Anti-Inflammatory Ergosteroid Derivatives from the Coral-Associated Fungi <i>Penicillium oxalicum</i> HL-44.

Abstract

To obtain the optimal fermentation condition for more abundant secondary metabolites, Potato Dextrose Agar (PDA) medium was chosen for the scale-up fermentation of the fungus <i>Penicillium oxalicum</i> HL-44 associated with the soft coral <i>Sinularia gaweli</i>. The EtOAc extract of the fungi HL-44 was subjected to repeated column chromatography (CC) on silica gel and Sephadex LH-20 and semipreparative RP-HPLC to afford a new ergostane-type sterol ester (<b>1</b>) together with fifteen derivatives (<b>2</b>-<b>16</b>). Their structures were determined with spectroscopic analyses and comparisons with reported data. The anti-inflammatory activity of the tested isolates was assessed by evaluating the expression of pro-inflammatory factors <i>Tnfα</i> and <i>Ifnb1</i> in Raw264.7 cells stimulated with LPS or DMXAA. Compounds <b>2</b>, <b>9</b>, and <b>14</b> exhibited significant inhibition of <i>Ifnb1</i> expression, while compounds <b>2</b>, <b>4</b>, and <b>5</b> showed strong inhibition of <i>Tnfα</i> expression in LPS-stimulated cells. In DMXAA-stimulated cells, compounds <b>1</b>, <b>5</b>, and <b>7</b> effectively suppressed <i>Ifnb1</i> expression, whereas compounds <b>7</b>, <b>8</b>, and <b>11</b> demonstrated the most potent inhibition of <i>Tnfα</i> expression. These findings suggest that the tested compounds may exert their anti-inflammatory effects by modulating the cGAS-STING pathway. This study provides valuable insight into the chemical diversity of ergosteroid derivatives and their potential as anti-inflammatory agents.