Antibacterial hydroxycinnamic esters from Piper caninum from Paluma, North Queensland, Australia. The crystal and molecular structure of (+)-bornyl coumarate

Abstract The crude chloroform bark extract of PIPER CANINUM (Piperaceae) exhibits antibacterial activity against the Gram-positive bacteria, BACILLUS CEREUS, STAPHYLOCOCCUS AUREUS, and STREPTOCOCCUS PNEUMONIAE. The antibacterial agents in this extract have been isolated using bioactivity-directed chromatographic techniques and identified by NMR spectroscopy as (+)-bornyl P-coumarate and bornyl caffeate. A single-crystal X-ray structure has been carried out on (+)-bornyl P-coumarate. The compound crystallizes in the orthorhombic space group P2 1 2 1 2 1 (#19) with A = 12.659(4), B = 13.281(4), and C = 10.177(3) Å. Fullmatrix least-squares refinement converged at R = 0.047, and RW = 0.058.