Composition, physicochemical properties, and anti-fatigue activity of water-soluble okra (Abelmoschus esculentus) stem pectins

Int J Biol Macromol. 2020 Dec 15;165(Pt B):2630-2639. doi: 10.1016/j.ijbiomac.2020.10.167. Epub 2020 Oct 26.

Abstract

Okra, Abelmoschus esculentus (L.) Moench, an annual herbaceous plant, is widely distributed in tropical and subtropical regions. Water-soluble pectic hydrocolloids from okra stems (HOS) were extracted and purified using polydivinylbenzene HP-20 resins. The sugar composition of the purified HOS with an weight-average molecular weight of 178.4 ± 2.1 kDa and a polydispersity index of 1.02 ± 0.02 contained galacturonic acid (34%), galactose (31%), rhamnose (21%), arabinose (4.2%), glucuronic acid (2.5%), xylose (1.2%), and other monosaccharides (6.1%) by weight. Its favorable rheological behaviors were evident on relatively higher concentrations (20, 25, and 30 mg/mL) and moderately lower pH levels (3 and 5) of HOS. The anti-fatigue experiments in vivo demonstrated that a high dose of HOS (450 mg/kg feed) prolonged the exhaustive swimming time of mice, significantly induced an increase in blood glucose and glycogen, and decreased lactic acid and serum urea nitrogen levels. HOS digestion in vivo was fairly conducive to the improvement of energy storage capacity and renal function for physically induced fatigue, compared with the conventional herbal supplement Panax quinquefolium. Accordingly, HOS exhibits potential for reutilization of okra stem waste.

Keywords: Anti-fatigue activity; Okra stems; Pectins.

MeSH terms

  • Abelmoschus / chemistry*
  • Animals
  • Arabinose / chemistry
  • Arabinose / isolation & purification
  • Fatigue / blood
  • Fatigue / drug therapy*
  • Galactose / chemistry
  • Galactose / isolation & purification
  • Glucuronic Acid / chemistry
  • Glucuronic Acid / isolation & purification
  • Hexuronic Acids / chemistry
  • Humans
  • Lactic Acid / blood
  • Mice
  • Monosaccharides / chemistry
  • Monosaccharides / isolation & purification
  • Pectins / chemistry*
  • Pectins / pharmacology
  • Physical Conditioning, Animal
  • Plant Extracts / chemistry
  • Plant Extracts / pharmacology
  • Plant Stems / chemistry*
  • Rhamnose / chemistry
  • Rhamnose / isolation & purification
  • Rheology
  • Swimming
  • Water / chemistry
  • Xylose / chemistry
  • Xylose / isolation & purification

Substances

  • Hexuronic Acids
  • Monosaccharides
  • Plant Extracts
  • Water
  • Lactic Acid
  • galacturonic acid
  • Pectins
  • Glucuronic Acid
  • Xylose
  • Arabinose
  • Rhamnose
  • Galactose