Characterization of phenolic components of black teas of different origins and the effect of brewing duration on quality properties.

This research aims to identify the phytochemical constituents of 79 different samples of black tea, including varieties from India, Iran (IrT), Turkey (TT), and Sri Lanka. In addition, this study investigates the effect of varying brewing times on the quality characteristics of tea. Therefore, we analyzed the phytochemical content of tea using a novel LC-MS/MS method that we developed, which identifies 53 different phenolic compounds. Furthermore, objective evaluations were conducted on the total phenolic compound, total flavonoid compound, antioxidant activity, and color values at 15, 30, and 60-min brewing intervals. The prevailing phenolic compounds discovered in the corresponding tea classifications were quantitatively analyzed to be quinic acid, epicatechin gallate, epigallocatechin gallate, epicatechin, epigallocatechin, gallic acid, nicotiflorine, and isoquercitrin. The study found that the TT and IrT groups had the richest phytochemical content and the highest antioxidant activity. The Turkish tea group had the highest measurement for the desired red color, which is considered a sensory property. Infusion color, antioxidant activity, and total phenolic and flavonoid contents showed significant increases with prolonged brewing time. It was important to note that the chemical composition of tea varies according to its origin and brewing conditions. Extending the brewing time improved the quality of the tea. It should be noted, however, that longer brewing times result in a more intense release of flavonoids, and this increase may have a pro-oxidant effect.

GC-MS and LC-MS Pesticide Analysis of Black Teas Originating from Sri Lanka, Iran, Turkey, and India.

The purpose of this study is to investigate pesticide residues in the imported and domestic tea sold in Turkey and to detect their compliance with maximum residue limits (MRL) and Acceptable Daily Intake (ADI). A total of 79 samples were analyzed by using LC-MS/MS and GC-MS devices with AOAC 2007.01 method to investigate 603 pesticide residues. According to the results, pesticide residues were found in a total of 28 tea samples. Pesticide residues were found in the countries of origin at the rates as follows: Iran (100%), India (33.3%) and Sri Lanka (17.3%). No pesticide residue was detected in the tea produced in Turkey. The compounds such as Diuron, Ethion, Cypermethrin, Thiacloprid, Thiamethoxam, Fenpyroximate, Acetamiprid, Imidacloprid, Flubendiamide, Deltamethrin and Hexythiazox were detected in positive samples. Seven types of pesticide residues exceeded the MRL determined by the Turkish Food Codex for 15 types (53.57%) for 28 samples with pesticide residue detected. Additionally, 4 types of pesticide residues were determined to exceed the ADI determined by the Codex Alimentarius for 13 (46.42%) of 28 samples with pesticide residue detected. These results have showed that the imported tea entering Turkey was not adequately analyzed in the customs control laboratories or the maximum residual limits were not clearly determined.

Bioactive component analysis and investigation of antidiabetic effect of Jerusalem thorn (Paliurus spina-christi) fruits in diabetic rats induced by streptozotocin.

ETHNOPHARMACOLOGICAL RELEVANCE: The extracts of Jerusalem thorn fruits (JT-FE) have been commonly used for the treatment of diabetes mellitus in Turkey. AIM OF THE STUDY: In this study, it is aimed to investigate the effects of the JT-FE, prepared by decoction, on blood glucose, insulin and glycated haemoglobin levels of diabetic rats induced with streptozotocin (STZ). Hypoglycemic activity of the extracts was examined in streptozotocin-induced diabetic rats. MATERIALS AND METHODS: For this purpose, pre-prandial blood sugar, insulin and glycated hemoglobin levels were measured. To investigate active substances that were responsible for the antidiabetic activity, phytochemical analysis was carried out with optimized and validated LC-MS/MS method using 53 phytochemicals in JT-FE. In addition, ICP-OES analysis was performed to determine the mineral content. RESULTS: The findings of the study demonstrate that when insulin and JT-FE applied groups were compared with the diabetic control group, their blood sugar and glycated hemoglobin levels were seen to statistically decrease (p < 0,001). Morewer, When JT-FE treated groups were compared with insulin-treated groups, a statistically decrease (p < 0,05) in their levels was observed. On the other hand, it was also found that the increase in extract concentration didn't contribute significantly to antidiabetic activity. As a result of the phytochemical analysis, total of 31 different phenolic compounds were defined in JT-FE. The major components of JT-FE (as analyte/g extract) were; rutin (98753.4 ± 24.39 µg), catechin (58695.3 ± 12.971 µg), hesperidin (47445.2 ± 15.894 µg), quinic acid (38279.5 ± 14.239 µg) and malic acid (17536.8 ± 2.279 µg). In the mineral analysis we made; Sodium, calcium, magnesium and phosphorus elements were found at macro level, Zn and Cr3+ minerals were found at trace level. CONCLUSION: Our findings show that JT-FE, prepared by decoction, is rich in phenolic and mineral content and strong in antihyperglycemic activity. That's why Jerusalem thorn fruits can be a useful antidiabetic phytotherapy agent.

Phytochemical Analysis of Paliurus spina-christi Fruit and Its Effects on Oxidative Stress and Antioxidant Enzymes in Streptozotocin-Induced Diabetic Rats.

Oxidative stress can play an important role in the autoxidation of glucose, glycation of proteins and activation of polyol metabolism, and the development of various complications in diabetes. This study investigated the protective effect of Paliurus spina-christi (PSC) fruit against diabetes-induced pathologies such as inflammation caused by oxidative stress and its phytochemical content. The bioactive compounds of Paliurus spina-christi fruit extract (PSC-FE) prepared by the infusion method were determined by LC-MS/MS analysis, and the metal reduction and radical removal activity were determined in vitro by DPPH, ABTS, FRAP and CUPRAC methods. The effect of PSC-FE on catalase and superoxide dismutase enzymes and lipid peroxidation in streptozotocin-induced diabetic rat tissues was determined in vivo. For determining in vivo antioxidant activity, the study was carried out on 30 Wistar albino male rats that were distributed into 3 research and 2 control groups. As a result of LC-MS/MS analysis, malic acid (28,424.18 ± 3.21 µg/g PSC-FE) and rutin (23,459.68 ± 3.73 µg/g PSC-FE) are the highest among the 22 phenolic compounds. The PSC fruit water extracts were determined to have a more powerful antioxidant activity than standard antioxidants. In those groups that received PSC-FE, catalase and superoxide dismutase enzyme levels that decreased in patient group were found to have a statistically meaningful increase in treatment groups (P < 0.01). Although malondialdehyde amount, the last product of lipid peroxidation, was observed to have a statistically meaningful increase in patient group when compared with control group, this increase was decreased in all treatment groups in a statistically meaningful manner (P < 0.01). The PSC was seen to be more successful, when compared with standard antioxidants. The PSC-FE was found to have a rich phenolic diversity. It can be said that the PSC may have a significant therapeutic effect on diabetes caused by oxidative stress due to its biological activities and content.