Dietary arachidonic acid improves age-related excessive enhancement of the stress response.

OBJECTIVE: The aim of this study is to understand whether the responsiveness of the hypothalamic-pituitary-adrenal (HPA) axis to stress increases excessively with aging in senescence-accelerated mice-prone 10 (SAMP10) and to investigate the role of arachidonic acid (ARA) in this process. MATERIALS AND METHODS: The area under the curve of CORT concentration (CORT-AUC), an index of the HPA axis responsiveness to stress, was assessed in SAMP10 subjected to a 30-minute restraint stress up to 120 minutes after the restraint stress onset. Furthermore, the HPA axis responsiveness was evaluated in aged SAMP10 fed 0.4% ARA-containing diet (ARA group) or control diet (CON group) for 4 weeks. Three weeks later, these mice were divided into a group with a 30-minute restraint stress (CON-S or ARA-S group) and a group without restraint stress (CON-NS or ARA-NS group). Hippocampi were collected after stress release and fatty acid and glucocorticoid receptor (GR) protein levels were evaluated in the nucleus and cytosol. RESULTS: The CORT-AUC of aged SAMP10 was 21% significantly higher than that of young SAMP10. In the ARA group, hippocampal ARA was 0.5% significantly higher than that in the CON group. CORT-AUC in the ARA group was 24% significantly lower than that in the CON group. The ratio of GR protein levels in the nucleus and cytosol in the ARA-S group was 1.72 times significantly higher than that in the ARA-NS group but no difference was observed between the CON-S and CON-NS groups. CONCLUSIONS: Dietary ARA seems to suppress age-related excessive enhancement of the HPA axis responsiveness via attenuation of age-related decline in hippocampal GR translocation into the nucleus after stress loading, which may contribute to an improvement of mental health.

Cancer chemopreventive activity of diversin from Ferula diversivittata in vitro and in vivo.

A prenylated coumarin (diversin, 1) together with four new sesquiterpene lactones (diversolides A, D, F and G, 2-5) isolated from the roots of Ferula diversivittata were studied for their possible inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA). All of the tested compounds were active against EBV-EA activation. Among these compounds diversin (IC(50): 7.7) exhibited the strongest inhibitory effect and was selected to examine its effects on in vivo two-stage mouse skin carcinogenesis induced by 7,12-dimethylbenz[a]anthracene (DMBA) as initiator and TPA as promoter. Treatment with compound 1 (85nmol) along with DMBA/TPA inhibited papilloma formation up to week 7 and the percentage of papilloma bearers was approximately 93.3% at week 20. The average number of papillomas formed per mouse was only 5.5 even at week 20. The results of the present investigation indicated that diversin might be valuable as a potent cancer chemopreventive agent and its potency was comparable with those of curcumin and quercetin, two well-known cancer chemopreventive agents.

Diglucosyl-glycerolipids from the marine sponge-associated Bacillus pumilus strain AAS3: their production, enzymatic modification and properties.

The marine strain Bacillus pumilus strain AAS3, isolated from the Mediterranean sponge Acanthella acuta, produced a diglucosyl-glycerolipid, 1,2-O-diacyl-3-[beta-glucopyranosyl-(1-6)-beta-glucopyranosyl)]glycerol, with 14-methylhexadecanoic acid and 12-methyltetradecanoic acid as the main fatty acid moieties (GGL11). On a 30 l scale, using artificial seawater supplemented with glucose (20 g/l), yeast extract (10 g/l), and suitable nitrogen/phosphate sources, growth-associated glycoglycerolipid production reached its maximum yield of 90 mg/l after 11 h. Lipase-catalyzed modification of the native substance led to the deacylated parent compound (GG11), which could be reacylated using the same enzyme system to afford a new dipentenoyl-diglucosylglycerol (GGL12) as the major product upon addition of 4-pentenoic acid to the medium. GGL11 decreased the surface tension of water from 72 mN/m to 29 mN/m and the interfacial tension of the water/ n-hexadecane system from 44 to 5 mN/m. Anti-tumor-promoting studies on this class of diglucosyl glycerol products showed that the carbohydrate/glycerol backbone (GG11) has a more potent inhibitory activity than the acylated compounds. The diglucosyl-glycerol GG11 strongly inhibited growth of the tumor cell lines HM02 and Hep G2 (50% inhibition at approximately 1 microg/ml), while the glycerolipids GGL11 and GGL12 were less active or had no effect.

Crown gall -- a plant tumour with biological activities.

