A Review on the Pharmacognostical Preliminary Phytochemical Screening and Antioxidant Activity of Thea Sinensis Leaves

Introduction: Tea (Camellia sinensis) is the most highly consumed beverage in the world in addition to water. The most common way of preparation is by immersing the tea bag in hot or cold water. In Colombia, it is a recent trend and the market is growing continuously.

Objective: The objective of this study is to compare the antioxidant characteristics of four brands of green tea sold in Colombia at room and hot temperature in relation to the preparation conditions.

Methods: The commercial brands of green tea (Oriental®, Lipton®, Hindu®, Jaibel®) were used in an aqueous extraction at two temperatures: Cold tea extract (25°C) and hot tea extract (80°C). Total Polyphenol Concentration (TPC) was determined by Folin-Ciocalteu method; Total Flavonoid Content (TFC) was determined by spectrophotometric method and the antioxidant capacity was determined by two methods: DPPH radical capture assay and the Oxygen Radical Absorbance Capacity (ORAC) assay. Finally, a method to quantify the catechins of the tea extracts, High Performance Liquid Chromatography (HPLC) was applied.

Results: The TPC vary between: 2.53 mg GAE/g-14.63 mg GAE/g sample for cold tea extract and 29.34 mg GAE/ g-55.06 mg GAE/g sample for hot tea extract. The TFC vary between: 2.67 mg CE/g 7.08 mg CE/g per sample for the cold tea extract and 5.43 mg CE/g-8.41 mg CE/g sample for hot tea extract. A similar profile assays: For cold tea extract: 22.36 mg TE/g-41.29 mg TE/g sample for DPPH and 22.95 mg TE/g-46.25 mg TE/g sample for ORAC. Similarly, for hot tea extract the following ranges were: 38.50 mg TE/ g-110.01 mg TE/g sample for DPPH and 23.40 mg TE/ g-113.60 mg TE/g sample for ORAC. In general, the values obtained in each assay for each brand were as follows: Oriental®>Lipton®>Hindu®>Jaibel®. The chromatographic profiles showed the presence of ten compounds.

Conclusion: These results confirm that the aqueous extraction of green tea at 80°C leads to the formation of infusions made up of compounds with higher antioxidant capacity in comparison with extractions at room temperature.

Author(s): Sonima CK

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