This
study hypothesized that long carbon chain cationic arginine
(Arg) esters can be considered as toxicologically harmless preservatives.
Arg-esters with C
18
and C
24
carbon chains, namely,
arginine-oleate (Arg-OL) and arginine-decyltetradecanoate (Arg-DT),
were synthesized. Structures were confirmed by FT-IR,
1
H NMR, and mass spectroscopy. Both Arg-esters were tested regarding
hydrophobicity in terms of log
P
octanol/water
, critical micelle concentration (CMC), biodegradability, cytotoxicity,
hemolysis, and antimicrobial activity against
Escherichia
coli
(
E
.
coli
),
Staphylococcus
aureus
(
S
.
aureus
),
Bacillus
subtilis
(
B
.
subtilis
),
and
Enterococcus
faecalis
(
E
.
faecalis
). Log
P
octanol/water
of arginine was raised from −1.9 to 0.3
and 0.6 due to the attachment of C
18
and C
24
carbon chains, respectively. The critical micelle concentration
of Arg-OL and Arg-DT was 0.52 and 0.013 mM, respectively. Both Arg-esters
were biodegradable by porcine pancreatic lipase. In comparison to
the well-established antimicrobials, benzalkonium chloride (BAC) and
cetrimide, Arg-esters showed significantly less cytotoxic and hemolytic
activity. Both esters exhibited pronounced antimicrobial properties
against Gram-positive and Gram-negative bacteria comparable to that
of BAC and cetrimide. The minimum inhibitory concentration (MIC) of
Arg-esters was <50 μg mL
–1
against all
tested microbes. Overall, results showed a high potential of Arg-esters
with long carbon chains as toxicologically harmless novel preservatives.