Chemical composition and antioxidant activity of certain Morus species

In the present work, the fruits of four Morus species, namely Morus alba (white mulberry), Morus nigra (black mulberry), Morus laevigata (large white fruit), and Morus laevigata (large black fruit), were analyzed for proximate composition, essential minerals, and antioxidant potentials. For this purpose, the ripe fruits were collected from the northern regions of Pakistan. The major nutritional components (moisture, ash, lipids, proteins, fibres, carbohydrates, and total sugar) were found to be in the suitable range along with good computed energy. Total dry weight, pH, and titratable acidity (percent citric acid) were (17.60 +/- 1.94)-(21.97 +/- 2.34) mg/100 g, (3.20 +/- 0.07)-(4.78 +/- 0.15), and (0.84 +/- 0.40)%-(2.00 +/- 0.08)%, respectively. Low riboflavin (vitamin B-2) and niacin (vitamin B-3) contents were recorded in all the fruits, while ascorbic acid (vitamin C) was in the range from (15.20 +/- 1.25) to (17.03 +/- 1.71) mg/100 g fresh weight (FW). The mulberry fruits were rich with regard to the total phenol and alkaloid contents, having values of (880 +/- 7.20)-(1650 +/- 12.25) mg/100 g FW and (390 +/- 3.22)-(660 +/- 5.25) mg/100 g FW, respectively. Sufficient quantities of essential macro-(K, Ca, Mg, and Na) and micro-(Fe, Zn, and Ni) elements were found in all the fruits. K was the predominant element with concentration ranging from (1270 +/- 9.36) to (1731 +/- 11.50) mg/100 g, while Ca, Na, and Mg contents were (440 +/- 3.21)-(576 +/- 7.37), (260 +/- 3.86)-(280 +/- 3.50), and (240 +/- 3.51)-(360 +/- 4.20) mg/100 g, respectivly. The decreasing order of micro-minerals was Fe > Zn > Ni. The radical scavenging activity of methanolic extract of fruits was concentration-dependent and showed a correlation with total phenolic constituents of the respective fruits. Based on the results obtained, mulberry fruits were found to serve as a potential source of food diet and natural antioxidants.