Bioactive saponins and glycosides. XXIII. Triterpene saponins with gastroprotective effect from the seeds of Camellia sinensis--theasaponins E3, E4, E5, E6, and E7.
The saponin fraction from the seeds of the tea plant [Camellia sinensis (L.) O. KUNTZE (Theaceae)] was found to exhibit potent protective effects on ethanol- and indomethacin-induced gastric mucosal lesions in rats. Five new triterpene saponins, theasaponins E3 (1), E4 (2), E5 (3), E6 (4), and E7 (5), were isolated together with 11 known saponins from the saponin fraction. The chemical structures of 1-5 were elucidated on the basis of chemical and physicochemical evidence. Among the isolated saponins, theasaponins E1 (6), E2 (7), and E5 (3) and assamsaponin C (10) showed an inhibitory effect on ethanol-induced gastric mucosal lesions at a dose of 5.0 mg/kg, p.o. and their activities were stronger than that of omeplazole. With regard to the structure-activity relationships of theasaponins, the following structural requirements for a protective effect on ethanol-induced gastric lesions were suggested; 1) the 21- and/or 22-acyl groups are essential for the activity, 2) acetylation of the 16-hydroxyl group reduce the activity.
Yoshikawa
Masayuki
M
Kyoto Pharmaceutical University, Misasagi, Japan. shoyaku@mb.kyoto-phu.ac.jp
Morikawa
Toshio
T
Li
Ning
N
Nagatomo
Akifumi
A
Li
Xian
X
Matsuda
Hisashi
H
D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal; D000897:Anti-Ulcer Agents / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D028244:Camellia / Q000737:chemistry*; D002240:Carbohydrate Sequence; D002492:Central Nervous System Depressants; D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D000431:Ethanol; D006868:Hydrolysis; D007213:Indomethacin; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008969:Molecular Sequence Data; D051381:Rats; D017207:Rats, Sprague-Dawley; D012503:Saponins / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D012639:Seeds / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D013276:Stomach Ulcer / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control
D000894:Anti-Inflammatory Agents, Non-Steroidal; D000897:Anti-Ulcer Agents; D002492:Central Nervous System Depressants; D012503:Saponins; D000431:Ethanol; D007213:Indomethacin