The Effect of Microwave Pretreatment on the Extraction Rate of Flavonoid, Anthocyanins, Antioxidant Compounds and Antimicrobial Activity of Punica Granatum Var. Pleniflora (Persian Golnar)

Microwave energy is non-ionizing radiation that causes the molecule to move and is a good way to extract compounds from plant extracts. This study aimed to investigate the effect of three independent variables including solvent type (water and methanol 80%), time (3, 6, and 9 minutes), and microwave power (100, 200, and 300 watts) on the flavonoids, anthocyanins, antioxidant properties (IC50) of the Persian Golnar plant or Punica granatum var. pleniflora (PGP) extract. According to results, simultaneous optimization of extraction conditions with 95.609% desirability in 300-watt microwave power, 9 minutes, and use of methanol solvent the flavonoid content was 5.7597 mg­/g, anthocyanin content was 4.7983 µmol/g, and IC50 value was 6.5063 mg/ml. The highest average of minimum inhibitory concentration and minimum Bactericidal concentration of PGP extract were 1250 and 5000 µg/ml, respectively against Clostridium perfringens and Escherichia coli, and the better antimicrobial effect was against Staphylococcus aureus with the highest diameter of zone of inhibition (11 mm) compared to Escherichia and Clostridium perfringens. According to the results of this study, microwave pretreatment with optimized conditions can be used to extract significant amounts of phenolic and antimicrobial compounds of PGP extract as a rich source of antioxidants with minimal damage to its effective compounds.