Accumulation, extraction, purification, and antioxidants characteristics of proanthocyanidins from Chinese dwarf cherry ( Cerasus humilis )

Background Cerasus humilis is rich in proanthocyanidins (PAs), which confer antioxidant activity. However, little is known about PAs in C. humilis fruits. Objective This study aimed to analyze the accumulation characteristics, extraction, purification, and antioxidant activities of C. humilis PAs. Methods The total proanthocyanidins content (TPAC) and total antioxidant capacity (TAOC) of fruits of three C. humilis varieties (Jing-Ou 1, Jing-Ou 2, and Nong-Da 4) were determined. PA extraction was optimized using an orthogonal experimental design. The purification process of macroporous resin method was optimized and the purified PAs of C. humilis fruit was further refined by gelatin precipitation methods. The antioxidant capacity of C. humilis PAs before and after purification was by 2,2-biphenyl-1-picrylhydrazyl (DPPH) assay and 2, 2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay in vitro . Results TPAC and TAOC showed a positive correlation and decreased in all three varieties as fruits ripened . After ripening, Jing-Ou 2 had the highest PAs content. The optimal solvent extraction method yielded a TPAC of 883.0 mg/100 g FW. The purity of PAs reached 47.52% using the macroporous resin method and 98.14% using gelatin precipitation. IC 50 values of the purified PAs were comparable to those of vitamin C at the same mass concentration. Conclusions In this study, C. humilis PAs were systematically investigated for the first time. Not only its dynamic changes during fruit development were analyzed, but also the extraction and purification methods were optimized. Meanwhile, its antioxidant activity was verified, which provided a theoretical basis for the development and utilization of C. humilis PAs as antioxidants in functional foods and pharmaceutical formulations and sheds light on the health benefits of the species.