甘肃产4种香茶菜的主要次生代谢产物的抑菌活性

Antimicrobial activity of major secondary metabolites from Isodon species on common microbials

采用滤纸片法测定甘肃产4种香茶菜主要次生代谢产物对6种常见微生物的抑菌活性.结果显示,二萜wangzaozin A和leukamenin E抑制革兰氏阳性菌(G^+)的活性明显强于weisiensin B、rabdosin B和epinodosin,其中epinodosin活性最弱;但5种二萜抑制革兰氏阴性菌(G^-)大肠杆菌的活性弱于3种三萜(熊果酸、3β-乙酰熊果酸和二羟基熊果酸);3种三萜中熊果酸和3β-乙酰熊果酸对G^-菌大肠杆菌有抑菌活性,但对3株G^+菌无抑制作用,而二羟基熊果酸却对G^+菌以及G^-菌均显示了抑制活性,并且,二萜和三萜化合物对G^+菌和G^-菌具有互补抑菌效应;另外,2种黄酮化合物胡麻素和欧槲寄生甙乙,以及甾体化合物β-谷甾醇和胡萝卜甙未显示抑菌作用.表明二萜和三萜不同分子结构决定了其不同的抗菌活性、其互补及抑菌效应,揭示了香茶菜属植物抗菌功效可能的科学基础.

Antimicrobial activities of the maior secondary metabolites from Isodon plant are tested on six common microbials by filter paper assay. Antimicrobial effects of ent-kauranoid diterpenoids wangzaozin A and leukamenin E on the Gram-positive bacteria are stronger than that of weisiensin B. rabdosin B and epinodosin; the inhibitory effect of the five diterpenoids on the Gram-negative bacteria （Escherichia coli） is lower than that of the three triterpenoids（ursolic acid, 3β-acetyl- ursolic acid, 2α, 3α-dihydroxy-urs-12-en- 28-oic acid）; triterpenoids including 2α, 3α-dihydroxyurs-12-en-28-oic acid and ursolic acid show antimicrobial activities against Gram-negative bacteria, but negative to the Gram-positive bacteria, while the triterpenoids 3β-acetyl- ursolic acid show antimicrobial activities against both Gram-positive and Gram- negative bacteria. Additionally, 2 kinds of {lavonoids （pedalitin and flabogadorinin） and 2 kinds of steroids（β-sitosterol and daucosterol） show out negative antimicrobial activities. The results show that the different molecular structures of diterpenoids and triterpenoids determined their antimicrobial activities, and these chemical compounds （diterpenoids and triterpenoids） show complementary and additive antimicrobial effects against Gram-positive and Gram negative bacteria, which reveal a possible antimicrobial reason of the Isodon plant.