Petroleum ether, acetone, 80% MeOH and water extracts of crown gall, a plant tumour, obtained from Eucalyptus globulus tree were screened for cytotoxic, antioxidant, antiinflammatory, embryotoxic, antitumour-promoting and antimicrobial activities. In terms of bioactivity the 80% MeOH extract was most effective followed by the acetone extract. The petroleum ether extract showed weak to moderate cytotoxic activity in dose-dependent manner against PC12 cells, mouse L fibroblasts and 1321N1 glia cells, whereas the hydroalcohol extract had no or a weak cytotoxic effect. The 80% MeOH extract exhibited strong antioxidant activity. Based on the in vitro HET-CAM assay all the extracts were effective against inflammation. The extracts did not show any embryotoxic effect at the concentrations tested. Antitumour-promoting activity (100% inhibition; 100 microg/mL) was observed in the 80% MeOH and acetone extracts. In the antimicrobial screening all extracts displayed predominantly antifungal activity against Candida sp. The extracts also showed various levels of antibacterial activity against E. faecalis, Ps. aeruginosa, Bac. subtilis and Staph. epidermidis. From the results of the investigations it can be concluded that crown gall is a valuable plant tumour tissue having interesting biological activities.

Cancer chemopreventive activity of odorine and odorinol from Aglaia odorata.

In the course of our continuing search for novel cancer chemo-preventive agents from natural sources, we have carried out a primary screening in vitro assay of the compounds isolated from Aglaia odorata. Consequently, aminopyrrolidine-diamides, odorine and odorinol, were obtained as active constituents. These compounds exhibited potent anti-carcinogenic effects in a two-stage carcinogenesis test of mouse skin induced by 7,12-dimethylbenz[a]anthracene (DMBA) as an initiator and 12-O-tetradecanoylphorbol-13-acetate (TPA) as a promoter. Further, both compounds showed remarkable inhibitory effects in two-stage mouse skin carcinogenesis models induced by nitric oxide (NO) donors such as (+/-)-(E)-methyl-2-[(E)-hydroxyimino]-5-nitro-6-methoxy-3-hexenamide (NOR-1) or peroxynitrite as an initiator and TPA as a promoter. From these results, it was concluded that odorine and odorinol inhibited both the initiation and promotion stages of two-stage skin carcinogenesis.

Cancer chemoprevention by ginseng in mouse liver and other organs.

Oral administration of red ginseng extracts (1% in diet for 40 weeks) resulted in the significant suppression of spontaneous liver tumor formation in C3H/He male mice. Average number of tumors per mouse in control group was 1.06, while that in red ginseng extracts-treated group was 0.33 (p<0.05). Incidence of liver tumor development was also lower in red ginseng extracts-treated group, although the difference from control group was not statistically significant. Anti-carcinogenic activity of white ginseng extracts, besides red ginseng extracts, was also investigated. In the present study, the administration of white ginseng extracts was proven to suppress tumor promoter-induced phenomena in vitro and in vivo. It is of interest that oral administration of the extracts of Ren-Shen-Yang- Rong-Tang, a white ginseng-containing Chinese medicinal prescription, resulted in the suppression of skin tumor promotion by 12-o-tetradecanoylphorbol-13-acetate in 7,12-dimethylbenz[a]anthracene-initiated CD-1 mice. These results suggest the usefulness of ginseng in the field of cancer prevention.

Cancer chemopreventive activity of naphthoquinones and their analogs from Avicennia plants.

As a part of screening studies for cancer chemopreventive agents (anti-tumor promoters), six natural and four synthetic naphthoquinones and five of their analogs were tested for their inhibitory activities against Epstein-Barr virus early antigen activation induced by 12-O-tetradecanoylphorbol-13-acetate in Raji cells. Some of the 1,4-naphthoquinones and their analogs were found to show remarkably potent activities, without showing any cytotoxicity. 1,4-Furanonaphthoquinone (5) and its analog (9) isolated from Avicennia plants (Avicenniaceae), having an alcoholic OH group on the dihydrofuran-ring, displayed the most potent activity. Furthermore, avicenol-A (9) exhibited a marked inhibitory effect on mouse skin tumor promotion in an in vivo two-stage carcinogenesis test. The result of the present investigation indicated that some of these 1,4-naphthoquinones and their analogs might be valuable as potent cancer chemopreventive agents.

Cancer chemopreventive activity of carotenoids in the fruits of red paprika Capsicum annuum L.

Capsanthin and related carotenoids isolated from the fruits of red paprika Capsicum annuum L. showed potent in vitro anti-tumor-promoting activity with inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced by the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA). Among them, capsanthin diester and capsorbin diester showed strong inhibitory effects. Furthermore, capsanthin , capsanthin 3'-ester and capsanthin 3,3'-diester , major carotenoids in paprika, exhibited potent anti-tumor-promoting activity in an in vivo mouse skin two-stage carcinogenesis assay using 7, 12-dimethylbenz[a]anthracene as an initiator and TPA as a promoter.

Chemopreventive activity of isoquinoline alkaloids from Corydalis plants.

