A simple, fast, and inexpensive non-chromatographic method for the isolation of pinostrobin from boesenbergia rotunda rhizome

Abstract

Pinostrobin is a plant-derived natural compound with high pharmacological and economic value. Pinostrobin exhibits various biological activities and is widely distributed in plant species. In addition to its wide distribution, pinostrobin is the main chemical ingredient of Boesenbergia rotunda rhizome. To date, pinostrobin is obtained by direct isolation from its sources, mainly from the B. rotunda rhizome, by utilizing various chromatographic methods. However, these chromatography-based isolation methods are time-consuming, laborious, and expensive. This study aimed to provide a method to isolate pinostrobin from B. rotunda rhizome without utilizing chromatographic techniques. Dried powder of B. rotunda was macerated in petroleum ether. The liquid extract obtained was concentrated and stored at a temperature of −20 ℃ for 18 h until pale yellow precipitates were formed. The precipitates were filtered and dissolved in warm methanol and stored at a temperature of −20 ℃ for 18 h. The formed yellowish crystals were decanted, filtered, and washed with cold methanol (4 ℃) to obtain colorless pinostrobin crystals. The crystals were dried and weighed. The purity of the crystals was determined by high-performance liquid chromatography. Meanwhile, the chemical structure of the crystals was verified based on its infrared, ultraviolet, and nuclear magnetic resonance (i.e., 1 H-NMR, and13C-NMR) spectra. This study provides a “shortcut” method to isolate pinostrobin from B. rotunda rhizome, with a yield of 2.36% and purity of ≥ 99%. This study provides a simple, fast, and inexpensive method to obtain pinostrobin without using chromatographic techniques.