Curcuminoids isolated

Nagano T, Oyama Y, Kajita N, Chikahisa L, Nakata M, Okazaki E, Masuda T. (1997). New curcuminoids isolated from Zingiber cassumunar protect cells suffering from oxidative stress a flow-cytometric study using rat thymocytes and H202. Jpn J Pharmacol. 75(4) 363-70. 

The anti-inflammatory activity of curcumin and its derivatives is associated with the hydroxyl and phenol groups in the molecule, which are also essential for the inhibition of prostaglandins, PG synthetase and leucotriene synthesis (LT) (Kiuchi et al., 1982, 1992 Iwakami, et al, 1986). Claeson et al. (1993, 1996) suggested that the antiinflammatory action and the antiparasitic activity were associated with the (3-dicarbo-nylic system with conjugated double bonds (dienes) (Araujo et al., 1998, 1999). The better skin penetration and lipophylicity is attributed to the presence of a diene ketone system. Calebin-A, a novel curcuminoid isolated from turmeric, protects neuronal cells from (3-amyloid insult. The hydroxy group at para-position of this compound is most critical for the expression of biological activity (Kim et al., 2001). 

Turmeric contains two main classes of compounds the curcuminoids responsible for the yellow color and the aroma compounds. The coloring principle of turmeric consists of three major phenolic derivatives curcumin, demethoxycurcumin, and bisdemethoxycurcumin. Commercially available products called curcumins contain curcumin (l,7-bis(4-hydroxy-methoxyphenyl)-l,6-heptadiene-3,5-dione) as the major component (about 77% of total curcuminoids). Some other minor phenohc compounds such as cyclocurcumin and calebin were also isolated from turmeric. See Figure 5.2.1. 

Four different commercially available varieties of turmeric containing curcumin were isolated, separated by column chromatography, and identified by spectroscopy. The purity of the curcuminoids was analyzed by an improved HPLC method, performed on a Ci8 column using methanol, acetic acid, and acetonitrile and detection at 425 nm. The total percentages of curcuminoids in turmeric were between 2.34... 

The main coloured substances in the rhizomes are curcumin (1,7-bis (4-hydroxy-3-methoxy prenyl)-l, 6-heptadiene-3, 5-dione) and two related demethoxy compounds, demethoxy curcumin and fczs-demethoxy curcumin, which belong to the group of diarylheptanoids (see Fig. 6.1). Besides these three forms of curcuminoids, three minor constituents have also been isolated (Srinivasan, 1952) that are supposed to be geometrical isomers of curcumin. One of these is assumed to be a cis-trans geometrical isomer of curcumin based on its UV spectrum, lower m.p. and lower stability when compared with curcumin, which has a trans-trans configuration. Heller (1914) isolated an isomer of curcumin with a diketone structure. 

A new curcuminoid, cyclocurcumin, possessing nematocidal activity, was isolated from the mother liquor by repeated purification as a yellow gum (Kiuchi et al, 1993). It had the same molecular formula as curcumin, but differed in structure by an intramolecular Michael addition of the enol-oxygen to the enone group. The chemical structures of these components are given in Fig. 6.2. 

Isolation of curcuminoids from turmeric has been reported by numerous workers. However, extraction of pure curcumin from the plant... 

Besides curcuminoids and oils, C. longa also contains some polysaccharides. Three acidic polysaccharides were isolated from turmeric ( Ukon ) by hot water extraction, followed by precipitation with ethanol, with remarkable activity on the reticuloendothelial system (RES) (Gonda et al., 1990). The components were purified on a column of DEAE Sephadex A-25 and named as Ukon A, Ukon B and Ukon C. 

Curcuminoids, a group of natural products originally isolated from the Indian spice turmeric, have been known to be potent antioxidant and antiinflammatory agents for many years. Curcuminoids reduce tissue factor (TF) gene expression through the inhibition of the AP-1 and NF-kB transcription factors and thus lead to the loss of angiogenesis initiation [61, 62]. 

From the rhizomes of C. longa, several curcuminoids (237-240) [191], (245,246) [192] and two curcumin related phenolic compounds (247,248) [191] were isolated. Antioxidant activity of the two phenolic compounds 247 and 248 was determined by inhibiting the autooxidation of linoleic acid and comparing the activity with that of curcumin [191]. Compounds 247 and 248 showed stronger activity than that of curcumin. It seems to indicate that the chelation of the 1,3-diketone moiety is not so important... 

Masuda T., Jitoe A. Antioxidative and antiinflamatory compounds from tropical gingers isolation, structure determination, and activities of cassumunins A, B, and C, new complex curcuminoids from Zingiber cassumunar. Journal of Agricultural and Food Chemistry, 42 1850-1856 (1994). 

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