不同干燥方法对薄荷药材中多元功效成分的影响与评价

　　[摘要] 采用GC-MS和UPLC-TQ-MS技术分析评价不同干燥方法对薄荷药材中2种单萜类、4种酚酸类、5种黄酮类化学成分的组成及含量变化，考察干燥方法对其化学成分的影响；利用TOPSIS综合分析法进行综合评价，为薄荷药材适宜干燥方法的确定提供依据。结果显示，干燥方法对薄荷醇、咖啡酸、迷迭香酸含量影响最大，其次为绿原酸、香叶木素-7-O-葡萄糖苷；同温度下，热风干燥对活性成分的保留作用优于微波干燥与红外干燥；低温（40～45 ℃）干燥对活性成分总量的保留显著高于高温（60～70 ℃）干燥；微波杀青处理样品酚酸类化学成分总量显著高于未杀青样品，表现出一定的杀酶作用；TOPSIS评价结果显示，薄荷药材产地加工最适干燥方法为热风变温45～60 ℃干燥。该研究为薄荷药材产地适宜干燥加工方法的确定提供了依据，也为富含挥发油药材的产地加工共性技术形成提供了有益的探索和借鉴。
　　[关键词] 薄荷；干燥方法；GC-MS；UPLC-TQ-MS；TOPSIS综合评价
　　[Abstract] To provide a scientific basis for the selection of the appropriate drying method for Mentha Haplocalyx Herba （MHH）， determine 2 monoterpenes， 4 phenolic acids and 5 flavonoids in MHH by GC-MS and UPLC-TQ-MS methods， and investigate the effects of the drying methods on the changes in contents of these analytes. The qualities of products obtained with different drying methods were evaluated by the multivariate statistical method of Technique for Order Preference by Similarity to Ideal Solution（TOPSIS）. Results showed that the drying methods had the greatest impact on menthol， caffeic acid， and rosemary acid， which were followed by chlorogenic acid and diosmetin-7-O-glucoside. The contents in these analytes processed with hot-air-drying method were higher than those with microwave-drying and infrared-drying methods at the same temperatures. The contents in these analytes processed under low temperature （40-45 ℃） were higher than those under higher temperature （60-70 ℃）. Above all， the contents in phenolic acids processed with microwave fixation （exposed under microwave at 100 ℃ for several minutes） were obviously higher than those of not being processed， showing an inhibition of some enzymes in samples after fixation. The TOPSIS evaluation showed that the variable temperature drying method of ′Hot-Air 45-60 ℃′ was the most suitable approach for the primary drying processing of MHH. The results could provide the scientific basis for the selection of appropriate drying method for MHH， and helpful reference for the primary drying process of herbs containing volatile chemical components.
　　[Key words] Mentha haplocalyx； drying method； GC-MS； UPLC-TQ-MS； TOPSIS evaluation
　　doi：10.4268/cjcmm20152424
　　唇形科植物薄荷Mentha haplocalyx Briq.以干燥地上部分入药，味辛，性凉，归肺、肝经，具有疏风散热，清利头目，利咽透疹，疏肝行气的功效。现代研究显示，薄荷植物中富含以单萜类化学成分为主要组成的挥发油，以及黄酮类、酚酸类等化学成分^[1-6]，多具有显著的生物活性，为其传统功效发挥的主要物质基础^[7-10]。
　　薄荷药材产地传统加工方法为夏、秋二季茎叶茂盛或花开至三轮时，选晴天，分次采割后阴干或晒干。传统干燥方法存在干燥周期长、易受天气条件影响、干燥后药材质量不均一等弊端。近年来，基于现代干燥原理与技术的干燥方法逐渐应用于中药材产地干燥加工过程，并表现出干燥时间短、干燥条件可控、产品质量稳定等优点^[11]。目前常用的中药材现代干燥技术主要有微波干燥、红外干燥、热风干燥等。微波干燥具有穿透力强、脱水快，干燥同时也可起到杀虫卵、灭酶的作用，常用于易发生褐变或霉烂的花类、茎叶类以及全草类药材干燥前的杀青处理；红外干燥内外加热同时进行，脱水效率较热风干燥高，适用于含水量大、易霉变，以及贵重中药材的干燥加工；热风干燥以流动热风加热药材并带走水分，其优点是干燥设备成本低，干燥效率高，不受天气条件限制，温度可控，适用于大多数中药材的干燥加工^[11]。

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