Structure of a new echinocystic acid bisdesmoside isolated from Codonopsis lanceolata roots and the cytotoxic activity of prosapogenins.
We isolated a new saponin named codonoposide (1) from the roots of Codonopsis lanceolata (Campanulaceae) and characterized it as 3-O-[beta-D-xylopyranosyl(1-3)-beta-D-glucuronopyranosyl]-3beta,16alpha-dihydroxyolean-28-oic acid 28-O-[beta-D-xylopyranosyl (1-3)-alpha-L-rhamnopyranosyl (1-2)-alpha-L-arabinopyranosyl] ester by chemical, physicochemical, and 2DNMR techniques. Complete hydrolysis of 1 produced a sapogenin (1a), and the partial hydrolysis and further isolation afforded two prosapogenins (1b, 1c). The structures of 1a, 1b, and 1c were found to be 3beta,16alpha-dihydroxyolean-28-oic acid (echinocystic acid, 1a), 3-O-beta-D-glucuronopyranoside of 1a, and 3-O-beta-D-xylopyranosyl (1-3)-beta-D-glucuronopyranoside of 1a, respectively, on the basis of spectroscopic data. On MTT assay, 1a showed marginal cytotoxic activity whereas 1b exhibited more cytotoxicity than 1a. However, the bisdesmosylsaponin 1 exhibited no cytotoxicity (IC(50)>0.3 mM against tested cell lines). This result indicated that glycoside linkage of glucuronic acid at C-3 enhances the cytotoxicity of sapogenin (1a), and additive glycosylation of xylose to 1b strongly enhances the cytotoxicity of 3-O-monosaccharides (1b). Therefore, true forms of codonoposide for the cytotoxicity must be sapogenins or prosapogenins.
Lee
Kyung-Tae
KT
College of Pharmacy, Kyung-Hee University, Seoul, Korea.
Choi
Jongwon
J
Jung
Won-Tae
WT
Nam
Jung-Hwan
JH
Jung
Hyun-Ju
HJ
Park
Hee-Juhn
HJ
D002236:Carbohydrate Conformation; D016923:Cell Death / Q000187:drug effects*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D029745:Codonopsis / Q000737:chemistry*; D006868:Hydrolysis; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D018517:Plant Roots / Q000737:chemistry*; D012503:Saponins / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D016339:Spectrometry, Mass, Fast Atom Bombardment; D013329:Structure-Activity Relationship
D012503:Saponins; C463759:codonoposide; C026473:prosapogenin