Extraction solvent affects the antioxidant, antimicrobial, cholinesterase and HepG2 human hepatocellular carcinoma cell inhibitory activities of Zanthoxylum bungeanum pericarps and the major chemical components

Abstract Chinese prickly ash (Zanthoxylum bungeanum Maxim.) is widely grown in China where it is of high economic importance. Its pericarps are rich in bioactive compounds and are in common use both as food additives, for their distinctive flavor, and as traditional medicines, to treat various diseases. The method of extraction of these compounds is important. This study evaluates the effects of the solvent on the yields of the major components and their biological activities - antioxidant, antimicrobial, cholinesterase and HepG2 human hepatocellular carcinoma cell (HepG2) inhibitory. Seven common solvents were used: water, methanol, acetic acid, chloroform, ethanol, ethyl acetate and benzene. Acetic acid produced the highest extract yield (24.69%), while benzene produced the lowest (7.54%). The ethanol extract had the highest phenolic content (81.19 ± 4.81 g gallic acid equivalents (GAE) /kg extract), the methanol extract had the highest flavonoid content (110.69 ± 8.49 g rutin equivalents (RE)/kg extract) and the benzene extract had the lowest (22.42 ± 2.1 g RE/kg extract). Procyanidin was the most abundant component in the extracts (125.35–350.98 mg/100 g pericarps). The water extract showed strong antioxidant activity for OH scavenging activity (0.45 mg/mL of half-maximal inhibitory concentration (IC50)), reducing power (RP) (RP0.6 mg/mL = 3.93) and ferric reducing ability of plasma (FRAP) (FRAP0.6 mg/mL = 0.48). Methanol and acetic acid were the most effective extracts for inhibition of Staphylococcus aureus, while chloroform was most effective for antimicrobial activity against Candida albicans and HepG2 growth inhibition rate (0.39 mg/mL of IC50). The inhibitory activities of the water and methanol extracts on butyrylcholinesterase (BChE) were stronger than on acetylcholinesterase (AChE) with selectivity indices of 0.74 and 0.28, respectively. Methanol (1.02 mg/mL of IC50 for AChE and 0.28 mg/mL of IC50 for BChE) was most effective for cholinesterase inhibitory activity. The total phenolic content, total flavonoid content, total alkaloid content and warfarin content were significantly correlated with the first two principal component analysis axes, indicating some relationship between these components and their biological activities. Extracts of Z. bungeanum pericarps are a good source of compounds having significant biological activities for the pharmaceutical industry.