Optimisation of Anthocyanin Extraction from Purple Pitaya and Verification of Antioxidant Properties, Antiproliferative Activity and Macrophage Proliferation Activity

To separate and purify anthocyanins from purple pitaya (H. polyrhizus) with SP825 resin, the adsorption properties of the SP825 resin were evaluated by static and dynamic experiments with respect to the following parameters: pH, temperature, dilution multiple of the sample solution and concentration of the ethanol eluting agent. The data from the static experiments were fitted to the pseudo-second-order kinetics model (R2 = 0.9919) and Freundlich isotherm model (R2 = 0.9672). A total of 658 mg of anthocyanins were contained in 1000 g of H. polyrhizus fresh fruits (both peel and pulp), which could be made into 1.5 g of anthocyanin-rich extract from H. polyrhizus (AEHP) containing 520 mg of anthocyanins. Overall, 79% of the anthocyanins were extracted. The AEHP showed strong DPPH radical scavenging activity, ABTS radical scavenging activity, hydroxyl radical scavenging activity, reducing power, ferrous metal ion chelating ability and SOD-like activity. Moreover, the AEHP inhibited the proliferation of the human colorectal cancer cell line DLD-1 and accelerated the growth of macrophage cells. Finally, the AEHP was proven to have a high tinctorial power and physiological and health functions.