Evaluation of antioxidant and anti-inflammatory effects of three different Rubus coreanus Miq. by-products

Abstract

Purpose: To investigate the antioxidant and anti-inflammatory properties of three different Rubus coreanus Miq. by-products in stimulated BV-2 microglial cells and explore its underlying physiological efficacy. Methods: Cell viability assessment was performed by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Lipopolysaccharide (LPS) was used to activate BV-2 microglia. Total polyphenol and total flavonoid contents were determined by the method of Folin-Denis. As three different Rubus coreanus Miq. by-products remaining after extraction of Rubus coreanus, High performance liquid chromatography (HPLC)) finger printing, ABST (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging assay, and NO (nitric oxide) inhibitory assay were performed. Results: Three different Rubus coreanus by-product extract did not exhibit any signs of cytotoxicity to BV-2 cells up to 100 μg/ml concentration (p < 0.5). The LPS-activated excessive release of NO in BV-2 cells was significantly inhibited by Rubus coreanus by-product extract (p < 0.5) at 500 μg/mL). Total polyphenol and total flavonoid contents were highest in 50 % ethanol wine processing by-product (p < 0.5 at 30, 50, 70 and 100 %, respectively). The by-product of wine processing had the lowest RC50 radical scavenging effect (16.53 μL/ml). The quercetin content of the wine processing by-product was the highest in the 70% ethanol extract at 6.26 mg/g (p < 0.5 at 30, 50, 70 and 100%, respectively). Conclusion: These results reveal that of the three other by-products, wine processing by-product has the highest antioxidant and anti-inflammatory activities. The use of these by-products has high added value for industrial production; furthermore, they are a potential treatment for various inflammatory diseases.