Study On Antifungal Constituents Of Pogonatherum Crinitum

Pogonatherum crinitum(Thunb.)Kunth is the perennial herb of Pogonatherum in Gramineae,mainly distributes in Fujian,Zhejiang,Taiwan of China and other areas.There are some researches about the chemical constituents and biological activity in Pogonatherum plants,the researches on the pest control and prevention,however,have not still been reported.From the view of phytochemistry and pesticide science,this thesis primarily studied on the chemical constituents and antifungal activities of P.crinitum.The main results are as follows.1.Inhibition effects of the extracts from P.crinitum against 20 plant pathogenic fungi were tested by mycelium growth rate method.The result showed that aqueous extract(2.00 g/L)had moderate activities against the 14 tested fungi,and the n-butanol phase and the ethyl acetate phase have higher activities than the aqueous extract.The inhibition rate of ethyl acetate phase(2.00 g/L)were over 50%against 8 pathogenic fungi,and the inhibition rate against R.solani,C.higginsianum,F.gramine-arum and P.capsici were 45.99%,53.52%,61.59%and 100.00%respectively.The result of toxicity test showed that the EC50 value of ethyl acetate phase against R.solani,C.higginsianum,F.graminearum and P.capsici were 1.48,2.45,1.56 and 0.52 g/L,respectively.2.Ten compounds were isolated from the ethyl acetate extract from P.crinitum by means of silica gel column chromatography,polyamide column chromatography,ODS reverse phase column chromatography,Sephadex LH-20 column chromatography and recrystallization.The structures of the constituents were identified by ESI-MS,13C NMR,1H NMR as tricin-7-O-?-D-glucopyranoside(1),tricin(2),luteolin-6-C-?-boivinopyranoside-7-O-?-glucopyranoside(3),rutin(4),quercetin(5),caffeic acid(6),spicatolignan B(7),?-adenosine(8),1,2,4-trihydroxy-benzene(9)and 1,2-tidroxy-4-methoxybenzene(10).Compound 1,5,7,8 and 10 were obtained from P.crinitum for the first time.3.Inhibition effects of compound 1-10 against R.solani and P.capsici had been tested by method of spore germination.The result showed that compound 3-7 have significant inhibiting effect on two tested plant pathogens.The EC50 of compound 3-7 against R.solani were18.54,48.31,40.43,32.8 and 103.61 mg/L,and against P.capsici were 21.38,52.19,41.36,36.13 and 87.83 mg/L,respectively.Compound 3 had the best antifungal activities,EC50 of which against R.solani and P.capsici were 18.54 and 21.38 mg/L.In conclusion,the extracts from P.crinitum had moderate antifungal activities and some antifungal constituents were obtained from P.crinitum,which could be explored as botanical fungicides.