Letseka Thabiso E, Sepheka Ntjana J, Dubery Ian A, George Mosotho J
Department of Chemistry and Chemical Technology, National University of Lesotho, P.O. Box 180, Roma 100, Lesotho.
Department of Biochemistry, University of Johannesburg, P.O. Box 524, Johannesburg 2006, South Africa.
Plants (Basel). 2022 Oct 17;11(20):2749. doi: 10.3390/plants11202749.
Essential oils are vital constituents of oil-bearing plants. However, their screening still demands harvesting of the plant for laboratory analysis. We report herein a simple, rapid and robust headspace bubble-in-drop microextraction screening technique (BID-SPME) requiring only small amounts of plant material. The optimised method uses 0.5 g of the crushed plant leaves sample obtained in a 2 mL capped chromatography vial, heated to 55 °C and sampled with 2 µL heptadecane in a Hamilton gastight syringe equilibrated for 15 min exposed to the headspace volume. The method was applied to three plants, , and , which are known for their essential oil content. The method was able to extract at least 80% of the oil constituents in such abundance that they could be easily annotated using the gas chromatography-mass spectrometry (GC-MS) mass spectral libraries. The major volatile organic compounds (VOCs) detected included tagetone, terpinen-4-ol, ocimenone, caryophyllene, dihydrotagetone, terpinolene and artemisia ketone, just to mention a few, at different concentrations in different plants. Importantly, these annotated VOCs were also reported in other studies in the same and even different plants, extracted using normal steam distillation and importantly those reported in the literature for different extraction techniques.
精油是含油植物的重要成分。然而，对其进行筛选仍需要采集植物样本用于实验室分析。我们在此报告一种简单、快速且可靠的顶空气泡滴微萃取筛选技术（BID-SPME），该技术仅需少量植物材料。优化后的方法是将在2 mL带盖色谱瓶中获得的0.5 g粉碎的植物叶片样品加热至55°C，并用在汉密尔顿气密注射器中的2 μL庚烷进行采样，该注射器平衡15分钟后暴露于顶空体积中。该方法应用于三种以其精油含量而闻名的植物，[此处原文缺失植物名称]。该方法能够提取至少80%的油成分，其含量丰富，以至于使用气相色谱-质谱联用仪（GC-MS）质谱库能够轻松对其进行注释。检测到的主要挥发性有机化合物（VOCs）包括万寿菊酮、萜品-4-醇、紫罗酮、石竹烯、二氢万寿菊酮、萜品油烯和艾蒿酮等，仅列举其中几种，它们在不同植物中的浓度各不相同。重要的是，这些注释的挥发性有机化合物在其他研究中也有报道，这些研究使用常规水蒸气蒸馏法从相同甚至不同的植物中提取，并且在文献中也有关于不同提取技术的报道。
