New Friedelane Derivatives From the Leaves of Codiaeum variegatum Var. “Gold Dust” and Their Antibacterial Activity

Four new cinnamoyl friedelane-type triterpenoids named codigatums A–D ( 1–4 ) alongside with four known compounds 3 α-friedelinol ( 5 ), kaempferol ( 6 ), vitexin ( 7 ), and isovitexin ( 8 ) were isolated from the methanol extract of the leaves of Codiaeum variegatum var “Gold Dust”. Compound 4 was characterized in a mixture containing 1 and 5 , meanwhile compounds 7 and 8 were identified as a mixture. The structures of these compounds were established on the basis of 1D and 2D NMR data supported by LR/HR-ESI data together with reported literature. Minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of plant constituents were determined against Staphylococcus aureus ATCC 29213, Streptococcus pneumoniae 2R, Klebsiella pneumoniae 1A, and Salmonella Typhi ATCC 6539 by using broth microdilution assay. The flavonoid mixture ( 7 –8 ) (8 ≤ MIC ≤ 32 μg/mL) and codigatum B ( 2 ) (32 ≤ MIC ≤ 128 μg/mL), displayed the highest activity and may serve as potential starting points for the development of new antibacterial agents.