Mechanisms underlying the protective effects of San-Bai decoction against UV radiation on the skin.

Summary

A TCM-derived topical extract (USBT2627) demonstrated photoprotective efficacy in a double-blind, placebo-controlled clinical study, improving colorimetric measures (L*, ITA°) and reducing erythema under UV challenge. Integrated in silico/in vitro/in vivo evidence, including transcriptomics, implicates modulation of ET-1, pigmentation, oxidative, and cytokine signaling pathways.

Key Findings

• In a double-blind, placebo-controlled clinical study, 5% USBT2627 increased L* (p=0.048) and ITA° (p=0.022) and reduced erythema (p=0.016) under UV exposure.
• USBT2627 suppressed melanin accumulation in a pigmented 3D skin model, indicating in vitro skin-lightening activity.
• Transcriptomic profiling revealed modulation of ET-1 signaling, pigmentation pathways, oxidative response, and cytokine signaling.
• Network pharmacology linked >800 potential targets to SBD components, supporting a multi-target mechanism.

Clinical Implications

Suggests a potential adjunctive topical photoprotective strategy; supports integrating transcriptomic readouts into early-phase cosmeceutical evaluation. Counseling can include measurable benefits on erythema and color metrics.

Limitations

• Clinical sample size and duration were not specified, limiting generalizability and long-term inference
• Complex multi-component extract complicates attribution to specific actives and dose–response characterization

Future Directions

Larger, longer RCTs with standardized UV challenge and head-to-head comparisons versus established photoprotectives; fractionation studies to identify active moieties and dose–response relationships.