Food bioscience | 2021
Inhibitory effects of orally administered pectic polysaccharides extracted from the citrus Hallabong peel on lung metastasis
Abstract
Abstract In this study, we investigated the anti-metastatic effect of the pectic polysaccharide HBE-0, extracted from peels of Hallabong, Korea citrus by pectinase digestion and ethanol precipitation. HBE-0 comprises 64.4% neutral sugars and 31.7% uronic acid including 14 types of monosaccharides. IL-6 and IL-12 were secreted in a dose-dependent manner by peritoneal macrophages stimulated with HBE-0. Intravenous administration of HBE-0 significantly augmented the cytolytic activity of NK cells. In lung metastasis assays using Colon26-M3.1 carcinoma cells, prophylactically intravenous administration of HBE-0 at a dose of 50\xa0mg/kg showed up to 90% inhibitory effect on lung metastasis. Furthermore, NK cells depletion by anti-asialo-GM1 partially reduced the inhibitory effect of HBE-0 on lung metastasis. Further, oral administration of HBE-0 induced NK cell cytotoxicity and dose-dependently inhibited lung metastasis. These results suggest that HBE-0 isolated from Hallabong peels possesses anti-metastatic activity and supports its potential as a health-functional or pharmacological agent in commercial applications by increasing the high added-value of discarded agricultural byproducts.