Inhibition of neuroinflammation by novel derivatives of Biochanin A

Hyper activation of microglia is known to spark the release of inflammatory mediators, which have been shown to contribute to neurodegenerative disease progression and severity. Hence, targeting of these immune mechanisms could lead to future therapeutic or preventive strategies for dementia diseases (1). Estrogens have been shown to improve the symptoms of neurodegenerative diseases by binding to estrogen receptors (ERs) and producing an anti-inflammatory effect (2). Isoflavones are phytoestrogens that have been known to display anti-inflammatory effects. Biochanin A (BCA) is a ERβ-selective isoflavone phytoestrogen found in red clover (3). In this study, we have synthesized two BCA derivatives 1 and 2, and evaluated them for anti-inflammatory effect on lipopolysaccharide (LPS) activated BV2 cells microglia. BCA was dissolved in Et2O and anhydrous pyridine under stirring. After heated at 35°C, undecylisocyanate (0.04 ml) and lauric acid (0.04 ml) were added resulting in Compound 1 (5-hydroxy-3-(4-methoxyphenyl)-4-oxo-4H-chromen-7-yl undecylcarbamate)and Compound 2 (5-hydroxy-3-(4-methoxyphenyl)-4-oxo-4H-chromen-7-yl dodecanoic acid) respectively. Cultured BV2 (Banca Biologica e Cell Factory, Italy) were treated with compound 1 (5, 10, 15 and 20 µM) and compound 2 (5, 10, 15 and 20 µM) 30 min before stimulation with LPS (100 ng/ml) for a further 24 h. Supernatants were collected and levels of nitric oxide (NO), tumor necrosis factor alpha (TNFα), cytokine IL-6 and prostaglandine E2 (PGE2) were measured using ELISA. All experiments were performed at least three times and in triplicates. Statistical analysis was performed using one-way ANOVA with post-hoc Student Newman-Keuls test (multiple comparisons). Compounds 1 and 2 produced a significant and concentration-dependent reduction in the production of NO (***p<0.001). However, Compound 1 blocked the production of TNFα (***p<0.001) and IL-6 (*p<0.05), while Compound 2 showed no effects. Neither compound individually did not produce significant reduction of PGE2 production. Our results suggest that compound 1 exhibited inhibition of neuroinflammation in LPS-activated BV2 microglia. There is a need for further investigation of the mechanism(s) of action of these compounds in the light of the observed effects on pro-inflammatory mediators.

1. Heneka MT et al. (2015). Lancet Neurol 14: 388-405.

2. Zhao L et al. (2013). J Alzheimers Dis 37: 403-419.