Preparative separation of punicalin from waste water of hydrolysed pomegranate husk by macroporous resin and preparative high-performance liquid chromatography

The present study investigated a fast and cost-effective method for the preparation of punicalin from waste water of hydrolysed pomegranate husk by H-103 macroporous resin and preparative high-performance liquid chromatography (HPLC) using a mobile phase consisting of 10% (v/v) of methanol and 0.1% TFA in water for primary separation and a mobile phase consisting of 30% (v/v) of methanol and 0.1% TFA in water to remove gallic acid and other minor impurities. 120 ml of waste water, which contained about 480 mg punicalin, could produce 1147 mg of punicalin-rich extract of 36.4% punicalin after separation by H-103 macroporous resin. 349 mg of 97% punicalin could be obtained after purified by preparative HPLC. The recovery per litre of waste water was more than 70%. The product was assessed by analytical HPLC and characterised by MS and 1H NMR and 13C NMR. This method is practical for industrial applications and could provide a low-cost means to use a currently underutilized industrial by-product.