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ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Produce Safety and Microbiology Research » Research » Publications at this Location » Publication #310936
Title: Antiadopogenic effects of rice hull smoke extract in 3T3-L1 cells

Author
item KIM, SUNG PHIL - Ajou University Of Korea
item NAM, SEOK HYUN - Ajou University Of Korea
item Friedman, Mendel

Submitted to: Food & Function
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/11/2015
Publication Date: 7/20/2015
Citation: Kim, S., Nam, S., Friedman, M. 2015. Antiadopogenic effects of rice hull smoke extract in 3T3-L1 cells. Food and Function. doi: 10.1039/C5FO00469A.

Interpretive Summary: In previous studies we describe the production and composition of a new, commercially available liquid rice hull smoke extract (RHSE) prepared by pyrolysis of rice hull followed by liquefaction of the resulting smoke. GC/MS revealed that the smoke contained 161 structurally different compounds. In follow-up studies we found that RHSE inhibited the growth of the foodborne pathogen Salmonella Typhimurium in laboratory media and in vivo in mice and protected mice against the virulent disease called endotoxemia. These multifunctional benefits suggested the possibility that one or more of the bioactive compounds in the extract might also exhibit antiadipogenic properties associated with obeisity. In the present study we discovered that at concentration of 0.1% and 0.5% RHSE was shown to reduce the cellular lipid of pre-adipocyte cells by 72% and 88%, respectively compared to the control without RHSE, indicating a strong antiadipogenic effect. Detailed studies of the mechanism of the beneficial effect indicate that RHSE might have an antiobesity function through the AMPK (activated protein kinase) signalling pathway. The results of the present study show that because RHSE exhibited strong dose-dependent antiadipogenic effects in a cell line that produces adipocytes (fat cells) it has the potential to inhibit obesity in vivo in animals and humans. The observed beneficial properties and our earlier report on the antimicrobial effectiveness of the extract against Salmonella Typhimurium in culture and in infected mice suggest that the extract has the potential to serve as multifunctional food preservative that might have advantages over widely used wood-derived liquid smoke.

Technical Abstract: The present study investigates the inhibitory effects of a rice hull smoke extract (RHSE) against adipogenesis in 3T3-L1 pre-adipocyte cells. At concentrations of 0.1% and 0.5% RHSE, MDI-induced cells were shown to reduce their cellular lipid content by about 72% and 88%, respectively, compared to that in control cells without RHSE, indicating a strong antiadipogenic effect. The assessment of cell viability using the MTT assay showed that RHSE concentrations up to 0.5% (v/v) were not cytotoxic to the 3T3-L1 cells, regardless of differentiation status of the cells. The antiadipogenic effect was accompanied by the following changes in factors of the cells. Inhhibition of adiponectin both in its mRNA and protein production level, i.e. the protein expression pattern was similar to the mRNA expression pattern. RHSE activated AMP-activated protein kinase (AMPK) through increasing phosphorylation during the early phase of MDI-induced differentiation. Quantitative reverse transcriptase polymer chain reaction (qRT-PCR) and Western blot analyses of associated genes showed a dose-dependent suppression (inhibition) by RHSE of the expression of the peroxisome proliferator-activated receptor-' (PPAR'), CCAAT-enhancer binding protein (C/EBPa), and sterol regulatory element-binding protein 1c (SREBP-1c) at the late stage of differentiation. These mechanistic aspects of the antiadipogenic effect induced by RHSE are similar to those reported by other investigators. These results suggest that RHSE might have an antiobesity function through the AMPK signaling pathway in 3T3-L1 cells.