Determination of Antioxidant and Antimicrobial Compounds of Ganoderma lucidum Extract in Laboratory Different Conditions

Due to the disadvantages of synthetic antioxidants, natural antioxidants have attracted more attention in recent years. Plants are a rich source of phenolic and flavonoid compounds among the most important natural antioxidants. Therefore, the objective of this study was to optimize the extraction of flavonoids, total phenols, antioxidant and antimicrobial compounds from Ganoderma (G) lucidum by ultrasonic pretreatment. To do so, independent variables including type of solvent (ethyl acetate, ۵۰% ethanol, and ۵۰% ethyl acetate), extraction time (۶, ۹, and ۱۲ min), and ultrasonic power (۱۵۰, ۲۰۰, and ۲۵۰ W) as well as Box-Behnken response surface methodology (RSM) were used. The results showed that the simultaneously optimized conditions for obtaining the maximum flavonoid content (۱۴.۳۳۴۸ mg/g) and total phenolic content (۲۴.۶۶۴۸ mg/g) and the lowest IC۵۰ (۲.۳۹۸۷ mg/mL) with ۱۰۰% desirability included ultrasonic power of ۲۵۰ W, ultrasonic time of ۱۲ min and ethanol solvent. The highest mean minimum inhibitory concentration (MTC) and minimum bactericidal concentration (MBC) of G. lucidum extract obtained by ultrasonic pretreatment were ۲۵۰۰ and ۵۰۰۰ μg/ml, respectively, against Clostridium perfringens. Optimal treatment using ultrasonic pretreatment had superior antimicrobial activity against Staphylococcus aureus with the largest diameter of non-growth halo (zone of inhibition) (۱۴.۳۳ mm) compared to E. coli and C. perfringens. Therefore, ultrasound is a valuable method for extracting bioactive compounds of G. lucidum. The extracted natural antioxidants can be incorporated into the food formulations to replace synthetic antioxidants.

Keywords:

Ganoderma lucidum , Ultrasound , Flavonoid , total phenolic content , antioxidants