Standardized Morinda citrifolia L. and Morinda elliptica L. leaf extracts alleviated fatigue by improving glycogen storage and lipid/carbohydrate metabolism.

The antifatigue properties of Morinda elliptica (ME) leaf were compared with Morinda citrifolia (MC) leaf extracts. Sixty Balb/C mice were administered (N = 10): control water, standardized green tea extract (positive control 200 mg/kg body weight [BW]), either 200 or 400 mg MC/kg BW, or either 200 or 400 mg ME/kg BW). The mice performances, biochemical, and mRNA expressions were evaluated. After 6 weeks, the weight-loaded swimming time to exhaustion in the mice consuming 400 mg MC/kg, were almost five times longer than the control mice. The gene expressions analysis suggested the extracts enhanced performance by improving lipid catabolism, carbohydrate metabolism, electron transport, antioxidant responses, energy production, and tissue glycogen stores. The MC and ME extracts enhanced stamina by reducing blood lactate and blood urea nitrogen levels, increasing liver and muscle glycogen reserve through augmenting the glucose metabolism (glucose transporter type 4 and pyruvate dehydrogenase kinase 4), lipid catabolism (acyl-Coenzyme A dehydrogenases and fatty acid translocase), antioxidant (superoxide dismutase 2) defence responses, electron transport (COX4I2), and energy production (PGC1α, NRF1, NRF2, cytochrome C electron transport, mitochondrial transcription factor A, UCP1, and UCP3) biomarkers. The MC (containing scopoletin and epicatechin) was better than ME (containing only scopoletin) or green tea (containing epicatechin and GT catechins) for alleviating fatigue.