Inhibition of angiotensin-I-converting enzyme by tetrahydroxyxanthones isolated from Tripterospermum lanceolatum.
Five tetrahydroxyxanthones, 3,4,6,7-tetrahydroxyxanthone [1], 1,3,5,6-tetrahydroxyxanthone [2], 3,4,5,6-tetrahydroxyxanthone [3], 1,3,6,7-tetrahydroxyxanthone [4], and 2,3,6,7-tetrahydroxyxanthone [5] isolated from Tripterospermum lanceolatum inhibited angiotensin-I-converting-enzyme activity in a dose-dependent manner. The mode of inhibition of the tetrahydroxyxanthones (THXs) was found to be competitive inhibition. When the tetrahydroxy groups of THXs were blocked with acetyl groups, the angiotensin-I-converting-enzyme inhibitory activity was abolished, suggesting that the tetrahydroxy groups are indispensible for the inhibitory activity.
Chen
C H
CH
Institute of Biochemistry, College of Medicine, National Taiwan University, Taipei, Republic of China.
Lin
J Y
JY
Lin
C N
CN
Hsu
S Y
SY
D000806:Angiotensin-Converting Enzyme Inhibitors / Q000302:isolation & purification / Q000494:pharmacology*; D000818:Animals; D004365:Drugs, Chinese Herbal / Q000737:chemistry*; D008297:Male; D051381:Rats; D011918:Rats, Inbred SHR; D014966:Xanthenes / Q000302:isolation & purification / Q000494:pharmacology*
D000806:Angiotensin-Converting Enzyme Inhibitors; D004365:Drugs, Chinese Herbal; D014966:Xanthenes