ANTI-AGEING
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Skin anti-ageing properties of a microalga extract
Giorgio Dell’Acqua, Francesca Germani – Akott
Microalgae are considered to be single-cell factories. When cultivated in bioreactors, they consistently produce a sustainable and safe biomass through an optimal photosynthesis process, where culture media, pH, temperature, nutrients, and levels of dissolved oxygen and CO2
are strictly controlled. The biomass is rich in
active ingredients with healthy benefits, including sugars, amino acids, lipids, polyphenols and vitamins.1 While the lipidic fraction of microalgae has
found applications in biofuels and nutritional supplements,2
the additional presence in the
water-fraction of high levels of carbohydrates, amino acids and polyphenols has supported the use of microalgae extracts in cosmetics as well, specifically for their antioxidant, anti- inflammatory, moisturising, lightening and anti- ageing properties.3-5 Moreover, by cultivating microalgae and
controlling their growth as well as their content, it is possible to produce functional actives sustainably and reproducibly. This optimised process reduces the need for a wild source, and is therefore more sustainable and also cleaner because there is no risk of pollutants. We cultivated a specific Nannochloropsis
microalga from the North Sea, Nannochloropsis Granulata, in controlled and optimised conditions. This microalga, which was first identified in the mid-1990s,6
has a high
photosynthetic efficiency, with a large biomass. While the lipid component of the microalga is usually directed towards the nutritional supply chain, the remaining water-soluble fraction is mostly viewed as a by-product and wasted.
Because of its value, we extracted the water-
soluble fraction containing sugars, amino acids and polyphenols, and concentrated it in an active ingredient for topical use. We then tested the capacity of the product, whose trade name is Akosky Vanity (INCI: Glycerin, Aqua (Water), Nannochloropsis Granulata Extract), to reduce skin ageing, specifically its ability to stimulate collagen production in cell lines and to increase skin firmness and elasticity in healthy volunteers when applied in a finished formulation.
Material & methods Extract preparation & analysis Nannochloropsis Granulata was sourced from the North Sea bordering the coast of Denmark. The microalga was then grown in photobioreactors in a specific culture media and controlled for pH, temperature, nutrients, dissolved oxygen and CO2
. Sunlight was used
as the energy source to produce biomass by photosynthesis. The water-soluble fraction of the biomass was then extracted and this was followed by lyophilisation. The final concentrated powder was then solubilised into the final product. Analysis of the extract identified the major
components to be carbohydrates (7.6%), amino acids (8.6%) and polyphenols (1.2%). Interestingly, analytical investigation of the amino acid component identified glycine and proline as the most abundant (data not shown). These amino acids are essential building blocks for collagen.
Photobioreactors using sunlight as a natural energy source
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In vitro testing Human primary fibroblasts were grown in 96- well plates using a commercial culture medium (Promocell, Greiner BioOne). All assays were performed in duplicates (two wells/condition). The Nannochloropsis Granulata extract powder was dissolved in culture medium at a concentration of 0.002% (w/v) for testing. Cells were seeded at 5,000/well and after 96
Nannochloropsis granulata
hours the active powder was added. Cells were then incubated for another 48 hours. At the end of the incubation period, cells were counted for cytotoxicity (nuclei staining with NucBlue and image analysis, nuclei count n=5). The results were compared to control wells (no active treatment). To test for collagen production, the same
protocol was used with the addition of a positive control (vitamin C at 10 µm + TGFβ at 10 ng/ mL). At the end of the treatment, procollagen I and collagen I proteins were detected by immunostaining with specific antibodies, followed by image analysis. An ImageXpress® Micro XLS microscope
(Molecular Devices), with a 20x objective coupled to Dichroic filters was used for visualisation. Four fields per well were acquired. To quantify fluorescence, images were analysed using MetaXpress software (Molecular Devices), and the results expressed as the mean +/- SD.
Clinical study A panel of 30 female subjects, aged between 40 and 70, was selected to apply on the skin a water-based gel containing 2% of the active ingredient or to apply a placebo gel with no active ingredient (Aqua, Glycerin, Sodium Acrylate/Sodium Acryloyl Dimethyl Taurate Copolymer, Ethylhexylglycerin, Phenoxyethanol ± Nannochloropsis Granulata extract). The subjects were divided in two groups of 15, one receiving the gel containing the active, the other receiving the gel without active (placebo). The gel was applied on the face, twice a day (morning and evening) for 56 days, on dry and clean skin after normal cleansing. It was massaged in gently until it was completely absorbed. During this period, four specific instrumental
and clinical parameters were evaluated: skin firmness, elasticity, tonicity and lifting. The measurements and the evaluations were taken at: T0, the baseline, before the use of the product; T28, 28 days after the use of the product; and T56, 56 days after the use of the product. Skin firmness and elasticity were measured using a skin suction machine. During this test, a negative pressure was
created by the device, the skin was drawn into the aperture of a probe and, after a defined time, released again (Cutometer MPA 580, Khazaka Electonic). Data were expressed in mm for skin firmness and in percentage for skin elasticity. Skin tonicity and skin lifting were analysed
by a dermatologist using visual examination and scale grading, and graded on a 0-5 scale. For
February 2022 PERSONAL CARE
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