以不同类型的低共熔溶剂为提取剂，采用微波辅助蒸馏法从胡椒叶中提取精油。比较了不同类型的低共熔溶剂，并对影响精油得率的主要因素(液料比、微波功率、提取时间)进行了单因素试验和响应面的工艺优化。结果表明：氯化胆碱-尿素低共熔溶剂为最佳提取剂，当其液料比为16:1 mL/g，微波功率480 W，提取时间53 min时。在此条件下，精油最大得率为1.42%。对比试验发现：此方法对精油得率明显优于水蒸气蒸馏法和微波辅助蒸馏法，分别提高了17.48%、5.66%。通过用气相色谱-质谱(GC-MS)对精油的化学成分进行了鉴定，共34种物质，主要成分为异桉油烯醇（25.47%）、δ-榄香烯（17.52%）、石竹烯（8.27%）、α-荜澄茄油烯（7.07%）、α-古芸烯（5.59%）、(+)-喇叭烯（5.02%）。以氯化胆碱-尿素作为低共熔溶剂提取胡椒叶精油的方法是可行的。

Essential oils were extracted from pepper leaves by microwave-assisted distillation using different types of deep eutectic solvents as solvents. Different types of eutectic solvents were compared, and the main factors affecting the yield of essential oils (solvent-solid ratio, microwave power, extraction time) were optimized by single factor test and response surface methodology. The results showed that the choline chloride-urea deep eutectic solvent was the best extractant, when the conditions was as follow: solvent-solid ratio of 16:1 (mL/g), the microwave power of 480 W, and the extraction time of 53 min. Under these conditions, the maximum yield of essential oil was 1.42%. The comparison test indicated that the yield of the essential oil was significantly better than that of steam distillation and microwave-assisted distillation, which increased by 17.48% and 5.66%, respectively. The chemical constituents of the essential oils were identified by gas chromatography-mass spectrometry (GC-MS). A total of 34 substances, the main components were isospathulenol (25.47%), δ-elemene (17.52%), caryophyllene (8.27%), α-cubebene (7.07%), α- gurjunene (5.59%), (+)-ledene (5.02%). A method for extracting pepper leaves essential oil by using choline chloride-urea as deep eutectic solvent could be feasible.

海南省重点研发计划项目（ZDYF2019058）