Well-aging: A new strategy for skin homeostasis under multi-stressed conditions

Abstract

Background: Several studies evidenced significant increase of cortisol is the consequence of UV or emotional stress and leads to various deleterious effects in the skin.

Aim: The well-aging, a new concept of lifestyle, procures an alternative to the anti-aging strategy. We demonstrated that Tephrosia purpurea extract is able to stimulate well-being hormones while reducing cortisol release. Furthermore, we hypothesized that the extract could positively influence the global skin homeostasis.

Method: We evaluated the impact of the extract on cortisol, β-endorphin, and dopamine, released by normal human epidermal keratinocytes (NHEKs). A gene expression study was realized on NHEKs and NHDFs. The protein over-expression of HMOX1 and NQO1 was evidenced at cellular and tissue level. Finally, we conducted a clinical study on 21 women living in a polluted environment in order to observe the impact of the active on global skin improvement.

Results: The extract is able to reduce significantly the cortisol release while inducing the production of β-endorphin and dopamine. The gene expression study revealed that Tephrosia purpurea extract up-regulated the genes involved in antioxidant response and skin renewal. Moreover, the induction of HMOX and NQO1 expression was confirmed on NHDFs, NHEKs and in RHE. We clinically demonstrated that the extract improved significantly the skin by reducing dark circles, represented by an improvement of L*, a*, and ITA parameters.

Conclusion: Tephrosia purpurea extract has beneficial effects on skin homeostasis through control of the well-being state and antioxidant defenses leading to an improvement of dark circles, a clinical features particularly impacted by emotional and environmental stress.

Keywords: Tephrosia purpurea extract; antioxidant; beta-endorphin; cortisol; dopamine; healthy aging; well-aging.

Figure 1

Cortisol release by NHEKs under basal or cortisone‐treated conditions in the presence or not of Tephrosia purpurea extract at 1%. Student's t test in comparison with untreated + cortisone at 1 µmol/L with **P < 0.01

Figure 2

Beta‐endorphin production by NHEKs under basal condition or treated with Tephrosia purpurea extract at 0.0025%, 0.0125%, and 0.0625%. Dibutyryl cyclic AMP at 2 mmol/L was used as a positive reference. Student's t test in comparison to untreated condition, with ** P < 0.01, * P < 0.05

Figure 3

Evaluation of the extracellular content in dopamine release by NHEKs under basal condition and treated with Tephrosia purpurea extract at 1%. Amantadine hydrochloride at 0.1 µmol/L was used as positive reference. Student's t test in comparison to untreated condition, with ** P < 0.01

Figure 4

Genes over‐regulated after 24 h of treatment with Tephrosia purpurea extract at 1% in NHDFs (A) and NHEKs (B). Student's t test in comparison to untreated condition, with *** P < 0.001, ** P < 0.01, and * P < 0.05

Figure 5

HMOX‐1(A) and NQO‐1(B) protein expressions using NHEKs and NHDFs treated with Tephrosia purpurea extract at 1% after 24 and 48 h of treatment, respectively. ANOVA analysis of variance and Dunnett's comparison test comparing treated conditions to their respective control *** P < 0.001, ** P < 0.01, and * P < 0.05

Figure 6

HMOX‐1 and NQO‐1 protein expressions in reconstructed human epidermis (RHE) topically treated for 48 h with Tephrosia purpurea extract formulated in cream at 1%. The quantification of protein expression is proportional to immunofluorescence intensity (green staining) measured using image analysis and converted in arbitrary unit. The percentage of improvement is obtained in comparison to the untreated condition. The significance is calculated with a mix model of ANOVA followed by Fisher statistical test in comparison to placebo for the active and in comparison to DMSO for both positive references with *** P < 0.001 and * P < 0.05

Figure 7

Effect of Tephrosia purpurea extract at 2% after 14 and 28 d of treatment on L* parameter (a), ITA (b) and a* parameter (c). Mixed ANOVA model *** P < 0.001, ** P < 0.01, and * P < 0.05

Figure 8

Illustrative macrophotographie were acquired by Visia CR under crossed polarized light after 28 d of cream application containing Tephrosia purpurea extract at 2% in comparison to a placebo