Optimization of Extraction of Flavonoid, Total Phenolic, Antioxidant, and Antimicrobial Compounds from Ganoderma Lucidum by Maceration Method

Plants are a rich source of phenolic and flavonoid compounds which are among the most important natural antioxidants. The aim of this study was to optimize the extraction of flavonoid, total phenolic, antioxidant, and antimicrobial compounds from Ganoderma (G) Lucidum by the maceration method. To do so, independent variables including temperature, extraction time, and type of solvent along with Box-Behnken Response Surface Methodology (RSM) were used. The results of single optimization of the independent variables showed the highest flavonoid content (15.19 mg/g) with 100% desirability at an extraction time of 48 h, the temperature of 60 °C by using ethanol solvent. The highest total phenolic content (16.96 mg/g) with 99.96% desirability was observed at an extraction time of 26 h, a temperature of 60 °C by using ethanol solvent. The highest amount of antioxidant compounds (3.03 mg/g) or the lowest IC50 value (mg/mL) with 100% desirability was found at an extraction time of 48 h at a temperature of 60 °C by using ethanol solvent. The results of simultaneous optimization of the extraction conditions by maceration method showed the highest flavonoid content (15.20 mg/g), total phenolic content (16.01 mg/g), and the lowest IC50 (3.03 mg/mL) with 98.157% desirability at extraction time of 48 h, the temperature of 60 °C using ethanol solvent. The highest mean Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of G. lucidum extract obtained by the maceration method were 2500 and 5000 μg/mL, respectively against Clostridium perfringens and Escherichia E. coli. The predicted optimized treatment had superior antimicrobial activity against Staphylococcus aureus with a non-growth halo (Zone of inhibition) diameter of 10.60 mm as compared to C. perfringens and E. coli. The results revealed that the G. lucidum extract obtained by the maceration method could be introduced as an antioxidant and antimicrobial source in marketable food products.