Skin-Lightening Agent with Different Pathways of Action ... - Dermage

COSMETICS
SKIN-LIGHTENING
To sum up, ET-1 as well as α-MSH control
dendricity and have an influence on
phagocytosis - the transfer of melanosomes
from melanocytes to keratinocytes.
In keratinocytes the melanosomes form
the secondary lysosomes around the keratinocyte
nucleus. Melanosomes in dark
skin differ from those in skin types I and
II, they are larger and packaged as single
units, whereas the melanosomes in fair
skin are smaller and packaged in groups.
During differentiation of keratinocytes
in the Stratum corneum the degradation
of the melanosome unit is much stronger
in skin types I and II than in dark skin,
which generates a kind of »melanin dust
effect« and make these skin types appear
less pigmented (20).
To study the influence of Belides on melanosome
transfer we used a Fluosphere
beads model. For simulation of melanosome
uptake HaCaT cells were irradiated
for phagocytosis stimulation with UV
light. It could be shown that 1.0 or 1.5%
Belides (1 DIV) significantly reduced the
Fluosphere uptake (25.9 and 40.9%
related to cell count), compared to control
cultures (set to 100% uptake), when
the phagocytic activity was monitored
(Fig. 9).
Furthermore, microscopic images taken
from control cultures and cultures preincubated
with Belides showed that a lower
number of FluoSphere beads were accumulated
around the cell nuclei when
the keratinocytes were treated with Belides
(Fig. 10).
The in vitro results demonstrate that Belides
acts as a functional ingredient at
different stages of melanogenesis. By influencing
pathways of action before, during
and after melanin synthesis Belides
effectively reduces skin pigmentation.
Finally, to demonstrate that Belides produces
a noticeable lightening effect on
human skin an initial in vivo study was
carried out on 5 volunteers from the
Philippines (age: 19-39; 4 females, 1 male)
over a period of 4 weeks.
The results show a significant lightening
effect in comparison to the untreated
and placebo areas when oil-in-water formulations
(O/W) containing 2 or 5% Belides
were applied twice daily (Fig. 11).
Already after 14 days of application a
tremendous effect could be observed.
Skin lightening was increased to 20.3
and 30.8% while after 28 days to 19.3
and 31.5% (p < 0.05 versus untreated).
These results show that the whitening
process is complete already after 14 days
and continued application of the active
does not further lighten the skin. Moreover,
a complete knock-out of melanogenesis
could be risky for melanocyte
survival. Therefore, Belides acts as a gentle
modulator of skin pigmentation.
Fig. 10 Microscopic images showing (a) the Fluosphere uptake (red FluoSphere beads,
1.0 µm size) in control and (b) in Belides (1%) treated HaCaT cultures (1 DIV).
For visualization of the phagocytosis cells were counterstained with DAPI (blue
nuclei). Picture images were taken using a Leica DMIL fluorescence microscope
(Leica, Germany; PHAGO 3 oil lense 100 x, excitation filter: 515 - 560 nm)
Fig. 11 Efficacy test on human skin (pilot study) demonstrate the skin-lightening
activity of Belides (chromameter readings). Formulations were applied by 5 volunteers
twice daily on the inner forearm. Values are related to initial conditions
(p