Antibacterial compounds from Planchonia careya leaf extracts.
OBJECTIVE
The leaves of Planchonia careya (F. Muell.) R. Knuth (Lecythidaceae) have been traditionally implemented in the treatment of wounds by the indigenous people of northern Australia, although the compounds responsible for the medicinal properties have not been identified. In this study, antibacterial compounds from the leaf extracts were isolated and characterized, and the biological activity of each compound was assessed.


METHODS
Compounds were isolated from the leaf extracts using HPLC-piloted activity-guided fractionation. The minimum inhibitory concentrations (MICs) were assessed with plate-hole diffusion assays, and the cytotoxicity was determined with MTT assays using monkey kidney epithelial (MA104) cells.


RESULTS
Six known compounds were isolated from the leaf extracts and were identified as 1, (+)-gallocatechin; 2, gallocatechin-(4alpha-->8)-gallocatechin; 3, 9(S)-hydroxy-10E,12Z-octadecadienoic acid (alpha-dimorphecolic acid); 4, 2alpha,3beta,24-trihydroxyolean-12-en-28-oic acid (hyptatic acid-A); 5, 3beta-O-cis-p-coumaroyltormentic acid; and 6, 3beta-O-trans-p-coumaroyltormentic acid. Compounds 5 and 6 were weakly selective for vancomycin-resistant Enterococcus (VRE) compared with eukaryotic cells, with an MIC of 59.4microg/mL and a 50% inhibitory concentration (IC(50)) of 72.0microg/mL for MA104 cells.


CONCLUSIONS
The isolation of six antibacterial compounds from the leaves of Planchonia careya validates the use of this species as a topical wound-healing remedy.
McRae
Jacqui M
JM
Faculty of Life and Social Sciences, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia.
Yang
Qi
Q
Crawford
Russell J
RJ
Palombo
Enzo A
EA
D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology* / Q000633:toxicity; D001419:Bacteria / Q000187:drug effects*; D002460:Cell Line; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects; D000882:Haplorhini; D020128:Inhibitory Concentration 50; D031381:Lecythidaceae / Q000737:chemistry*; D008826:Microbial Sensitivity Tests; D010936:Plant Extracts / Q000737:chemistry* / Q000494:pharmacology* / Q000633:toxicity; D018515:Plant Leaves / Q000737:chemistry
D000900:Anti-Bacterial Agents; D010936:Plant Extracts