# 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

## TL;DR

A 12-week clinical trial found that a purple perilla leaf extract improved cognitive function in people with cognitive impairment, without safety issues.

## Contribution

This study provides clinical evidence for the efficacy and safety of a standardized purple perilla leaf extract in cognitive impairment.

## Key findings

- PE improved cognitive function scores more than placebo in multiple domains.
- No significant changes in plasma Aβ or BDNF levels were observed.
- No safety concerns were identified during the intervention.

## Abstract

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.