Effects of refining process on Camellia vietnamensis oil: Phytochemical composition, antioxidant capacity, and anti-inflammatory activity in THP-1 macrophages

This study aimed to explore the changes in phytochemical composition and inflammatory response of Camellia vietnamensis oil (CO) during refining. Four refined CO samples [degummed (DGO), deacidified (DAO), decol-orized (DCO), and deodorized (DOO)] were prepared from crude CO (CCO). Five CO samples were measured for their composition of fatty acids, sterols, tocopherols, polyphenols, and oxidation products as well as anti-inflammatory activity in lipopolysaccharide (LPS)-induced THP-1 macrophages. The content of phytochemi-cals was significantly decreased with the deepening of the refining degree, especially after deacidification. CCO and DGO showed anti-inflammatory activity by inhibiting the production of pro-inflammatory cytokines and activation of NF-kappa B induced by LPS. Deacidification and decolorization of CO decreased its anti-inflammatory activity. The accumulation of oxidation products after deodorization in CO aggravated the inflammatory response. Trans-cinnamic, kaempferol, and protocatechuic acid in CO were crucial for their anti-inflammatory effects. These findings underlined that moderate refinement is suggested to retain its bioactive ingredients and anti-inflammatory ability.