Abdullah Abu Tareq Mohammad, Sayka Mahbuba Ibrahim, Rahman Mohammad Mahfuzur, Sharif Miskat, Khan Tanzir Ahmed, Jahan Sharmin, Mazumdar Reaz Mohammad, Uddin Mohammad Nashir, Hoque Md Mozammel
Institute of Food Science and Technology (IFST), Bangladesh Council of Scientific and Industrial Research (BCSIR), Dhaka, 1205, Bangladesh.
Department of Food Engineering & Tea Technology, Shahjalal University of Science & Technology, Sylhet, Bangladesh.
Heliyon. 2024 Mar 29;10(7):e28760. doi: 10.1016/j.heliyon.2024.e28760. eCollection 2024 Apr 15.
Tea () is a widely consumed beverage known for its numerous health benefits, largely attributed to its rich content of quality determining secondary metabolites such as methylxanthine compounds and bioactive phenolic compounds. The goal of this study was to find out variations of the levels of methylxanthines, bioactive phenolic compounds, and antioxidant activity in methanolic and hot water extracts of 129 tea samples grown in three different ecological regions of Bangladesh named Panchagar, Sylhet, and Chattogram. Methylxanthine and bioactive phenolic compounds were determined by using HPLC-DAD, and the antioxidant profile was analysed by UV-vis spectrophotometric methods for methanol and hot water extracts of tea leaves. The IC values showed the trend as Panchagar > Sylhet > Chattogram and Sylhet > Chattogram > Panchagar for water and methanol extract, respectively. The results revealed significant ( < 0.05) variations in the levels of methylxanthines content: Panchagar > Chattogram > Sylhet. Caffeine was significantly higher (103.02 ± 5.55 mg/g of dry extract) in the methanolic extract of tea leaves of Panchagar district and lower (53.33 ± 4.30 mg/g of dry extract) in the hot water extract of Sylhet district. Panchagar and Chattogram possessed significantly ( < 0.05) higher catechin content for methanol (57.01 ± 5.50 mg/g dry extract) and hot water (55.23 ± 4.11 mg/g dry extract) extracts, respectively. The utilization of canonical discriminant functions yielded highly favorable outcomes in the classification of tea from three distinct cultivation origins in Bangladesh, relying on their inherent features. This study demonstrated the potential effects of geographical variations on the bioactive compounds and antioxidant properties of tea, emphasizing the importance of regional differences in tea cultivation for optimizing its health benefits as well as dispersing tea cultivation across the country.
茶是一种广泛饮用的饮品，因其诸多健康益处而闻名，这在很大程度上归因于其富含的决定品质的次生代谢产物，如甲基黄嘌呤化合物和生物活性酚类化合物。本研究的目的是找出在孟加拉国三个不同生态区域潘查加尔、锡尔赫特和吉大港种植的129个茶叶样本的甲醇提取物和热水提取物中甲基黄嘌呤、生物活性酚类化合物水平以及抗氧化活性的变化。采用高效液相色谱 - 二极管阵列检测器（HPLC - DAD）测定甲基黄嘌呤和生物活性酚类化合物，并通过紫外 - 可见分光光度法分析茶叶甲醇提取物和热水提取物的抗氧化特性。IC值分别显示出对于水提取物和甲醇提取物，趋势为潘查加尔＞锡尔赫特＞吉大港以及锡尔赫特＞吉大港＞潘查加尔。结果显示甲基黄嘌呤含量水平存在显著（P＜0.05）差异：潘查加尔＞吉大港＞锡尔赫特。潘查加尔地区茶叶的甲醇提取物中咖啡因含量显著更高（103.02±5.55毫克/克干提取物），而锡尔赫特地区的热水提取物中咖啡因含量更低（53.33±4.30毫克/克干提取物）。潘查加尔和吉大港的甲醇提取物（57.01±5.50毫克/克干提取物）和热水提取物（55.23±4.11毫克/克干提取物）中儿茶素含量分别显著（P＜0.05）更高。利用典型判别函数，基于茶叶的固有特征，在对来自孟加拉国三个不同种植产地的茶叶进行分类时产生了非常有利的结果。本研究证明了地理差异对茶叶生物活性化合物和抗氧化特性的潜在影响，强调了茶叶种植区域差异对于优化其健康益处以及在全国范围内分散茶叶种植的重要性。
