Antioxidant properties of different extracts of black mulberry (Morus nigra L.)

In vitro antioxidant properties of 3 different extracts of black mulberry (Morus nigra L.) were investigated. Acidified methanol, acidified water, and non-acidified methanol/water solutions were used to prepare extracts. Different solvents caused different protonation on black mulberry anthocyanin structures, which were predicted according to their UV-VIS spectrum. Extracts indicated 2 main peaks at about ~280 and ~520 nm with different peak areas in their UV-VIS spectrum. The rank of extracts’ total phenolic content and reducing power values were both found to be in correlation with their absorbance at ~280 nm. Meanwhile the same relationship was observed between DPPH scavenging activity and absorbance values at ~520 nm. Acidified extract of black mulberry was higher in β-carotene prevention and DPPH radical scavenging activity than non-acidified extract. However, non-acidified extract represented a higher reducing power and metal chelating activity, and a higher content of total phenolics.