iridoids and Skin-Neoplasms

Swertia chirata, is a bitter plant, used in the Indian system of medicine (Ayurveda) for various human ailments. Our laboratory was the first to report the chemopreventive effect of this plant. The antiproliferative and pro-apoptotic action of amarogentin rich fraction of S. chirata is now demonstrated on a mouse skin carcinogenesis model. Immunohistochemical localization revealed a reduction in proliferating and increase in apoptotic cells in skin lesion following treatment, also reflected in the expression of molecular markers--Cox-II and caspase-3 proteins. It may be possible to calculate relative risk, relative protection and attributable risk from the action of test agents on proliferation and apoptosis.

Topics: 9,10-Dimethyl-1,2-benzanthracene; Animals; Apoptosis; Caspase 3; Cell Proliferation; Cyclooxygenase 2; Disease Models, Animal; Down-Regulation; Electrophoresis, Polyacrylamide Gel; Glucosides; In Situ Nick-End Labeling; Iridoids; Male; Medicine, Traditional; Membrane Proteins; Mice; Phytotherapy; Plant Extracts; Skin Neoplasms; Swertia; Up-Regulation

[structure in text] From the leaves of Morinda citrifolia, a new unusual iridoid, named citrifolinoside (1), showing significant inhibition of UVB-induced Activator Protein-1 (AP-1) activity in cell cultures, has been isolated. Its structure was elucidated on the basis of detailed high-field 1D and 2D spectral analysis.

Topics: Glucosides; Iridoid Glucosides; Iridoids; Magnetic Resonance Spectroscopy; Molecular Structure; Phytotherapy; Plants, Medicinal; Rubiaceae; Skin Neoplasms; Structure-Activity Relationship; Transcription Factor AP-1; Tumor Cells, Cultured; Ultraviolet Rays

In the course of our continuing search for novel cancer chemopreventive agents from natural sources, several kinds of Labiatae plants were screened. Consequently, the iridoid glycoside derivative, 8-acetylharpagide (8-AcHarp), was obtained from the flowering whole plant of Ajuga decumbens as an active constituent. This glycoside exhibited the remarkable inhibitory effect on two-stage carcinogenesis test of mouse skin tumors induced by nitric oxide (NO) donor, (+/-)-(E)-methyl-2-[(E)-hydroxyimino]-5-nitro-6-methoxy-3-hexen eamide (NOR 1) as an initiator and 12-O-tetradecanoylphorbol-13-acetate (TPA) as a promoter. Further, 8-AcHarp exhibited potent anti-tumor-promoting activity on two-stage carcinogenesis test of mouse hepatic tumor using N-nitrosodiethylamine (DEN) as an initiator and phenobarbital (PB) as a promoter.

Topics: Animals; Anticarcinogenic Agents; Antigens, Viral; Carcinogens; Diethylnitrosamine; Female; Glucosides; Iridoids; Liver Neoplasms, Experimental; Mice; Mice, Inbred ICR; Mice, Inbred SENCAR; Nitro Compounds; Plant Extracts; Plants, Medicinal; Pyrans; Skin Neoplasms