Anthraquinones from Morinda officinalis roots enhance adipocyte differentiation in 3T3-L1 cells.

To search for anti-diabetic and insulin-sensitising natural products, the effect on adipocyte differentiation was investigated by assessing fat accumulation in 3T3-L1 preadipocytes using Oil Red O staining. Fractionation and separation of n-hexane and CHCl₃ fractions of Morinda officinalis (Rubiaceae) using several chromatographic methods led to the isolation of three anthraquinones, 1,2-dimethoxyanthraquinone (1), alizarin-2-methyl ether (2) and rubiadin-1-methyl ether (3). Among them, alizarin-2-methyl ether (2) showed the strongest enhancing activity, followed by rubiadin-1-methyl ether (3) and 1,2-dimethoxyanthraquinone (1). At a concentration of 100 µM, alizarin-2-methyl ether (2) enhanced adipocyte differentiation by up to 131% (compared to insulin-treated cells). Thus, these compounds could be beneficial in the treatment of diabetes.