Solophenols B–D and Solomonin: New Prenylated Polyphenols Isolated from Propolis Collected from The Solomon Islands and Their Antibacterial Activity.

Three new prenylated flavonoids, namely, solophenols B (<b>1</b>), C (<b>2</b>), and D (<b>3</b>), as well as a new prenylated stilbene, solomonin (<b>4</b>), were isolated from propolis collected from the Solomon Islands. In addition, 17 known compounds were identified. The structures of the new compounds were determined by a combination of methods, including mass spectrometry and NMR. These new compounds and several known compounds were tested for antibacterial activity against <i>Staphylococcus aureus</i>, <i>Bacillus subtilis</i>, and <i>Pseudomonas aeruginosa</i>. Most of them exhibited potent antibacterial activity. These findings may indicate that propolis from the Solomon Islands has potential applications as an ingredient in food additives or pharmaceuticals