Atlabachew Minaleshewa, Chandravanshi Bhagwan Singh, Redi-Abshiro Mesfin
Department of Chemistry, Bahir Dar University, P. O. Box 79, Bahir Dar, Ethiopia.
Blue Nile Water Institute, Bahir Dar University, P. O. Box 79, Bahir Dar, Ethiopia.
Chem Cent J. 2017 Oct 17;11(1):107. doi: 10.1186/s13065-017-0337-6.
Khat (Catha edulis Forsk) is an evergreen shrub of the Celastraceae family. It is widely cultivated in Yemen and East Africa, where its fresh leaves are habitually chewed for their momentary pleasures and stimulation as amphetamine-like effects. The main psychostimulant constituents of khat are the phenylpropylamino alkaloids: cathinone, cathine and norephedrine.
In this study, simple procedures based on preparative HPLC and salting-out assisted liquid-liquid extraction (SALLE) based methods were developed respectively for large scale isolation and the extraction of psychoactive phenylpropylamino alkaloids; cathinone, cathine and norephedrine, from khat (Catha edulis Forsk) chewing leaves, a stimulant and drug of abuse plant. The three khat alkaloids were directly isolated from the crude oxalate salt by preparative HPLC-DAD method with purity > 98%. In addition, a modified (SALLE) method has been developed and evaluated for the extraction efficiency of psychoactive phenylpropylamino alkaloids from khat (Catha edulis Forsk) chewing leaves. An in situ two steps extraction protocol was followed without dispersive SPE clean up. The method involves extraction of the samples with 1% HAc and QuEChERS salt (1.0 g of CHCOONa and 6.0 g of MgSO) followed by subsequent in situ liquid-liquid partitioning by adding ethyl acetate and NaOH solution. The optimized method allowed recoveries of 80-86% for the three alkaloids from khat sample with relative standard deviation (RSD) values less than 15% and limits of detection (0.85-1.9 μg/mL).
The method was found to be simple, cost-effective and provides cleaner chromatogram with good selectivity and reproducibility. The SALLE based protocol provided as good results as the conventional extraction method (ultrasonic assisted extraction followed by solid phase extraction, UAE-SPE) and hence the method can be applicable in forensic and biomedical sectors.
巧茶（Catha edulis Forsk）是卫矛科的一种常绿灌木。它在也门和东非广泛种植，在那里其新鲜叶子常被咀嚼以获得类似苯丙胺作用的即时愉悦感和刺激。巧茶的主要精神兴奋成分是苯丙基氨基生物碱：卡西酮、去甲伪麻黄碱和去甲麻黄碱。
在本研究中，分别开发了基于制备型高效液相色谱法和盐析辅助液液萃取（SALLE）法的简单程序，用于从巧茶（Catha edulis Forsk）咀嚼叶（一种兴奋剂和滥用药物植物）中大规模分离和提取精神活性苯丙基氨基生物碱；卡西酮、去甲伪麻黄碱和去甲麻黄碱。通过制备型高效液相色谱 - 二极管阵列检测法直接从粗草酸盐中分离出这三种巧茶生物碱，纯度>98%。此外，还开发并评估了一种改进的（SALLE）方法用于从巧茶（Catha edulis Forsk）咀嚼叶中提取精神活性苯丙基氨基生物碱的效率。采用原位两步萃取方案，无需分散固相萃取净化。该方法包括用1%乙酸和QuEChERS盐（1.0 g醋酸钠和6.0 g硫酸镁）萃取样品，随后通过加入乙酸乙酯和氢氧化钠溶液进行原位液液分配。优化后的方法使巧茶样品中三种生物碱的回收率为80 - 86%，相对标准偏差（RSD）值小于15%，检测限为（0.85 - 1.9 μg/mL）。
该方法简单、成本效益高，能提供选择性和重现性良好的更纯净色谱图。基于SALLE的方案与传统萃取方法（超声辅助萃取后固相萃取，UAE - SPE）效果相当，因此该方法可应用于法医和生物医学领域。
