Conglomeratin: a new antibacterial flavonol derivative from Macaranga conglomerata Brenan (Euphorbiaceae).

A new prenylated kaempferol, conglomeratin (), alongside known compounds including flavonoids ( and ), ellagic acid derivatives ( and ), triterpenoids ( and ), and a coumarin () were isolated from the leaves () and stem bark () of . Their structures were elucidated using spectroscopic and spectrometric techniques. The antibacterial assay was performed using disc diffusion method against Gram-positive and Gram-negative microorganisms. Compound was significantly active against ATCC 27853 (MIC = 7.8 µg/mL) and moderately active towards ATCC 25923, ATCC 25922 and ATCC 31488 (MIC = 62.5 µg/mL). Compound showed potency against ATCC 27853 (MIC = 1.0 µg/mL) while and were selective towards ATCC 31488 (MIC = 7.8 and 1.0 µg/mL, respectively). These findings suggest that prenylation of flavonoids may contribute to improving their broad-spectrum antimicrobial activities.