Extraction optimization of polyphenols from fruits of Pyracantha fortuneana (Maxim.) Li by ultrasonic assistant method and their antibacterial activity.

The present study was designed to utilise ultrasound assistance technology to optimize the extraction conditions of polyphenols, and identify their antibacterial activity from fruits of Pyracantha fortuneana (Maxim.) Li, facilitated by the use of orthogonal experiment methodology. A four factors and three levels of orthogonal design was carried out to elucidate the effect of ethanol concentration, solvent-to-solid ratio, ultrasonic temperature and time on the yields of the polyphenols. The results showed that the optimal conditions were as follows: ethanol concentration 70%, solvent-to-solid ratio 70:1, ultrasonic temperature 30°C, and ultrasonic time 40 min, the maximum polyphenol yield was 5.58mg/g under the optimum extraction condition. The extracted hydro-alcohol polyphenols showed the excellent antibacterial potential to both Staphylococcus aureus and Escherichia coli with the minimum inhibitory concentration (MIC) 10 mg/ml and 20 mg/ml, and the corresponding diameter of inhibition zone (DIZ) was 7.4 and 6.8 mm, respectively. The results indicated the ability of ultrasound assistance technology to obtain polyphenols from fruits. Furthermore, present results highlighted that fruits of Pyracantha fortuneana (Maxim.) Li are a potential natural source of bioactive compounds with strong antibacterial activity. These compounds could be considered for potential application in nutraceutical and functional foods ingredient or pharmaceutical applications.