Total phenolic content, antioxidant and antibacterial activities of fruits of Eucalyptus globulus cultivated in Algeria

Crude extract from fruit of Eucalyptus globulus (E. globulus) was screened for its in vitro antioxidant and antibacterial properties. Antioxidant activity was measured by two methods, namely the reducing power and lipid peroxidation inhibition. Antibacterial activity was determined by using disc diffusion method against three bacteria (Staphylococcus aureus: ATCC 6538, Bacillus subtilis: ATCC 6633 and Klebsiella pneumoniae: E 47). The extract exhibited moderate inhibition of lipid peroxidation of linoleic acid emulsion (51.34 ± 0.72%) and high reducing power (IC50 = 39.52 μg/mL). It also exhibited strong antibacterial activity against B. subtilis and S. aureus with minimum inhibitory concentration (MIC) values of 30 μg/mL and 80 μg/mL, respectively. These results suggest that fruits of E. globulus have interesting antibacterial and antioxidant activities.

► Phenolic and tannin contents of extract were high in fruit extract of Eucalyptus globulus. ► Flavonoids content was poor in fruit extract of E. globulus. ► Extract exhibited moderate inhibition of lipid peroxidation of linoleic acid emulsion. ► Extract exhibited high reducing power. ► Extract of E. globulus exhibited strong antibacterial activity against the Gram positive strains.