Abstract:
Bacterial secondary metabolites play a major role in the alleviation of diseases; however,
the cytotoxicity of other metabolites cannot be ignored as such metabolites could be detrimental to
human cells. Three Staphylococci strains Staphylococcus aureus, staphylococcus epidermidis and staphylococcus
saprophyticus were used in the experiments. These strains are well known to cause hospital
and community-acquired infections. Secondary metabolites from S. aureus isolated from milk of
cows with clinical features of mastitis (swollen udders and the production of watery clotted milk),
S. saprophyticus (ATCC 35552), and S. epidermidis (ATCC 51625) were exposed to a minimal medium
then screened using Gas Chromatography High-Resolution Time-of-flight Mass Spectrometry (GCHRTOF-
MS) and identified with Nuclear Magnetic Resonance (NMR). From S. epidermidis, two
compounds were isolated: oleamide and methyl palmitate; three from S. aureus, including fluoranthene,
3-methyl-2-phenyl-1H-pyrrole, and cyclo(L-Leu-L-Propyl); while S. saprophyticus yielded
succinic acid, 1,2,6-hexantriol, veratramine, and 4-methyl-pentyl-amine. The secondary metabolites
were tested for cytotoxicity using the Vero cell line. Fluoranthene exhibited toxicity with an LC50 of
0.0167 mg/mL to Vero cells, while the other metabolites did not. Methyl palmitate was the least toxic
of all of the metabolites. The results imply that none of the compounds, except fluoranthene, pose
any danger to human cells.
