Ahmed Farhana, Rahman Mohammad Sharifur
Phytochemical Research Laboratory, Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Dhaka, Dhaka, 1000, Bangladesh.
BMC Complement Altern Med. 2016 Jul 26;16:247. doi: 10.1186/s12906-016-1239-1.
Callistemon citrinus (Curtis.) (Family- Myrtaceae) is a popular evergreen shrub in Bangladesh. In the present study, the leaves of this plant have been assessed comprehensively for free radical scavenging, thrombolytic and membrane stabilizing activities.
The leaves were collected, powdered and extracted with methanol. The extract was then concentrated and successively fractionated into petroleum ether, carbon tetrachloride, chloroform and aqueous soluble fractions. The extractives were investigated for free radical scavenging, thrombolytic and membrane stabilizing activities.
In case of 1,1 diphenyl-2-picrylhydrazyl (DPPH) and hydrogen peroxide radical scavenging assays, the crude methanol extract of the leaves showed the highest free radical scavenging activity among the tested materials including standard ascorbic acid (p = 0.0000). Besides, this extract was also found significantly rich (p = 0.0000) in phenolics and flavonoids compared to other organic fractions. In thrombolytic study, the petroleum ether fraction exhibited significantly stronger thrombolysis (p = 0.024) than other leaf extractives but was weaker than the standard streptokinase. In membrane stabilizing assay, the activity of chloroform fraction was similar to that of standard acetylsalicylic acid (p = 1.000) in hypotonic solution induced hemolysis. However, membrane stabilization activity of this chloroform fraction was found significantly stronger than that of the standard (p = 0.0000) in heat induced hemolysis.
This study has revealed the medicinal capabilities of different organic fractions of C. citrinus displaying free radical scavenging, thrombolysis and membrane stabilizing antiinflammatory potentials. Further bioactivity guided isolation is required to obtain pharmacologically secondary metabolites.
柠檬桉（Curtis.）（桃金娘科）是孟加拉国一种受欢迎的常绿灌木。在本研究中，对该植物的叶子进行了全面的自由基清除、溶栓和膜稳定活性评估。
采集叶子，粉碎后用甲醇提取。提取物浓缩后依次分离成石油醚、四氯化碳、氯仿和水溶性部分。对提取物进行自由基清除、溶栓和膜稳定活性研究。
在1,1 - 二苯基 - 2 - 苦基肼（DPPH）和过氧化氢自由基清除试验中，叶子的粗甲醇提取物在所测试的材料（包括标准抗坏血酸）中显示出最高的自由基清除活性（p = 0.0000）。此外，与其他有机部分相比，该提取物在酚类和黄酮类物质方面也显著丰富（p = 0.0000）。在溶栓研究中，石油醚部分表现出比其他叶子提取物更强的溶栓作用（p = 0.024），但比标准链激酶弱。在膜稳定试验中，在低渗溶液诱导的溶血中，氯仿部分的活性与标准乙酰水杨酸相似（p = 1.000）。然而，在热诱导的溶血中，发现该氯仿部分的膜稳定活性明显强于标准品（p = 0.0000）。
本研究揭示了柠檬桉不同有机部分具有自由基清除、溶栓和膜稳定抗炎潜力的药用能力。需要进一步进行生物活性导向分离以获得药理活性次生代谢产物。
