Bioassay-guided isolation of vilasinin–type limonoids and phenyl alkene from the leaves of <i>Trichilia gilgiana</i> and their antiplasmodial activities

Abstract

Bioassay-guided fractionation of the CH₂Cl₂-MeOH (1:1) leaves extract of <i>Trichilia gilgiana</i>, yielded two new vilasinin-type limonoids named gilgianin A (<b>1</b>) and gilgianin B (<b>2</b>), one new phenyl alkene derivative designated as gilgialkene A (<b>3</b>), along with six known compounds: rubescin H (<b>4</b>), TS3 (<b>5</b>), trichirubine A (<b>6</b>), sitosteryl-6'-<i>O</i>-undecanoate-<i>β</i>-D-glucoside (<b>7</b>), scopoletin (<b>8</b>), and octadecane-2-one (<b>9</b>). Their structures were elucidated based on spectroscopic analysis and comparison with literature data. Compounds <b>5</b> and <b>6</b> exhibited the highest antiplasmodial activity with IC₅₀ values of 1.14 and 1.32 μM respectively. Moreover, compound <b>5</b> was very cytotoxic with CC₅₀ value of 0.88 µM, compared to compound <b>6</b>, which was not cytotoxic (CC₅₀ > 10 µg/mL). Compounds <b>1 (</b>IC₅₀ = 9.84 µM), <b>2</b> (IC₅₀ = 11.04 µM) and <b>4</b> (IC₅₀ = 10.71 µM) presented good antiplasmodial activity while also exhibiting significant cytotoxicity, with CC₅₀ values ranging from of 14.45 to 29.7 µM.[Formula: see text].