Cobra Venom Of Guangxi

Objective:To separate and purify the hypotensive factor(HF) from cobra venom of Guangxi and study its biological activity,hypotensive effect,inhibition of cardiomyocyte hypertrophy and cytotoxicity.Methods:(1) HF was purified from the cobra venom of Guangxi by Sephacryl S-100 and Superose 12.Molecular weight and purity were calculated by analyzing the results of SDS-PAGE and HPLC.Inhibitory activity of ACE and the activity of Arginine Esterase(AE)were also used to detect the effect of HF.The effect of HF on contraction of rabbit duodenum was observed in vitro.(2)LD₅₀in mice of HF was calculated by Bliss.The hypotensive effects in both normal rats and SHR were detected by BL-420 biological signal analysis system.(3)The adrenaline-induced hypertrophy in cardiomyocytes was analyzed by method of morphology.The inhibition of proliferation of HF was studied on two cultured tumor cells(Be17404,SGC7901)and myocardial-fibroblast by MTT.Results:(1) SDS-PAGE showed a single band by HF under reducing and non-reducing conditions and a molecular weight of 8.18KD.Recovery rate of protein was 5.70%.The result of high performance liquid chromatography(HPLC)showed a single peak.HF was consisted of a single polypeptide chain of 12 amino acids. HF could strengthen the effect of contraction by BK in rabbit duodenum in vitro. (2)Experiment of acute toxicity in mice was researched and the LD₅₀was 23.13mg/kg.The confidence interval(95%)of LD₅₀was 20.98-25.66mg/kg.HF could increase the descents of blood pressure by BK in normal rats and SHR at the dosage of 80μg/kg.(3)HF could inhibit obviously the surface area of cardiomyocytes induced by adrenaline.The cytotoxicity effect of HF on Be17404,SGC7901 and MF cells was also found with a fine concentrationdependent relationship.Conclusion:HF may be an angiotensin-converting enzyme inhibitor resulting in hypotensive effect.