5-4--dihydroxy-7-3--dimethoxyflavone and chrysoeriol

Phytochemical investigation of the acetone extract of the aerial parts of Leucas stelligera afforded four new compounds (1-4) belonging to the labdane diterpene series as well as two known flavones, velutin (5) and chrysoeriol (6). Structure elucidation of the new compounds was carried out using 1D and 2D NMR spectroscopic data and single-crystal X-ray crystallography of compound 1. Compounds 1-4 exhibited selective antimycobacterial activity against Mycobacterium tuberculosis with IC50 values in the range 5.02-9.80 μg/mL.

Topics: Antitubercular Agents; Crystallography, X-Ray; Diterpenes; Drug Screening Assays, Antitumor; Flavones; Hep G2 Cells; Humans; India; Inhibitory Concentration 50; Lamiaceae; Microbial Sensitivity Tests; Molecular Conformation; Molecular Structure; Mycobacterium tuberculosis; Nuclear Magnetic Resonance, Biomolecular

Recent studies have shown that some flavonoids are modulators of proinflammatory cytokine production. In this study, velutin, a unique flavone isolated from the pulp of açaí fruit (Euterpe oleracea Mart.), was examined for its effects in reducing lipopolysaccharide-induced proinflammatory cytokine tumor necrosis factor (TNF)-α and interleukin (IL)-6 production in RAW 264.7 peripheral macrophages and mice peritoneal macrophages. Three other structurally similar and well-studied flavones, luteolin, apigenin and chrysoeriol, were included as controls and for comparative purposes. Velutin exhibited the greatest potency among all flavones in reducing TNF-α and IL-6 production. Velutin also showed the strongest inhibitory effect in nuclear factor (NF)-κB activation (as assessed by secreted alkaline phosphatase reporter assay) and exhibited the greatest effects in blocking the degradation of inhibitor of NF-κB as well as in inhibiting mitogen-activated protein kinase p38 and JNK phosphorylation; all of these are important signaling pathways involved in production of TNF-α and IL-6. The present study led to the discovery of a strong anti-inflammatory flavone, velutin. This compound effectively inhibited the expression of proinflammatory cytokines TNF-α and IL-6 in low micromole levels by inhibiting NF-κB activation and p38 and JNK phosphorylation.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Apigenin; Arecaceae; Cell Line, Transformed; Cells, Cultured; Flavones; Flavonoids; Fruit; Gene Expression Regulation; Interleukin-6; Lipopolysaccharides; Luteolin; Macrophage Activation; Macrophages, Peritoneal; MAP Kinase Signaling System; Mice; Mice, Inbred C57BL; NF-kappa B; RNA, Messenger; Structure-Activity Relationship; Tumor Necrosis Factor-alpha