scholarly journals VALIDATION OF ANALYTICAL METHOD AND INVESTIGATION INTO THE EFFECTS OF BREWING TEMPERATURE ON TOTAL POLYPHENOL CONTENTS IN TEA INFUSIONS PREPARED FROM VIETNAMESE TEA PRODUCTS

2021 ◽  
Vol 18 (6) ◽  
pp. 993
Author(s):  
Nguyễn Công Hậu ◽  
Lê Thị Anh Đào ◽  
Nguyễn Phạm Như Quỳnh ◽  
Nguyễn Thành Nho
Keyword(s):  
Gallic Acid ◽  
Analytical Method ◽  
Viet Nam ◽  
Total Polyphenol ◽  
Tea Infusions ◽  
Validation Of Analytical Method

 Sản xuất từ lá của cây Camellia sinesis L. (Kuntz), trà được xem là một trong những thức uống phổ biến nhất trên thế giới và cây trà được trồng ở khoảng 30 quốc gia. Trong nghiên cứu này, phương pháp Folin-Ciocalteu được áp dụng để xác định hàm lượng polyphenol tổng (quy về milli đương lượng gam của gallic acid, GAE) trong các mẫu trà thành phẩm (ba mẫu trà cổ thụ bao gồm trà đỏ, trà xanh, trà trắng và một mẫu trà oolong) dựa trên ISO 14502-1:2005 với một số thay đổi, cụ thể là chiết một lần bằng dung môi chiết methanol:nước (7:3, v/v) có sự hỗ trợ của siêu âm ở 70 oC với tỉ lệ chiết 0.200:10.00 (g:mL). Phương pháp phân tích được thẩm định trên thiết bị UV-Vis 1800 của hãng Shimadzu với độ tuyến tính phù hợp (R2 > 0.995), khoảng tuyến tính 10-70 mg GAE L–1, độ lặp lại và độ tái lặp tốt (%RSD lần lượt là 0.79 và 1.2% cho độ lặp trong ngày và giữa các ngày) và tỉ lệ phục hồi cao (trên 98% cho các mẫu thêm chuẩn). Hàm lượng polyphenol tổng (giá trị trung bình tính bằng mg GAE g–1 khối lượng khô trong dấu ngoặc đơn) thể hiện xu hướng giảm dần giữa các mẫu trà, cụ thể trà trắng (206.62)  trà xanh (201.33) > trà đỏ (167.42) > trà oolong (139.18) do sự khác biệt về mức độ oxy hoá trong quá trình lên men, đặc biệt đối với trà đỏ và oolong. Hàm lượng polyphenol phóng thích vào nước trà thể hiện xu hướng chung tăng dần khi tăng nhiệt độ pha trà, ngoại trừ mẫu trà oolong có xu hướng riêng, có thể do cấu trúc “cuộn xoắn” của loại trà này, dẫn đến thời gian ngâm trà cần phải dài hơn để polyphenol có thể được phóng thích ổn định và hoàn toàn. Nghiên cứu này đóng góp một phần khiêm tốn để làm giàu thêm dữ liệu cho các sản phẩm trà Việt Nam trong bối cảnh lượng trà sản xuất và xuất khẩu cao.  

PHYTOCHEMICAL CONSTITUENTS, ANTIOXIDANT ACTIVITY AND ACUTE ORAL TOXICITY OF POMEGRANATE (PUNICA GRANATUM L.) FRUIT PEEL EXTRACT

2019 ◽  
pp. 7-14
Author(s):  
Hai Trieu Ly ◽  
Tuan Anh Vo ◽  
Viet Hong Phong Nguyen ◽  
Thi My Sa Pham ◽  
Bich Thao Lam ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Gallic Acid ◽  
Radical Scavenging ◽  
Dry Weight ◽  
Punica Granatum ◽  
Acute Oral Toxicity ◽  
Oral Toxicity ◽  
Fruit Peel ◽  
Total Polyphenol ◽  
Punica Granatum L

