A new and original source has recently been found as the result of collaboration between extraction research experts and the brewery industry. Using an innovative and patented extraction process, the polyphenols have been collected from malted barley at the end of the fermentation process, giving a highly rich composition that demonstrates free-radical quenching and whitening activity.
A nutritious source
Barley, otherwise known as Hordeum vulgare, is a cereal grain belonging to the family of grass. One of the most grown cereals in the world, it can adapt to a large variety of climates, from sub-Arctic to sub tropical. This capacity to be grown locally makes barley a crop with a positive environmental impact. Bursting with nutritional properties and particularly high protein content, it plays a major role in animal nutrition but also provides a source of fermentable material for beer, distilled drinks and other food products. When barley is used for malt, the barley is steeped in water, under controlled conditions, causing it to germinate. At this stage it is known as green malt. This is then dried or roasted in a kiln, a process called kilning, which stops the germination. The barley, previously hard and rich in insoluble starch, at this stage is transformed into malt, a more friable grain that is rich in soluble compounds. Most malt production is used to produce beer and other alcoholic drinks with a small quantity used by the food industry in cake and bread production. In the production of beer, the malt is stirred in heated water and the starch content is transformed into sugar. After diverse mixing and filtering steps, the mixture is cooled in an exchanger at the desired temperature of fermentation and yeast is added to transform the sugar into alcohol, flavours and carbonic gas. Once matured, the beer is filtered to eliminate solids but often, despite this filtration step, the beer remains cloudy, in particular at low temperatures due to association of malt polyphenols with proteins. These polyphenols, undesirable in the beer due to the cloudiness, are an incredibly rich source of antioxidants. By adsorption onto a resin then a patented desorption process, this rich composition, rather than be discarded, can now be extracted, concentrated and brought to the cosmetic industry as a powerful skin care active. Once the malt polyphenols are desorbed from the resin they are collected in a water/propanediol medium which has the advantage of not requiring addition of preservatives for storage. The commercial name of this product is Malt Secrets. One hundred per cent natural, Malt Secrets is approved by Ecocert Greenlife to be used in ecological and organic cosmetics.
Unique composition
The biological properties of this fully natural active stem from its unique composition in polyphenols. Polyphenols are proven multifunctional actives that act as antioxidants, stabilising collagen and elastin and protecting from the dangerous effects of UV.1,2 The malted barley treated with this specific manufacturing process yields a precise polyphenol blend of a particularly rich nature. The polyphenols of Malt Secrets belong to a family called Oligomeric Proanthocyanidins (OPC). Procyanidins are very active molecules that have been highly studied and have been used as nutritional and therapeutic supplements since the 1980s. They are also known to contribute to anti-ageing and wrinkle protection, enhancement of microcirculation and even hair loss reduction.3,4,5 OPC with a low polymerisation degree have been shown to have better biological efficacy than larger molecules.6 In the case of Malt Secrets (now referred to as ‘the malted barley active’), the composition is particularly concentrated in procyanidin A2, a procyanidin dimer of low molecular weight and high efficiency (Fig. 1). It also contains the monomers of procyanidins (catechin, epicatechin) and proanthocyanidin polymers (condensed tannins) alongside a high concentration of ferulic acid. Ferulic acid (hydroxycinnamic acid, Fig. 2) is a well known key ingredient for numerous applications. Ferulic acid, like many phenols, is an antioxidant and can reduce oxidative stress in the skin.7,8 Ferulic acid acts also on the most classical depigmentation pathway: it is considered as a powerful reducer that inhibits the oxidation that drives melanogenesis.
Proven antioxidant activity
Chronological ageing and extrinsic ageing both generate oxidative stress which translates into production of reactive oxygen species (ROS) inside the cells. ROS lead to damaging effects through an oxidative aggression towards all biological macromolecules resulting in the disruption of their integrity and functionality within the skin. Lipid peroxidation is a well known consequence of this oxidative stress, affecting skin lipids, whether on the surface (squalene) or in deeper layers (polyunsaturated fatty acids in membrane phospholipids). It is a chain reaction initiated by, among other things, the singlet oxygen (1O2), a reactive species of oxygen mainly produced by UVA. In biochemical tests, the malted barley active complex demonstrates an ability to inhibit the formation of singlet oxygen with a dose-dependent effect (Fig. 3). Another reactive species involved in the oxidative phenomenon, the superoxide anion (O2•–), is also inhibited by the malted barley active. The anti-radical activity against this anion is dose dependent and effective from only 0.1% of the product (Fig. 4). These results illustrate the antioxidant efficacy of the barley malt product towards the two major Reactive Oxygen Species that initiate the oxidative cascade. As a consequence, this complex should protect the skin’s lipids against free radical damage. Another test, based on the oxidation of arachidonic acid, has been conducted to demonstrate anti-lipoperoxidant activity. This test can demonstrate the potential of an ingredient to protect skin lipids from oxidative stress. The results for the malted barley active complex are shown in Figure 5. The results show a strong inhibition of lipid peroxidation from only 0.5% of the malted barley active with a dose-dependant effect. To complete these studies and evaluate the global anti-radical activity, a DPPH test was carried out. The results, given in Figure 6, clearly show strong anti-radical activity at very low concentrations. In all four of these tests, the liquid extraction medium (propanediol/water) was tested in parallel and in no cases showed antioxidant properties. The entire activity can be attributed to the OPC rich polyphenol blend obtained from the malted barley.
