<i>ent-</i>Strobane and <i>ent</i>-Pimarane Diterpenoids from <i>Siegesbeckia pubescens</i>

Two strobane diterpenoids, strobols A (<b>1</b>) and B (<b>2</b>), 15 new pimarane diterpenoids (<b>3</b>–<b>6</b> and <b>8</b>–<b>18</b>), and the known compounds kirenol (<b>19</b>), darutigenol (<b>20</b>), and <i>ent</i>-2β,15,16,19-tetrahydroxypimar-8­(14)-ene (<b>7</b>) were isolated from the aerial parts of <i>Siegesbeckia pubescens</i> Makino. The structures of the new compounds were established based on the interpretation of HRESIMS and NMR analysis. The configurations of <b>1</b>, <b>6</b>, and <b>17</b> were confirmed by X-ray crystallographic data. Compounds <b>3</b>, <b>5</b>, and <b>11</b> inhibited the migration of MB-MDA-231 breast cancer cells induced by the chemokine epithelial growth factor, with IC₅₀ values of 4.26, 3.45, and 9.70 μM, respectively

Synthesis and evaluation of nitrogen-containing derivatives of 3,11-dioxo-olean-12-en-30-oic acid against HIV-1 protease

Thirteen nitrogen-containing derivatives of 3,11-dioxo-olean-12-en-30-oic acid were synthesised by introducing various amino acids and nitrogen-containing heterocyclic groups at the 30-carboxyl group, starting from 18β-glycyrrhetinic acid. Among the 13 derivatives, 10 exhibited inhibitory activity against HIV-1 PR, with IC50 values ranging from 0.19 to 0.94 mM. Notably, derivatives 2, 3 and 5 displayed relatively moderate inhibitory activity, with IC50 values below 0.24 mM. Molecular docking studies provided further insights into the interaction between derivatives (2, 3 and 5) and the active sites of HIV-1 PR. The results revealed favourable hydrophobic-hydrophobic and hydrogen bonding interactions, with docking scores ranging from −6.22 to −7.00 and glide emodel values from −62.9 to −48.6 (kcal/mol). These findings underscore the potential of derivatives 2, 3 and 5 as promising candidates for the development of HIV-1 PR inhibitors.</p