Chemopreventive effects of the juice of Vitis coignetiae Pulliat on two-stage mouse skin carcinogenesis.

Our study revealed the inhibitory effect of Vitis coignetiae Pulliat, known as Yamabudo in Japan, at the stages of multi-step carcinogenesis. The juice of Vitis coignetiae (Y-grape juice) was antimutagenic toward dimethylbenzo[a]anthracene (DMBA), aflatoxin B1, and benzo[a]pyrene in the Ames test. The Y-grape juice was also antigenotoxic in the micronucleus test using HepG2 cells toward DMBA and aflatoxin B1. Topical and oral administration of the Y-grape juice to mice inhibited the induction of inflammation of 12-O-tetradecanoylphorbol-13-acetate (TPA). Topical and oral administration of the Y-grape juice significantly decreased the incidence and mean number of tumors in mice skin with the 2-stage tumorigenesis protocol. To elucidate the mechanisms underlying the antiinflammatory and antitumor promotion activity of the Y-grape juice, the effect of Y-grape juice on cyclooxygenase-2 (COX-2) activity in mouse ear treated with TPA was studied. Both topical and oral application of the Y-grape juice inhibited the TPA-induced increase in COX-2 activity. Caftaric acid, isolated and identified from the Y-grape juice, was antimutagenic toward DMBA and prevented TPA-induced inflammation in mice, suggesting caftaric acid participates in chemopreventive effect/activities of Y-grape juice.

Anti-genotoxic activity of Vitis coignetiae Pulliat towards heterocyclic amines and isolation and identification of caftaric acid as an antimutagenic component from the juice.

Our study demonstrated that the formation of DNA adducts in liver, lungs, colon and kidneys of mice given a carcinogenic heterocyclic amine, 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) or 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), in the diet significantly decreased following the administration of the juice of Vitis coignetiae, purple berries from a vine tree. The juice of V. coignetiae significantly inhibited the clastogenicity and mutagenicity of heterocyclic amines in the micronucleus assay and the Ames test, and was an effective inhibitor of the activities of phase I enzymes (cytochrome P450 1A1 and cytochrome P450 1A2) and enhancer of the activities of phase II enzymes (uridine 5'-diphospho-glucuronosyltransferase and glutathione S-transferase). We investigated the purification and isolation of an active compound in the juice of V. coignetiae using antimutagenicity as a separation marker. Caftaric acid, a polyphenolic compound, was identified as a component responsible for antimutagenicity in the juice of V. coignetiae towards the carcinogenic heterocyclic amine 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2). This is the first report of antimutagenicity of caftaric acid. Caftaric acid was reported as an inhibitor of the protein-protein interactions mediated by the Src-family kinases. The impact of the juice of V. coignetiae and its constituents on tumor initiation and promotion thus warrants further study.

Influences of cross pollination on pollen tube growth and fruit set in Zuili plums (Prunus salicina).

Zuili plum (Prunus salicina L.) trees usually set fruit poorly, although they produce high quality fruit. To elucidate the causes of the poor fruit set, pollen tube growth into pistils and fruit set percentage were investigated after cross-, self- and open-pollination. Ovule development in Zuili pistils was also investigated. Pollen tube penetration into the ovules via the obturator and micropyle was best when Zuili pistils were pollinated by cv. Black Amber (P. domestica) pollen grains, although cross-pollinations with Hongxinli and Miili (P. salicina) pollen were more effective than self- and open-pollination. The fruit set percentage was also highest in pistils pollinated with Black Amber pollen grains. Morphological observation of Zuili pistils revealed that the trees produce "double pistils", developing two ovaries from a basal pistil, at a rate as high as 28%. In such abnormal pistils, most ovules were lacking an embryo sac or were entirely degenerated. The percentage of normally developed ovules was 24.3% and 8.9% in normal and double pistils, respectively. From these results, we conclude that the main causes of poor fruit set of Zuili plums are a lack of effective cross-pollination and the production of high percentages of double pistils in which normally developed ovules are scarcely formed.

Effects of post-harvest light conditions on quality and aromatic volatile formation in 'Hakuho' peach (Prunus persica Batsch) fruits.

The effect of light condition during post-harvest storage on fruit quality of 'Hakuho' peach (Prunus persica Batsch) was examined. Fruits were harvested at the immature stage (7 d before the tree-ripening stage) and firm-ripe (3 d before the tree-ripening) stage and stored at 25 degrees C under light (ca 80 micromol m(-2) s(-1) at the fruit top by a fluorescent lamp) and in darkness. The light and dark conditions did not significantly influence the ethylene production rate except for the fully ripened fruits harvested at firm-ripe stage and stored under light. However, no difference in fruit firmness was detected among treatments at full-ripe stage. The skin anthocyanin content increased significantly during storage under light. Total soluble solid (TSS) content of juice at the full ripe stage was not affected significantly by the storage condition, although titratable acidity (TA) in immature harvested fruits decreased more quickly during storage under light compared with those stored in darkness. Dark storage limited the decrease in juice asparagine to some extent. Aromatic lactones, such as gamma-decalactone and gamma-dodecalactone, both in skin and in flesh tissues increased more rapidly when the fruits were stored under a light condition, irrespective of fruit harvest stage. From these results, we conclude that fruit storage under a light condition is better for fruit quality of the 'Hakuho' peaches than storage in darkness.