Highly Selective Purification of Grewia asiatica Anthocyanin Based on Macroporous Resins

Abstract

In the present study, enactments and separation characteristics of five extensively utilized adsorbents for enhancement and purification of Grewia asiatica Anthocyanins (ACNs) extracts were analysed. Among five tested resins (AB-8, Sepabeads Sp-700, C18SPE Cartridge, Sepabeads Sp-207 and AB-80), AB-8 resin exhibited the best adsorbent ability for Grewia asiatica ACNs (84.24mg/mL resin). Results of static adsorption tests revealed that AB-8 resin selected for kinetics and isotherm experiments followed a pseudo 2nd order model along with Langmuir isotherm. In order to improve operational procedure, dynamic adsorption and desorption tests were done on a packed column of AB-8 resin. Optimum factors for subsequent adsorption-desorption experiments; processing volume 20ml, flow rate 2 mL/min with elution solvent of acidified methanol (1%v/v) were used. HPLC and LC-MS/MS profiles of the purified extract confirmed seven ACNs in Grewia asiatica samples, out of which cyanidin-3-O-(6"acetylglucoside) comprises 44-63% (695 μg/g) of total ACNs composition. Moreover, pigment purification using AB-8 resin did not alter ACNs mixture composition after purification but enhance the peak intensity and gives effective purification. Hence present work reveals that the separation procedure established through column chromatography providing an effective methodology to enhance the purification of ACNs from Grewia asiatica.