粗毛纤孔菌三萜类化合物的诱导合成及其抗氧化功能分析

Induced Biosynthesis and Antioxidant Properties of Triterpenoids in Inonotus hispidus

为探索外源诱导剂对粗毛纤孔菌生物合成三萜类化合物及其抗氧化功能的影响,采用茉莉酸甲酯、水杨酸、油酸、水曲柳煎汁、Mn^(2+)、Fe^(2+)、Cu^(2+)7种诱导剂在不同浓度条件下对粗毛纤孔菌菌丝体生长以及胞内三萜类化合物生物合成情况进行研究,并测定粗毛纤孔菌三萜类化合物的抗氧化功能。结果表明,7种诱导剂均显著促进粗毛纤孔菌菌丝体生长及三萜类化合物合成,其中油酸效果最为显著,在第0天加入3%油酸可得到菌丝体量为(7.146±0.131)g/L,菌丝体中三萜含量为(56.377±3.178)mg/g,三萜总量为402.870 mg/L,与不加入诱导剂的对照组相比三萜总量增加了143.74%。抗氧化能力实验表明,经过7种诱导剂得到的三萜类化合物的抗氧化能力也存在差异,其中油酸诱导的粗毛纤孔菌三萜类化合物抗氧化效果最好,总还原力为1.342,1,1-二苯基-2-三硝基苯肼自由基清除率IC_(50)为0.099 mg/mL,羟自由基清除率IC_(50)为1.294 mg/mL,超氧阴离子自由基清除率IC_(50)为0.001 mg/mL,与对照组相比各自由基清除率分别提高了79.48%、66.71%、28.10%及29.22%。本研究为诱导剂在粗毛纤孔菌三萜类化合物生物合成上应用以及开发新的抗氧化剂提供科学数据。

This study aimed to explore the effect of exogenous inducers on the biosynthesis and antioxidant properties of triterpenoids in Inonotus hispidus. We used seven inducers at different concentrations including methyl jasmonate(MeJA),salicylic acid(SA), oleic acid, willow branch decoction, Mn^2+, Fe^2+ and Cu^2+. The results showed that all the seven inducers signiflcantly promoted the mycelial growth of I. hispidus and the biosynthesis of triterpenoids, oleic acid being the most effective among these. A mycelial biomass yield of(7.146 ± 0.131) g/L was obtained by the addition of 3% oleic acid at the beginning of fermentation. The content of triterpenoids in the mycelia was(56.377 ± 3.178) mg/g, and the total production of triterpenoids was 402.870 mg/L, which was increased by 143.74% compared with the control group without any inducer added. The antioxidant tests showed that the antioxidant capacity of triterpenoids varied with inducer type. Among these inducers, oleic acid induced triterpenoids with the strongest antioxidant effect;the total reducing power was 1.342, and the IC50 values for scavenging of 1,1-diphenyl-2-picrylhydrazyl(DPPH), hydroxyl and superoxide anion radicals were 0.099, 1.294 and 0.001 mg/mL, respectively. The total reducing power and the free radical scavenging rates were increased by 79.48%, 66.71%, 28.10% and 29.22% compared with those of the control group, respectively. The results can provide scientific data for the application of inducers in the biosynthesis of triterpenoids and hence the development of new antioxidants.