SKIN CARE
Peptides: Their role in epigenetic processes
Jelena Miladinović-Delić - Beauty Core, UK
Anti-ageing initiatives, aiming to interfere with the biological ageing process, have attracted much attention through history. With the improvement and wide accessibility of healthcare as well as an increase in wealth of the general population, the expectations and the demand for anti-ageing actives can only be expected to rise in the future. A number of different types of peptides
have been available and used to formulate skin care products, supporting anti-ageing claims. In our daily lives, we encounter the terms ‘protein’ and ‘peptide’ sometimes being used interchangeably. However, we might be uncertain whether these terms refer to the same or different structures. Are there any significant differences
between protein and peptide molecules? What can we expect in terms of the behaviour of peptide molecules? Proteins are complex organic compounds,
made from a number of amino acids, with high molecular mass. They are unstable in highly acidic mediums and susceptible to denaturation at raised temperatures (typically above 37°C).2 On the other hand, peptides are fragments
of proteins, composed from a lower number of amino acids, connected in a defined sequence. For example, di-peptide is made from two amino acids, tri-peptide of three amino acids and so on (up to fifty amino acids in a peptide), in a defined sequence, specific for the given peptide, as shown in Figure 1. Similar to proteins, peptides are also complex molecules, as shown in Figure 2.
Amino acids Peptide
Figure 1: Schematic representation of differences of peptide vs. protein The amino acids, building blocks of
peptides, are mutually connected by a covalent bond, formed so that the carboxyl group of one amino acid reacts with the amino group of another amino acid. However, the bonds that hold amino acids together in a protein or peptide molecule are susceptible to denaturation.2
Based on the above, it may be presumed
that the protein and peptide share common characteristics, in particular, when it comes to the complexity of the structure and sensitivity to degradation caused by changes in pH of the medium and raised temperature (for example above 40°C). Similar to proteins, peptides are susceptible to the chemical degradation and denaturation
HN O O
N H
O O OH
H N
O
N H
OH O O S
H N
O
N H
NH2 Figure 2: Complex chemical formula of acetyl-hexapeptide-8
www.personalcaremagazine.com O
HN NH2 NH
NH2 NH
H N
O NH2 Protein
both in vitro and in vivo. However, more research is needed to better understand the stability of peptides when incorporated into cosmetic products, the factors affecting the degradation kinetics and the behaviour of a peptide molecule over a period of time. For this to be evaluated, specific, reliable and sensitive instrumental analytical methods detecting the presence and quantity of peptide molecule incorporated into a cosmetic formulation are required. The same instrumental methods may be used for detection of proteins and peptides in the sample (for example use of infrared spectroscopy or nuclear magnetic resonance). Both peptides and proteins formulated
as topical preparations for dermal delivery have exhibited a major obstacle in their permeability to penetrate the epidermis. However, several modalities have been utilised to overcome this, such as the use of chemical penetration enhancers for dermal delivery of peptides.4
The basic characteristics of peptides,
their chemical structure, as well as their application in the domain of medicine and cosmetic science are the subjects of my own professional interest but it is also the focus of the wider academic and international research community. The extent of public and professional
interest for this topic became obvious to me back in 2018, when I was invited to participate in a number of international conferences as a guest speaker on the topic of the application and significance of use of peptides in skin
October 2021 PERSONAL CARE
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