孜然乙醇提取物的工艺优化及对酪氨酸酶活性的抑制作用

以孜然为原料,在单因素实验的基础上,以酪氨酸酶抑制率为指标,采用响应面法优化孜然乙醇提取物的提取工艺,并测定不同极性部位对酪氨酸酶的影响及孜然乙醇提取物中主要活性成分的含量。结果表明,孜然乙醇提取物抑制酪氨酸酶的最优提取工艺为:乙醇体积分数71%,液料比16：1 (mL/g),提取时间2.2 h,提取温度83 ℃,在此条件下其对酪氨酸酶活性的抑制率达(42.61%±0.56%),与预测值43.20%接近,表明响应面分析的结果可靠;孜然乙醇提取物中多酚、黄酮、皂苷、多糖四种活性成分的含量分别为(1.35%±0.03%)、(4.40%±0.29%)、(0.76%±0.04%)、(4.89%±0.28%);孜然乙醇提取物不同极性部位对酪氨酸酶均有抑制作用,且呈浓度依赖关系,其IC₅₀大小顺序为:水相 > 石油醚相 > 正丁醇相 > 乙酸乙酯相。因此,优化得到的孜然乙醇提取物抑制酪氨酸酶的提取工艺合理、可行,乙酸乙酯和正丁醇部位对酪氨酸酶活性的抑制能力较强,多酚、黄酮、皂苷、多糖等都可能是孜然乙醇提取物抑制酪氨酸酶的功效成分。

Optimization of extraction process of ethanol extracts from cumin (Cuminum cyminum L.)and measurement of anti-tyrosinase activity

The response surface methodology was adopted to optimize the extraction process of anti-tyrosinase from ethanol extract of cumin, which was based on the single factor experiment. In addition, the content of main active components and the effect on tyrosinase activity from different polar fractions of cumin extract were investigated. The results revealed that the optimized extraction conditions of anti-tyrosinase from ethanol extract in cumin were as follows:ethanol concentration 71% (v/v), liquid-solid ratio 16:1 (mL/g), extraction time 2.2 h and extraction temperature 83℃. Under these conditions, the inhibition rate of ethanol extract (0.8 mg/mL)was up to (42.61%±0.56%), which was very close to the predicted value 43.20%. It was demonstrated that the analysis results of response surface methodology were reliable. The contents of polyphenols, flavonoids, saponins and polysaccharides in cumin ethanol extract were (1.35%±0.03%), (4.40%±0.29%), (0.76%±0.04%), (4.89%±0.28%), respectively. In addition, all the polar fractions of cumin extract had inhibitory effect on tyrosinase with a concentration dependent manner, the value of IC₅₀ in turn was as follow:water fraction, petroleum fraction, n-butanol fraction and ethyl acetate fraction. Therefore, the optimized extraction process of anti-tyrosinase from ethanol extract of cumin was reasonable and feasible. In addition, ethyl acetate and n-butanol fractions possessed greater inhibitory effect on tyrosinase than that of others. Moreover, polyphenols, flavonoids, saponins and polysaccharides may be the effective components of inhibiting tyrosinase activity by cumin extracts.