Chemopreventive effect of Ocimum sanctum on DMBA-induced hamster buccal pouch carcinogenesis

Ocimum sanctum L., a plant having multi-medicinal properties, has been inve stigated for its chemopreventive activity against 7,12-dimethylbenz (a) ant hracene (DMBA)-induced hamster buccal pouch carcinogenesis. O. sanctum, in the form of fresh leaf paste, aqueous extract and ethanolic extract were to pically applied and the extracts were orally administered to buccal pouch m ucosa of animals exposed to 0.5% of DMBA. Incidence of papillomas and squam ous cell carcinomas were significantly reduced, and increased the survival rate in the topically applied leaf paste and orally administered extracts t o animals. Among them, the orally administered aqueous extract showed profo und effect than the other two forms. Histopathological observations made on the mucosa confirmed these findings. Further fluorescent spectral studies at 405 nm excitation on the mucosa of control, DMBA and extracts orally adm inistered experimental animals showed a prominent maxima at 430 nm for cont rol, 628 nm for DMBA induced carcinomas while aqueous and ethanolic extract s administered animals showed at 486 nm and 488 nm, respectively. The fluor escent intensity at 630 nm (FI630nm) was significantly reduced and the rati o of fluorescent intensities at 520 nm and 630 nm (FI520nm/630nm) were sign ificantly increased in orally administered extracts compared to DMBA treate d animals. These observations suggest that the orally administered extract of O. sanctum may have the ability to prevent the early events of carcinoge nesis. (C) 1998 Elsevier Science Ltd. All rights reserved.