Phenolic Profile, Antioxidant and Antimicrobial Activities of Algerian Maclura Pomifera (Rafin) Schneider Fruit Extract

Abstract

The aim of this study is to find out the phenolic profile of ethyl acetate extract of Maclura pomifera (M. pomifera) fruit polyphenols (EAEMPFP) using HPLC/MS and to evaluate its antioxidant and antimicrobial activities. Antioxidant activity was assessed with DPPH (2, 2-Diphenyl-1-picrylhydrazyl), β-carotene bleaching method and Ferric Reducing Antioxidant Power (FRAP) assays. The EAEMPFP antimicrobial activity was determined using the agar diffusion and microbroth dilution methods against thirteen different strains. Polyphenol and flavonoid contents of M. pomifera were determined using the Folin-Ciocalteu and AlCl₃ methods, respectively. EAEMPFP total polyphenol content (103.87 ± 6.35 mg gallic acid equivalent/g) is higher than that of flavonoids (31.33 ± 1.71 mg quercetin equivalent/g). HPLC/MS revealed five phenolic compounds, five flavonoids and coumarin. Ferulic acid and caffeic acid were the most abundant with 1.07 and 1.05 mg/mL of extract, respectively. The ability of EAEMPFP to scavenge DPPH (IC50 = 121.94 µg/mL) and to reduce the ferric iron (IC50 = 2.54 mM Fe²⁺/mL) is dose-dependent. The IC50 of β-carotene bleaching (380.06 µg/mL of EAEMPFP) is higher than that of the standards (i.e. ascorbic acid and quercetin). The FRAP test has shown that the antioxidant activity of EAEMPFP is lower than that of ascorbic acid but higher than that of quercetin. Inhibition zones diameters generated by EAEMPFP antimicrobial activity towards the different strains ranged from 8.2 ± 0.1 (for the beneficial strain Lb rhamnosus) to 27.2 ± 0.1 mm (for the pathogenic strain: Shigella dysenteriae CRCT 457). These findings have shown that M. Pomifera fruit is a potential source of bioactive substances of interest such as polyphenols.