Synthesis and anti-inflammatory evaluations of β-lapachone derivatives

beta-Lapachone (beta-LAPA), a natural product from the lapacho tree in South America, is a potential chemotherapeutic agent that exhibit a wide variety of pharmacological effects such as anti-virus, anti-parasitic, anti-cancer, and anti-inflammatory activities. In order to discover novel anti-inflammatory agents, we have synthesized a series of beta-LAPA derivatives for evaluation. Among them, 4-(4-methoxyphenoxy) naphthalene-1,2-dione (6b) was found to be able to inhibit NO and TNF-alpha released in LPS-induced Raw 264.7 cells. Inhibition of iNOS and COX-2 was also observed in compound 6b treated cells. Mechanism studies indicated that 6b exhibited anti-inflammatory properties by suppressing the release of pro-inflammatory factors through down-regulating NF-kappa B activation. In addition, it suppressed NF-kappa B translocation by inhibiting the phosphorylation of p38 kinase. Our results also indicate that the inhibitory effect of 6b on LPS-stimulated inflammatory mediator production in Raw 264.7 cell is associated with the suppression of the NF-kappa B and MAPK signaling pathways. A low cytotoxicity (IC50 = 31.70 mu M) and the potent anti-inflammatory activity exhibited by compound 6b make this compound a potential lead for developing new anti-inflammatory agents. Further structural optimization of compound 6b is on-going. (C) 2012 Elsevier Ltd. All rights reserved.