Phytochemical, antimicrobial, anticancer and anti-Alzheimer investigation of the hydro-alcoholic leaf extract of Eucalyptus globulus L. in laboratory conditions

This research evaluated the phytochemical, antimicrobial, anticancer and anti-Alzheimer properties of eucalyptus leaf extract (Eucalyptus globulus L.). The fresh leaves of the plant were collected from the suburbs of Rasht in the fall 2016. Extraction was done by maceration method and the composition of the extract was determined by GC-MS method. The antimicrobial effects of the extract were investigated on Staphylococcus aureus, Escherichia coli, Listeria monocytogenes, and Salmonella typhimurium by agar well diffusion method and its MIC and MBC values were determined. The anticancer effect was determined by MTT test on the colon cancer cell line, the antioxidant effect was determined by DPPH method, and the inhibitory effect of the extract on the production of amyloid nano-fibrils was determined by Congored spectroscopy. Eucalyptol and Globulol were the most abundant in the extract. The diameter of the halo of non-growth of Eucalyptus hydro-alcoholic extract in the well diffusion method on Escherichia coli, Staphylococcus aureus, Listeria monocytogenes, and Salmonella typhimurium were 12, 22, 26, and 15 mm, respectively. Also, the results of MIC and MBC in Escherichia coli and Staphylococcus aureus were 0.625 and 1.25, respectively. These results in Listeria monocytogenes were 1.25 and 2.5; also, the results of MIC and MBC in Salmonella Typhimurium were 5 and 10 mg/ml, respectively. The highest anticancer activity, antioxidant effect, and inhibition of the production of amyloid nano-fibrils were observed at 100, 10, and 0.4 mg/ml of the extract, respectively. Due to its antimicrobial, antioxidant, and anti–amyloidogenic properties, eucalyptus extract can help treat infection and reduce the growth of cancer cells and the complications of Alzheimer's disease.