Phytochemical, antibacterial and anti-Alzheimer's evaluation of turmeric medicinal plant extract (Curcuma longa) by inhibiting the production of amyloid nanobiofibrils

Turmeric, scientifically known as Curcuma longa L., belongs to the zingiberaceae family. Due to the need to find new antimicrobial drugs, in this study the phytochemical evaluation, antibacterial and inhibitory effects of turmeric extract were investigated on the production of amyloid nanobiofibrils. Dry and abraded skin of the plant was prepared from India in autumn 2016 and then extracted by maceration method. Analysis of secondary compounds of the extract was performed by gas chromatography-mass spectrometry. The anti-microbial effect of aqueous and hydro-alcoholic extract of turmeric was investigated by the agar well diffusion method, MIC and MBC on two Escherichia coli and Staphylococcus aureus bacteria. Anti-Alzheimer's effects of Hydro-alcoholic extract on the production of amyloid fibrils were studied by spectrophotometry. The results showed that Turmerone and Zingiburn were the most abundant compounds in hydro-alcoholic extract with 21.26% and 11.65%, respectively. The diameter of the non-growth halo in the hydro-alcoholic extract was 12 for Escherichia coli and 13 mm for Staphylococcus aureus and in the case of aqueous extract, no growth halo was created. The MIC was reported in hydro-alcoholic extracts for Staphylococcus aureus and Escherichia coli at 26 and 53, respectively and in the aqueous extract for both bacteria at 123 mg/ml. MBC levels were also reported in the presence of hydro-alcoholic extracts for Staphylococcus aureus and Escherichia coli at 53 and 106, respectively and for aqueous extract for both bacteria at 247 mg/ml. Increasing the concentration of Hydro-alcoholic extract reduced the production of amyloid fibrils by up to 40 % of the initial amount and this decrease was confirmed by transmission electron microscopy. Hydro-alcoholic extract of turmeric with antimicrobial and reducing effects on the production of amyloid fibrils, can be used as one of the useful drugs to reduce the complications of Alzheimer's disease.