Eurycoma longifolia Jack and Its Quassinoids Stimulate Lipolysis in 3T3-L1 Adipocytes

In recent years, the prevalence of obesity has increased globally, due to changes in lifestyle and eating habits. Medicinal plants from local biodiversity in Southeast Asian region represent one of the most promising resources to address this prevailing metabolic disease. This study aims to investigate anti-obesity property of Eurycoma longifolia Jack and elucidate the active compounds, as well as to demonstrate their cellular mechanism of actions.

Fifty percent methanolic extract of E. longifolia was tested for its activity to reduce lipid accumulation in 3T3-L1 adipocytes. While, measurement of glycerol released from the cells to culture medium was conducted to investigate lipolysis stimulation. The results showed that the E. longifolia extract reduced lipid accumulation and increased glycerol release in the adipocytes. Isolation of active compounds was then conducted based on the stimulation of glycerol release. Two active compounds were successfully isolated and identified as Eurycomanone and 13β,21-epoxyeurycomanone, unique quassinoids contained in E. longifolia.

Fig. 1

To investigate the mechanism of actions, the extract of E. longifolia and the isolated compounds were subjected to inhibitory challenges on the stimulation of glycerol release. Inhibitory challenges demonstrated that the extract stimulated lipolysis through cAMP-dependent protein kinase (PKA) and extracellular signal-regulated kinase (ERK) pathways, while the quassinoids worked through PKA pathway. Western blotting analysis of these potential kinases also confirmed the activation of PKA and ERK by the extract, and PKA by the isolated quassinoids.

These findings provide scientific basis of lipid reduction activity of plant-based traditional medicine, E. longifolia. Since this plant species has not been extensively studied for its anti-obesity property, this work promotes further investigation for its use in the treatment of obesity.

Lahrita L, Kato E, Kawabata J. J Ethnopharmacol 2015; 168, 229 – 236.