Structural analysis and anti-obesity effect of a pectic polysaccharide isolated from Korean mulberry fruit Oddi (Morus alba L.)

• Mulberry polysaccharide JS-MP-1 was defined as a rhamnogalacturonan type I (RG I) polymer.
• JS-MP-1 carries arabinan and arabinogalactan (AG II) side chains.
• JS-MP-1 dose-dependently reduces the viability of 3T3-L1 pre-adipocyte cells.
• JS-MP-1 induces mitochondrial dysfunction and apoptosis in pre-adipocyte cells.
• JS-MP-1 has in vitro anti-obesity effects via inhibition of adipocyte proliferation.

A water-soluble polysaccharide JS-MP-1 was isolated from Korean mulberry fruits Oddi (Morus alba L.). Sugar linkage analysis and NMR data confirmed that it is a rhamnogalacturonan type I (RG I) polymer carrying arabinan and arabinogalactan (AG II) side chains. JS-MP-1 reduced dose-dependently the viability of 3T3-L1 pre-adipocyte cells, significantly stimulated the cleavage of caspases 9 and 3 and poly (ADP-ribose) polymerase (PARP) and decreased the ratio of Bcl-2 to Bax expression level that led to mitochondrial dysfunction and apoptosis in pre-adipocyte cells. The apoptotic death was mediated by stimulation of MAPKs (ERK and p38) signalling pathway. These results suggest that JS-MP-1 is able to reduce the number of fat cells and the mass of adipose tissue via inhibition of pre-adipocyte proliferation and thus JS-MP-1 itself or a crude aqueous Oddi extract containing this polysaccharide can be used as functional ingredient of health-beneficial food supplements for the treatment or prevention of obesity disorders.