This double-blind, randomized, parallel groups study was conducted to investigate the effects of a lipid extract of Zanthoxylum armatum DC. (ZA) on cognitive function, mood and cerebral blood-flow (CBF) parameters in the pre-frontal cortex during cognitive task performance.

To do so, 82 healthy males and females (aged 30 to 55 years) received a single dose or were supplemented for 56 days with either a placebo or 2.8 g of ZA medium-chain triglyceride (MCT) oil extract (corresponding to 80 mg ZA extract).

Results showed that a single dose of ZA (Day 1) had acute improvements on a ‘Speed of Attention’ factor and the Rapid Visual Information Processing (RVIP) task, in comparison to placebo. However, following ZA participants were less accurate on the name-to-face recall task. After 56 days of ZA consumption (Day 56), speed was enhanced on a global ‘Speed of Performance’ measure. Participants also completed more correct Serial 3s Subtractions at the 3 hours assessment and were less mentally fatigued throughout the day than participants consuming placebo. These effects were complemented on both Day 1 and Day 56 by modulation of cerebral blood-flow parameters. In conclusion, Zanthoxylum armatumimproves aspects of cognitive performance (speed of performing tasks) and reduces hemodynamic responses in the frontal cortex during task performance in healthy humans.

Kennedy D, Wightman E, Khan J, Grothe T, Jackson P. The Acute and Chronic Cognitive and Cerebral Blood-Flow Effects of Nepalese Pepper (Zanthoxylum armatum DC.) Extract-A Randomized, Double-Blind, Placebo-Controlled Study in Healthy Humans. Nutrients. 2019;11(12):E3022.