Eighteen isoquinoline alkaloids including protoberberines (1-12), benzophenanthridines (13-16) and an aporphine (17) isolated from plants of Corydalis species (Fumariaceae) were tested for inhibitory effects on Epstein-Barr virus early antigen activation induced by 12-O-tetradecanoylphorbol 13-acetate in Raji cells. In a primary screening test, all of the isoquinoline alkaloids showed inhibitory activity with the IC50 values being in the range of 140-410 mol ratio/32 pmol TPA. The data demonstrate that these isoquinoline alkaloids might be valuable as anti-tumor promoters.

Cancer chemopreventive agents. New depsidones from Garcinia plants.

In a search for cancer chemopreventive agents from natural sources, chemical constituents of two kinds of Garcinia plants, Garcinia neglecta and Garcinia puat, collected in New Caledonia, were examined. Five new depsidones, garcinisidone-B (2), -C (3), -D (4), -E (5), and -F (6), were isolated, and their structures were determined by spectrometric analyses. Inhibitory effects of these depsidones on EBV-EA activation induced by TPA in Raji cells were also demonstrated.

Cancer chemopreventive agents, 4-phenylcoumarins from Calophyllum inophyllum.

In a search for anti-tumor-promoting agents, we carried out a primary screening of ten 4-phenylcoumarins isolated from Calophyllum inophyllum L. (Guttiferae), by examining their possible inhibitory effects on Epstein--Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol-13-acetate in Raji cells. All of the compounds tested in this study showed inhibitory activity against EBV, without showing any cytotoxicity. Calocoumarin-A (5) showed more potent activity than any of the other compounds tested. Furthermore, calocoumarin-A (5) exhibited a marked inhibitory effect on mouse skin tumor promotion in an in vivo two-stage carcinogenesis test. The results of the present investigation indicate that some of these 4-phenylcoumarins might be valuable as potential cancer chemopreventive agents (anti-tumor-promoters).

Lignans as anti-tumor-promoter from the seeds of Hernandia ovigera.

Seven lignans (2-8) isolated from the seeds of Hernandia ovigera L. (Hernandiaceae) were tested for their inhibitory effects on Epstein-Barr virus early antigen activation induced by 12-O-tetradecanoylphorbol 13-acetate in Raji cells. Using a primary screening test, all the lignans showed inhibitory activity with IC50 470-590 mol ratio/32 pmol TPA. The data demonstrated that these lignans might be valuable anti-tumor-promoters.

Abietane diterpenoids from the cones of Larix kaempferi and their inhibitory effects on Epstein-Barr virus activation.

Four known (1-3, 8) and four new abietane diterpenes, 15-hydroxy-8alpha,14alpha,12alpha,13alpha-diepoxyabietan-18-oic acid (4), 7alpha,8alpha,13beta,14beta-diepoxyabietan-18-oic acid (5), 18-nor-abieta-8,11,13-triene-4alpha,7alpha,15-triol (6), and abieta-8,11,13-triene-7alpha,15,18-triol (7) were isolated from the CHCl3 extract of the cones of Larix koempferi. A known compound, 13,14-seco-13,14-dioxoabiet-13-en-18-oic acid (8) was isolated from natural sources for the first time. Their structures were determined by chemical and spectroscopic methods including 1D and 2D NMR techniques. The absolute stereostructure of 5 was determined by X-ray crystallographic analysis. The inhibitory effects of these compounds on Epstein-Barr virus early antigen (EBV-EA) activation induced by the tumor promoter, 12-O-tetradecanoylphorbol-13-acetate (TPA), were examined as a primary screening for antitumor promotors.

Cancer chemopreventive activity of 3,5,6,7,8,3',4'-heptamethoxyflavone from the peel of citrus plants.

Nobiletin and 3,5,6,7,8,3',4'-heptamethoxyflavone (HPT), isolated from the peel of Citrus plants, were examined for the anti-tumor-initiating activity on two-stage carcinogenesis of mouse skin tumors induced by a nitric oxide donor, (+/-)-(E)-methyl-2-[(E)-hydroxyimino]-5-nitro-6-methoxy-3-hexenamide, as an initiator and 12-O-tetradecanoylphorbol-13-acetate as a promoter. HPT exhibited the remarkable anti-tumor-initiating effect on mouse skin and it suggested the possibility of HPT being a chemopreventive agent against nitric oxide (NO) carcinogenesis.

Anti-tumor-promoting activity of the diterpene from Excoecaria agallocha. II.

Eight new diterpenoids (1-8) have been isolated from the wood of Excoecaria agallocha (Euphorbiaceae) and their inhibitory effects on the induction of Epstein-Barr virus early antigen (EBV-EA) in Raji cells were examined to search for potent anti-tumor-promoters from natural resources. Of these compounds, the secolabdane-type diterpenoid, compound 7 exhibited a remarkable inhibitory effect on EBV-EA induction, and a significant anti-tumor-promoting effect in the mouse two-stage carcinogenesis test using 7,12-dimethylbenz[a]anthracene and 12-O-tetradecanovl-phorbol-13-acetate.

