Chemical Constituents from Pedicularis rex C. B. Clarke
Hong-Biao Chua,b, Ning-Hua Tana, and Yu-Mei Zhanga
a State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of
Botany, Chinese Academy of Sciences, Kunming 650204, China
b Graduate School of the Chinese Academy of Sciences, Beijing 100039, China
Reprint requests to Prof. Dr. Ning-Hua Tan or Dr. Yu-Mei Zhang. Fax: +86-871-5223800.
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Z. Naturforsch. 2007, 62b, 1465 – 1470; received June 5, 2007
One new iononeglycoside
–250 . Among them, compounds 247–249 are new. Compound 249 exhibits weak cytotoxic activity against HepG2 and MCF-7 human cell lines [ 109 ]. Four megastigmane derivatives 251–254 and 257 were isolated in 2012 [ 7 ], [ 112 ]. A new iononeglycoside 255 was also isolated from this plant. This is the first report of the occurrence of iononeglycosides in Ajuga species [ 111 ]. Table 6 Sesquiterpenoids. No. Name Source Part Ref. 246 Glecholone A. decumbens aerial part [ 7 ] 247 3 α -Acetoxy-1 α ,8 β -dihydroxyeudesm-7(11)-en-8,12-olide A. forrestii whole plant [ 109
have been published .
The exciton chirality method is also useful for the stereochemical analysis of the
aglycone part in glycosides. Recently, the determination of the absolute stereo-
chemistry of natural 3,4-dihydroxy-ß-iononeglycosides has established the con-
figuration as being 3ß,4ß (3S,4R) .
Furthermore, a lot of ORD and CD spectroscopy has been done in the field of
carotenoid chemistry. In a fundamental paper by Klyne's and Weedon's groups 
ORD spectra of carotenoids have been studied systematically. Extensive CD studies