Planta Med 2014; 80 - P1L25
DOI: 10.1055/s-0034-1394683

Antibacterial activity of crude extracts from Santalum spictatum and Acacia ligulata

D Jæger Knudsen 1, 2, B Lindberg Møller 2, P Weinstein 1, S Semple 1
  • 1Sansom Institute for Health Research, School of Pharmacy and Medical Sciences, University of South Australia, PO Box 2471, Adelaide, 5001, Australia
  • 2Plant Biochemistry Laboratory, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark

This study forms part of an investigation into various pharmacological activities of crude extracts from different tissues of two native Australian plant species; the hemi parasitic species Santalum spicatum (sandalwood) and its host Acacia ligulata. Both plants species are known to have been used in Australian traditional medicine. Seven different crude extracts of S. spicatum and A. ligulata were prepared using ethanol and DCM:MeOH as extraction solvents. The extracts were tested for various activities including antibacterial effects, wound healing and cytotoxicity in human cancer cell lines. In the antibacterial assays, extracts were screened for activity against six different Gram-positive and Gram-negative bacteria related to human health. The broth micro-dilution assay was used to determine the minimum inhibitory and bactericidal concentrations (MIC and MBC) of the plant extracts against the bacterial strains. Five of the crude extracts from S. spicatum and A. ligulata showed activity against one or more of the bacterial strains, most activity was observed against Streptococcus pyogenes with MIC values ranging from 62.5 to 250 µg/ml. Activity was also observed against Staphylococcus epidermidis (1000 µg/ml), Staphylococcus aureus species (250 to 1000 µg/ml) and the Gram-negative Pseudomonas aeruginosa (1000 µg/ml). All of the active extracts were also found to have a bactericidal effect against S. aureus (500 to 1000 µg/ml) and S. pyogenes (500 to 1000 µg/ml).

Through this study it has been shown that several crude extracts from S. spicatum and A. ligulata have antibacterial activity and may contain novel antibacterial compounds that could be isolated and characterised. Isolated compounds could have a potential to be used in drug development of new antimicrobial agents. Further studies using activity guided fractionation and structural elucidation techniques will aim to identify the active compounds from the crude extracts.