Polysaccharides from South Tunisian Moringa alterniflora Leaves: Characterization, Cytotoxicity, Antioxidant Activity, and Laser Burn Wound Healing in Rats

Abstract

Phytochemical properties have recently increased the popularity of plant polysaccharides as wound dressing materials. This work aims at studying the structural characteristics of polysaccharides extracted from Moringa leaves (Moringa Leaves Water Soluble Polysaccharide: MLWSP), and its antioxidant activities, cytotoxic effects, and laser burn wound healing effects in rats. This MLWSP was structurally characterized. Results showed 175.21 KDa and 18.6%, respectively, for the molecular weight and the yield of the novel extracted polysaccharide. It is a hetero-polysaccharide containing arabinose, rhamnose, and galactose. XRD suggested a semi-crystalline structure of the studied polymer and FT-IR results revealed a typical polysaccharide structure. It is composed of 50 to 500 µm rocky-shaped units with rough surfaces and it was found to inhibit the proliferation of the human colon (HCT-116) (IC₅₀ = 36 ± 2.5 µg/mL), breast (MCF-7) (IC₅₀ = 48 ± 3.2), and ovary cancers (IC50 = 24 ± 8.1). The MLWSP showed significant antioxidant effects compared to Trolox (CI₅₀ = 0.001 mg/g). Moreover, promising wound healing results were displayed. The effect of MLWSP hydrogel application on laser burn injuries stimulated wound contraction, re-epithelization, and remodeling phases 8 days after treatment. The wound healing potential of MLWSP may be due to its significant antioxidant activity and/or the huge amount of monosaccharide molecules.

Keywords: biological activities; hydrogel; in vivo activity; polysaccharide characterization; re-epithelialization.

Figure 1

Scan of SWSP within the wavelength range of 200–800 nm.

Figure 2

X-ray diffraction patterns of MLWSP.

Figure 3

(A) TLC profile of the MLWSP 1: Arabinose, 2: Xylose, 3: Fructose, 4: Glucose, 5: Tagatose, 6: Mannose, 7: Rhamnose, 8: Galactose, 9: Hydrolyzed sample, 10: Non hydrolyzed sample. (B) HPLC chromatogram profiles of MLWSP. Samples were applied to the Sugar KS-800 column at a flow rate of 0.5 mL/min.

Figure 3

(A) TLC profile of the MLWSP 1: Arabinose, 2: Xylose, 3: Fructose, 4: Glucose, 5: Tagatose, 6: Mannose, 7: Rhamnose, 8: Galactose, 9: Hydrolyzed sample, 10: Non hydrolyzed sample. (B) HPLC chromatogram profiles of MLWSP. Samples were applied to the Sugar KS-800 column at a flow rate of 0.5 mL/min.

Figure 4

Fourier transformed the infrared spectrum of MLWSP.

Figure 5

SEM images of MLWSP. (A) Morphology at 50× (scale bar is 500 µm). (B) Morphology at 250× (scale bar is 100 µm).

Figure 6

Antioxidant activity assessed by the (DPPH) radical scavenging capacity assay, (ABTS) assay, and ferric reducing (FRAP) assay in MLWSP. Values are the mean of three replicates ± standard deviation.

Figure 7

Laser Burn wounds chronicity taken for the different groups on days 0, 2, 4, 6, and 8. Group I was treated with physiological serum; Group II was treated with glycerol; Group III was treated with “Cytol Basic”, and Group IV: was treated with MLWSP hydrogel.

Figure 8

Representative photomicrographs of the epidermal and dermal architecture of wounds on the 8th day of treated rats with (A): physiological serum (Group I); (B): glycerol solution (Group II); (C): Cytol Centella (Group III); or (D): MLWSP hydrogel (Group IV). Tissues were stained with hematoxylin-eosin and visualized at 100× magnification. E: epidermis; D: dermis; F, hair follicle; C, collagen; and I, inflammatory cell.