Optimization of process parameter for theaflavin extraction from black tea (Camellia sinensis) as an inhibitor potential of rdrp SARS-CoV-2 using response surface methodology

Theaflavins and their derivatives such as theaflavin gallate have shown a broad spectrum of antiviral activity against several viruses, including influenza A B and hepatitis C viruses. Theaflavins could inhibit RdRp activity through blocking the active site in the catalytic pocket of RdRp in SARS-CoV-2, SARS-CoV and MERS-CoV. The extraction process is carried out using distilled water as solvent. The effect of three independent variabels: temperature (70-90°C), time (5-25 minutes), and solvent-solid ratio (30:1 - 50:1) on the extraction process of theaflavin from black tea were investigated. Response Surface Methodology was applied for optimization of the three process parameters and expressed at the second-order polynomial. The research showed that temperature was the most influencing variable for the theaflavin extraction from black tea (Camellia sinesis). The optimal condition for the extraction of theaflavin from black tea were performed at temperature of 90°C, 25 minutes and solvent: solid ratio 50:1 (ml/g). © 2023 Author(s).

Characterization in silico of bioactive compound in tea plant as a potentials inhibitor of SARS-CoV-2 Mpro

One of the screenings of the chemical structure that has the potential as an active major protease (Mpro) inhibitor in SARS-CoV-2 is bioactive compounds, such as oolonghomobisflavan-A, theaflavin-3-O-gallate, and theaflavin (TF). These bioactive compounds are main components of catechin oxidation, which contribute color, taste, and aroma to black tea. Enzymatic oxidation events in black tea processing have started at the beginning of the mill. In silico studies of active site Mpro as an inhibitor of SARS-CoV-2 were conducted using Protein Data Bank from a web platform. This analysis was carried out using the AutoDock Vina software integrated with PyRx 0.8. The molecular docking results were visualized in 3D and 2D with the BIOVIA Discovery Studio software with the result that amino acid residues and chemical bonds formed were visible, indicating the binding site of a target protein. The production of bioactive compounds through the tea fermentation process accelerated the oxidation rate of catechins into the contained bioactive compounds, which was analyzed using a spectrophotometer with a wavelength of 380 nm. Bioactive compound analysis used the response surface methodology. The results of docking the oolonghomobisflavan compound with Mpro indicated the highest binding affinity, namely −8.0 kcal/mol;however, the oolonghomobisflavan compound with Mpro did not show the same interaction as the control. On the contrary, for the docking of theaflavin-3’-Ogallate with Mpro, the binding affinity was −6.3 kcal/mol and showed the same interaction with the control, namely, LysA:137, where the compound formed hydrogen bonds, and analysis of the selected compound was carried out on the theaflavin-3’-O-gallate compound. The optimal operating conditions for the extraction process were at a flow rate of 17.65 l/minute with a fermentation time of 50 minutes, which produced a maximum theaflavin level of 0.938%. © 2022 Mohamad Endy Yulianto et al. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/).

Optimization of UV-photo fermentation conditions theaflavin from tea leaves (Camellia sinensis) using response surface methodology (RSM) as inhibitor in SARS-CoV-2

Theaflavin (TF) is a component of fermented (enzymatic oxidation) catechin compounds synthesized during tea leaf fermentation, giving a golden yellow color, taste, and aroma to black tea. Theaflavins, which are rich in antioxidants, can treat cancer, obesity, diabetes and are potential as an inhibitor in SARS-CoV-2. Photo fermentation using ultraviolet (UV) has the advantage of penetrating the stoma cell wall in tea leaves and accelerating the oxidation of tea leaves that have gone through the milling process before the fermentation stage. This study aimed to optimize the photo fermentation process of theaflavin compounds from fresh tea leaves through response surface methodology (RSM). The highest theaflavin was obtained at a flow rate of 6 L/minute and a long irradiation time of 55 min, with a theaflavin content of 0.6705%. RSM states that the oxygen flow rate is the most influential factor with an R-Square value of 0.60814 means only 60.814% variation in data can be described by the model. (C) 2022 The Authors. Published by Elsevier Ltd.