AN IN VITRO STUDY OF CINNAMOMUM ZEYLANICUM AS NATURAL INHIBITOR OF ANGIOTENSIN-CONVERTING ENZYME (ACE) ON SHEEP (OVIS ARIES) TISSUES

Objective: The present study was aimed to find the angiotensin-converting enzyme (ACE) inhibitory activity using the methanolic extract of Cinnamomum zeylanicum (as a natural inhibitor) on sheep tissues as the enzyme source. Methods: Hippuryl-histidyl-leucine (HHL) as a substrate, tissue ACE activity was measured spectrophotometrically at 228 nm. For an incubation period of 30 minutes at 37°C, the linearity of ACE activity of kidney, lung, and testis enzyme was established. A known medicinal plant C. zeylanicum was used as natural inhibitor of ACE. In this enzyme assay, inhibitory effect of methanolic extract of C. zeylanicum on kidney, lung and testicular ACE was determined. ACE activity was confirmed by captopril, a standard inhibitor of ACE. Results: In the presence of a methanolic extract of C. zeylanicum (10:1), ACE activity was determined and this has inhibited ACE activity very significantly. C. zeylanicum leaves extract has reduced sheep kidney, lung, and testis ACE activity by 70.06%, 12.63%, and 20.23%, respectively. Conclusion: Significant inhibition was observed in the kidney ACE than in lung and testis ACE activity. This can propose that there may be a possible role in controlling blood pressure or reduction in cardiovascular diseases. Some plants with the great medicinal property may be considered as promising sources of natural inhibitors of ACE for medicine and commercial uses. This comprehensive study may show numerous beneficial effects as a potential therapeutic agent for lowering blood pressure. Keywords: Angiotensin-converting enzyme, Natural angiotensin-converting enzyme inhibitor, Kinetic assay, Hippuryl-histidyl-leucine, Cinnamomum zeylanicum, Cardiovascular diseases.