芒果苷对马铃薯晚疫病菌的抑菌作用机制初探

芒果苷是知母Anemarrhena asphodeloides中的一种有效成分,室内生物测定结果表明,其 对马铃薯晚疫病菌Phytophthora infestans的菌丝生长有较强的抑制作用,其EC50值为32.65 μg/mL, 但对游动孢子释放的抑制作用较弱,其EC50值为100.97 μg/mL。采用考马斯亮蓝G-250比色法对马铃薯晚疫病菌菌丝体内蛋白质含量变化的测定结果表明,芒果苷对晚疫病菌菌丝体的蛋白质合成有抑制作用;在浓度低于12.5 μg/mL时,芒果苷对晚疫病菌菌丝体细胞膜的通透性影响不大,随浓度的增加,使菌丝体细胞膜电导率明显增大。利用孢子悬浮液中溶氧量的变化进行呼吸代谢抑制试验的结果显示:芒果苷对马铃薯晚疫病菌呼吸代谢的糖酵解途径(EMP)、三羧酸循环(TCA)、磷酸戊糖途径(HMP)均有抑制作用,其中对HMP途径的抑制作用最明显。

Preliminary Studies on the Mode of Action of Mangiferinagainst Phytophthora infestans

Mangiferin is an active ingredient of traditional Chinese medicinal herb Anemarrhena asphodeloides.Bioassay tests in vitro showed that mangiferin could inhibit the mycelium growth of Phytophthora infestans intensively,with EC50 value 32.65 μg/mL,but it has low inhibitory effect on the zoospore release of P.infestans with EC50 value 100.97 μg/mL.Coomassie brilliant blue G-250 colorimetric method was used to test the protein variations of P.infestans mycelia.The result indicated that mangiferin inhibited the protein biosynthesis of P.infestans.It could influence the permeability of the cell membrane of P.infestans at higher concentration,but the effect was not significant at the lower concentration 12.5 μg/mL.Dissolved oxygen content in zoospores suspension was used to test the respiratory inhibition effect of mangiferin on P.infestans.The results revealed that mangiferin had significant inhibition effect on metabolic pathways such as glycolytic pathway (EMP),tricarboxylic acid cycle (TCA) and hexose monophosphate pathway (HMP),and the inhibition effect on HMP was the most significant.