Efficacy and Safety of Standardized Ethanol Extract of Purple Perilla (Perilla frutescens Britton var. acuta Kudo) Leaves in Cognitive Impairment: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial.

Objectives

This randomized, double-blind, placebo-controlled 12-week clinical trial evaluated the efficacy and safety of a standardized ethanol extract of purple perilla leaves (Perilla frutescens Britton var. acuta Kudo; PE) in adults with cognitive impairment.

Methods

Subjects who met the inclusion criteria were randomly assigned in a 1:1 ratio to one of two groups and received PE (n = 50, 500 mg/day) or placebo (n = 50) for 12 weeks. The primary efficacy outcomes included cognitive function, which was assessed by the Korean mini-mental status examination-2 (K-MMSE-2) and the Alzheimer's disease assessment scale-cognitive subscale (ADAS-Cog), and plasma amyloid β (Aβ) and brain-derived neurotrophic factor (BDNF) levels, which were measured as secondary biochemical markers. The safety biomarkers were also assessed before and after the intervention.

Results

After 12 weeks of intervention, the K-MMSE-2 total score, the K-MMSE-2 subdomain scores (attention and calculation and language), the ADAS-Cog total score, and the ADAS-Cog subscale scores (word recall, commands, delayed word recall, naming, word recognition, and recall instructions) showed statistically significant between-group improvements compared with the placebo group. Improvements were observed in both groups, whereas the magnitude of cognitive enhancement was greater in the PE group, indicating an effect beyond placebo-related responses. No statistically significant between-group differences were observed in plasma Aβ or BDNF levels. The safety evaluation found no clinically significant changes.

Conclusions

Twelve-week administration of PE significantly improved cognitive outcomes without safety concerns, suggesting its potential as a standardized botanical ingredient for supporting cognitive function in individuals with early cognitive impairment.