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In Vitro Evaluation of n-docosanol and Floraesters K-100 Cytotoxicity and Antiviral Activity Vs. Herpes Simplex Virus HSV-1

Summary of tests conducted by ViroMed Laboratories, Inc. 2540 Executive Drive, St. Paul, MN 55120 and monitored by Technikos Research Associates(Summary of tests conducted by ViroMed Laboratories, Inc. 2540 Executive Drive, St. Paul, MN 55120 and monitored by Technikos Research Associates)


Literature and commercial use of n-docosanol (NDOC), an industrially available fatty alcohol confirms its antiviral effect vs. the HSV-1 virus.  Jojoba oil is a long chain ester comprised of linked fatty alcohols and fatty acids.  Hydrolysis of the jojoba oil molecule utilizing KOH as a catalyst results in a mixture of polar hydrophilic salts and nonpolar fatty alcohols known as Floraesters K-100 (FEK-100).  A clear cut, dose dependent effect of FEK-100 vs. the Herpes Simplex Virus strain 6143 has been determined.  The following is a synopsis of the test protocols and the results obtained.

Step 1

Determine the cytotoxicity of the test item.  The test item(s) must be effective in reducing plaque formation of the herpes simplex virus without being toxic to the Vero cells on which the virus are grown and tested.

Cytotoxicity Results:

NDOC demonstrated no cytotoxicity at 250 mg/ml (25%), the highest concentration tested.  Concentrations of FEK-100 in excess of 3.56 mg/ml (0.356%) reduced the concentration of viable Vero cells by 50%.  Therefore, NDOC was subsequently tested for effect vs. the herpes simplex virus at maximum concentrations of 250 mg/ml (25%) and FEK-100 was tested at a concentration range of 0.025 mg/ml (0.0025%) up to 10 mg/ml (1.0%).

Step 2

Determine the IC50 of each test item.  The IC50 is the concentration at which a 50% reduction of virus plaques is observed for a test item.  In each test procedure viable Vero cells are dosed with a range of non-toxic concentrations of the test item and allowed to stand for a period of time.  Afterwards, the Vero cells are challenged with various concentrations of herpes simplex virus and the virus is allowed to infect the Vero cells.  Infected cells at each test item concentration are compared to controls infected without first pre-treating with the test item.

Antiviral Results:

The IC50 of NDOC was determined to be 1.0 mg/ml (0.1%).  The IC50 of FEK-100 was determined to be 0.02 mg/ml (0.002%) i.e. a concentration of 50 times more NDOC was required to achieve the equivalent antiviral effect of FEK-100 in the tests conducted.


The above antiviral testing was conducted using the virus strain VML-6143 of Type-1 Herpes Simplex (HSV-1).  An isopropyl derivative of jojoba oil (Floraesters IPJ) was included in the testing but did not exhibit as strong an effect vs. the HSV-1 virus as did NDOC or FEK-100.  However, Floraesters IPJ did demonstrate a dose-dependent inhibition of plaque formation against virus strain 15671, an acyclovir resistant strain.   FEK-100 was not tested vs. virus strain 15671. 

A CD of the complete ViroMed Laboratories test report is available upon request.