Eurycoma longifolia, A Potential Phytomedicine for the Treatment of Cancer: Evidence of p53-mediated Apoptosis in Cancerous Cells

Background: Eurycoma longifolia is a well-documented herbal medicine that has gained widespread recognition due to its versatile pharmacological activities including anticancer, antimalarial, antimicrobial, antioxidant, aphrodisiac, anti-inflammatory, anxiolytic, anti-diabetic, antirheumatism and anti-ulcer. Plethora of in vitro and in vivo studies evidenced their excellent antiproliferative and anticancer efficacy against various types of human cancers. Objective: This review was aimed to critically analyze the therapeutic viability and anticancer efficacy of Eurycoma longifolia in the treatment of cancer and also to propose its molecular and translational mechanism of cytotoxicity against cancerous cells. Results: Among a range of medicinally active compounds isolated from various parts (roots, stem, bark and leaves) of Eurycoma longifolia, 16 compounds have shown promising anti-proliferative and anticancer efficacies. Eurycomanone, one of the most active medicinal compounds of Eurycoma longifolia, displayed a strong dose-dependent anticancer efficacy against lung carcinoma (A-549 cells) and breast cancer (MCF-7 cells); however, showed moderate efficacy against gastric (MGC-803 cells) and intestinal carcinomas (HT-29 cells). The prime mode of cytotoxicity of Eurycoma longifolia and its medicinal compounds is the induction of apoptosis (programmed cell death) via the up-regulation of the expression of p53 (tumor suppressor protein) and pro-apoptotic protein (Bax) and downregulation of the expression of anti-apoptotic protein (Bcl-2). A remarkable alleviation in the mRNA expression of various cancer-associated biomarkers including heterogeneous nuclear ribonucleoprotein (hnRNP), prohibitin (PHB), annexin-1 (ANX1) and endoplasmic reticulum protein-28 (ERp28) has also been evidenced. Conclusion: Eurycoma longifolia and its medicinal constituents exhibit promising anticancer efficacy and thus can be considered as potential complementary therapy for the treatment of various types of human cancers.