Plant-Derived Extracts Plus Vitamin E and/or Aloe Vera Protect Against Intrinsic/Extrinsic Stressor in Human Skin: In Vitro and Clinical Evidence.

BACKGROUND: Humans are exposed to physical, biological, chemical, and psychological stressor throughout their life span. In recent years many medicinal plants have been shown to induce stress adapting and protective functions. Plant-derived extracts and vitamin E exhibit stress protection or resistance by normalizing cellular homeostasis and enhancing resistance to toxic stimuli to overcome cellular damage. Here we report the evaluation of a topical preparation (product test materials; PTM) containing an ingredient blend of Rhodiola Rosea, Eleutherococcus Senticosus (Siberian Ginseng), Rhaponticum Carthamoides, Inonotus Obliqus, and Slegainella Lepidophylla as the base formula and tested the addition of Lespedeza Capitata (leaf/stem) extract plus vitamin E and/or Aloe Vera to determine the induced protective functions in human skin when challenged with intrinsic and extrinsic stressors.

METHODS: The base topical preparation plus Lespedeza Capitata extract plus vitamin E or the base topical preparation plus vitamin E and Aloe Vera were assayed in vitro on (a) intrinsically stressed excised abdominoplasty skin, (b) full thickness (FT) skin equivalent models post-treated with a combination of ultra-violet (UV) B light (250 mJ/cm2) and diesel particular matter (DPM) (75 µg/mL) skin, for their effect on antioxidant, inflammation, and stress biomarker geners. Additionally, the bioadaptive activity of the PTMs was confirmed in providing resilience and protection against UV-induced erythema. For example, in a clinical study, daily topical application of the PTMs on the buttocks of 20 woman (18-78 years old), average age of 51.1 years, median body mass index (BMI) of 26.5 for 8 weeks followed by 2 minimal erythema dose (MED) of UVB exposure was accessed 24 hours after irradiation. Statistical analysis was performed by t -test and ANOVA, repectively.

RESULTS: Pretreatment with the topical PTMs on intrsinically stressed skin significantly reduced the expression of the stress gene biomarkers, p53, pro-inflammatory cytokines Interleukin-1β ( IL-1β ) and Tumor Necrosis Factor-α ( TNFα ) and the pro-apoptotic BCL2 associated X, apoptosis regulator (BAX) values compared to controls. Topical application of the PTMs on Full Thickness (FT) human skin treated with UVB light and DPM significantly enhanced the stress response by activating heat shock transcription factor 4 ( HSF4 ) and heat shock protein family B (small) member 1 ( HSPB1 ) gene levels belonging to the heat shock protein ( HSP ) family by significantly increasing the expression of heme oxygenase 1 ( HMOX1 ). At the same time, significantly reducing IL-1β levels were observed plus protection of skin cells from toxicity ocurred by significantly increasing the expression of B-cell lymphoma 2 ( BCL2 ) (anti-apoptotic gene). In the clinical study, daily topical applications of the PTMs for 8 weeks followed by 2MED of UVB irradiation with clinical assessment 24 hours later revealed a significantly reduced intensity of erythema when compared to the buttock region treated with UVB alone.

CONCLUSIONS: The PTMs containing adaptogen ingredients may confer stress resistance and induce stress protective responses against intrinsic as well as extrinsic stressors as demonstrated by the obtained in vitro and clinical evidence.