Green algae, and in particular Chlorella vulgaris, are part of the new innovative ingredients in cosmetics. Rich in antioxidants and vitamins, these organisms offer numerous benefits, especially for the skin. Here are a few.
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Green Algae in Cosmetics: What are the Properties for the Skin?
Summary
- Benefit No.1: Green algae slow down skin ageing
- Benefit No. 2: Green algae could reduce vascular imperfections
- Benefit No. 3: Green algae promote and accelerate healing
- Benefit No. 4: Green algae enhance skin hydration
- Sources
Published March 26, 2024,
by
Kahina, Scientific Editor
—
8 min read
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Benefit No.1: Green algae slow down skin ageing.
In a study conducted by Barbara OBERMAYER and Patrick STOLZ, a test was utilised to assess the influence of micro-algae extracts, including thegreen algae C. vulgaris at 15 μg/L, on the collagen I content of human fibroblasts. The extract of C. vulgaris had a positive impact on the synthesis of collagen I, dependent on the concentration of micro-algae.
At a concentration of 0.4%, we observe an increase in collagen synthesis of approximately 30% compared to the control. At a concentration of 1.6%, collagen synthesis increases by 50% compared to the control. The extract of C. vulgaris therefore appears to have a connective tissue strengthening activity and thus slows down skin ageing.
Furthermore, a study conducted by Indah RAYA aimed to analyse the antioxidant activity of Chlorella vulgaris for its use as an antioxidant cream. The cream containing C. vulgaris demonstrated an antioxidant activity of 61.90%, whereas the cream without the algae had an antioxidant activity of 3.46%. C. vulgaris therefore appears to have a significant antioxidant activity , thus enabling it to counteract the effects of oxidative stress on the skin, namely skin ageing.
The extract of green algae would reduce the expression of the matrix metalloproteinase-1 (MMP-1) in human cell lines. MMP-1 is an enzyme that breaks down collagen and associated growth factors. Inhibiting the expression of this enzyme could therefore be one of the mechanisms by which green algae improves skin elasticity.
C. vulgaris is also capable of inhibiting lipid peroxidation and interacts with both enzymatic and non-enzymatic antioxidant systems, mitigating and resisting oxidative stress. The high levels of antioxidants found in C.vulgaris, such as carotenoids, astaxanthin, canthaxanthin, flavoxanthin, loraxanthin, and neoxanthin, may prove to be effective agents in preventing damage, particularly skin damage, caused by oxidation. During oxidative stress (pollution, tobacco, UV, etc.), free radicals are produced, which accelerate the skin ageing process. Antioxidants then capture these free radicals by trapping singlet oxygen and limit the damage.
Benefit No. 2: Green algae could reduce vascular imperfections.
Pierre-Yves MORVAN wanted to verify the effects of Chlorella vulgaris on the skin's microcirculation. His initial aim was to study the effects on angiogenesis, which is the production of blood vessels, using a model in vitro of human cells. C. vulgaris at 0.1% reduced the length of the vessels by -46% compared to the control.
The researcher then focused on vascular imperfections. Seventeen women applied a cream containing Chlorella vulgaris at 1% twice a day for 84 days. The volunteers had visible lesions: small varicose veins, small spider angiomas, and telangiectasias. C. vulgaris at 1% visibly reduced the redness of the vascular lesions: up to -64% after 28 days of use and up to -77% after 84 days. The treatment has improved the size and colour of the vascular lesions.
C. vulgaris could therefore be of interest for skin conditions related to redness and telangiectasias, such as rosacea for example. One of the mechanisms involved could potentially be the inhibition of angiogenesis, a process associated with the redness of rosacea. The author suggests that this effect could be the result of a reduction in the action of the vascular endothelial growth factor (VEGF), responsible for angiogenesis, by the overexpression of the metalloproteinase-3 inhibitor (TIMP3), being an antagonist of the VEGF receptor.
