Investigation of antioxidant, cytotoxic, tyrosinase inhibitory activities, and phenolic profiles of green, white, and black teas

Abstract

Objectives To determine of antioxidant, cytotoxic and tyrosinase inhibitory (TI) activities, and phenolic profiles with a new high performance liquid chromatography (HPLC) method of green, white and black teas. Methods Antioxidant activities of the teas were examined by means of scavenging of the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), and cupric reducing antioxidant capacity (CUPRAC). The phenolic contents were investigated by means of HPLC. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to evaluate the cytotoxic potential of tea extracts in cancer and normal cell lines. TI activity was investigated against diphenolase (DOPA), using kojic acid as a positive control. Results The green tea extract exhibited stronger antioxidant than white and black tea extracts. The green tea contained syringaldehyde, p-coumaric acid, benzoic acid, and quercetin. The white tea extract had the highest tyrosinase inhibitor activity. The extracts exhibited higher cytotoxic potential toward cancer cells than normal cells. The methanol extract of green tea had the highest cytotoxic potential, while the water extracts were less toxic. Conclusion The green, white, and black teas can be regarded as an important in terms of rich antioxidant, tyrosinase inhibitor, and cytotoxic activities in both the pharmaceutical and food industries.

Biological activity, and volatile and phenolic compounds from five Lamiaceae species

“…The method developed by Korkmaz et al was used for the detection of benzoic acid, p‐OH benzoic acid, quercetin, coumaric acid, sinapic acid, syringaldehyde and vanillic acid compounds in the extract prepared in methanol (10 mg/mL) 37 . HPLC device from Shimadzu Corporation, LC 20AT, Kyoto, Japan, was used in the HPLC analysis with C18 column (150 × 4.6 mm, 5 μm, Zorbax).…”

Determination of Phenolic Contents by HPLC, and Antioxidant, Antimicrobial, Antityrosinase, and Anticholinesterase Activities of Psephellus huber-morathii

“…Signals were identified at 232, 246, 260, 270, 280, 290, 308, and 328 using DAD detection at a column temperature of 25ºC. HPLC analyses were carried out using validated and modified methods in our previous study [20,21].…”

“…The antioxidant activities of extracts have been assessed by Ferric reducing antioxidant power (FRAP), cupric reducing antioxidant capacity (CUPRAC), and 2,2-diphenylpicrylhydrazyl (DPPH) radical scavenging. Phenolic constituents were measured using reverse phase-high performance liquid chromatography (RP-HPLC), and Korkmaz et al; JPRI, 26(1): 1-10, 2019; Article no.JPRI.47659 2 antimicrobial activity was investigated using the agar well diffusion method. Total phenolic content, FRAP, and CUPRAC results of aqueous extract have been better than methanolic extract, except for DPPH activity.…”

Antioxidant, Antimicrobial, Cytotoxic, Anticholinesterase, Antityrosinase Activities and Characterisation of Volatile Compounds of Verbascum oocarpum by SPME and GC-FID/MS

“…Vanillic acid, p-hydroxy benzoic acid, syring aldehyde, p-coumaric acid, sinapic acid, benzoic acid and quercetin standards were used for HPLC analysis [6]. Stock solutions of the prepared standards were diluted at concentrations of 5-100 µg mL -1 to produce calibration curves.…”