Senomorphic Activity of a Novel Standardized Propolis Extract in Human Dermal Fibroblasts: Molecular Insights Into Clinically Proven Anti‐Wrinkle Efficacy

Background We recently demonstrated in a randomized controlled trial (RCT) that a Standardized Propolis Extract (SPE), produced via a patented non‐alcoholic PEG 400/lecithin process, achieves significant clinical anti‐wrinkle efficacy (34% wrinkle depth reduction). The present study investigates the underlying molecular mechanisms, specifically its potential senomorphic activity—the ability to modulate the Senescence‐Associated Secretory Phenotype (SASP) without inducing cell death. Objective To evaluate the senomorphic activity of this chemically defined SPE (standardized to 1318.43 μg/g total phenolic markers) in an in vitro model of oxidative stress‐induced senescence, providing molecular insights into its clinically observed anti‐aging effects. Methods Human Dermal Fibroblasts (HDFs) were pre‐treated with SPE (0.01%, 0.05%) or Rapamycin (3 μM, reference senomorphic control). Senescence was induced via a validated stress‐induced premature senescence (SIPS) protocol (200 μM H 2 O 2 , 2 h). Gene expression for senescence markers (CDKN2A/p16, CDKN1A/p21), SASP cytokines (IL‐6, IL‐8), and cell cycle regulators (CDK4, CDK2, CCNE1) was quantified by qPCR. An exploratory study on Mesenchymal Stem Cells (MSCs) assessed SA‐β‐galactosidase activity qualitatively. Results The 0.05% SPE demonstrated potent senomorphic activity, significantly suppressing the key SASP marker IL‐6 (FC: −7.78, p = 0.003)—comparable to the Rapamycin control (FC: −8.1, p = 0.003). Uniquely, SPE induced transcriptional upregulation of CDK4 (FC: +6.71, p = 0.002) and CDKN1A/p21 (FC: +2.33, p = 0.005), effects not observed with Rapamycin. In exploratory MSC experiments, SPE qualitatively reduced SA‐β‐gal staining. Conclusion This first‐in‐class standardized propolis extract demonstrates distinct senomorphic activity, suppressing the inflammatory SASP (IL‐6) while inducing transcriptional modulation of pro‐regenerative pathways (CDK4). These molecular findings provide mechanistic insights consistent with the extract's clinically proven anti‐wrinkle efficacy, supporting its positioning as an evidence‐based active ingredient for dermo‐cosmetic formulations targeting inflammaging.