Curcumin antioxidant activity

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. ... 

Jayaprakasha, G.K., Jaganmohan Rao, L., and Sakariah, K.K., Antioxidant activities of curcumin, demethoxycurcumin and bisdemethoxycurcumin. Food Chem., 98, 720, 2006. 

A series of natural and synthetic products have also shown antiamyloid properties as amyloid scavengers or P-breakers. One example is the phenolic yellow curry pigment curcumin, which has potent anti-inflammatory and antioxidant activities and can suppress oxidative damage, inflammation, cognitive deficits, and amyloid... 

Curcuma longa L. C. domestica L. Yu Jin (Turmeric) (tuber) 1-curcamene, sesquiterpene, camphor, camphene, curmarin, curzernone, curzenene, curcumol, furanodienone, furanodiene, zederone, curcolone, diol, procurcumenol, curdione, curcumin. 33-398-460-510 Anti-inflammatory, antitumor, anti-infectious properties, antioxidative activity. Activate blood flow, remove blood stasis. 

Somparn P, Phisalaphong C, Nakornchai S, Unchern S, Morales NP. 2007. Comparative antioxidant activities of curcumin and its demethoxy and hydrogenated derivatives. Biol Pharm Bull 30 74—78. 

The antioxidant activity of curcumin has been investigated for over 30 years [Sharma, 1976], Curcumin has been shown to inhibit lipid peroxidation,... 

Dutta S, Murugkar A, Gandhe N, Padhye S. 2001. Enhanced antioxidant activities of metal conjugates of curcumin derivatives. Met Based Drugs 8 183-188. 

Priyadarsini KI, Maity DK, Naik GH, Kumar MS, Unnikrishnan MK, Satav JG, Mohan H. 2003. Role of phenolic O-H and methylene hydrogen on the free radical reactions and antioxidant activity of curcumin. Free Radio Biol Med 35 475-484. 

Sharma OP. 1976. Antioxidant activity of curcumin and related compounds. Biochem Pharmacol 25 1811-1812. 

The decreased potency of 14 probably resulted from the offsetting influences of the electron donating and steric effects. In the three models, tetrahydrocurcumin showed comparable activity with curcumin, which implies that the enhanced electron delocalization of the double bonds may not be essential in terms of curcumin s antioxidant activity in these three bioassay models. 

Recently, Youssef et al. [24] reported the synthesis of curcumin analogs as potential antioxidant and cancer chemopreventive agents. The general structures of the synthesized analogs are shown in Fig. (8). These compounds were tested for scavenging ability of DPPH free radicals and in an ATP chemiluminescence assay. The SAR conclusions from the results were mainly consistent with the prior conclusions drawn by other researchers. In addition, they found that di-substitution of the central methylene group resulted in decreased antioxidative activity. 

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... 

The transcription of HIV-1 provims is regulated by both cellttlar and viral factors. Various pieces of evidence suggest that Tat protein secreted by HlVl-irrfected cells may have additional activity in the pathogenesis of AIDS because of its ability to also be taken up by noninfected cells. Barthelemy et al. " showed that curcumin used at 10 to lOOnAT inhibited Tat transactivation of HlVl-LTR lacZ by 70 to 80% in HeLa cells. To develop more efficient curcumin derivatives, the researchers synthesized and tested in the same experimental system the inhibitory activity of reduced curcumin (Cl), which lacks the spatial stracture of curcumin allyl-curcumin (C2), which possesses a condensed allyl derivative on curcumin that plays the role of metal chelator and tocopherylcurcumin (C3), whose stmctural alterations enhance the antioxidant activity of the molecule. Results obtained with the Cl, C2, and C3 curcumin derivatives showed a significant inhibition (70 to 85%) of Tat transactivation. Despite the fact that tocopheryl-curcumin (C3) failed to scavenge 0 , this curcumin derivative exhibited the most activity 70% inhibition was obtained at InM, while only 35% inhibition was obtained with the curcumin. 

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