The Effect of Adding Different Tea Powders on Bioactive Compounds, Antioxidant and Anti-Inflammatory Activities of Coconut Latte in THP-1 Macrophages via NF-κB Pathway

This study aimed to evaluate the effects of adding teas to coconut latte extracts’ (CLs) bioactivities by measuring free radical scavenging ability, polyphenol content, and inhibition of lipopolysaccharide (LPS) induced inflammation in THP-1 macrophages (human monocytic leukemia cell line).

Antioxidant activity was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH)•, 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS)+, and ferric reducing antioxidant power (FRAP) assays. The anti-inflammatory effects and underlying mechanisms were investigated by measuring cytokine secretion, gene expression, and key protein levels. Polyphenols were identified and quantified by LC-MS/MS.

The total contents of phenols and flavonoids, and antioxidant capacity of coconut latte extracts (NCL) were significantly increased by coconut latte with black tea extract (BCL), coconut latte with oolong tea extract (OCL) and especially coconut latte with green tea extract (GCL). NCL showed few anti-inflammatory activities by decreasing (increasing) the transcription of COX2, IL13, IL8, and IL10 Heme oxygenase-1 (HO1) and Interleukin-1β (IL-1β) secretion, which were significantly increased by three tea CLs, especially GCL, via greater inhibition (enhancement) of all above genes (except IL13) and transcriptions of IL1B, IL6 (NRF2), inhibition of phosphorylated NF-κB and tumour necrosis factor (TNF-α) expression. Sixteen key polyphenols were quantified in CLs and increased significantly in three tea CLs (greatest in GCL). Correlation analysis suggested the crucial role of polyphenols in CLs’ bioactivities.

The tea, especially GCL, increases the functionality of the coconut latte, which is helpful for developing functional coffee.