Study On Antifungal Constituents Of Water-soluble Constituents From Pogonatherum Crinitum

Pogonatherum crinitum(Thunb.)Kunth with abound resources is the perennial herb of Pogonatherum in Gramineae,growing on hillsides,stone joints,barren soil or shrubby undercast wetlands.P.crinitum rarely infected by pests and diseases,and has a unique advantage in disease resistance.So antifungal active components of the water-soluble constituents from P.crinitum were studies in this paper,in order to explore the possibility of P.crinitum as the plant resource of botanical fungicides.The main results are as follows.1.Antifungal activities of water-soluble constituents from P.crinitum against 17 plant pathogenic fungi were tested by mycelium growth rate method.The result showed that water-soluble constituents(2 g/L)had antifungal activities against 17 plant pathogenic fungi.The inhibition rate of water-soluble constituents against F.graminearum,H.maydis and P.aphanidermatum were 50.19%,58.20%and 63.14%,respectively.The results of toxicity test showed that the ECso value of water-soluble constituents against F.graminearum,H.maydis and P.aphanidermatum were 1.84 g/L,1.42 g/L and 1.16 g/L,respectively.2.Twenty one compounds were isolated from the water-soluble constituents from P.crinitum by column chromatography and preparative high performance liquid chromatography.The structures of the compounds were identified by UV,ESI-MS,13C NMR,1H NMR as schaftoside(1),luteolin-6-C-?-D)-glucopyranoside-8-C-?-L-Arabmopyr anoside(2),luteolin-6-C-?-boivinopyranoside-7-O-?-Glucopyranoside(3),isorhamnetin-3-O-rutinoside(4),kaempferol-3-O-rutinoside(5),tricin-7-O-?-D-glucopyranoside(6),Tricin-7-O-[?-D-apifuranoside(1?2)]-?-D-glucopyranoside(7),baicalin(8),baicalein(9),taxilfolin(10),Luteolin(11),syringaresinol-4--O-?-D-glucopyranoside(12),?-adenosine(13),Sinapyl 4-O-?-D-glucopyranoside(14),ethyl caffeate(15),stigmas-terol(16),sitosterol(17),protocatechuic acid(18),4-hydroxybenzyl alcohol(19),vanillin(20),4-hydroxybenzal dehyde(21).Compound 1,2,4,6,7,8,9,10,12,14,15,18,19,20 and 21 were obtained from P.crinitum for the first time.3.Antifungal activities of compounds 1-21 against H.maydis and P.aphanidermatum were tested by mycelium growth rate method.The result showed that compound 2,6,8,9,15,20 and 21 have significant antifungal activities on P.aphanidermatum.Compound 2,9,15,20 and 21 have significant antifungal activities on H.maydis.The results of toxicity test showed that the EC50 value of luteolin-6-C-?-D-glucopyranoside-8-C-?-L-arabmopyranoside(compound 2)against H.maydis and P.aphanidermatum were 130.31mg/L and 79.88 mg/L,respectively.The toxicity of compound 2 against H.maydis were slightly higher than commercial products eugenol(EC50 value:156.96 mg/L)and the toxicity against P.aphanidermatum were slightly lower than eugenol(EC50 value:69.40 mg/L).So compound 2 has better antifungal activity.4.Observations from scanning with an Optical microscope discovered that the growth of F.graminearum,H.maydis and P.aphanidermatum were inhibited after water-soluble constituents and luteolin-6-C-?-D-glucopyranoside-8-C-a-L-arabmopyranoside treatment compared with the control.The mycelial morphology of F.graminearum showed a wrinkled surface and increasing vacuoles after water-soluble constituents treatment compared with the control.The mycelial morphology of H.maydis and P.aphanidermatum showed twist and uneven thickness after water-soluble constituents and luteolin-6-C-?-D-glucopyranoside-8-C-?-L-arabmopyranoside treatment compared with the control.