Background:
The use of medicinal plants for general wellbeing and disease treatment is a common practice among tribal
communities of Kokrajhar districts of Assam. However, little works have been done to study the pharmacological aspect of the plants.
Objectives:
The present study intends to study the antioxidant and antiproliferative properties of selected medicinal plants used by the
tribal communities of Kokrajhar district of Assam since ancient times.
Methods:
Five traditionally important medicinal plants namely, Cassia fistula, Citrus grandis, Lindernia crustacea, Sacciolepis
myosuroides, and Zingiber zerumbet were investigated for antioxidant, antiproliferative (cytotoxic) and apoptosis-inducing potential in
the malignant cancer cell line. Phytochemical content such as phenolic and flavonoid content were estimated following standard protocol.
The methanolic extract of plants were investigated following phosphomolybdate method (TAC), FRAP, DPPH, ABTS, and TBARS
assays. Antiproliferative activities of the plants were carried out by MTT assay in DL and PBMC cells. The apoptotic study was carried
out following the acridine orange and ethidium bromide staining method and fluorescent microscopic imaging. Based on the significant
(P≤0.05) high apoptotic inducing potential of the plant and to further dissect the molecular mode of action including downstream
biological action, major phytochemicals derived from L. crustacea were investigated for its prospective binding affinity with antiapoptotic cancer target proteins.
Results:
Antioxidant studies by FRAP, DPPH, ABTS, and TBARS assay revealed that all the five plants contain considerable free radical
scavenging activity. C. fistula showed the strongest free radical scavenging activity while the fruit peel extract of C. grandis showed poor
activity. The overall antioxidant activities of plants such as TAC, FRAP, DPPH, ABTS, and TBARS may be arranged in decreasing
activity as C. fistula > Z. zerumbet > L. crustacea > S. myosuroides > C. grandis. MTT based cell proliferation study showed that all the
plants extract significantly (P≤0.05) inhibited cell viability with negligible cytotoxicity (~5-12%) in normal cells. Moreover, L. crustacea
showed promising antiproliferative and apoptosis-inducing ability against Dalton’s lymphoma. It is worth mentioning that the major
bioactive compounds of the most potent plant extract, L. crustacea interacted with anti-apoptotic proteins (cancer target) with
higher affinity and the results are compared with reference inhibitors.
Conclusion:
It is worth noting that these plants have the potential to consider for further scientific studies in different cell lines and
animal models. Furthermore, isolation and characterization of bioactive compound(s), may promise the discovery of new and valuable
drugs candidate to tackle various human diseases.