Glycyrrhizin and its aglycone,
glycyrrhetic acid has been found useful for various therapeutic purposes.
Glycyrrhizin has been shown to possess many physiological functions like anti-inflammatory activity, detoxification and inhibition of carcinogenic promoters. 12-O-Tetradecanoyl phorbol-13-acetate (TPA), a well-known phorbal
ester is known for its
tumor promotion activity. The induction of
inflammation in skin mediated by TPA is believed to be governed by
cyclooxygenase (COX),
lipoxygenase and
ornithine decarboxylase (ODC). These markers of inflammatory responses are important for skin
tumor promotion. In our present study, we studied the chemopreventive effect of
glycyrrhizin on TPA (20 nmol/0.2 mL
acetone/animal, topically)-induced oxidative stress and hyperproliferation markers in skin. TPA enhanced lipid peroxidation with reduction in the level of
catalase,
glutathione,
glutathione peroxidase,
glutathione reductase and
glutathione-s-transferase. TPA treatment also enhanced ODC activity and [3H]
thymidine incorporation into cutaneous
DNA. Prophylactic treatment of mice with
glycyrrhizin (2.0 & 4.0 mg/0.2 mL
acetone/animal, topically) resulted in a significant decrease in cutaneous microsomal lipid peroxidation (P < 0.001) and recovery of cutaneous
glutathione content (P < 0.001) and its dependent
enzymes. A significant inhibition in ODC activity and
DNA synthesis (P < 0.001) was also observed. Thus, the results demonstrate that pretreatment with
glycyrrhizin is protective against TPA-induced oxidative stress and
tumor promotion in Swiss albino mice.