82 SKIN PROTECTION driver in inflammation.13 The increase in air
pollution that we experience today, has well- documented harmful effects on human skin.14
The skin is exposed to environmental
air pollutants, such as volatile organic compounds (VOCs), particulate matter (PM), and ozone (O3
). Prolonged exposure to high
levels of pollutants can induce alterations in skin homeostasis which is associated with ageing,15
cancer16 and inflammatory skin
conditions.17 Inflammation and oxidative stress
induced by PM are key mechanisms involved in the skin’s degradation of collagen (Fig 3), and the over-expression of the matrix metalloproteinases (MMP’s), and thus skin ageing.18
Under oxidative stress,
Nrf2 Nuclear factor (erythroid-derived 2)- like 2), is activated to mitigate the negative effects, and plays a vital role in protecting keratinocytes from oxidative damage. Nrf2 translocates to the nuclei of keratinocytes, binds to the antioxidant response element, and thereby regulates the expression of a large host of genes that are involved in cellular antioxidant protection.19 The matrix metalloproteinases (MMPs), a
family of peptidase enzymes are responsible for the degradation of extracellular matrix components, including collagen-1.18
Matrix metalloproteinase-1
(MMP-1) is expressed in migrating keratinocytes and pollution, which includes smoke, will induce MMP-1 expression leading to premature skin ageing.18,20 Oxidative stress leads to the activation
of the Nuclear factor-erythroid-2-related factor 2 (Nrf2) pathway. In cells under homeostatic conditions, cytosolic transcription factor Nrf2 is kept at low levels by proteasomal degradation triggered by the Keap1 protein complex (Fig 3). When cells are under oxidative stress, free radicals induce the Nrf2 to release itself from Keap1, escaping from proteasomal degradation, and then it translocates to the nucleus. In the nucleus, Nfr2 binding commences the transcription of antioxidant enzymes, including heme oxygenase-1 (HO-1), glutathione peroxidase (GPx), glutathione S-transferase (GST), superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), NAD(P)H:quinone oxidoreductase-1 (NQO1), glutamine-cysteine ligase (GCL), and glutathione synthetase (GS). These enzymes act by reducing cellular oxidative stress and free radical formation, which ultimately leads to a wide variety of ageing disorders, including the skin.20
Test samples Mideka Ximenia SeedOil (MXSO) was formulated into a simple cosmetic vehicle at 2% (P1) and 5% (P2) respectively. A simple vehicle carrier minus MXSO was used as a control.
PERSONAL CARE EUROPE
Table 1: Fatty acid content of Mideka Ximenia Seed Oil. Fatty acid profile Myristic Acid
Palmitoleic Acid Palmitic Acid
Linoleic Acid + Linolenic Acid Oleic Acid Stearic Acid
8-Octadecynoic Acid Ximenynic Acid Eicosenoic Acid
Eicosanoic Acid (or Arachidic Acid) Erucic Acid
Behenic Acid
Tetracosenoic Acid (or Nervonic Acid) Lignoceric Acid
Ximenic Acid (or Hexacosenoic Acid) Hexacosanoic Acid
Ximenixic Acid (or Octacosenoic Acid) Octacosanoic Acid Triacontenoic Acid Unidentified lipids
O OH Ximenixic Acid OH Ximenic Acid H3 C O OH Xymenynic Acid Figure 2: Chemical structures of the very long chain fatty acids found in Ximenia americana seed oil.
Ex vivo performance of MXSO Human skin explants with an average diameter of 12 mm (±1mm), were prepared from an abdominoplasty of a 47-year-old Caucasian female. Explants were kept in BEM culture medium (BIO-EC’s Explant Medium) in a humidified atmosphere with CO2
(5% v/v) at 37 C. The pollutants mix
(ML) used was Merck ICP standardised heavy metals supplemented with benzene,
xylene, toluene and diesel particles (NIST), together with exposure to cigarette smoke. Test products (P1 and P2) and vehicle (E) were applied topically based on 2 μl per explant (2 mg/cm2
) and spread using a
small spatula. On day 0, explants were placed in 2 mL of culture medium. Controls (T) did not receive any treatment. On day 4, explants of test batches were placed, into a PolluBox®
O
Results as % peak area 0.1 0.4 1.8 0.4
59.1 1.7 1.2 1.9 1.0 0.5 0.8 1.1 2.9 2.2 2.7 2.0 4.8 1.1 1.9
12.3
system (Fig 4) and September 2020
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