ANGIOTENSIN CONVERTING ENZYME (ACE) INHIBITORY ACTIVITY OF ALOE VERA (ALOE BARBADENSIS MILLER) RAW GEL

Aloe barbadensis miller raw gel (KJM) was extracted and purified to homogeneity and then identified as a single band with a molecular weight greater than 250 kDa by toluidine blue staining on a sodium dodecyl sulfate-polyacrylamide gel electrophoresis gel treated with 2-mercaptoethanol. The purified KJM was shown to inhibit ACE in a dose-dependent manner (28.7–59.8% ACE inhibition by 102.46–409.84 µg/mL KJM, respectively) using (N-(3-[2-furyl]acryloyl)-Phe-Gly-Gly) (FAPGG) as a substrate by spectrophotometry. The concentration of KJM required for 50% inhibition (IC50) of ACE activity was 256.2 µg/mL, whereas that of captopril was 0.00781 µM (0.0095 nmole). Commercially available polysaccharide pectin (102.46–307.38 µg/mL) did not exhibit any inhibitory activity against ACE. Detection of FAPGG and FAP using fluorescent silica TLC or C 18 reversed-phase HPLC showed that KJM inhibited ACE. KJM exhibited mixed inhibition of ACE, and the Michaelis constant was 0.33 mM in the presence of KJM. Consumption of Aloe barbadensis Miller raw gel may be beneficial for human blood and vascular health.