In Vitro Characterization of Hom pathum Rice Extract and Exploratory Evaluation of an Extract-Containing Facial Mask in Adults Aged 30–50 Years: A Randomized Controlled Trial

This study characterized the in vitro properties of a Hom pathum rice extract and explored the clinical performance of a facial mask containing the extract. In this single-center, assessor-blinded, two-arm randomized controlled trial, 60 patch-test-negative healthy adults aged 30–50 years were allocated 1:1 to a no-treatment control group or to a treatment group that applied a multi-ingredient facial mask containing 0.27% (w/w) Hom pathum rice extract for 30 min twice weekly for 12 weeks. Hydration, elasticity, oiliness, melanin, and erythema were assessed at the forehead, cheek, and chin. Complete-case week-12 comparisons used ANCOVA adjusted for the corresponding baseline value, age, and sex, followed by Benjamini–Hochberg correction across the 15 between-group comparisons. Forty-nine participants completed follow-up (control, 24; treatment, 25). The ethanolic extract showed 55% DPPH radical-scavenging activity, an IC50 of 2.29 ± 0.02 mg/mL, and a total phenolic content of 0.01 ± 0.00 mg GAE/mg extract; total flavonoids were below the assay detection limit at 5 mg/mL. Six comparisons were nominally significant, of which three remained significant after false-discovery-rate correction: higher forehead hydration (adjusted mean difference, 9.42 AU; 95% CI, 2.79 to 16.06; p = 0.007; q = 0.033), lower chin oiliness (−33.15 μg/cm2; 95% CI, −52.40 to −13.89; p = 0.001; q = 0.022), and lower cheek melanin (−68.65 AU; 95% CI, −112.89 to −24.41; p = 0.003; q = 0.026). However, none of the 15 comparisons reached nominal or FDR-adjusted significance in the intention-to-treat multiple-imputation sensitivity analysis (all p ≥ 0.092). No intervention-related adverse effects were recorded among the enrolled patch-test-negative participants. These findings apply to the formulation and application procedure as a whole and were not statistically confirmed in the intention-to-treat sensitivity analysis; they therefore warrant confirmation in an adequately powered, double-blind, vehicle-controlled trial with a prespecified primary outcome. ClinicalTrials.gov: NCT06475222. Funding: Burapha University, Thailand Science Research and Innovation, and the National Science Research and Innovation Fund.