Recovery of chlorogenic acid from haskap leaves (Lonicera caerulea) using aqueous two-phase extraction

The concept of a biorefinery can be applied to the haskap plant (Lonicera caerulea), where the berries are harvested but the leaves are an under-utilized resource. In this study, aqueous two-phase extraction (ATPE) was used to extract chlorogenic acid (CGA) from haskap leaves. The consumption of CGA is associated with health benefits and it is sold as a natural health supplement. Two different aqueous two-phase systems (ATPSs), consisting of ethanol/sodium dihydrogen phosphate (NaH2PO4) and ethanol/potassium phosphate dibasic (K2HPO4), were compared. The factors investigated were salt/ethanol composition and extraction time. The ethanol/NaH2PO4 system had higher yield of 85.03 mg CGA/g leaves, partition coefficient of 40.41, and 92.97% extraction efficiency. The yield from conventional Soxhlet extraction was 109.74 mg CGA/g leaves; however, this required a much longer extraction time of 24 h. LC-HRMS also showed the presence of CGA, and possibly lonicerin, rutin, and diosmin isomers in the leaf extracts.