Abstract
Skin aging is the most visible element of the aging process, giving rise to a major concern for many people. Plants from the Ericaceae family generally have antioxidant and anti-inflammatory properties, making them potential anti-aging active ingredients. This study aimed to evaluate the safety and anti-aging efficacy of a Kalmia angustifolia extract using reconstructed skin substitutes. The safety evaluation was performed using a 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) assay, while the efficacy was determined by assessing antioxidant and anti-inflammatory activity and analyzing skin substitutes reconstructed according to the self-assembly method by histology and immunofluorescence staining (elastin, collagen-1, collagen-3, aquaporin-3). The cell viability assay established the safety of the extract at a concentration up to 200 μg/mL. The Oxygen Radical Absorbance Capacity (ORAC) assay and a cell-based assay using 2’,7’-dichlorofluorescein-diacetate (DCFH-DA) revealed a strong antioxidant activity with an ORAC value of 16 µmol Trolox Equivalent/mg and a half-maximal inhibitory concentration (IC50) of 0.37 ± 0.02 μg/mL, while an interesting anti-inflammatory activity was found in the inhibition of NO production, with an inhibition percentage of NO production of 49 ± 2% at 80 µg/mL. The isolation and characterization of the extract allowed the identification of compounds that could be responsible for these biological activities, with two of them being identified for the first time in K. angustifolia: avicularin and epicatechin-(2β-O-7, 4β-6)-ent-epicatechin. Histological analyses of skin substitutes treated with the extract showed an increase in dermal thickness compared with the controls. K. angustifolia extract enhanced the expression of elastin and collagen-1, which are usually decreased with skin aging. These results suggest that K. angustifolia has promising antioxidant efficacy and anti-aging potential.
Highlights
We have proven that the skin substitute model developed in our research center is a useful tool for assessing anti-aging efficacy in the dermocosmetic field
We have shown that the K. angustifolia extract seems to be safe for use in cosmetics, and that it has a strong antioxidant capacity and a good anti-inflammatory activity
This study suggests that the K. angustifolia extract at 25 μg/mL could have a potential anti-aging effect on the dermal compartment since the extract increased dermal thickness, and enhanced elastin and collagen-1 expression
Summary
Skin aging is a natural physiological process of concern for many people. It is the first visible sign of advancing age and skin degeneration. The formulation of anti-aging cosmetic products has gained importance in the last few years due to the desire to limit this appearance of aging. Skin aging is characterized by multiple changes at a biological level, which include a decrease in cell proliferation, resulting in epidermal atrophy, and a decrease in dermal components such as fibroblasts and elastin and collagen fibers, and a decrease in dermal thickness in older adults [1,2]. Skin aging is characterized by multiple changes at a biological level, which include a decrease in cell proliferation, resulting in epidermal atrophy, and a decrease in dermal components such as fibroblasts and elastin and collagen fibers, and a decrease in dermal thickness in older adults [1,2]. 4.0/).
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