Investigation of antimicrobial and alpha-glucosidase inhibitor activities of Morus alba L.

Abstract

Morus alba L. is a medical plant and food that has been used for a long time and commonly known as mulberry. Mulberry can be cultivated in the sub-tropical area of Asia. Leaves of mulberry are popularly consumed as mulberry tea. The aim of this study was to investigate the bioactivities of mulberry leaves in water extract and hydro-ethanol extract. Antimicrobial activities were evaluated by minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) assay. Broth microdilution was performed according to CLSI guidelines. Both mulberry leaves extract, were tested against Bacillus cereus ATCC 11778, Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923, Staphylococcus epidermidis ATCC 12228, Cutibacterium acnes ATCC 6919 and Pseudomonas aeruginosa ATCC 9027. All MIC value against tested bacteria were more than 4 mg/ml in all extracts. Besides, both extracts were tested in the alpha-glucosidase inhibition assay. This study was used acarbose as a standard to compare with mulberry extracts. Alphaglucosidase was inhibited by acarbose (IC50 = 312.5 μg/ml). The IC50 values of water extract and 70% ethanol extract were 31.25 μg/ml and 46 μg/ml, respectively. The inhibition of alphaglucosidase is involved with postprandial hyperglycemia reduction in type 2 diabetes. Therefore, both mulberry leaves extracts, water extract and 70% ethanol extract, demonstrated an interesting alpha-glucosidase inhibition activity. Moreover, both extracts were more effective than acarbose. These might indicate the potential of this plant to develop as a food supplement in type 2 diabetes patients.