Lightening efficacy
Lightening cosmetics are steadily increasing their part of total sales of the personal care market. Initially used exclusively to whiten the skin, now the range of applications has increased in particular to treat dark spots and uneven skin complexion. An abnormal increase in the quantity of melanin in the epidermis is the main cause of hyperpigmentation. Sun exposure, reactive oxygen species and the ageing process are all well known to produce such pigmentation spots, but the mechanism is not always fully understood. Brightening actives can act on the production and metabolism of melanin in the skin by inhibiting melanin production in melanocytes or limiting the diffusion of melanin pigments in the epidermis. Some natural compounds are known to reduce melanin production but particular attention should be paid to the toxicity of such molecules as some efficient whiteners such as kojic acid present toxicity disadvantages. The malted barley active contains polyphenols and ferulic acid, both of which are known in the literature to act on melanin production. The efficacy of this active was therefore studied using an in vitro method. The malt complex was tested versus placebo on melanocytes (B16 cell line) using NDP-MSH ([NLe4, D-Phe7]- -melanocyte stimulating hormone trifluoroacetate salt), a stable analog of the natural hormone -MSH which stimulates pigmentation. The placebo, propanediol and water, was the vehicle used to collect the polyphenols. Kojic acid was used as a positive control. Melanocytes were seeded in 96-well plates and cultured according to standard protocol. Cells were incubated for 72 hours with the test compounds. The results are shown in Figure 7. The total quantity of melanin was evaluated measuring the absorbance at 405 nm of each sample. Results are expressed as percentage of inhibition of melanin compared to control stimulated by MSH. The malted barley active, used at 1%, totally inhibits the melanin synthesis induced by NDP-MSH. There is a clear dose response effect and the placebo has no activity. The difference between the malted barley active and placebo is highly significant. This active not only inhibits the melanin synthesis induced by NDP-MSH, but also reduces the basal melanin content. Cell viability (MTT assay) was evaluated on cell monolayers. The results are given in Figure 8. Indeed, kojic acid which is recognised as a very efficient whitening agent presents toxicity problems. This ingredient is banned in many countries worldwide. On the contrary, the malted barley composition is totally safe, with no cytotoxic effect whatsoever at the recommended use levels, while kojic acid used at 0.32% damages 80% of the melanocytes. The lightening activity of the malted barley active is therefore not due to an effect on cell viability but a true activity on the melanogenesis pathway. This melanin synthesis inhibiting activity alongside the antioxidant efficacy is a new and powerful treatment to prevent the appearance of hyper pigmentation and age spots.
Conclusion
The brewing of barley is able to provide the cosmetic industry with a new source of active. Collaboration between extraction experts and a brewer has allowed the collection and concentration of the malt polyphenols, normally discarded during the production of beer. This ecologically designed and sustainable ingredient named Malt Secrets demonstrates interesting activity on the skin. The malt complex, rich in proanthocyanidins dimers and ferulic acid, has a wide reaching antioxidant and antiradical activity. Tested against the reactive oxygen species (ROS) singlet oxygen radical and superoxide radical, Malt Secrets shows high efficacy at low amounts with a dose dependant effect. Tests also show a strong inhibition of lipid peroxidation and overall anti-radical activity. A whitening efficacy has also been demonstrated on this active. Tested on melanocytes, Malt Secrets, used at 1%, totally inhibits MSH induced melanin synthesis with a clear dose response effect. Totally natural, sustainable and validated by certification bodies such as Ecocert Greenlife, this new active shows potential for anti-ageing lines and all cosmetic products destined to fight pigmentation disorders.
References
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