Background: The natural antioxidants have an important role in the prevention of many diseases. The aim of study is to investigate phytochemical components, antioxidant activity and acute oral toxicity of Pomegranate (Punica granatum L.) fruit peel (PFP) extract. Materials and methods: Phytochemicals of PFP were determined by qualitative chemical tests, thin layer chromatography, total polyphenol and flavonoid contents. The PFP extract was evaluated for antioxidant activity by DPPH assay and MDA assay. In vivo acute oral toxicity test was conducted using Karber-Behrens method to determine LD50. Results: Results illustrated that PFP mainly contains flavonoids, alkaloids, tannins, triterpenes, saponins, and coumarins. PFP extract exhibited the total polyphenol and flavonoid contents with 189.97 mg gallic acid equivalent/g dry weight and 9.42 mg quercetin equivalent/g dry weight, respectively. The DPPH free radical scavenging and anti-lipid peroxidation activities of PFP extract were expressed with IC50 value of 4.80 μg/mL and 0.38 μg/ mL, sequentially. Simultaneously, the Dmax (the maximum dose administered to mice that no toxicity was observed) of PFP extract was determined to be 21.28 g/kg, equivalent to 35.64 g dried herb. Conclusion: The PFP extract is relatively safe and revealed high antioxidant activity. Key words: Punica granatum L.; polyphenols; flavonoids; gallic acid; quercetin; antioxidant activity; acute oral toxicity

Сrude Plant Extracts Mediated Polyphenol Oxidation Reactions in the Presence of 3-Methyl-2-Benzothiazolinone Hydrazone for the Determination of Total Polyphenol Content in Beverages

2018 ◽  
Vol 15 (1) ◽  
pp. 11-20 ◽  
Author(s):  
Maria A. Morosanova ◽  
Anton S. Fedorov ◽  
Elena I. Morosanova
Keyword(s):  
Hydrogen Peroxide ◽  
Ferulic Acid ◽  
Gallic Acid ◽  
Caffeic Acid ◽  
Crude Extract ◽  
Reaction Rates ◽  
Green Bean ◽  
Polyphenol Content ◽  
Total Polyphenol ◽  
Total Polyphenol Content

Background: The consumption of antioxidants, including phenolic compounds, is considered important for preventing the oxidative damage diseases and ageing. The total polyphenol content (TPC) is the parameter used to estimate the quality of plant-derived products. Methods: Phenol oxidase activity of green bean (Phaseolus vulgaris) crude extract (in the presence of hydrogen peroxide) and banana (Musa sp.) pulp crude extract has been studied spectrophotometrically using catechol, gallic acid, caffeic acid, ferulic acid, and quercetin as substrates. All studied compounds have been oxidized in the presence of green bean crude extract and hydrogen peroxide; all studied compounds except ferulic acid have been oxidized in the presence of banana pulp crude extract. Michaelis constants (Km) and maximum reaction rates (Vmax) have been determined for oxidation in the presence of green bean crude extract and hydrogen peroxide (Km are 3.8×10-4 M, 1.6×10-3 M, 2.2×10-4 M, 2.3×10-4 M, 1.4×10-4 M and Vmax are 0.046 min-1, 0.102 min-1, 0.185 min-1, 0.053 min-1, 0.041 min-1 for catechol, gallic acid, caffeic acid, ferulic acid, and quercetin, respectively) and for oxidation in the presence of banana pulp crude extract (Km are 1.6×10-3 M, 3.8×10-3 M, 2.2×10-3 M, 4.2×10-4 M and Vmax are 0.058 min-1, 0.025 min-1, 0.027 min-1, 0.015 min-1 for catechol, gallic acid, caffeic acid, and quercetin, respectively). The influence of 3-methyl-2-benzothiazolinone hydrazone (MBTH) on the oxidation reactions kinetics has been studied: Michaelis constants values decrease and maximum reaction rates increase, which contributes to the increase in sensitivity of the determination. Results: Kinetic procedures of Total Polyphenol Content (TPC) determination using crude plants extracts in the presence of MBTH have been proposed (time of analysis is 1 min). For gallic acid (used as a standard for TPC determination) detection limit is 5.3×10-5 M, quantitation limit is 1.8×10-4 M, and linear range is 1.8×10-4 - 1.3×10-3 M for green bean crude extract; detection limit is 2.9×10-5 M, quantitation limit is 9.5×10-5 M, and linear range is 9.5×10-5 - 2.4×10-3 M for banana pulp crude extract. Proposed procedures are characterized by higher interference thresholds for sulfites, ascorbic acid, and citric acid compared to pure enzymes (horseradish peroxidase and mushroom tyrosinase) in the same conditions. Compared with standard Folin-Ciocalteu (FC) method the procedures described in this work are also characterized by less interference and more rapid determination. Conclusion: The procedures have been applied to TPC determination in tea, coffee, and wine samples. The results agree with the FC method for tea and coffee samples and are lower for wine samples, probably, due to sulfites interference.

