Flemingins G–O, Cytotoxic and Antioxidant Constituents of the Leaves of <i>Flemingia grahamiana</i>

The known flemingins A–C (<b>1</b>–<b>3</b>) and nine new chalcones, named flemingins G–O (<b>4</b>–<b>12</b>), along with deoxyhomoflemingin (<b>13</b>) and emodin (<b>14</b>) were isolated from a leaf extract of <i>Flemingia grahamiana</i>. The isolated chalcones were found to have a geranyl substituent modified into a chromene ring possessing a residual chain, as shown by spectroscopic methods. The leaf extract showed an IC₅₀ value of 5.9 μg/mL in a DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging assay. The chalcones flemingins A, B, C, G, and H were active in the DPPH radical scavenging assay (ED₅₀ 4.4–8.9 μM), while flemingins A and C showed cytotoxicity against MCF-7 human breast cancer cells (IC₅₀ 8.9 and 7.6 μM, respectively)

Busseihydroquinones A–D from the Roots of <i>Pentas bussei</i>

Four new naphthohydroquinones, named busseihydroquinones A–D (<b>1</b>–<b>4</b>), along with a known homoprenylated dihydronaphthoquinone (<b>5</b>), were isolated from the CH₂Cl₂/MeOH (1:1) extract of the roots of <i>Pentas bussei</i>. Although the genus <i>Pentas</i> is frequently used by traditional healers for the treatment of malaria, only marginal activities against the chloroquine-sensitive (D6) and the chloroquine-resistant (W2) strains of <i>Plasmodium falciparum</i> were observed for the crude root extract and the isolated constituents of this plant

Design, Synthesis, and Biological Evaluation of Chromone-Based p38 MAP Kinase Inhibitors

3-(4-Fluorophenyl)-2-(4-pyridyl)chromone derivatives were synthesized and evaluated as p38 MAP kinase inhibitors. Introduction of an amino group in the 2-position of the pyridyl moiety gave p38α inhibitors with IC₅₀ in the low nanomolar range (e.g., <b>8a</b>, IC₅₀ = 17 nm). The inhibitors (<b>8a</b> and <b>8e</b>) showed excellent selectivity profiles when tested on a panel of 62 kinases, as well as efficient inhibition (<b>8e</b>) of p38 signaling in human breast cancer cells