Abstract: The phytosterols extracted from avocado using saponification method were qualitatively and quantitatively analyzed and their antioxidant and antibacterial activity were studied. β-Sitosterol, campesterol, cholesterol and stigmasterol were detected at levels of 59.47, 30.36, 15.34, and 2.72 mg/100 g in the phytosterols by gas chromatography-tandem mass spectrometry (GC-MS/MS), respectively. The phytosterols had significant scavenging capacity against 1,1-diphenyl-2-picrylhydrazyl radical, hydroxyl radical and superoxide anion radical with half maximal inhibitory concentration of 6.82, 35.92 and 17.08 μg/mL, respectively, using VE as the control. The antibacterial activity of the phytosterols against three tested strains, as determined by inhibition zone method, was in the descending order of Bacillus subtilis > Staphylococcus aureus > Salmonella > Escherichia coli, indicating that the phytosterols from avocado had good antibacterial activity.

Key words: avocado, phytosterol, antioxidant activity, antibacterial activity