Background: Combretum vendae A.E. van Wyk (Combretaceae) is used for the treatment of bacterial related infections and oxidative related
diseases by indigenous people of South Africa. Dried leaves extracts of
C. vendae were investigated for bioactivity against a variety of bacterial
strains and their antioxidant potential evaluated.
Materials and methods: Constituents of leaf material were serially extracted using solvents of varying polarities, TLC chromatograms of the
fractions were sprayed with 2,2 diphenyl-1-picrylhydrazyl (DPPH) to determine the presence of antioxidant compounds. Bio-autography was
used to determine the number of antibacterial compounds active against
Staphylococcus aureus
,
Enterococcus faecalis
,
Eschericha coli
and
Pseudomonas aeruginosa
. Minimum inhibitory concentration (MIC) values were determined using serial microplate dilution method. The
chloroform fraction was subjected to bio-assay guided column chromatography to isolate the active compound.
Results: The mass extracted by different solvents was below 10% dry weight. MIC values for different extracts against different pathogens
ranges from 0.08 to 0.64 mg/ml. The compound isolated was identified as acacetin having an R
f value of 0.28 following elution in the Ethanol:
Methanol: Water [E: M: W (10: 1.35: 1 v/v). Acacetin had MIC values ranging from 0.16 to 0.35 mg/ml.
Conclusion: We report for the first time the isolation of acacetin as the main antibacterial compound from the leaves of
Combretum vendae.
