Essential oil extracted from Hirami lemon (Citrus reticulata var. depressa) agricultural waste promotes mitochondrial biogenesis in C2C12 skeletal muscle cells

With increasing awareness of the circular economy, extracting valuable components from agricultural waste offers opportunities to create high-value products. Citrus reticulata var. depressa (CD), endemic to Taiwan, produces sour fruits mainly for juice, leaving significant peel waste. In this study, we extract essential oil (CDEO) from CD peels and examines its effects on skeletal muscle energy metabolism. ATP measurements and mitochondrial staining show that CDEO enhances ATP content, mitochondrial membrane potential, and mass in C 2 C 12 cells. RT-PCR and Western blot analyses indicate that CDEO activates the p-AMPK/SIRT1/PGC-1α pathway and upregulates Nrf1, Nrf2, and TFAM expression. Among the identified constituents, γ -terpinene was found to be the major bioactive compound, capable of promoting ATP production and mitochondrial biogenesis. Future studies should further investigate mitochondrial function and evaluate its anti-fatigue potential using in vivo models. • This study explores the extraction of essential oil (EO) from discarded Citrus reticulata var. depressa (CD) peels, promoting circular economy principles by transforming agricultural by-products into high-value resources. • γ -Terpinene is identified as the main bioactive component in CDEO, responsible for enhancing ATP production and mitochondrial activity, with potential applications in muscle performance and fatigue reduction. • The essential oil of CD and γ -Terpinene stimulates the p-AMPK/SIRT1/PGC-1α pathway and upregulates Nrf1, Nrf2, and TFAM gene expression, contributing to improved mitochondrial function. • The essential oil of CD increases ATP content, enhances mitochondrial membrane potential, and boosts mitochondrial mass in C 2 C 12 mouse skeletal muscle cells.