Leucidal® Liquid is based on an
antimicrobial peptide originally derived from the lactic acid bacteria, Leuconostoc kimchii. L. kimchii is one of 15
species of microorganisms that make up the mixed culture used for producing the Korean
dietary staple known as kimchi, a type of fermented cabbage.
lactic acid bacteria, L. kimchii is capable of restricting the growth of other microorganisms
by acidifying its environment, but as is common in
nature, it is not content to limit itself to a single mechanism of defense. In
addition to acidifying its environment, it also
produces a novel antimicrobial peptide. Using modern fermentation and
bioprocessing technology, AMT has commercialized this antimicrobial peptide to produce Leucidal® Liquid.
The first step
in the development of this product was to determine the peptide’s potential
ability to inhibit the growth of a variety of
bacteria and fungi. Using standard serial dilution protocols in growth media,
the Minimum Inhibitory Concentrations
(MICs) for Leucidal®
determined for a variety of both bacterial and fungal organisms. The results of
these tests are shown in Table 1.
MIC screening results warranted further testing to confirm its ability to
provide product preservation. A Double
Challenge Test was completed using 2% Leucidal® Liquid in a generic
cream base formulation. Samples were inoculated with E. coli, P.
aeruginosa, S. aureus, K. pneumoniae, C. albicans, A. niger, and B. cepacia. During the
first 28-day incubation period, samples were periodically collected and tested
for the presence of these microorganisms. Following this initial 28 days of incubation,
the cream samples were then re-inoculated with the microbial cultures and
sampled over an additional 28-day period. Table 2 shows the positive
preservation results for Leucidal® Liquid.
peptides have been found to provide skin moisturization properties, Leucidal® Liquid was used in a
comparative study to evaluate its ability to provide cosmetic benefits, in
addition to the demonstrated antimicrobial function. A skin moisturization
study was performed using a generic cream base, compared with the same cream base
containing 1% Leucidal® Liquid. As demonstrated by the results of
this study, shown in Table 3, the addition of 1% Leucidal® Liquid to the base
cream formulation provided a 10% increase in moisturization. Based on these results,
adding this innovative product provides the formulator the opportunity to
capitalize on both the natural antimicrobial properties of Leucidal® Liquid, as well as
its ability to provide potent moisturizing benefits to the cosmetic formulation.
These properties make it ideal for applications addressing numerous skin and
As with all
biological materials, some attention must paid to the conditions under which Leucidal® Liquid is used. Based
on bench-scale evaluations, as well as actual product applications, Leucidal® Liquid has been found to
be effective over a wide range of typical cosmetic and personal care product
The product has been found to be heat stable up to 70°C and active under both acidic
(pH 3) and
conditions (pH 8).
Quick Tips when
using Leucidal® Liquid:
1. We recommend
starting with 4.0% Leucidal® Liquid.
2. Monitor the
interaction of Leucidal® Liquid with other ingredients for
3. Incorporate Leucidal® Liquid into
formulations at a pH between 3 and 8, during the cooling phase
of the process at temperatures lower than 70°C
testing has shown that Leucidal® Liquid can tolerate temperatures of up to 70°C
for a period of 8 hours without having any impact on MIC performance.
nature of Leucidal®
the main formulating concern potential incompatibility
with highly anionic ingredients, such as thickeners. Please request from us for more information
regarding specific anionic thickeners. The use of solubilizing agents may help
improve clarity in cases where haziness is observed.
Leucidal® Liquid towards the end of the formulating process: A successful recommendation
is adding Leucidal®
the end of the formulating process and after the
formulation has cooled to below 70°C. Please request from us for recommended
specific anionic thickeners.
Leucidal® Liquid has been in use
for almost a decade now and has been proven to be a very compatible
ingredient for formulating.