Antioxidant Activity of Mulberry Fruit Extracts

Muhammad Arfan,Ryszard Amarowicz,Rasool Khan,Anna Rybarczyk

doi:10.3390/ijms13022472

Abstract

Phenolic compounds were extracted from the fruits of Morus nigra and Morus alba using methanol and acetone. The sugar-free extracts (SFEs) were prepared using Amberlite XAD-16 column chromatography. All of the SFEs exhibited antioxidant potential as determined by ABTS (0.75–1.25 mmol Trolox/g), DPPH (2,2-diphenyl-1-picrylhydrazyl) (EC50 from 48 μg/mL to 79 μg/mL), and reducing power assays. However, a stronger activity was noted for the SFEs obtained from Morus nigra fruits. These extracts also possessed the highest contents of total phenolics: 164 mg/g (methanolic SFE) and 173 mg/g (acetonic SFE). The presence of phenolic acids and flavonoids in the extracts was confirmed using HPLC method and chlorogenic acid and rutin were found as the dominant phenolic constituents in the SFEs.

Highlights

The mulberry belongs to the Morus genus of the Moraceae family
The highest total polyphenolic contents (TPC) was obtained for a Morus nigra acetonic sugar-free extracts (SFEs) (173 mg/g), followed by a Morus nigra methanolic SFE (164 mg/g); the lowest TPC was obtained for a Morus alba methanolic SFE (119 mg/g)
Using extracts obtained with 70% ethanol for 4 h at room temperature, the crude extract of five different Korean cultivars of Morus alba fruits showed only 0.95–2.57 mg gallic acid equivalents (GAE)/g [15]

Summary

Introduction

The mulberry belongs to the Morus genus of the Moraceae family. There are 24 species of Morus, with at least 100 known varieties [1]. The flavonol glycosides isolated from mulberry leaves [quercetin 3-(-malonylglucoside), rutin, and isoquercitin] inhibited human LDL oxidation induced by copper [5]. The antioxidant potential of the extracts obtained from mulberry leaves and fruits was investigated by several authors. The antioxidant properties of mulberry leaf extracts were investigated by Arabshahi-Delouee and Urooj [14] by various experimental methods including the iron (III) reducing capacity, the total antioxidant capacity, the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity and an in vitro inhibition of ferrous sulphate-induced oxidation of lipids. The antioxidant activities of ethanolic extracts of five mulberry cultivars from Korea were determined using the DPPH radical assay, haemoglobin-induced linoleic acid system, and reducing power. The aim of this work was to obtain extracts from white and black mulberry species, and assess their relative antioxidant activities

Results and Discussion

Experimental Section

Conclusions