Curcuminoids from turmeric

Further studies are required to unravel this mystery of how the methoxy substitutions and the a, p-unsaturated p-diketone moiety actually influence conformational changes, lipophillicity, electron density distribution, and redox properties of curcuminoids. Correlating these physicochemical properties with the unique pleiotropic effects of curcuminoids is a rewarding exercise. Such studies would definitely provide proper reasoning in understanding these markedly different antioxidant, antitumor, and anti-inflammatory activities of natural curcuminoids from turmeric. 

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

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. 

Curcuminoids, yellow colorants, from turmeric (Curcuma)... 

Curcumin is a hydrophobic polyphenol derived from turmeric the rhizome of the herb Curcuma longa. Traditionally, turmeric and other curcuminoids have been used in therapeutic preparations for various ailments in different parts of the world. Numerous therapeutic effects of curcumin/turmeric have been confirmed by modern scientific research. It is a highly pleiotropic molecule that modulates numerous targets, including the activation of transcription factors (e.g., NF-kB, STAT-3, AP-1, NRF-2, PPR-y, HIF-1), receptors (e.g., HER-2, IL-8, CXCR-4), kinases (e.g., EGFR, ERK, JAK, AAPK), cytokines (e.g., TNF, IL, MIP, MCP), enzymes (e.g., MMP, iNOS, GST, ATPase), and... 

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). 

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 and other constituents of turmeric are well known for their antiinflammatory activity. Turmeric extract, volatile oils from turmeric and curcuminoids were reported to possess this property in different experimental models of inflammation in mice, rats, rabbits and pigeons (Arora et ah, 1971 Ghatak and Basu, 1972 Chandra and Gupta, 1972). Thus, curcuminoids are effective against carrageenan-induced oedema in rats (Srivastava et al.,... 

Polyketides with one or two phenylpropa-noid moieties and only one carbon derived from malonyl-Co A are the raspberry aroma/>-hydroxy-phenylbutan-2-one, the curcuminoids of turmeric Curcuma), and phenylphenalenones from Musa dmd Anigozanthos species (Fig. 23). Curcuminoids and phenylphenalenones contain two phenylpropanoid moieties on both sides of the acetate-derived carbon and are therefore classified as diaryIheptanoids. These two groups of natural products are pigments due to their conjugated system of 7i-electrons. Curcuminoids are widely used as spices and also have antiinflammatory, antioxidative, and anti-cancer properties (Joe et al., 2004). 

Turmeric, dried and cured, generally yields from 1.5 to 5.0% volatile oil. However, C. aromatica Salisb. is generally high in volatile oil (4-8%) and low in curcuminoids... 

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]. 

In vitro Cox-2 inhibitory potency and selectivity data often fail to predict clinical usefulness. In order to predict in vivo performance, they must be related to bioavail-abihty data. For example, although the wild blueberry and turmeric test products performed well in vitro, bioavailability data from the literature suggests that the presmned active ingredients in such products, anthocyanins and curcuminoids, respectively, would possess only local anti-inflammatory activity (i.e., in the GI tract)... 

In a dose escalation study of single doses of a standardized turmeric extract (95% curcuminoids), healthy volunteers were administered doses from 0.5 to 8 g. Tolerance was reported as excellent at all dose levels. Adverse events, including yellow stool, diarrhea, headache, and rash, were reported at doses of 1 g and above (Lao et al. 2006). In a dose... 

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