Curcumin structures

Begum AN, Jones MR, Lim GP, Morihara T, Kim P, Heath DD, Rock CL, Pruitt MA, Yang F, Hudspeth B, Hu S, Faull KF, Teter B, Cole GM, Frautschy SA. 2008. Curcumin structure-function, bioavailablity and efficacy in models of neuroinflammation and Alzheimer s. J Pharmacol Exp Ther, in press. 

Antioxidant capacities of common individual curcuminoids were determined in vitro by phosphomolybdenum and linoleic acid peroxidation methods. Antioxidant capacities expressed as ascorbic acid equivalents (pmol/g) were 3099 for curcumin, 2833 for demethoxycurcumin, and 2677 for bisdemethoxycurcumin at concentrations of 50 ppm. The same order of antioxidant activity (curcumin > demethoxycurcumin > bisdemethoxycurcumin) was observed when compared with BHT (buty-lated hydroxyl toluene) in linoleic peroxidation tests. The antioxidant activity of curcumin in the presence of ethyl linoleate was demonstrated and six reaction products were identified and structurally characterized. The mechanism proposed for this activity consisted of an oxidative coupling reaction at the 3 position of the curcumin with the lipid and a subsequent intramolecular Diels-Alder reaction. ... 

Fig. 21. The chemical structures of curcumin (enol and keto forms).

Scheme 2.2 Structural diagrams for curcumoid compounds curcumin and carthamin...

Chemical structures of reported inhibitors of HIV-1 integrase. (I) aurintricarboxylic acid monomer (II) cosalane (III) dihydronaphthoquinone or DHNQ (IV) primaquine (V) caffeic acid phenethyl ester or CAPE (VI) quercetin (VII) quercetagetin (VIII) AG1717 (IX) 3-conidendrol (X) suramin (XI) curcumin. 

Holy JM. 2002. Curcumin disrupts mitotic spindle structure and induces micronuclea-tion in MCF-7 breast cancer cells. Mutat Res 518 71-84. 

Dinkova-Kostova AT, Talalay P. 1999. Relation of structure of curcumin analogs to their potencies as inducers of Phase 2 detoxification enzymes. Carcinogenesis 20 911-914. 

Based on the structure of curcumin, a series of styrylpyrazoles, styrylisoxazole, and styrylisothiazoles were synthesized and found to be dual inhibitors of COX and 5-LOX tested in rat basophilic leukemia cells. The most potent COX and 5-LOX dual inhibitor had IC50 values at 0.9 pM and 1.2 pM, respectively [159],... 

It is insoluble in water but soluble in ethanol and acetone. The structure and synthesis of curcumin as a diferuloylmeth-ane was confirmed by the work of Lampe (1910), and also by Majeed et al. (1995). 

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. 

An interesting property of curcuminoids is their anti-HIV effect, which has been demonstrated during in vitro and in vivo experiments, including a limited number of human studies (Lin et al., 1994). HIV infection is characterized by a complex command system, the structural part of which is called Tong terminal repeat (LTR), which results in virus activation or inactivation. Drugs that interfere with LTR may be of potential therapeutic value in delaying active HIV infection and the progression of AIDS. Curcumin has been found to inhibit activation of the LTR and to decrease HIV replication effectively (Li et al., 1993). 

Masuda, T., Toi, Y., Bando, H., Maekawa, T., Takeda, Y. and Yamaguchi, H. (2002) Structural identification of new curcumin dimers and their contribution to the antioxidant mechanism of curcumin. Journal of Agricultural and Food Chemistry 50, 2524-2530. 

The TPA-induced conversion of xanthine dehydrogenase to XO is reduced by curcumin to the basal level noted in untreated cells. The activity of XO is remarkably inhibited by curcumin in vitro but not by its structurally related compounds caffeic acids, chlorogenic acid, and ferulic acid. When Colo205 colorectal carcinoma cells... 

Lin L, Lee KH. Structure-activity relationships of curcumin and its analogs with different biological activities. In Studies in Natural Products Chemistry, Volume 33. Ur-Rahman A, ed. Elsevier, New York, pp. 785-812. 

F ure 6. The structures of the gingerols from Zingiber officinale and curcumin from Curcuma longa L. with activity against Helicobacter pylori. 

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