Pesticides Analysis in Beans by Gas Chromatography Couplet with Tandem Mass Spectrometry

2021 ◽  
Vol 6 (4) ◽  
Author(s):  
Mizutani G ◽  
◽  
Bustillos O ◽  
Keyword(s):  
Gas Chromatography ◽  
Analytical Method ◽  
Extraction Procedure ◽  
Quadrupole Mass ◽  
Triple Quadrupole Mass Spectrometer ◽  
Mineral Salts ◽  
Pesticides Residues ◽  
Solid Liquid ◽  
Validation Of Analytical Method ◽  
Iron And Calcium

Beans are part of the basic diet alimentation for Brazilian population, as they gather proteins, carbohydrates, vitamins, mineral salts, fibers, amino acids and essential nutrients such as iron and calcium, being a complete food that can be compared with the amount of protein that the meat has. Considering the beans world production, in development countries represent almost 50%, being that Myanmar, India and Brazil the top three position. The use of pesticides is widely spread in these countries to reduce agricultural losses due to pests that interfere with grain production. Therefore the risk that could be generated from foods pesticides residues makes their analyses of quantification mandatory. The purpose of this work was to develop an analytical method to quantitatively characterize fungicides pesticides residues, flutriafol, procymidone and tebuconazole that were used to angular spot control, anthracnose, rust and alternaria spot, white mold fungi, present in beans, by means of gas chromatography coupled with a triple quadrupole mass spectrometer. Samples of beans, Phaseolus vulgaris L, types white, black, string and Vigna angularis, type adzuki, had been bought in grains store and supermarkets at metropolitan São Paulo city. The validation of analytical method was explored for sensitivity, selectivity, precision. The extraction procedure was performed in two different forms, QuEChERS, and solid-liquid extraction with low temperature. Through this methodology, reached below the maximum limit allowed by Brazilian law 0.5mgkg-1 for procymidone and 0.1mgkg-1 for flutriafol and tebuconazole. Several samples of four types of beans were tested and all of them had procymidone identified and 7% of samples higher than the law limit.

scholarly journals Development and validation of analytical method by HPLC-DAD for determination of vasodilator active in pharmaceutical ophthalmic forms

2020 ◽  
Vol 41 ◽  
Author(s):  
Aina Liz Alves Cesar ◽  
Larissa Caldeira Navarro ◽  
Alaíde de Matos Silva ◽  
Rachel Oliveira Castilho ◽  
Gisele Assis Castro Goulart ◽  
...  
Keyword(s):  
Analytical Method ◽  
Development And Validation ◽  
Validation Of Analytical Method

Polyphenols, tannins and caffeine content and antioxidant activity of green teas coming from organic and non-organic production

2013 ◽  
Vol 30 (3) ◽  
pp. 263-269 ◽  
Author(s):  
Renata Kazimierczak ◽  
Ewelina Hallmann ◽  
Anna Rusaczonek ◽  
Ewa Rembiałkowska
Keyword(s):  
Antioxidant Activity ◽  
Phenolic Acids ◽  
High Performance ◽  
Production Systems ◽  
Organic Production ◽  
Appreciable Effect ◽  
Total Polyphenols ◽  
Total Polyphenol ◽  
Tea Infusions ◽  
Exposed Surface Area

AbstractAmong infusions of green teabags and leafy green teas from organic and non-organic production systems we measured and compared the content of phenolic acids, flavonols and total polyphenols by spectrophotometry, the content of tannins by titration and the content of caffeine by high-performance liquid chromatography (HPLC). In addition, the antioxidant activity of the infusions was determined by spectrophotometry. The results obtained have shown that organic teas contained significantly more flavonols and tannins. However, the content of phenolic acids was higher in non-organic teas. The teas from organic and non-organic production did not differ in terms of total polyphenol content and antioxidant activity. There were no differences in leaf teas in relation to the teabags in contents of phenolic acids, tannins and total polyphenols. Organic teas had higher content of catechin C than the non-organic ones, but at the same time non-organic teas had more epigallocatechin 3-gallate (EGCG) in comparison to organic teas. Epigallocatechin (EGC) and epicatechin (EC) were not found to be different between the two groups of tea. Catechin was found to be significantly higher in teabags, while the EGCG was higher in leaf teas. The reason for this may be the oxidation of teabags, which have a greater exposed surface area. There was no appreciable effect of the form of tea on the content of tannins, caffeine, flavonols, phenolic acids, total polyphenols, EGC and EC as well as the antioxidant activity of the tea infusions examined.

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