Clinical Trials

Historically man has tried to modify his own skin pigmentation.
Makeup is obviously a temporary solution but consumers often want more:
Black and Asian phenotypes sometimes wish to have their skin lightened
White, red-haired or Asian phenotypes look for ways to attenuate or remove certain hyperpigmentations.
To respond to the needs of this market, Clinica has developed ALL CLEAR:


SKIN AND PIGMENTATION

The melanin cycle is at the heart of skin pigmentation.It is in the melanocytes, cells located in the basal layer of the skin, that the pigment responsible for skin coloration is synthesized: the melanin

Its principal role is to protect the skin from the sun’s radiations.These substances proved the natural protection that filters the sun’s rays after they cross the stratum corneum.

Skin coloration will mainly depend on the type (eumelanin or phaeomelanin) and quantity of melanin produced.

  • The black phenotype has naturally intense eumelanic pigmentation.Therefore, they enjoy optimum photoprotection.
  • The white and Asian phenotypes also have eumelanic pigmentation, but less intense.Therefore, the quality of their photoprotection varies greatly.
  • Finally, the red-haired phenotype have a phaeomelanic pigmentation, which affords no photoprotection.


MELANIN METABOLISM

Two types of melanins are synthesized from the same starting amino acid, which is then oxidised to DOPA (DihydrOxyPhenylAlanine), then to Dopaquinone, by the action of a specific enzyme, Tyrosinase.The two metabolic pathways then split to produce either eumelanin or phaeomelanin.

Melanin is synthesized inside the melanosomes, which are contained in the melanocytes.These organelles are then transferred into the neighbouring keratinocytes, where they deliver melanin.

The melanin will then be degraded in the white and re-haired phenotypes, partially degraded in the Asian phenotype and will remain almost intact in the black phenotype, explaining their excellent photoprotection.

The regulation of melanin synthesis is the result of the complex influence of multiple parameters :
genetic factors, nutrition, endorcrinology, age, microcirculation and sun exposure…


ALL CLEAR :

AN INTELLIGENT SYSTEM


ALL CLEAR combines the benefits of different components which act at different levels.

This patented system consists of a fraction obtained by fermentation (kojic and lactic acids), a licorice extract and TRANSCUTOL®.

A: The kojic acid present in Gatuline® Whitening acts on the melanocytes to inhibit the tyrosinase activity, therefore reducing melanin synthesis.This was demonstrated by in vitro and ex vivo tests.

B: The effect of kojic acid would be facilitated in vivo by the presence of TRANSCUTOL®, an absorption enhancer that improves the penetration into the epidermis and creates a reservoir at the dermal-epidermal junction.This is particularly interesting for this application because the melanocytes are located in the basal layer of the epidermis.

C: The presence of an A.H.A., lactic acid, would influence cell renewal and, therefore, would contribute to melanin degradation in the most superficial layers of the epidermis.

D: Finally, the presence of licorice extract in this system allows for all the benefits of the other components and for a perfect tolerance profile.These soothing properties of licorice extract are due to the presence of glycyrrhetinic acid.

SUBSTANTIATION

The efficacy of ALL CLEAR was evaluated using several substantiation tests:

  • Preliminary evaluation of cytotoxicity
  • In vitro and ex vivo effects on tyrosinase activity
  • In vivo effect on skin coloration
  • In vivo effect on age spots.


EVALUATION OF CYTOTOXICITY

On human fibroblast culture

A preliminary study was performed on human fibroblast culture.The method consists of an evaluation of the cytotoxicity of the product by a Neutral Red assay (membrane integrity) and by an MTT test (mitochondrial succinyldehydrogenase activity) after 48 hours of incubation with different concentrations of the test product.

At concentrations £5 ,mg/ml in the culture medium,Gatuline® Whitening does not produce any significant changes in cellular viability.

On human melanocyte culture

The results of this preliminary study on fibroblasts allowed the determination of the concentration range to be applied to the target cells, the melanocytes.The cytotoxicity was evaluated by a Neutral Red assay after 72 hours of incubation.
Gatuline® Whitening was shown to have a low cytotoxicity, with a IC50 of 20.5 mg/ml.

