石榕树中补骨脂素分离鉴定及其抗真菌活性

Isolation and identification of psoralen from Ficus abelii and its antifungal activity

[目的]分离出石榕树中能够有效抑制植物病原真菌的活性单体化合物并探索其抗真菌活性。[方法]采用生物活性追踪和化学分离相结合的方法对石榕树甲醇提取物进行分离,运用质谱、核磁共振氢谱和碳谱并结合相关文献数据鉴定活性单体化合物。采用菌丝生长速率法测定活性单体化合物对7种植物病原真菌的抑菌活性。[结果]石榕树(叶)甲醇提取物对甘蔗凤梨病菌具有良好抑菌活性,在10 mg·mL^(-1)浓度下,抑菌率为100%。在浓度为1.5 mg·mL^(-1)时,石榕树(叶)石油醚、乙酸乙酯、正丁醇萃取物和水层萃余物对甘蔗凤梨病菌的抑菌率分别为58.73%、100.00%、39.49%和6.63%。表明石榕树(叶)乙酸乙酯层萃取物对甘蔗凤梨病菌的抑制作用最高,其EC_(50)值为0.430 7 mg·mL^(-1)。石榕树(叶)乙酸乙酯层萃取物进行柱色谱分离后得到对甘蔗凤梨病菌有较高抑菌活性的是LMNO1bc1a活性组分,0.1 mg·mL^(-1)的LMNO1bc1a活性组分对甘蔗凤梨病菌的抑菌率为100.00%。LMNO1bc1a组分经结晶、重结晶纯化后命名为SRS-1,SRS-1经NMR和MS技术鉴定为补骨脂素(psoralen)。SRS-1对甘蔗凤梨病菌、甘蓝黑斑病菌、玉米大斑病菌、罗汉果白绢病菌、柑橘砂皮病菌、茶轮斑病菌、烟草黑胫病菌这7种植物病原真菌都有一定的抑菌活性,其EC_(50)值分别为0.018 2、0.038 8、0.040 9、0.051 2、0.080 7、0.092 7、0.115 4 mg·mL^(-1)。[结论]从石榕树中分离出抑菌活性单体化合物SRS-1,鉴定为补骨脂素,其对甘蔗凤梨病菌、甘蓝黑斑病菌、玉米大斑病菌、罗汉果白绢病菌、柑橘砂皮病菌、茶轮斑病菌、烟草黑胫病菌这7种植物病原真菌都有一定的抑菌活性。

[Objective]The current study aimed to isolate and identify the active monomeric compounds from Ficus abelii that can effectively inhibit plant pathogenic fungi and to explore their antifungal activities.[Method]A combination of bioactivity-guided isolation and chemical separation was used to isolate compounds from the methanol extracts of F.abelii.The active monomeric compounds were identified using mass spectrometry(MS),proton nuclear magnetic resonance(1H-NMR),carbon nuclear magnetic resonance(13C-NMR),and related literature data.The antifungal activities of the isolated monomeric compounds from F.abelii against seven plant pathogenic fungi were determined using the mycelial growth rate method.[Result]The results showed that the methanol extract of F.abelii(leaves) had good antifungal activities against Thielaviopsis paradoxa,causal agent of pineapple disease in sugarcane,with an inhibition rate of 100% at the concentration of 10 mg·mL~(-1).At a concentration of 1.5 mg·mL~(-1),the petroleum ether,ethyl acetate,n-butanol,and aqueous extracts of F.abelii had inhibition rates of 58.73%,100.00%,39.49%,and 6.63% against T.paradoxa,respectively,indicating that the ethyl acetate extract possessed the highest inhibitory activity with a median effective concentration(EC_(50)) value of 0.430 7 mg·mL~(-1).After column chromatography of the ethyl acetate extract,the active fraction LMNO1bc1a showed a 100% inhibition rate against T.paradoxa at a concentration of 0.1 mg·mL~(-1).The LMNO1bc1a fraction was crystallized and recrystallized,resulting in the pure compound named SRS-1,which was identified as psoralen using NMR and MS techniques.SRS-1 exhibited antifungal activity against seven plant pathogenic fungi,including T.paradoxa,Alternaria oleracea,Exserohilum turcicum,Athelia rolfsi,Citrus melanoses,Pesta-lotiopsis theae,and Phytophthora parasitica.with EC_(50) values of 0.018 2,0.038 8,0.040 9,0.051 2,0.080 7,0.092 7,0.115 4 mg·mL~(-1),respectively.[Conclusion]The antifungal active monomer SRS-1,identified as psoralen,was isolated from F.hirta.It showed certain antifungal activity against seven plant pathogenic fungi,including T.paradoxa,A.oleracea,E.turcicum,A.rolfsi,C.melanoses,P.theae,and P.parasitica.