Exploring the microbiota-skin-brain axis: Chicory extract biotransformed into a postbiotic neurocosmetic enhancer of...

Measuring the influence of cosmetic ingredients on the microbiota-skin-brain axis is a difficult challenge. Here, we try to build a connection between the commensal S. epidermidis, its post-biome, influence on neurotransmitter release in skin and emotional response to the use of an extract from Cichorium intybus.

Measurement of skin evenness with physical measurements, objective and subjective perception. Measurement of emotional arousal with galvanic skin response, advanced facial and eye tracking system, and electro encephalography. Of note, not only were the subjects investigated but also the person caressing the treated subjects. The influence of the skin's microbiota was determined using a 3D epidermal skin model, a keratinocyte/neuron coculture, and bacterial cultures.

C. intybus extract leads to smooth skin and positive excitement of subjects using the cosmetic formulation. Additionally, it evoked positive emotions in a person caressing the treated skin. Treatment of Staphylococcus epidermidis with the extract induced the secretion of bioactive post-biotics that promote neurotransmitter release, suggesting a potential stimulatory effect on neuronal activity. Given that this bacterial stimulation does not involve proliferation, we define this prebiotic state as 'activated rest.'

C. intybus extract is a candidate to elucidate the complex relationship between skin microbiota, skin perception, and emotional response of subjects using cosmetic products, even influencing social interaction on others.