Inhibitory effects of 3-O-acyl-(+)-catechins on Epstein-Barr virus activation

In the course of an exploratory investigation of antitumor-promoting catechins, 3-O-acyl-(+)-catechins of varying carbon lengths from C(4) to C(18) were assessed for inhibitory effects on the activation of the Epstein-Barr virus early antigen. Like 3-O-acyl-(-)-epigallocatechins, the (+)-catechin derivatives showed promising effects with the C-3 acyl chain of C(8)-C(11) carbon atoms.     

Three new quassinoids,ailantinol E,F, and G,from Ailanthus altissima

Three new quassinoids, ailantinol E (1), ailantinol F (2), and ailantinol G (3), and related compounds were isolated from Ailanthus altissima grown in Taiwan. Their structures were elucidated from spectral evidence. Each new quassinoid was evaluated for its antitumor promoting effects against Epstein-Barr virus early antigen activation introduced by 12-O-tetradecanoylphorbol-13-acetate in Raji cells. The new quassinoids were found to show potent activity without showing any cytotoxicity. The screening for inhibitors against nitric oxide donor action was also conducted using the new quassinoids and some standard samples.     

Porritoxins, metabolites of Alternaria porri, as anti-tumor-promoting active compounds

To search for possible cancer chemopreventive agents from natural sources, we performed primary screening of metabolites of Alternaria porri by examining their possible inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA) in Raji cells. The ethyl acetate extract of A. porri showed the inhibitory effect on EBV-EA activation. Three porritoxins (1-3) were obtained as inhibitory active compounds for EBV-EA from ethyl acetate extract. 6-(3',3'-Dimethylallyloxy)-4-methoxy-5-methylphthalide (2) showed the strongest activity among them. Inhibitory effect of porritoxin (1) and (2) was superior to that of beta-carotene, a well-known anti-tumor promoter. Furthermore, the structure-activity correlation of porritoxins and their related compounds were discussed.     

Isolation and characterization of dinochrome A and B,anti-carcinogenic active carotenoids from the fresh Water red tide Peridinium bipes

Two epimeric carotenoids, named dinochromes A (2) and B (3), were isolated from the fresh water red tide Peridinium bipes, as anti-carcinogenic compounds. The stereostructure of dinochrome A and B were characterized to be (3S,5R,6R,3'S,5'R,8'R)- and (3S,5R,6R,3'S,5'R,8'S)-5',8'-epoxy-6,7-didehydro-5,6,5',8'-tetrahydro-beta,beta-carotene-3,5,3'-triol 3-O-acetate, respectively by (1)H- and (13)C-NMR, and circular dichroism (CD) data. Dinochromes A (2) and B (3) inhibit 12-O-tetradecanoyl phorbol 13-acetate (TPA)-stimulated (32)P-incorporation into the phosholipids of HeLa cells. Furthermore, dinochrome A was found to inhibit the proliferation of human malignant tumor cells, such as GOTO, OST and HeLa cells.     

PHOTOCYTOTOXICITY OF WATER-SOLUBLE METALLOPORPHYRIN DERIVATIVES

Abstract— A new water-soluble porphyrin derivative, 2,4-bis(1-decyloxyethyl)-deuteroporphyrinyl–6,7-bisaspartic acid(C–10-DP), and its metal complexes (Ga, In, Sn, Zn, Mn, Cu, Ni and Fe) were examined for their physicochemical properties (absorption, fluorescene, triplet lifetime and partition coefficient) and photocytotoxicity on HeLa cells. The five derivatives with longer(>1ms) triplet lifetimes (free base, Zn, Ga, In and Sn complexes) exhibited remarkable photocytotoxicity, and the other derivatives (Mn, Cu, Ni and Fe), which had or were deduced to have fairly short (<0.01 ms) triplet lifetimes, manifested no photocytotoxicity, indicating that the triplet lifetime of these derivatives played a significant role in their photocytotoxicity. Cellular fluorescence due to C10-DP and its gallium complex was observed mainly on the plasma membrane at the concentrations showing significant photocytotoxicity with low (<32.6%) cytotoxicity in the dark(2–10 μM).     

3-epicabraleahydroxylactone and other triterpenoids from camellia oil and their inhibitory effects on Epstein-Barr virus activation

The structure of a triterpenoid isolated from the nonsaponifiable lipid (NSL) of the seed oil of the camellia (Camellia japonica L.; Theaceae) was established to be (20S)-3beta-hydroxy-25,26,27-trisnordammaran-24,20-olide (1; 3-epicabraleahydroxylactone) on the basis of spectroscopic and chemical methods. Six other triterpenoids isolated from the NSL were identified as 3-epicabraleadiol (2), ocotillol II (3), ocotillol I (4), dammarenediol II (5), (20R)-taraxastane-3beta,20-diol (6), and lupane-3beta,20-diol (7). Upon evaluation of the seven triterpenoids (1-7) with respect to their inhibitory effects on the induction of Epstein-Barr virus early antigen (EBV-EA) by 12-O-tetradecanoylphorbol-13-acetate (TPA) in Raji cells, three compounds (5-7) showed potent inhibitory effects against EBV-EA induction (IC(50) values of 277-420 mol ratio/32 pmol TPA).