Arabinan-rich pectic polysaccharide fraction from Malpighia emarginata fruits alleviates inflammatory pain in mice.

Malpighia emarginata (Malpighiaceae), popularly known as "acerola", is a tropical and subtropical fruit native to the Americas. Despite its high vitamin C content, which gives it a high antioxidant property, soluble dietary fibers, such as polysaccharides, are also abundant constituents of acerola (10% of the dried fruit). The acerola cold-water soluble (ACWS) fraction presented anti-fatigue and antioxidant effects in vivo and in vitro. To infer further systemic effects of ACWS, this study aimed to investigate the antinociceptive, anti-inflammatory, and antioxidant effects of ACWS in murine models of pain. In formalin-induced nociception, ACWS (0.1, 1, and 10 mg/kg) reduced only the inflammatory phase, and also (10 and 30 mg/kg) attenuated the acetic acid-induced writhing and leukocyte migration in the peritoneal cavity. The mechanical allodynia and paw edema induced by intraplantar injection of carrageenan were greatly reduced by ACWS (10 mg/kg). At the inflammatory pick induced by carrageenan (4 h), ACWS significantly reduced myeloperoxidase activity, TNF-α, IL-1ß, and PGE2 levels, and restored IL-10 levels. ACWS also exhibited antioxidant properties by decreasing lipid hydroperoxides content, increasing GSH levels, and restoring superoxide dismutase and catalase activities in the carrageenan model and 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging assay. Collectively, these results support the antinociceptive, anti-inflammatory, and antioxidant effects of ACWS and reveal a promising candidate for the treatment of inflammatory pain conditions.

Structure and intracellular antioxidant activity of pectic polysaccharide from acerola (Malpighia emarginata).

Malpighia emarginata is a tropical fruit plant, found naturally in the Caribbean islands and South America that produces an edible fruit known as acerola or Barbados Cherry. Its polysaccharides were obtained by aqueous extraction, subjected to a freezing and thawing process and ultrafiltration. A homogeneous fraction (ACWS-01E) was analyzed by sugar composition, HPSEC, methylation and NMR spectroscopy analyses. The results showed an arabinan-rich pectic polysaccharide, with 6.1×104g/mol and formed mainly by a high methyl esterified (DM=86%) homogalacturonan and branched arabinan. This latter is anchored in type I rhamnogalacturonan regions. The main chain of arabinan consisted of (1→5)-linked α-Araf, branched only at O-3. The potential ACWS-01E intracellular antioxidant activity against H2O2-induced oxidative stress in murine fibroblast cell line (3T3) was determined by DCFH-DA assay. The treatment with ACWS-01E significantly reduced H2O2-induced cytotoxic effect and the levels of reactive oxygen species (ROS). These findings suggested that ACWS-01E protected and improved NIH 3T3 cell viability from H2O2-induced toxicity by decreasing intracellular levels of ROS.

Anti-fatigue activity of an arabinan-rich pectin from acerola (Malpighia emarginata).

A fraction composed of an arabinan-rich pectin was extracted from acerola fruit (Malpighia emarginata) and named ACWS. This fraction presented 93% of total carbohydrate, relative molecular weight of 7.5×104g/mol, galacturonic acid, arabinose, galactose, xylose and rhamnose in 52.1:32.4:7.2:4.8:3.5 molar ratio and had its structure confirmed by NMR analysis. The anti-fatigue activity of ACWS was evaluated using the weight load swim test on trained mice. ACWS was orally administered at doses of 50mg/kg, 100mg/kg and 200mg/kg for 28days. Plasma biochemical parameters, respiration of permeabilized skeletal muscle fibers, and GSH levels and lipoperoxidation in the brain (pre-frontal cortex, hippocampus, striatum and hypothalamus) were determined. ACWS could lengthen the swimming time, increase the plasma levels of glucose, triglycerides, lactate, and the GSH levels in the hippocampus at all tested doses. The mitochondrial respiratory capacity of the skeletal muscle was increased at middle and high ACWS doses. This study provides strong evidence that M. emarginata pectic polysaccharide supplementation has anti-fatigue activity, can modify the kinetics of energy substrates (carbohydrate and fat) mobilization and the respiratory capacity of the skeletal muscle, as well the antioxidant status in the hippocampus of ACWS treated animals.