Isolation, purification and antioxidant activity of polysaccharides from the leaves of maca (Lepidium Meyenii)

Int J Biol Macromol. 2018 Feb;107(Pt B):2611-2619. doi: 10.1016/j.ijbiomac.2017.10.139. Epub 2017 Oct 31.

Abstract

Two fractions of polysaccharides (MLP-1 and MLP-2) were extracted from the leaves of maca (Lepidium Meyenii Walp.) by water, and purified using DEAE-52 ion exchange resin and sephadex G-200 clumns chromatography. An investigation was carried out for their structural characterization and antioxidant activity in vitro. The results indicated that MLP-1 was mainly composed of ribose, rhamnose, arabinose, xylose, mannose, glucose and galactose, with the molar ratio of 0.12:0.32:1.50:0.32:1.03:1.00:0.93; the MLP-2 was a homopolysaccharide composed of glucose. The molecular weight (Mw) of MLP-1 was 42756Da, and the Mw of MLP-2 was 93541Da. The FT-IR spectra showed the general characteristic absorption peak of maca leaf polysaccharides (MLPs). The evaluation of antioxidant activity revealed that MLP-1 had strong scavenging effects in vitro on hydroxyl, superoxide anion and DPPH radicals, whose EC50 (mg/mL) was 0.44, 0.21, and 0.82, respectively. Both MLP-1 and MLP-2 presented dose-dependently positive effects on the antioxidant-related parameters. The results suggested that the purified MLP-1 displayed better antioxidant capacities than that of MLP-1, which could be explored as potential antioxidant agents for the complementary medicine or functional foods.

Keywords: Antioxidant activity; Characterization; Maca leaves; Polysaccharides.

MeSH terms

  • Antioxidants / isolation & purification*
  • Antioxidants / pharmacology
  • Biphenyl Compounds / chemistry
  • Chromatography, Gas
  • Chromatography, High Pressure Liquid
  • Free Radical Scavengers / pharmacology
  • Lepidium / chemistry*
  • Molecular Weight
  • Monosaccharides / analysis
  • Picrates / chemistry
  • Plant Leaves / chemistry*
  • Polysaccharides / isolation & purification*
  • Polysaccharides / pharmacology
  • Spectrophotometry, Ultraviolet
  • Spectroscopy, Fourier Transform Infrared
  • Superoxides / chemistry

Substances

  • Antioxidants
  • Biphenyl Compounds
  • Free Radical Scavengers
  • Monosaccharides
  • Picrates
  • Polysaccharides
  • Superoxides
  • 1,1-diphenyl-2-picrylhydrazyl