A combination of green tea extract and l-theanine (LGNC-07) has been reported to have beneficial effects on cognition in animal studies. In this randomized, double-blind, placebo-controlled study, the effect of LGNC-07 on memory and attention in subjects with mild cognitive impairment (MCI) was investigated.
Ninety-one MCI subjects whose Mini Mental State Examination-K (MMSE-K) scores were between 21 and 26 and who were in either stage 2 or 3 on the Global Deterioration Scale were enrolled in this study. The treatment group (13 men, 32 women; average 57.58 years) took 1,680 mg of LGNC-07, and the placebo group (12 men, 34 women; average 56.28 years) received an equivalent amount of maltodextrin and lactose for 16 weeks.
Neuropsychological tests (Rey-Kim memory test and Stroop color-word test) and electroencephalography were conducted to evaluate the effect of LGNC-07 on memory and attention. Further analyses were stratified by baseline severity to evaluate treatment response on the degree of impairment (MMSE-K 21-23 and 24-26). LGNC-07 led to improvements in memory by marginally increasing delayed recognition in the Rey-Kim memory test (P¼.0572).
Stratified analyses showed that LGNC-07 improved memory and selective attention by significantly increasing the Rey-Kim memory quotient and word reading in the subjects with MMSE-K scores of 21-23 (LGNC-07, n¼11; placebo, n¼9).
Electroencephalograms were recorded in 24 randomly selected subjects hourly for 3 hours in eye-open, eye-closed, and reading states after a single dose of LGNC-07 (LGNC-07, n¼12; placebo, n¼12). Brain theta waves, an indicator of cognitive alertness, were increased significantly in the temporal, frontal, parietal, and occipital areas after 3 hours in the eye-open and reading states.
Therefore, this study suggests that LGNC-07 has potential as an intervention for cognitive improvement.