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目的研究红曲霉菌对姜黄素的微生物转化及转化总产物的自由基清除和抗脂质过氧化的作用,并对转化产物进行了初步分析。方法用本实验室保存的红曲霉菌对姜黄素进行微生物转化,同时设立菌株对照和底物对照;研究转化总产物对DPPH自由基的清除能力;研究转化总产物对食饵性高脂血症小鼠肝脏和血清MDA、SOD、GSH-Px等过氧化脂质的影响。用乙酸乙酯提取转化产物,用TLC、HPLC-DAD(Agilent Zorbax Extend C18柱,0.1%乙酸和乙腈梯度洗脱,流速1.0mL·min-1)对转化产物进行了初步分析。结果姜黄素转化总产物在10000～400mg·mL-1(相当于含姜黄素100～4mg·mL-1)内有很强的自由基清除能力,总产物浓度在100mg·mL-1还保留了47.46%的清除能力;而底物对照物在10000、2000mg·mL-1时有一定的清除能力,但浓度在400mg·mL-1时自由基清除能力已明显减弱,100mg·mL-1以下已基本消失。转化总产物500,200,100mg·kg·d-1(相当于姜黄素5,2,1mg·kg·d-1)均能降低高脂血症小鼠肝脏和血清的过氧化脂质,而菌株对照组(500mg·kg·d-1)和底物对照组(500mg·kg·d-1,相当于姜黄素5mg·kg·d-1)抗脂质过氧化作用不明显。研究超氧化物歧化酶、谷胱甘肽过氧化物酶,发现姜黄素转化产物对此二酶的作用不明显,其抗氧化作用可能并非通过改变此二酶的活性。转化产物经HPLC-DAD分析,发现可能存在6个转化产物,其保留时间分别为16.3,22.1,23.2,28.0,33.0,36.1min,其光谱图与姜黄素存在明显差异。结论姜黄素经红曲霉菌转化后形成了由6个代谢产物组成的新组合型天然姜黄素类似物群,其自由基清除能力和抗脂质过氧化作用显著增强。
Objective To study the effects of Aspergillus oryzae on the microbial transformation of curcumin and on the free radical scavenging and anti-lipid peroxidation of the total products, and the primary products of the transformation were analyzed. METHODS: The curcumin was transformed into microorganisms by using Monascus mold preserved in our laboratory. At the same time, strain control and substrate control were set up. The ability of scavenging DPPH free radical was studied. The effect of lipid peroxidation such as MDA, SOD and GSH-Px in liver and serum of rats. The conversion product was extracted with ethyl acetate and the conversion product was analyzed by TLC, HPLC-DAD (Agilent Zorbax Extend C18 column, gradient of 0.1% acetic acid and acetonitrile, flow rate 1.0 mL · min -1). Results The total curcumin product had strong free radical scavenging activity in the range of 10000-400mg · mL-1 (equivalent to 100-4mg · mL-1 containing curcumin). The total product concentration remained at 100mg · mL-1 47.46% of the scavenging capacity; while the substrate control at 10000, 2000mg · mL-1 have some scavenging ability, but the concentration of 400mg · mL-1 free radical scavenging capacity has been significantly reduced, 100mg · mL-1 the following Basically disappear. The total product of 500, 200 and 100 mg · kg · d-1 (corresponding to curcumin 5, 2, 1 mg · kg · d-1) all decreased the lipid peroxidation in the liver and serum of hyperlipidemic mice, (500mg · kg · d-1) and the control group (500mg · kg · d-1, equivalent to curcumin 5mg · kg · d-1) had no obvious anti-lipid peroxidation. Study of superoxide dismutase, glutathione peroxidase, curcumin conversion products found that the role of these two enzymes is not obvious, the antioxidant effect may not by changing the activity of these two enzymes. The results of HPLC-DAD analysis showed that there may be 6 transformation products with the retention times of 16.3,22.1,23.2,28.0,33.0,36.1min, respectively. There is a clear difference between their spectra and curcumin. CONCLUSION: Curcumin is a new type of natural curcumin analogue composed of 6 metabolites after being transformed by Monascus. Its free radical scavenging activity and anti-lipid peroxidation are significantly enhanced.