A narrative review on pharmacological significance of Eurycoma longifolia jack roots

Objective: This review is focused on the pharmacological properties of Eurycoma longifolia which is a popular herb and widely used by local folks in Southeast Asia including Malaysia. Background: The wide application of the herb is mainly contributed by its efficacy in treating many chronic diseases and promoting wellbeing. With the remarkable ethnomedicinal value, the plant, especially its root extracts have been intensively investigated for pharmacological significance in a systematic manner for decades. This includes both in vitro and in vivo studies focusing on the aphrodisiac, anticancer, antimalarial, antiosteoporotic and antidiabetic properties using different assays. Methods: A narrative review of previously reported data on the pharmacological importance of E. longifolia was systematically carried out. This covers data published in literature retrieved from the search engine of Google from 1980s until to date. The findings of the previous studies are gathered, organized and presented with the support of technical evidences and explanation. Conclusions: E. longifolia root extract was mostly reported to exhibit anticancer properties using different human cancerous cell lines, particularly breast cancer cells. Many reports also revealed the properties could be due to the presence of phytochemicals such as quassinoids, canthin-6-one and carboline alkaloids in the plant extracts. Eurycomanone and eurycomanol were likely to be compounds of quassinoids in promoting the other frequently reported activities such as antimalarial and anti-hyperglycaemic potentials. Interestingly, the water extract of the plant was not toxic with the acute oral LD50 up to 6 g/kg body weight of rats. The toxicity was most probably attributed to eurycomanone at high LD50 (5.27 g/kg). Most studies were focused on crude extract which was not properly characterized in term of phytochemical composition. It is important to well characterise plant extract in order to relate to its pharmacological significance. Possibly, optimized or standardized plant extract is used for subsequent experiments to ensure continuity in research activities. Plant species authentication is of utmost importance prior to any experimental works.