Extensive research within the past half-century has indicated that
curcumin (
diferuloylmethane), a yellow pigment in curry
powder, exhibits
anti-oxidant, anti-inflammatory, and pro-apoptotic activities. We investigated whether the anti-pre-
cancer activities assigned to
curcumin are mediated through an
anti-oxidant and
DNA-protecting mechanism. Patients with
oral leukoplakia,
oral submucous fibrosis or
lichen planus, and healthy individuals (n = 25 for each group) aged 17-50 years were selected. Salivary and serum oxidative markers such as
malonaldehyde (MDA),
8-hydroxydeoxyguanosine (8-OHdG),
vitamins C and E were measured just prior to the intake of
curcumin, after one week of
curcumin intake and following clinical cure of precancerous lesions. Serum and salivary
vitamins C and E showed increases, while MDA and 8-OHdG levels showed decreases in patients with
oral leukoplakia, submucous
fibrosis and
lichen planus after intake of
curcumin for all categories of precancerous lesions. The changes in these values were observed to be statistically significant after clinical cure of the disease (P < 0.05). The five-point rating scale for
pain, as well as lesion size in
oral leukoplakia, submucous
fibrosis and
lichen planus, improved significantly (P < 0.05). In addition, in submucous
fibrosis, mouth opening (P < 0.05) recovered significantly. In
oral leukoplakia, submucous
fibrosis and
lichen planus, the levels of serum and salivary
vitamins C and E increased significantly, while MDA and 8-OHdG levels decreased after 131(15), 211(17), and 191(18) days, respectively. Values for serum and salivary
vitamins C and E showed a significant decrease in
oral leukoplakia, submucous
fibrosis and
lichen planus, in contrast to healthy individuals, but increased significantly in all groups subsequent to
curcumin administration after clinical cure of lesions. Based on these results, we can conclude that
curcumin mediates its anti-pre-
cancer activities by increasing levels of
vitamins C and E, and preventing lipid peroxidation and DNA damage.