Bioprospecting Natural Ingredients Control Inflammaging and Promote Healthy Aging

Prolonged exposure to ultraviolet A (UVA) radiation contributes to skin photoaging by inducing cellular damage, impaired tissue renewal and cellular senescence, potentially contributing to chronic inflammation. Natural bioactive ingredients may represent promising strategies to protect skin homeostasis and promote healthy aging. This study aimed to investigate the safety and potential protective effects of an orchid extract from Cyrtopodium cardiochilum in a UVA-induced senescence model using human keratinocytes (HaCaT). First, extract cytotoxicity was assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay at concentrations ranging from 0.01% to 3% (n=3). Cells were then exposed to single UVA doses of 5 or 10 J/cm² to establish the experimental model. The effects of UVA and extract treatment on cell viability, migration and senescence were evaluated by MTT, scratch assay and immunofluorescence for p16, p21, β-galactosidase and Ki-67, respectively. The extract showed no cytotoxicity at any concentration tested. UVA reduced cell viability, which was not significantly restored by the extract. Initial experiments using extract treatment only after UVA exposure showed no apparent effect on the migration of irradiated cells. Considering the proposed preventive cosmetic application, the protocol was subsequently modified to include 2h of extract pretreatment before UVA exposure, followed by treatment after irradiation. Under this protocol, 0.1% extract accelerated migration of UVA-exposed cells. A single 5 J/cm² UVA exposure increased the expression of senescence-associated markers, while treatment with 0.1% and 0.3% extract appeared to attenuate this phenotype. Scratch and immunofluorescence results are preliminary (n=1). These findings indicate that the extract is well tolerated by HaCaT cells and may protect against UVA-induced functional and senescence-associated alterations, supporting its potential for skin well-aging applications.