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Seven kinds of polyphenol compounds having ACE activities were isoated and purified by Sephadex LH-20, MCI-gel CHP-20, μ-Bondapak C_(18) and Fuji-gel ODS G₃ sucessively from cacao bean(Ghana). The chemical structures of each compound were determined and identified using analyzers such as ¹H-NMR, ^(13)C-NMR, IR, MS, polarimeter and Elemental Analysis. Inhibition effects of isolated polyphenols on angiotensin converting enzyme (concerned with hypertension) were also observed. The results obtained were as follows,; The compounds isolated and identified were confirmed and determined as compound 1 [(+)-catechin], compound 2 [(-)-epicatechin], compound 3 [procyanidin B-1 : (-)-epicatechin-(4β→8)-(+)catechin], compound 4 [procyanidin B-2 : (-)-epicatechin-(4β→8)-(-)-epicatechin], compound 5 [procyanidin B-7 : (-)-epicatechin-(4β→6)-(+)-catechin], campound 6 (procyanidin B-2,3,3´-O-digallate), compound 7 [cinnamtannin A-2 : (-)-epicatechin-(4β→8)-(-)-epicatechin-(4β→8)-(-)-epicatechin-(4β→8)-(-)-epicatechin]. In the inhibition effect on ACE, procyanidin B-2,3,3´-O-digallate (compound 6) showed a higher value of 94.6% for ACE in 100μM than other compounds such as (+)-catechin (compound 1), (-)-epicatechin (compound 2), procyanidin B-1 (compound 3), procyanidin B-2 (compound 4), procyanidin B-7 (compound 5) and cinnamtannin A-2 (compound 7) showing 67.9%, 61.9%, 88.6%, 82.5%, 72.2% and 82.3% for ACE, respectively. Inhibition of 4β→8 in coupling bond on the ACE enzyme was more effective than that of 4β→6. Procyanidin containing gallate inhibited more effectively than those containing not any. It was also observed that a lot of hydroxy group in the compounds increased the inhibitory effect.
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