Food Engineering Department, Central Food Technological Research Institute (Council of Scientific and Industrial Research, India), Mysore, India.
J Liposome Res. 2012 Sep;22(3):215-23. doi: 10.3109/08982104.2012.658576. Epub 2012 Mar 8.
Seabuckthorn (SBT; Hipphophae rhamnoides) leaf extract obtained by supercritical carbon dioxide (SCCO(2)) using ethanol as an entrainer, containing mainly flavanoids as bioactive principles with antioxidant and antibacterial properties, was used for the preparation of liposomes. Liposomes are promising drug carriers with sustained release because they can enhance the membrane penetration of drugs, deliver the entrapped drugs across cell membranes, and improve extract stability and bioavailability. The aim of the present study was to compare the two different methods of liposome production: the Bangham thin-film method and SCCO(2) gas antisolvent method (SCCO(2) GAS) for the incorporation of SBT leaf extract in terms of particle size, morphology, encapsulation efficiency, antioxidant activity, and thermal stability. Liposomes obtained with the thin-film method were multilamellar vesicles with average particle size (3,740 nm), encapsulation efficiency (14.60%), and particle-size range (1.57-6.0 µm), respectively. On the other hand, liposomes by the SCCO(2) GAS method were nanosized (930 nm) with an improved encapsulation efficiency (28.42%) and narrow range of size distribution (0.48-1.07 µm), respectively. Further, the antioxidant activity of leaf extract of SBT was determined by the 2 diphenyl-1-picrylhydrazyl method and expressed as Trolox equivalents as well as of the intercalated extract in liposomes. The oxidative stability of SBT encapsulated in liposomes was again estimated using differential scanning calorimetry (DSC). Thermal-oxidative decomposition of the samples (i.e., pure liposomes and encapsulated extracts) and the modification of the main transition temperature for the lipid mixture and the splitting of the calorimetric peak in the presence of the antioxidants were also studied by DSC. After encapsulation in liposomes, antioxidant activity proved to be higher than those of the same extracts in pure form.
沙棘（Hipphophae rhamnoides）叶提取物，通过超临界二氧化碳（SCCO 2 ）使用乙醇作为夹带剂提取，主要含有类黄酮作为生物活性成分，具有抗氧化和抗菌特性，用于制备脂质体。脂质体作为一种有前途的药物载体，具有缓释作用，因为它们可以增强药物的膜穿透性，使包封的药物穿过细胞膜，并提高提取物的稳定性和生物利用度。本研究的目的是比较两种不同的脂质体制备方法：Bangham 薄膜法和 SCCO 2 气体反溶剂法（SCCO 2 GAS），以比较将沙棘叶提取物包封在脂质体中的粒径、形态、包封效率、抗氧化活性和热稳定性。薄膜法制备的脂质体是多层囊泡，平均粒径（3740nm）、包封效率（14.60%）和粒径范围（1.57-6.0μm）。另一方面，SCCO 2 GAS 法制备的脂质体为纳米级（930nm），包封效率（28.42%）提高，粒径分布范围较窄（0.48-1.07μm）。此外，通过 2，2-二苯基-1-苦基肼法测定沙棘叶提取物的抗氧化活性，并以 Trolox 当量表示，以及测定包封在脂质体中的提取物的抗氧化活性。通过差示扫描量热法（DSC）再次评估包封在脂质体中的沙棘的氧化稳定性。通过 DSC 研究了样品（即纯脂质体和包封提取物）的热氧化分解以及脂质混合物的主要相变温度的变化和抗氧化剂存在下的热谱峰的分裂。包封在脂质体中后，抗氧化活性证明高于纯形式的相同提取物。
