关键词: 银杏叶, 黄酮类化合物, 影响因子, 调控机理, 化学合成, 生物技术

Abstract: Current studies on flavonids of Ginkgo biloba leaves have been reviewed. Flavonoids come from the derivatives of the products of shikimate pathway and acetate-malonate pathway. Flavonoids contents in Ginkgo biloba leaves are controlled by genes to a great extent. However, other factors also play important roles, including photosynthesis, season, year, tree age, leaf maturity, plant seed-load, the reproductive ways of nursery stock, the variety, time and quantity of the fertilizer application and so on. The influence of the ecological factors on flavonolds content mainly takes place at young stage of Ginkgo biloba trees. Among all ecological factors, light and temperature are the most important. Recent reports have showed that the significance of the principal ecological factors influencing flavonoids content is in the following order:latitude, annual precipitation, annual mean sunshine percentage, and annual mean temperature. Regulating enzymes in flavonoids biosynthesis include L-phenylalanine ammonia-lyase(PAL), chalcone synthase(CHS), chalcone isomerase(CHI), UDP\|3\|O\|glucosyltransferase(UFGT),4\|coumanate coa ligase(4CL) according to recent research reports. Regulating mechanism of PAL was relatively known best. Ethylene and abscisic acid enhance flavonoids biosynthesis, while gibberellic acid has opposite effect. The effects of the growth promoting hormones have exhibited inconsistency. It is said that the mechanisms of plant hormones are connected with the regulation of enzyme activities and maturing process. The great progress in producing flavonoids by means of biological technology and chemical synthesis has been made. The inconsistent relationship between leaf yield and flavonoids content has been observed. The methods of increasing flavonoid content in \%Ginkgo biloba\% leaf have been commented and their outlook has been analysed in this paper.

Key words: Ginkgo biloba leaf, Flavonoids, Influential factor, Mechanism of control, Chemical synthesis, Biological technology