A set of studies performed by Sabinsa
Corporation revealed that Tetrahydrocurcuminoids is a potent antioxidant than the commonly
used synthetic antioxidant, Butylated Hydroxytoluene (BHT)
In the DPPH radical
scavenging method, the ability of an antioxidant to bind the 1:1
diphenyl-2-picrylhydrazyl-radical (a very stable free radical species) is measured using
various concentrations of the selected antioxidants.
The role of curcuminoids
as topical antioxidants has been validated in laboratory experiments. Curcuminoids are
reported to protect normal human keratinocytes from hypoxanthine/xanthine oxidase injury
in in vitro experiments. It was surmised in this study that since curcuminoids
synergistically inhibit nitroblue tetrazolium reduction, a decrease in superoxide radical
formation leading to lower levels of hydrogen peroxide could be their probable mode of
action. The authors of this study propose that lower levels of hydrogen peroxide, leading
to decreased cytotoxic effects, may be responsible for the protective effects of
curcuminoids11. This study suggests that curcuminoids and THC offer protection
to the skin and could be included in antioxidant topical preparations.
A recent study further
validated the well-known superior antioxidant properties of THC and explained the
mechanism of antioxidant action5. The inhibitory effects of curcumin and
tetrahydrocurcumin on lipid peroxidation of the erythrocyte membrane induced by
tertbutylhydroperoxide were studied. The results demonstrated that THC showed a greater
inhibitory effect than curcumin. The authors concluded that THC must scavenge free
radicals such as the tert-butoxyl radical and peroxyl radical efficiently. They attempted
to explain the mechanism of antioxidant action of THC on the basis of the molecular
structure (Figure 9). They concluded that the beta-diketone moiety of THC must exhibit
antioxidant activity by cleavage of the C-C bond at the active methylene carbon between
two carbonyls in the beta-diketone moiety. Since THC is one of the major metabolites of
curcumin, the authors propose that this compound may exhibit the observed physiological
and pharmacological properties in vivo by means of the beta-diketone moiety as
well as phenolic hydroxyl groups (Figure 9). |