Unravelling the comparative metabolite fingerprints and therapeutic effects of diverse teas

Abstract

The comparative metabolite fingerprinting and bioactivity of different teas viz. green tea, oolong tea, white tea, orthodox black tea, and Cut/crush, Tear and Curl (CTC) black tea as compared to unprocessed tea leaves (GTL) were elucidated. The fresh tender tea shoots collected from single location were processed into different tea forms and brewed homogenously. The mass fingerprinting analysis using ultra high performance liquid chromatography ion mobility quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-IMS) revealed substantial variability of key metabolites among different tea brews. Statistical analysis (Venn-diagram, Heatmap and PCA) has revealed significant variation in metabolites content among different teas. Catechins and caffeine were identified and quantified in all infusions using high-pressure liquid chromatography analysis. 2,2-diphenyl-1- picrylhydrazyl (DPPH) free radical scavenging assay, 2,2′-azino-bis (3 ethylbenzothiazoline-6-sulphonic acid (ABTS) radical cation decolourisation assay and ferric-reducing antioxidant power (FRAP) assay unveiled significant antioxidant potential by all the infusions. The results of α-glucosidase inhibition by different teas showed positive effects in management of postprandial hyperglycemia. The tea samples also unveiled significant results for nitric oxide inhibition in lipopolysaccharide-stimulated RAW 264.7 macrophages and cytotoxicity against A-549 and CT26.CL25 cancer cells. Hence, it has established that tea processing has substantial role on key metabolite composition and therapeutic potential of different tea infusions.