Bioactive triterpenoids from the stem bark of Picea glehni.

Two new triterpenoids, 3 alpha-methoxyserrat-14-en-21 beta-yl formate (1), and 24-methylcycloartenone (2), were isolated from the stem bark of Picea glehni (Fr. Schm.) Masters together with three known triterpenoids, 3 alpha-methoxyserrat-14-en-21 beta-ol, 3 beta-methoxyserrat-14-en-21 beta-ol, and piceanonol A. Compounds 1, 2, and a synthetic sample, 3 alpha-methoxyserrat-13-en-21 beta-yl formate showed potent inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced by the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA).

Constituents of Boronia pinnata.

A novel quinolone, pinolinone (1); seven new phenylpropanoids, boropinols A (2), B (3), C (4), boropinals A (5), B (6), C (7), and boropinic acid (8); and a new lignan, boropinan (9), were isolated from the roots of Boronia pinnata, and their structures were elucidated by NMR and MS analyses. In a search for novel cancer chemopreventive agents (antitumor-promoters), we screened 10 compounds isolated from the plant for their inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol-13-acetate in Raji cells. Boropinic acid (8) and 4'-hydroxy-3'-prenylcinnamaldehyde were observed to significantly inhibit the EBV-EA activation.

Cancer chemopreventive agents, labdane diterpenoids from the stem bark of Thuja standishii (Gord.) Carr.

Seven labdane-type diterpenoids from the stem bark of Thuja standishii (Gord.) Carr. (Cupressaceae) and their analogues showed strong inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA). Among these compounds, 15,16-bisnor-13-oxolabda-8(17), 11E-dien-19-oic acid was revealed to have the strongest inhibitory effect on the EBV-EA activation, being stronger than that of beta-carotene which has been intensively studied in cancer prevention using animal models. 15,16-bisnor-13-Oxolabda-8(17), 11E-dien-19-oic acid was also found to exhibit the excellent anti-tumor promoting activity in two-stage mouse skin carcinogenesis test using 7,12-dimethylbenz[a]anthracene and TPA.

Inhibitory effect of citrus nobiletin on phorbol ester-induced skin inflammation, oxidative stress, and tumor promotion in mice.

The intake of citrus fruits has been suggested as a way to prevent the development of some types of human cancer. Nitric oxide (NO) is closely associated with the processes of epithelial carcinogenesis. We attempted a search for NO generation inhibitors in Citrus unshiu. The active constituent was traced by an activity-guiding separation. NO and superoxide (O2-) generation was induced by a combination of lipopolysaccharide and IFN-gamma in mouse macrophage RAW 264.7 cells, and by 12-O-tetradecanoylphorbol-13-acetate (TPA) in differentiated human promyelocyte HL-60, respectively. Expression of inducible NO synthase and cyclooxygenase 2 proteins were detected by Western blotting. The in vivo anti-inflammatory and antitumor promoting activities were evaluated by topical TPA application to ICR mouse skin with measurement of edema formation, epidermal thickness, leukocyte infiltration, hydrogen peroxide production, and the rate of proliferating cell nuclear antigen-stained cells. As a result, nobiletin, a polymethoxyflavonoid, was identified as an inhibitor of both NO and O2- generation. Nobiletin significantly inhibited two distinct stages of skin inflammation induced by double TPA application [first stage priming (leukocyte infiltration) and second stage activation (oxidative insult by leukocytes)] by decreasing the inflammatory parameters. It also suppressed the expression of cyclooxygenase-2 and inducible NO synthase proteins and prostaglandin E2 release. Nobiletin inhibited dimethylbenz[a]anthracene (0.19 micromol)/TPA (1.6 nmol)-induced skin tumor formation at doses of 160 and 320 nmol by reducing the number of tumors per mouse by 61.2% (P < 0.001) and 75.7% (P < 0.001), respectively. The present study suggests that nobiletin is a functionally novel and possible chemopreventive agent in inflammation-associated tumorigenesis.

Anti-tumor promoting effects of sesquiterpenes from Maytenus cuzcoina (Celastraceae).

Ten sesquiterpenoids (1-10), with a dihydro-beta-agarofuran skeleton, were isolated from Maytenus cuzcoina (Celastraceae). Their structures were elucidated on the basis of spectral analysis, including homo- and heteronuclear correlations NMR experiments (COSY, ROESY, HMQC and HMBC), and chemical correlations. The compounds have been tested for their inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA), as a test for potential cancer chemopreventive agents. Compounds 1-3, 6 and 7 showed strong inhibitory effects on EBV-EA induction (100% inhibition at 1000 mol ratio/TPA). Their structure-activity relationship is discussed.