Constituents of the Stem Bark of Symphonia globulifera Linn. f. with Antileishmanial and Antibacterial Activities

The chemical investigation of the n -hexane fraction from the methanol extract of the stem bark of Symphonia globulifera Linn f., which displayed good in vitro activity against Leishmania donovani NR-48822 promastigotes (IC 50 43.11 µg/mL), led to the isolation of three previously unreported polyprenylated benzophenones, guttiferone U ( 1 ), V ( 2 )/W ( 3 ), and a new tocotrienol derivative named globuliferanol ( 4 ), along with 11 known compounds ( 5 – 15 ). Their structures were elucidated based on their NMR and MS data. Some isolated compounds were assessed for both their antileishmanial and cytotoxic activities against L. donovani and Vero cells, respectively. Guttiferone K ( 5 ) exhibited the best potency (IC 50 3.30 μg/mL), but with low selectivity to Vero cells. The n -hexane fraction and some compounds were also assessed in vitro for their antibacterial activity against seven bacterial strains. All the samples exhibited moderate to potent antibacterial activity (MICs ≤ 15.6 µg/mL) against at least one of the tested strains.