Satish P V V, Sunita K
Department of Zoology and Aquaculture, Acharya Nagarjuna University, Nagarjuna Nagar 522510, Guntur district, Andhra Pradesh, India.
BMC Complement Altern Med. 2017 Sep 11;17(1):458. doi: 10.1186/s12906-017-1958-y.
The objective of the current study was to assess the in vitro antiplasmodial activities of leaf, bark, flower, and the root of Pongamia pinnata against chloroquine-sensitive Plasmodium falciparum (3D7 strain), cytotoxicity against Brine shrimp larvae and THP-1 cell line. For in vivo study, the plant extract which has shown potent in vitro antimalarial activity was tested against Plasmodium berghei (ANKA strain).
The plant Pongamia pinnata was collected from the herbal garden of Acharya Nagarjuna University of Guntur district, Andhra Pradesh, India. Sequentially crude extracts of methanol (polar), chloroform (non-polar), hexane (non-polar), ethyl acetate (non-polar) and aqueous (polar) of dried leaves, bark, flowers and roots of Pongamia pinnata were prepared using Soxhlet apparatus. The extracts were screened for in vitro antimalarial activity against P. falciparum 3D7 strain. The cytotoxicity studies of crude extracts were conducted against Brine shrimp larvae and THP-1 cell line. Phytochemical analysis of the plant extracts was carried out by following the standard methods. The chemical injury to erythrocytes due to the plant extracts was checked. The in vivo study was conducted on P. berghei (ANKA) infected BALB/c albino mice by following 4-Day Suppressive, Repository, and Curative tests.
Out of all the tested extracts, the methanol extract of the bark of Pongamia pinnata had shown an IC value of 11.67 μg/mL with potent in vitro antimalarial activity and cytotoxicity evaluation revealed that this extract was not toxic against Brine shrimp and THP-1 cells. The injury to erythrocytes analysis had not shown any morphological alterations and damage to the erythrocytes after 48 h of incubation. Because methanolic bark extract of Pongamia pinnata has shown good antimalarial activity in vitro, it was also tested in vivo. So the extract had exhibited an excellent activity against P. berghei malaria parasite while decrement of parasite counts was moderately low and dose-dependent (P < 0.05) when compared to the control groups, which shown a daily increase of parasitemia, unlike the CQ-treated groups. The highest concentration of the extract (1000 mg/kg b.wt./day) had shown 83.90, 87.47 and 94.67% of chemo-suppression during Suppressive, Repository, and Curative tests respectively which is almost nearer to the standard drug Chloroquine (5 mg/kg b.wt./day). Thus, the study has revealed that the methanolic bark extract had shown promisingly high ((P < 0.05) and dose-dependent chemo-suppression. The phytochemical screening of the crude extracts had shown the presence of alkaloids, flavonoids, triterpenes, tannins, carbohydrates, phenols, coumarins, saponins, phlobatannins and steroids.
The present study is useful to develop new antimalarial drugs in the scenario of the growing resistance to the existing antimalarials. Thus, additional research is needed to characterize the bioactive molecules of the extracts of Pongamia pinnata that are responsible for inhibition of malaria parasite.
本研究的目的是评估印度戟叶豆的叶、树皮、花和根对氯喹敏感的恶性疟原虫（3D7株）的体外抗疟活性、对卤虫幼虫和THP-1细胞系的细胞毒性。对于体内研究，对已显示出强大体外抗疟活性的植物提取物进行伯氏疟原虫（ANKA株）测试。
印度戟叶豆从印度安得拉邦贡图尔区阿查里亚·纳加尔朱纳大学的草药园采集。依次使用索氏提取器制备印度戟叶豆干燥叶、树皮、花和根的甲醇（极性）、氯仿（非极性）、己烷（非极性）、乙酸乙酯（非极性）和水（极性）粗提物。对提取物进行针对恶性疟原虫3D7株的体外抗疟活性筛选。对粗提物进行针对卤虫幼虫和THP-1细胞系的细胞毒性研究。按照标准方法对植物提取物进行植物化学分析。检查植物提取物对红细胞的化学损伤。通过4天抑制、储存和治疗试验，对感染伯氏疟原虫（ANKA）的BALB/c白化小鼠进行体内研究。
在所有测试提取物中，印度戟叶豆树皮的甲醇提取物显示IC值为11.67μg/mL，具有强大的体外抗疟活性，细胞毒性评估表明该提取物对卤虫和THP-1细胞无毒。红细胞损伤分析显示，孵育48小时后，红细胞未出现任何形态改变和损伤。由于印度戟叶豆树皮甲醇提取物在体外显示出良好的抗疟活性，因此也进行了体内测试。该提取物对伯氏疟原虫表现出优异的活性，与对照组相比，寄生虫数量的减少适度较低且呈剂量依赖性（P<0.05），对照组的疟原虫血症每日增加，这与氯喹治疗组不同。提取物的最高浓度（1000mg/kg体重/天）在抑制、储存和治疗试验中分别显示出83.90%、87.47%和94.67%的化学抑制率，几乎接近标准药物氯喹（5mg/kg体重/天）。因此，该研究表明甲醇树皮提取物显示出有前景的高（P<0.05）且剂量依赖性的化学抑制作用。粗提物的植物化学筛选显示存在生物碱、黄酮类、三萜类、单宁、碳水化合物、酚类、香豆素、皂苷、鞣花单宁和甾体。
在对现有抗疟药耐药性不断增加的情况下，本研究有助于开发新的抗疟药。因此，需要进一步研究来鉴定印度戟叶豆提取物中负责抑制疟原虫的生物活性分子。