Furthermore, we had previously observed that C. vulgaris increases collagen synthesis. Collagen is a protein that is believed to have the ability to strengthen the walls of veins, and a deficiency has been linked to the development of varicosities. Weakened and less elastic venous walls would lead to the accumulation of blood in the vein, which widens it and makes it more visible. It can be hypothesised that the produced collagen would form a sort of "sheath" around the blood vessels to reduce their appearance, and therefore also reduce redness.
However, these results should be approached with caution. These effects have only been demonstrated once, in this context only. Further experiments are necessary to validate these points.
Benefit No. 3: Green algae promote and accelerate healing.
An experiment was conducted by Harun ACHMAD and his colleagues on the effect of a topical application of C. vulgaris on wound healing. To do this, nine pigs underwent four incisions on the right ear onto which an ointment based on C. vulgaris at three concentrations (5%, 10% and 15%) was applied. The control group received nothing. On histological sections, an increase in fibroblastic cells covering almost the entire wound surface from the seventh day of treatment was observed. By the fourteenth day, some fibroblastic cells had been lost and replaced by collagen tissue. More specifically, an increase in the number of fibroblasts was noted, dependent on the concentration of C. vulgaris with a marked efficacy of the ointment at a concentration of 15%.
| Concentration of Algae Extract (%) | Number of fibroblasts on the third day of treatment | Number of fibroblasts on the seventh day of treatment | Number of fibroblasts on the fourteenth day of treatment |
|---|---|---|---|
| 5% | 69 | 67 | 4 |
| 10% | 120 | 128 | 2.5 |
| 15% | 68 | 173 | 2.92 |
| Control (without cream) | 31 | 89 | 2 |
Furthermore, it was observed that in the group which received the ointment application, the fibroblasts increased and then decreased by the fourteenth day. In the control group, the increase continued until the fourteenth day, indicating a longer and less efficient healing time, as fibroblasts are supposed to give way to the collagen they produce. C. vulgaris would therefore, when applied topically, have the potential toimprove and accelerate wound healing.
The proliferation of fibroblasts in the healing process is naturally stimulated by IL-1β, the platelet-derived growth factor (PDGF) and the fibroblast growth factor (FGF). The content of the ointment based on extract of Chlorella vulgaris applied to animal wounds would stimulate the synthesis of growth factors, particularly FGF, which increases the activity of fibroblastic cells to produce collagen and form connective tissue so that the wound heals quickly.
Benefit No. 4: Green algae enhance skin hydration.
Indah RAYA and her team sought to verify the effectiveness of applying C. vulgaris on rat skin, through measuring skin hydration. The application of a cream containing 20 g of C. vulgaris was carried out once a day on the backs of the test animals. Before and after the massage, moisture was measured using a skin analyser.
Overall, the increase in skin water content in rats coated with C. vulgaris cream was higher than that of the cream without the addition of C. vulgaris. The C. vulgaris cream applied to female rats, for instance, increased the skin water content by 14.6%, while the cream without the addition of C. vulgaris increased the water content by 3.6%. No mechanism has yet been determined.
Sources
VERBEUREN T. J. & al. Chronic venous insufficiency: dysregulation of collagen synthesis. Angiology (2003).
STOLZ P. & al. Manufacturing microalgae for skin care. Cosmetics & Toiletries (2005).
MORVAN P. Y. Effect of Chlorella extract on skin. Personal Care (2007).
ACHMAD H. & al. Effect of the application of Chlorella vulgaris ointment to the number of fibroblast cells as an indicator of wound healing in the soft tissue of pig ears. Pesquisa Brasileira em Odontopediatria e Clínica Integrada (2020).
MORADI A. M. & al. Effect of microalga Chlorella vulgaris extract compared to vitamin C on collagen І and MMP-1 genes expression in human skin fibroblast cells. Journal of Animal Environment (2020).
RAYA I. & al. The effectiveness of Chlorella vulgaris cream applied to male and female rats. National Journal of Physiology, Pharmacy and Pharmacology (2020).
RAYA I. & al. Antioxidant activity of Chlorella vulgaris used as an antioxidant cream. Journal of Physics: Conference Series (2021).
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