LOW CYTOTOXICITY

IN VITRO EFFECT ON TYROSINASE ACTIVITY (ENZYMATIC METHOD)


Protocol

This method is based on the action of tyrosinase, which transforms DOPA into Dopaquinone.The kinetics of this reaction can be followed by spectrophotometry at 475nm.The influence of the addition of Gatuline® Whitening is evaluated compared to a reference representing 100% tyrosinase activity, equivalent to 0% inhibition.

Results

Tyrosinase inhibition (%)
Gatuline® Whitening (%)


Conclusion

The IC50 (Inhibitory Concentration 50) for Gatuline® Whitening is 0.04%, which is evidence of a strong capacity to inhibit tyrosinase.

In comparison, one would need a concentration 6% hydroquinone to attain the same results, but this would cause solubility and cytotoxicity problems.

This test also allowed confirmation of the excellent reproducibility of the activity on three different batches.


STRONG CAPACITY TO INHIBIT TYROSINASE IN VITRO


Ex vivo effect on Tyrosinase (human melanocyte culture)

Protocol

Tyrosinase activity was evaluated on human melanocyte culture, in contact with several concentrations of Gatuline Whitening, from 0.1 to 10mg/ml.

The optical densities measured at 490nm were converted to a “tyrosinase equivalent”
By comparing them to a standard curve using purified tyrosinase as a reference, then recalculated according to the amount of cellular proteins present.

Results

Tyrosinase Equivalents
(mU/µ g proteins)
Gatuline® Whitening (%)


Conclusion

The Efficacy Concentration 50 (EC50) is 4.55 mg/ml.


STRONG CAPACITY TO INHIBIT TYROSINASE EX VIVO


In vivo effect on skin colour

Protocol

10 human volunteers (Asian phenotype) applied on the forearms a cream containing 10% of Galutine® Whitening and a placebo without active, twice a day over a period of one month.


Method and instrumentation

Colorimetric measurement of the skin is obtained using CR 321 Chromameter, which transforms colours perceived in the spectrum of visible light into a digital code made up of three parameters:

L* : clarity (luminance)
a* : red to green spectrum
b* : blue to yellow spectrum

Parameters a*indicates the skin irritation degree. Therefore only the parameters L* and b* will be considered through the determination of the Individual Typological Angle (ITA°), which defines the skin pigmentation degree.

ITA° = {Arc tan L* – 50} x 180

b*pie

<10= very pigmented
10° – 28° = pigmented (dark)
28° – 41° = medium
41° -55°= clear
>55°= very clear


Results

Lightening percentage variations of means (Æ%) are calculated and proved the following results.

Even though sunny conditions induced a skin pigmentation of the placebo by 6%, a slight lightening of the treated zone by +0.6% was observed.

The lightening variation (Æ%) as a percentage of ITA variation obtained with the cream containing 10% Gatuline® Whitening versus the placebo without active was determined.

Æ% allows data already corrected from the variations due to the sunny conditions to be obtained.

The relative lightening of the skin between the treated area and the placebo area is 8.5%, corresponding to a positive effect on 64% of the panellists.


VISIBLE SKIN LIGHTENING


In vivo effect on age spots

Protocol

10 human volunteers (white phenotype) with age spots, applied on the hands a cream containing 10% of Gatuline Whitening and a placebo without active, twice a day over a period of one month.

Colorimetric measurement of the skin is achieved following the previously described method.

Results

Lightening percentage variations of means (Æ%) are calculated and provide the following results:

After a 30 day treatment, the lightening percentage of the spot on the area treated with the cream containing 10% Gatuline ®Whitening is 6% while the skin has darkened by 1% using the placebo without active.

However, one is mostly concerned with an evening of the skin colour instead of lightening the age spot itself.This is the reason why pigmentation discrepancy (ITA%), meaning the difference between the spotted zone and the non-spotted zone nearby, was determined.

The pigmentation discrepancy between the spotted zone and the non-spotted zone nearby was significantly (p=0.03) reduced by 11% using the cream containing 10% Gatluline® Whitening, while it was increased by 8% using the placebo without active.