Amal D Premarathna*, Rando Tuvikene
School of Natural Sciences and Health, Tallinn University, Narva mnt 29, 10120 Tallinn, Estonia.
Wound healing is an active, complex, integrated series of cellular, physiological, and biochemical changes initiated by the stimulus of injury in a tissue. The present study was performed to investigate the potential immunomodulatory abilities of polysaccharides extracted from seven different type of seaweeds species that were characterized by 1H NMR, HPLC-SEC and FTIR Spectrometry techniques. Red seaweed samples (Hypnea pannosa, Pterocladiella caerulescen, Gracilaria corticata, Gelidiopsis variabili, Chondrus crispus, Pyropia yeozensis, Furcellaria lumbricalis) were collected from Sri Lanka, Japan, Norway and Estonia. To determine the cytotoxicity and proliferation of polysaccharides, MTT and alamarBlue assays were used, respectively. The scratch and exclusion wound models were used on HaCaT and HDF cells to assess the cell proliferation and migration. RAW 264.7 cells were used to evaluate Nitric Oxide (NO) production and phagocytosis activities. Phagocytosis is a critical part of the immune system and was measured using natural red intake by microphages cells. Anti-inflammatory and wound healing activities were observed on RAW264.7, HDF and HaCaT cells treated with different polysaccharide fractions (obtained by cold and hot extraction). Polysaccharides from Gracilaria corticata at the concentration of 0.5 μg/μL, (P<0.05) showed the highest proliferative and migratory effects on HDF and HaCaT cells. RAW 264.7 cell proliferation and/or migration were higher for Hypnea pannosa (cold extracted polysaccharide, 0.5 μg/μL, 151.2 ± 13.5%) and Gracilaria corticata (hot extracted polysaccharide, 0.5 μg/μL, 158,4 ± 7,99%) compared to the control (100%). Scratch wound healing were remarkably enhanced in 24 and 48 h (P<0.05) when treated with polysaccharides from Hypnea pannosa and Furcellaria lumbricalis on HaCaT cells. RAW 264.7 treated with the Hypnea pannosa and Gelidiopsis variabilis showed a significantly increased NO production (P<0.05) within 24 h with 4.53 ± 0.14 μM and 4.59 ± 0.18 μM, respectively. Phagocytosis results also revealed that the healing process proceeded significantly faster when the cells were treated with Gelidiopsis variabilis, Chondrus crispus and Furcellaria lumbricalis polysaccharides. Cell proliferation and migration are significantly faster when treated with polysaccharide concentration of 0.5 μg/μL. Moreover, cold extracts of red algal polysaccharides did not cause any toxicity to RAW 264.7, HDF, or HaCaT cells within 24 h. Hypnea pannosa and Gracilaria corticata could be considered as potential healing agents. The effect comes from carrageenans, which promoted keratinocyte proliferation and fibroblast migration in this study. Polysaccharides found in red seaweeds have promising