Novel Danshen methoxybenzo[b]furan derivative antagonizing adipogenic differentiation and production of inflammatory adipokines

Abstract

Many benzo[b]furan lignans are known to be biologically active in nature. 2-(3'-Methoxy-4'-hydroxy-phenyl)-5-(3-hydroxypropyl)-7-methoxy-benzo[b]furan-3-carbaldehyde (XH-14) is found as a bioactive component isolated from the plant Salvia miltiorrhiza, commonly known as Danshen, which is a traditional Chinese medicine that is used as a cardiovascular medication. This study examined whether 3 different XH-14 derivatives can inhibit adipocyte differentiation and induction of the adipokines visfatin and resistin in 3T3-L1 adipocytes. Adipocytes were cultured and differentiated in Dulbecco's modified Eagle medium containing fetal bovine serum, 3-isobytyl-1-methylxanthine, dexamethasone, and insulin for 6-8d in the absence and presence of 1-25μM XH-14-derived benzo[b]furan derivatives. Nontoxic 2-(3'-methoxy-4'-hydroxy-phenyl)-6-(3-hydroxypropyl)-5-methoxy-benzo[b]furan (5-MBF) at ≥5μM attenuated cellular lipid accumulation and down-regulated induction of peroxisome proliferator activated receptors γ (PPARγ) and CCAAT enhancer binding protein α (C/EBPα) in a dose-dependent manner, as evidenced by Oil Red O staining and Western blot analysis. Such inhibition of PPAR( and C/EBP( by 5-MBF was achieved at transcriptional mRNA levels. However, 2-(3'-methoxy-4'-hydroxy-phenyl)-5-(3-hydroxypropyl)-7-methoxy-benzo[b]furan (7-MBF) and 2-(3'-methoxy-4'-hydroxy-phenyl)-5-(3-hydroxypropyl)-7-methoxy-benzo[b]furan (6-MBF) had minimal effects on adipogenic differentiation, suggesting a structure-activity relationship of methoxybenzo[b]furan derivatives as an inhibitor of adipogenic differentiation. Furthermore, ≥5μM 5-MBF retarded protein and mRNA expression of proinflammatory and insulin resistance-enhancing adipokines of visfatin and resistin in differentiated adipocytes. Induction of visfatin and resistin was, at least in part, mediated via adipocyte differentiation-associated activation of PPARγ signal targeting adipocyte protein 2 and stearoyl-CoA desaturase. These results demonstrate that the 2-(3'-methoxy-4'-hydroxy-phenyl)-3-hydroxypropyl benzo[b]furan lignan, with a methoxy group at the 5-position on the benzene ring, may be a promising agent for disturbance of adipogenic differentiation and for blockage of obesity-associated inflammatory and metabolic diseases.