Screening for the in vitro anti-tumor-promoting activities of edible plants from Malaysia

A total of 114 methanol extracts from 42 plant families of edible Malaysian plants were screened for their inhibitory activities toward tumor promoter 12-O-hexadecanoylphorbol-13-acetate (HPA)-induced Epstein-Barr virus (EBV) activation in Raji cells. By testing at a concentration of 200 μg/ml, 74% of the 114 extracts inhibited EBV activation by 30% or more. This rate is comparable to those observed in the previous tests on edible Thai (60%) and Indonesian (71%) plants, and, importantly, much higher than that (26%) observed for Japanese edible plants. Approximately half of the Malaysian plants did not taxonomically overlap those from the other three countries, suggesting that Malaysian plants, as well as Thai and Indonesian plants, are an exclusive source of effective chemopreventive agents. Further dilution experiments indicated an extract from the leaves of Piper betle L. (Piperaceae) to be one of the most promising species. The high potential of edible Southeast Asian plants for cancer chemoprevention is collectively discussed

Multiple functions of precursor BDNF to CNS neurons: negative regulation of neurite growth, spine formation and cell survival

<p>Abstract</p> <p>Background</p> <p>Proneurotrophins and mature neurotrophins elicit opposite effects via the p75 neurotrophin receptor (p75^NTR) and Trk tyrosine kinase receptors, respectively; however the molecular roles of proneurotrophins in the CNS are not fully understood.</p> <p>Results</p> <p>Based on two rare single nucleotide polymorphisms (SNPs) of the <it>human brain-derived neurotrophic factor (BDNF) </it>gene, we generated R125M-, R127L- and R125M/R127L-BDNF, which have amino acid substitution(s) near the cleavage site between the pro- and mature-domain of BDNF. Western blot analyses demonstrated that these BDNF variants are poorly cleaved and result in the predominant secretion of proBDNF. Using these cleavage-resistant proBDNF (CR-proBDNF) variants, the molecular and cellular roles of proBDNF on the CNS neurons were examined. First, CR-proBDNF showed normal intracellular distribution and secretion in cultured hippocampal neurons, suggesting that inhibition of proBDNF cleavage does not affect intracellular transportation and secretion of BDNF. Second, we purified recombinant CR-proBDNF and tested its biological effects using cultured CNS neurons. Treatment with CR-proBDNF elicited apoptosis of cultured cerebellar granule neurons (CGNs), while treatment with mature BDNF (matBDNF) promoted cell survival. Third, we examined the effects of CR-proBDNF on neuronal morphology using more than 2-week cultures of basal forebrain cholinergic neurons (BFCNs) and hippocampal neurons. Interestingly, in marked contrast to the action of matBDNF, which increased the number of cholinergic fibers and hippocampal dendritic spines, CR-proBDNF dramatically reduced the number of cholinergic fibers and hippocampal dendritic spines, without affecting the survival of these neurons.</p> <p>Conclusion</p> <p>These results suggest that proBDNF has distinct functions in different populations of CNS neurons and might be responsible for specific physiological cellular processes in the brain.</p

Growth-Promoting Factors in Young Lupinus Seeds (A. NATURAL SCIENCE)

1. The present study is concerned with cytokinin and embryo factor in young Lupinus seeds. 2. Partial purification of these factors was carried out. 3. The silver-precipitated fraction of the Lupinus extract stimulates cell-division of calluses of tobacco and carrot. It is promotive to the growth of radish leaf, and inhibitory to the degradation of chlorophyll of radish cotyledon. 4. Embryo factor and cytokinin in the Lupinus extract have different Rf values on paper chromatogram, indicating that they were different substances

Cytokinin Activities of Dihydrozeatin in Several Bioassays (A. NATURAL SCIENCE)

(±)-Dihydrozeatin was tested for its cytokinin activities in several bioassays and compared with different cytokinins. Dihydrozeatin stimulates the growth of tobacco callus at the concentrations of 10^-10^M with the optimum at 10^M, shoot development on tobacco callus at 10^M with 2×10^M IAA, the germination of lettuce seeds at 10^-10^M, the growth of radish leaf at 5×10^-5×10^M, and the development of lateral buds in pea seedlings at 5×10^M. This cytokinin inhibits the elongation of pea stem segment and delays senescence in detached wheat leaves at 10^-10^M. Dihydrozeatin is less active than zeatin and N^6-(isopentenyl) adenine (2iP) in these bioassays used, but it is of stronger activity than kinetin in the growth of tobacco callus and radish leaf and less effective in the germination of lettuce seeeds and the retention of chlorophyll

ナフトエ酸置換体の植物生長素性に関する研究

京都大学0048新制・課程博士農学博士農博第6号新制||農||3(附属図書館)学位論文||S35||214(農学部図書室)UT51-44-P2428京都大学大学院農学研究科農芸化学専攻(主査)教授 三井 哲夫, 教授 今村 駿一郎, 教授 中島 稔学位規則第5条第1項該当Kyoto UniversityDFA