VACCINE

International Journal Of Cosmetic Science • April 2012
In vitro induction of apoptosis, necrosis and genotoxicity
by cosmetic preservatives: application of flow cytometry
as a complementary analysis by NRU
Author information
Carvalho CM1, Menezes PF, Letenski GC, Praes CE, Feferman IH, Lorencini M.
Grupo Boticário
Research and Innovation Department
Biomolecular Research Laboratory
Av. Rui Barbosa no. 3450, 83.065-260
São José dos Pinhais, PR- Brazil
camilamc@grupoboticario.com.br
Abstract
Preservatives are used in cosmetics to prevent microbial contamination; however, some
preservatives are not free of allergenic and cytotoxic potential. Allergenicity and cytotoxicity
potential values are major aspects of preservative safety, which determine limitations
and maximum concentration dose in a cosmetic product. The purpose of this study was to
investigate and compare the in vitro apoptosis, necrosis and genotoxicity-inducing potential
of five different types of preservatives: Phenoxyethanol (PE), Propylparaben (PP), Methylparaben
(MP), Benzyl Alcohol (BA) and Ethylhexyl Glycerine (EG). In vitro experiments
were carried out on human dermal fibroblasts by a quantitative flow cytometry method,
using specific cell markers (Annexin V, Propidium Iodide and H2AX). We compared the
resulting cell viability by means of neutral red uptake (NRU) and established the IC(50) .
Our results showed that PE, PP, MP and BA have similar cytotoxic mechanisms (high apoptosis
and necrosis levels only at the test concentration of 1%), whereas EG showed only
an apoptosis pathway. For genotoxicity, both parabens yielded the highest values. Results
obtained by flow cytometry for necrosis were comparable to those produced by NRU; however,
NRU does not distinguish apoptosis from necrosis. We propose that flow cytometry is
a more sophisticated methodology for understanding the cytotoxic mechanisms of cosmetic
preservatives and can be used to complement the NRU.
“Our results showed that
Phenoxyethanol [a vaccine ingredient] ...
have similar cytotoxic mechanisms
(high apoptosis and necrosis levels only
at the test concentration of 1%) ...”
http://www.ncbi.nlm.nih.gov/pubmed/?term=22118339