Large-scale isolation of highly pure malaxinic acid from immature pear (Pyrus pyrifolia Nakai) fruit

Abstract

Malaxinic acid [4-(O-β-d-glucopyranosyl)-3-(3′-methyl-2′-butenyl)benzoic acid; MA] is one of the main compounds contained in pear fruit. The antifungal, antibacterial, and anticancer effects of MA have been reported. However, additional evaluations on the biological activity of MA have not been fully performed due to the lack of an MA standard. Therefore, in the present study, we established a large-scale isolation method to obtain highly pure MA from immature pear (Pyrus pyrifolia Nakai) fruit. The EtOAc-soluble acidic fraction (134.75 g) of pear fruit (18 kg fresh wt.) 60% EtOH extract (1,081.9 g) was purified by Amberlite XAD-2 (H2O/EtOH, stepwise), Diaion HP-20 (H2O/MeOH, stepwise), and Sephadex LH-20 (80% MeOH) column chromatographies. Then, the fractions containing MA were finally purified by high performance liquid chromatography using an Amide RP-C16 column on semi-preparative scale. The isolated MA (793 mg) was >99% pure, and total recovery was estimated to be 61.7%.