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Aims: This study investigated the antioxidant, hypolipidemic and angiotensin converting enzyme (ACE) inhibitory effects of flavonoid-rich fraction of H. thebaica on fat-fed obese wistar rats. Study Design: Twenty-five rats were divided into 5 groups of 5 rats each: Control (standard diet, untreated), Obese control (Fat-fed, untreated), Standard control (Fat-fed, treated with 70 mg/kg Atorvastatin), Groups 4 and 5 (Fat-fed, treated with 100 and 250 mg kg-1 flavonoid-rich fraction, respectively). The rats were given high fat diet to induce obesity, after which treatment was administered for fourteen (14) days, and on the 15th day, rats were sacrificed and blood samples collected. Results: From the results, induction of obesity significantly (P<0.05) increased body weight, some lipoproteins, ACE activity, superoxide dismutase, catalase and glutathione peroxidase levels, while HDL cholesterol and malondialdehyde levels decreased. Treatment of obese rats with the standard drug, atorvastatin and flavonoid-rich fraction of H. thebaica significantly (P<0.05) decreased ACE activity, total cholesterol, triglyceride and LDL cholesterol, while HDL cholesterol and malondialdehyde increased. Conclusion: This study has demonstrated that the flavonoid-rich fraction of H. thebaica is hypolipidemic, possesses antioxidant activities, and may contain potent ACE inhibitors.

Angiotensin converting enzyme (ACE) was isolatedand partially purifiedfrom the lungs of Wistarrats (Rattusnorvegicus). The ACE was characterized and its amino acids composition determined.ACE was purified by ammonium sulphate precipitation, dialysis and ge chromatography. The activity of the enzyme was assayed by a spectrophotometric method, which involves monitoring the rate of production of hippuric acid from the hydrolysis of Hippuryl Histidyl-L-Leucine by ACE.Protein concentration wasassay optimum temperature and pH of the isolated enzyme were also determined. From the results, crude enzyme had a total activity of 0.12 U and a specific activity of 0.048U/mg of protein.Precipitation of protein increased the specific activity to 0.050U/mg at a recovery rate of 62%. Upon dialysis, the activity of the enzyme decreased from 0.074U to 0.038Uwhile specific activityalso increased. At this stage, only about 31% of the enzyme activity was retained over t crude. After gel filtration the specific activity of the enzyme increased to 0.087U/mg at a purification fold of 1.8 and a final recovery of 25%.The enzyme had an optimum pH and temperature of 7.0 and 40 0 C, respectively. The partially purified enzyme is havingseventeen amino acids:KHRDTSGPGACVMILYF. In conclusion, angiotensin-converting enzyme can be isolated from rat lungs, but the purification steps needs to be modified to obtain an enzyme with higher yield and assessable for research in developing countries.

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