Comparison of different extraction methods on yield, purity, antioxidant, and antibacterial activities of proanthocyanidins from chokeberry (Aronia melanocarpa)

Proanthocyanidins are the most abundant phenols with high biological activities in chokeberry. The effects of ultrasonic-microwave assisted extraction (UMAE), ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), and traditional solvent extraction (TSE) on the yield, purity, antioxidant and antibacterial activities of crude chokeberry proanthocyanidins (CCP) were evaluated in this study. Results showed that UMAE exhibited the maximum yield (31.52 ± 0.8 mg/g fresh weight) and purity (16.34 ± 0.59%). The method of UMAE not only significantly aggravated the destruction of cells but also accelerated the release rate of proanthocyanidins from cells. Moreover, the CCP extracted by UMAE had the greatest antioxidant and antibacterial activities in the four methods. The IC50of ABTS·+, DPPH, superoxide anion scavenging abilities were 102.52 ± 0.84, 22.03 ± 0.55, 214.93 ± 1.33 μg/mL, respectively, and the MBC and MIC of Staphylococcus aureus, Streptococcus mutans, Pseudomonas aeruginosa, and Escherichia coliwere 5, 5, 10, 5 mg/mL, and 1.25, 1.25, 2.5, 1.25 mg/mL, respectively. According to the analysis of high performance liquid chromatography-mass spectrometry (HPLC-MS), the main proanthocyanidins in purified chokeberry proanthocyanidins (PCP) were B-type procyanidins, including procyanidin B2, B5 dimer, and procyanidin C1 trimer, with the degree of polymerization (DP) of 14. Therefore, UMAE is an effective extraction to obtain chokeberry proanthocyanidins, which is a potential antioxidant or antibacterial agent.