In Vitro Antioxidant, Anticoagulant and Antimicrobial Activity and in Inhibition of Cancer Cell Proliferation by Xylan Extracted from Corn Cobs

Abstract

Xylan is one of most abundant polymer after cellulose. However, its potential has yet to be completely recognized. Corn cobs contain a considerable reservoir of xylan. The aim of this work was to study some of the biological activities of xylan obtained from corn cobs after alkaline extraction enhanced by ultrasonication. Physical chemistry and infrared analyses showed 130 kDa heteroxylan containing mainly xylose:arabinose: galactose:glucose (5.0:1.5:2.0:1.2). Xylan obtained exhibited total antioxidant activity corresponding to 48.5 mg of ascorbic acid equivalent/g of xylan. Furthermore, xylan displayed high ferric chelating activity (70%) at 2 mg/mL. Xylan also showed anticoagulant activity in aPTT test. In antimicrobial assay, the polysaccharide significantly inhibited bacterial growth of Klebsiella pneumoniae. In a test with normal and tumor human cells, after 72 h, only HeLa tumor cell proliferation was inhibited (p < 0.05) in a dose-dependent manner by xylan, reaching saturation at around 2 mg/mL, whereas 3T3 normal cell proliferation was not affected. The results suggest that it has potential clinical applications as antioxidant, anticoagulant, antimicrobial and antiproliferative compounds.

Antioxidant and Antiproliferative Activities of Leaf Extracts fromPlukenetia volubilisLinneo (Euphorbiaceae)

“…The antioxidant activity was examined by conducting in vitro tests: total antioxidant capacity, hydroxyl radical scavenging, superoxide radical scavenging, ferric chelating, and reducing power, as previously described in [21, 22]. …”

Leads from Physical, Chemical, and Thermal Characterization on Cytotoxic Effects of Xylan-Based Microparticles

“…Indeed, these results were expected because this material is considered highly stable, nontoxic, and hydrophilic [10,32], even though anti-proliferative activity of xylan against HeLa cells has been reported as its AC50 = 1 mg/mL, as well as the activity of other polysaccharides [13]. Despite its low toxicity, at 24.8 mg·mL −1 the cell viability decreased (Figure 7a,c), probably as a result of the saturation of the medium with xylan and, consequently, the precipitation of xylan as result of its low solubility in aqueous medium at physiological pH [33].…”

“…Briefly, an alkali xylan solution was added into a chloroform:cyclohexane (1:4, v/v) mixture in order to obtain a W/O emulsion and then cross-linked using TC (Figure 1). According to the chemical composition of xylan from corn cobs described by Melo-Oliveira et al, the ratio of hydroxyl radicals to TC molecules was 4.7ˆ10´4 (molecules of xylan/molecules of TC) [13]. The PbMs were then washed three times with (1) an ethanolic solution containing 2% (v/v) polysorbate (Tween 80 and Tween 20, 1:1); (2) an ethanolic aqueous solution, 95˝GL; and (3) distilled water.…”

Preparation and Application of a Xylan-Based Antibacterial Additive Agent against <em>Escherichia Coli </em>Bacteria

“…Moreover, xylan also have great potential to be applied as antimicrobial materials after modification and have received increasing attentions. Recently, the importance of xylan-based macromolecules [29][30][31][32] and materials [33][34][35] have obtained increasing focus, including antimicrobial modification of xylan used in the fields of packaging film, food preservative as well as in biomedical areas [36][37][38][39] . There have been many ways reported to prepare xylan-based antimicrobial materials.…”