Anti-inflammatory, analgesic activities and gastro-protective effects of the phenolic contents of the red alga, Laurencia obtusa

IntroductionThe present study was conducted to evaluate anti-inflammatory, analgesic and gastro-protective activities of methanol/dichloromethane extract and its semi-purified fractions from the red alga Laurencia obtusa.MethodologyAnti-inflammatory activity was evaluated in vitro using cytometric bead array technology to follow up the secretion of TNF-α in lipopolysaccharide activated THP-1 cells and in vivo using carrageenan-induced rat paw edema test. Edema was induced with 1% carrageenan after 30 min of intra-peritoneal treatments. Paw thickness was checked at t = 1, 2, 3, 4 and 5 h. Analgesic activity was carried out using acetic acid-induced writhing test in mice. 1% of acetic acid was administrated intraperitoneally at the dose of 10 mL/kg, 30 min after treatment and the number of writhing was recorded during 30 min. Gastro-protective effect was determined using HCl/EtOH induced gastric ulcers in rats. 10 mL/kg of HCl/ethanol (60% ethanol in 150 mM HCl) was orally administrated to all groups after treatment. 1 h later, stomachs were examined for the presence of lesions.ResultsCrude extract and ethanol fraction showed an excellent inhibition of TNF-α secretion and a significant decrease in paw thickness (P < 0.05), 3 h after carrageenan injection. Ethanol fraction also showed a significant (P < 0.05) analgesic activity and an excellent decrease of gastric damages.DiscussionThese activities, observed especially with the crude extract and the ethanol fraction may be related to their phytochemical composition.ConclusionThis study indicates that the red alga L. obtusa may be useful for developing potential therapeutic substances with anti-inflammatory, analgesic and gastro-protective activities.