4种萜类化合物对蝴蝶兰茎腐病菌的抑制作用及机理的初步研究

Antibacterial activity and related mechanism of four terpenoids on the pathogen of Phalaenopsis amabilis stem rot

以从蝴蝶兰茎腐病斑分离的12株革兰氏阴性菌和2株真菌为试验材料,研究香茶菜属植物中2种二萜(leukamenin E和weisiensin B)以及2种三萜(熊果酸和2-α-羟基熊果酸)的抑菌活性,并对leukamenin E抑制病原菌尖镰孢生长的机理进行初步研究。结果表明,leukamenin E对2株真菌的抑制作用最强,熊果酸和2-α-羟基熊果酸次之,weisiensin B最弱;800μmol/L leukamenin E可破坏尖镰孢菌丝体细胞内微丝结构,并使菌丝细胞膜通透性显著增加,导致菌丝体极性生长受阻。4种萜类对12株细菌的抑制活性显示了明显的选择性和互补特性,leukamenin E对其中5种细菌有抑制作用,而weisiensin B则对其他4种细菌具有抑制活性,weisiensin B还对2种三萜均无抑制效应的细菌也有较强的抑制活性,揭示了香茶菜植物萜类分子结构多样性具有重要的化学生态学意义。

In this study,twelve Gram-negative bacteria and two fungi from Phalaenopsis amabilis stem rot were tested to evaluate the antibacterial activity of the ent-kaurane diterpenoids（leukamenin E and weisiensin B）and the triterpenes （ursolic acid and 2-α-hydroxy ursolic acid）.In addition,the antibacterial activity of leukamenin E to Fusarium oxysporum was preliminarily studied.The results showed that the antibacterial activity of leukamenin E was the strongest to the two fungi,while that of weisiensin B was the weakest and the two triterpenes had moderate activity.Leukamenin E at 800μmol/L could destroy the F-actin cytoskeleton of F.oxysporum,and make the cell membrane of F.oxysporum magnify obviously,resulting in hindered growth of mycelium polarity.The antibacterial activity of the four terpenoids showed obvious characteristics of selectivity and complementarity on twelve bacteria.Leukamenin E had antibacterial activity to five bacteria,while weisiensin B had antibacterial activity to other four bacteria.Weisiensin B had the antibacterial activity to the bacteria that were insensitive to two kinds of triterpenes.The test revealed that the diversity of molecular structure of terpenoids from Isodon plants had important significance in chemical ecology.