Antioxidant and Acetylcholinesterase Inhibitory Activities of Prenylated Dihydrostilbenes from Macaranga heynei

Macaranga which comprises of 300 species has abundant source of flavonoids, stilbenoids and terpenoids [1,2]. The chemical constituents isolated have demonstrated broad spectrum of pharmacological properties [2,3]. Hence, M. heynei was selected to examine the phytochemical study and bioactivities. The powdered leaves (2 kg) was macerated in methanol at room temperature for 24 hours to obtain methanolic crude extract (300 g) which was dissolved in 80% aqueous methanol followed by partition with hexane and ethyl acetate. The ethyl acetate crude extract (150 g) was fractionated by using vacuum liquid chromatography (VLC) with a gradient mixture of hexane:ethyl acetate to give seven combined fractions (MH1 – 7). Fraction MH2 (1 g) was subjected to radial chromatography (RC) twice with gradient eluent of hexane:ethyl acetate and chloroform:ethyl acetate subsequently to afford two pure compounds (1) (10 mg) and (2) (12 mg). By using VLC (hexane:ethyl acetate), column (chloroform:acetone) and preparative thin layer chromatography (hexane:ethyl acetate) on fraction MH3 (10.6 g), a pure compound (3)(14.7 mg) was successfully isolated. Based on spectroscopy analyses, the compounds were characterized as laevifolins A (1) and B (2) as well as a new compound X (3). These compounds exhibited strong activity on DPPH radical scavenging (< 5 uM) as well as moderate activity for acetylcholinesterase inhibitory (< 20 uM) (Figure 1).

Fig. 1

Greatest appreciation to Society for Medicinal Plant and Natural Product Research for the GA travel grant, MOHE (RAGS/1/2014/SG01/UITM/4) and Faculty of Applied Sciences for the financial support.

[1] Whitmore TC. Malayan Nature Journal 1967; 20: 89 – 99

[2] Lim TY, Lim YY, Yule CM. Food Chemistry 2009; 114: 594 – 599

[3] Magadula JJ. Journal of Medicinal Plant Research 2014; 8:489 – 503