Studies on curcumin and curcuminoids XVII. Variation in the content of curcuminoids inCurcuma longa L. from Nenal during one season

Studies on Curcumin and Curcuminoids. XXXIX. Photophysical Properties of Bisdemethoxycurcumin

“…The demethoxy- and bidemethoxy compounds can amount to nearly 40% of what is known as commercially available curcumin [ 1 ]. In some turmeric extracts bisdemethoxycurcumin is even shown to be the major constituent [ 2 ]. Curcumin is by far the most investigated curcuminoid, although some comparative studies on the naturally occurring curcuminoids have been performed.…”

The effect of the water on the curcumin tautomerism: A quantitative approach

“…There is substantial number of theoretical studies, showing 42 the strong predominance of the enol-keto form (1EK) in 1 and curcumin-like structures. 43 Additionally, 1EK is the tautomeric form existing in solid state [9]. In solution the tautomerism 44 of 1 has been studied by NMR [17,18], IR [5,10], UV-Vis absorption [11], and emission 45 [11,12,13,14,15,16] spectroscopies, showing that in most solvents the enol-keto tautomer is the 46 only existing one.…”

Phytochemical variation: How to resolve the quality controversies of herbal medicinal products?

“…For instance, the rhizome of Curcuma longa L., a common herb belonging to Zingiberaceae family that possesses an indeterminate history of medicinal and cosmetic uses in Ayurveda and Traditional Chinese Medicine, has displayed a notable variation in curcuminoid content and essential oil composition from different geographical origins (Pothitirat and Gritsanapan, 2006, Singh et al , 2010, Sumathi et al , 2008, Tønnesen et al , 1989.…”