Producing A Preliminary Study Of Flavonoids In Ginkgo Endophyte Strains

In this paper, 85 strains of endophytic fungi were isolated from Ginkgo biloba. They were identified as Colletotrichum sp., Sphaerosis sp., Fusarium sp., Stemphylium sp., Gloeosporium sp., Sphacelia sp., Guignardia sp. based on morphological taxonomy. The fermentation liquid of 4 strains can inhibit some bacteria. They were proved to produce flavone-like compounds by color reaction analysis. One strain of which the strain EG4 (Colletotrichum sp.) was excellent with steady properties and high production. It was proved that there were similar and same components with the ginkgo flavonoids in the fermentation liquid of EG4 by TLC and HPLC. It could be predicted by UV analysis the components bore the common structure of flavonoids, 4'-carboxyl, 5-carboxyl, 4-carbonyl, A-phenol hydroxyl group. 7-carboxyl,oxygenie substituting groups in 6 and 8 sites, without o-phenol hydroxyl group. Then the cultural characteristics of EG4 was preliminarily studied. The results showed that it could grow well in potato dextrose liquid medium. Glucose and NH4+ were very suitable for its growth, lactose, urea and NO2" could distinctly improve its ability to produce flavone-like compounds, the optimum temperature for mycelia growth is 28 C, the optimum pH is natural pH, 100mL media volume in 250mL flasks and 100r/min were propitious to develop. Vitamin B1 B2, C and FH4 could promote the growth rate of EG4 in different degree, FH4 and Ca2+ could clearly improve its ability to produce flavonoids. The optimum condition for fermentation is 20g/L lactose, 3.2g/Lurea, 28 C, natural pH, lOOmL media volume in 250mL flasks, 100 r/min, 0.5g/L Ca2+ and minimum FH4.