Structures of steroidal alkaloid oligoglycosides, robeneosides A and B, and antidiabetogenic constituents from the Brazilian medicinal plant Solanum lycocarpum.
In the course of our studies on antidiabetogenic compounds from natural medicines and medicinal foodstuffs, a methanolic extract of the fruits of Solanum lycocarpum showed an inhibitory effect on the increase of serum glucose levels in oral sucrose-loaded rats. Through bioassay-guided separation, three known steroidal alkaloid oligoglycosides, solamargine (1), solasonine (3), and 12-hydroxysolasonine (5), were isolated from the active fraction together with two new steroidal alkaloid oligoglycosides, robeneosides A (2) and B (4). The major constituents, solamargine (1) and solasonine (3), exhibited an inhibitory effect on the increase of serum glucose levels in oral sucrose-loaded rats. In addition, these compounds suppressed gastric emptying in mice. However, this methanolic extract from S. lycocarpum fruits did not have any effect on intestinal alpha-glucosidase (sucrase and maltase) in vitro. It was concluded that these steroidal alkaloid oligoglycosides, 1 and 3, inhibited the increase of rat serum glucose levels by suppressing the transfer of sucrose from the stomach to the small intestine.
Yoshikawa
Masayuki
M
Kyoto Pharmaceutical University, Misasagi, Yamashina-ku, Kyoto 607-8412, Japan. myoshika@mb.kyoto-phu.ac.jp
Nakamura
Seikou
S
Ozaki
Kenichi
K
Kumahara
Akira
A
Morikawa
Toshio
T
Matsuda
Hisashi
H
D000470:Alkaloids / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D000818:Animals; D001786:Blood Glucose / Q000187:drug effects; D001938:Brazil; D006027:Glycosides / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D007004:Hypoglycemic Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D015394:Molecular Structure; D010946:Plants, Medicinal / Q000737:chemistry*; D051381:Rats; D017208:Rats, Wistar; D032322:Solanum / Q000737:chemistry*; D013256:Steroids / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D000520:alpha-Glucosidases / Q000187:drug effects
D000470:Alkaloids; D001786:Blood Glucose; D006027:Glycosides; D007004:Hypoglycemic Agents; D013256:Steroids; C518550:robeneoside A; C518551:robeneoside B; D000520:alpha-Glucosidases