lupane and Papilloma

Ultraviolet light is the most common cause of skin cancers in human and several effects of ultraviolet light B (UVB) are thought to contribute to skin photocarcinogenesis. The generation of seven triterpenoids from the cones of Liquidamber styraciflua (Hamamelidaceae were examined for their nitric oxide (NO) scavenging activity as the first screening of an in vivo mouse skin anti-initiating assay. 3beta,25-epoxy-3alpha-hydroxylup-20(29)-en-28-oic acid (1), which showed the strongest inhibitory effect among these compounds, was studied further for its anti-tumor initiating activity on mouse models initiated with ultraviolet-B (UVB) and promoted with 12-O-tetradecanoylphorbol-13-acetate (TPA). Oral administration of the compound 1 during a period before and after the three times of UVB irradiation exhibited a remarkable effect: administration of 0.0025% solution of the compound 1 given orally only to the test group, which started 1 week before and ended 1 week after the irradiation, showed approximately 50% inhibition of tumor incidence and tumor multiplicity in comparison to the control group. Thus, compound 1 could act as a potent anti-tumor initiator in UVB radiation photocarcinogenesis.

Topics: Administration, Oral; Animals; Antineoplastic Agents, Phytogenic; Carcinogens; Female; Hamamelidaceae; Mice; Mice, Inbred SENCAR; Neoplasms, Radiation-Induced; Papilloma; Seeds; Skin Neoplasms; Tetradecanoylphorbol Acetate; Time Factors; Triterpenes; Ultraviolet Rays

Four known lupane-type triterpenoids, glochidonol (1), glochidiol (2), lup-20(29)-ene-1beta,3beta-diol (3) and glochidone (3) were isolated from the stem bark of Glochidion zeylanicum. Previously, lupeol (5), lup-20(29)-ene-3beta,24-diol (6) and betulin (7) were isolated from the stem bark of Phyllanthus flexuosus. This study reports the assays of these lupane-type triterpenoids: all isolates 1-7 and synthetic analogues, glochidonyl acetate (1a), lup-20(29)-ene-1,3-dione (1b) and lup-20(29)-ene 3beta,24-diacetate (6a) were tested for their inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol 13-acetate (TPA). Among them, the effects of compounds 2 (IC50 = 290 mol ratio/32 pmol TPA) and 3 (IC50 = 300) were stronger than the others. In addition, compound 2 exhibited a strong inhibitory effect on mouse skin tumor promotion in an in vivo mouse two-stage carcinogenesis test.

Topics: 9,10-Dimethyl-1,2-benzanthracene; Administration, Cutaneous; Animals; Antigens, Viral; Antineoplastic Agents, Phytogenic; Female; Herpesvirus 4, Human; Inhibitory Concentration 50; Mice; Mice, Inbred ICR; Papilloma; Phyllanthus; Phytotherapy; Plant Bark; Plant Extracts; Skin Neoplasms; Specific Pathogen-Free Organisms; Tetradecanoylphorbol Acetate; Triterpenes