Carbon‐13 nuclear magnetic resonance spectra of isoflavones

Abstract

The =C chemical shifts of a series of isoflavones having hydroxy, acetoxy, methoxy and methylenedioxy substituents are compared. Some general relationships between substitution patterns and chemical shifts, useful for the identitication of naturally occurring isoflavones, are outlined.

BIOACTIVE COMPOUNDS IN BENGKOANG (Pachyrhizus erosus) AS ANTIOXIDANT AND TYROSINASE INHIBITING AGENTS

“…The chemical shift value of H 6 in molecule 4 was relatively downfield because of the presence of -OH at C 5 . The NMR spectra of 4 are in accordance with the data of a hydroxylated daidzein reported by Murthy et al, (1986) and Shimoda et al, (2008). Thus, the compound 4 is elucidated as 5-hydroxy-daidzein-7-O-ß-glucopyranose.…”

Metabolism of daidzein by Nocardia species NRRL 5646 and Mortierella isabellina ATCC 38063

“…Furthermore, C-7 carbon signal is shielded by 7.1 ppm (from 163.7 to 156.6 ppm) which is consistent with an o-hydroxylation. Finally, the d c 61.5 value assigned for the new methoxyl group at 8-position is consistent with that of 7, 8-dimethoxy derivatives of isoflavone (Jha et al, 1980;Murthy et al, 1986). The proton doublet at d 7.42, assigned to H-2 0 and H-6 0 , is correlated with the carbon signal at d 157.7 and is assigned to C-4 0 .…”

Extraction and Purification of Fructus Sophorae Genistein and Physicochemical Properties of its Complex with Lecithin

“…Only small amount of the subdued peaks were observed, which showed the irregular characteristics of lecithin. This indicated that genistein might be relevant to lecithin and the effect undermined the crystalline characteristics of genistein [11][12][13].…”