Perbandingan Aktivitas Diuretik pada Berbagai Produk Seduhan Teh Hijau(Camellia sinensis L.)

Hipertensi merupakan masalah kesehatan yang berbahaya karena memiliki faktor resiko yang mengarah pada penyakit kardiovaskuler. Penggunaan diuretik berperan dalam terapi pengobatan seperti hipertensi, gagal jantung, serta edema. Diketahui bahwa teh hijau dapat berkhasiat sebagai diuretik. Penelitian ini bertujuan mengetahui perbandingan aktivitas diuretik pada berbagai produk teh hijau (Camellia sinensis L.). Pada uji aktivitas diuretik, 30 ekor mencit di bagi menjadi 6 kelompok yang terdiri dari kelompok I (CMC. Na 1%), Kelompok II (Furosemid), Kelompok III, IV, V dan VI merupakan kelompok perlakuan yang terdiri dari pemberian seduhan White Tea, Yellow Tea, Black Dragon Tea Dan Green Tea Premium dengan dosis 2g, 4g dan 6g yang diseduh dengan 200ml air suhu 70οC selama 5-15 menit. Pengukuran urin dilakukan setiap 1 jam selama 6 jam. Analisa data dilakukan dengan menggunakan spss versi 26 dengan taraf kepercayaan 95%. Seduhan white tea, yellow tea, dan black dragon tea pada dosis 2g tidak memiliki efek diuretik (p>0,05) sedangkan green tea premium 2g memiliki aktivitas diuretik namun lebih rendah dibandingkan dengan furosemid. Pada dosis 4g, white tea, yellow tea dan green tea premium memiliki aktivitas sebagai diuretik (p<0,05) namun masih lebih rendah dibandingkan dengan furosemid. Pada dosis 6g, white tea, yellow tea, black dragon tea memiliki aktivitas sebagai diuretik (p<0,05) namun masih lebih rendah dibandingkan dengan furosemid, sedangkan green tea premium dosis 6g memiliki aktivitas diuretik yang sebanding dengan furosemid (p>0,05). Dapat disimpulkan bahwa white tea, yellow tea, black dragon tea, dan green tea premium dosis 6g memiliki aktivitas diuretik.

A Review on the Antioxidant and Antiaging Properties of White Tea

The present review explored to extend the current knowledge by highlighting the antioxidative and antiaging profile of white tea. White tea, the least processed of the teas, is one of the least investigated and has the highest phenolic content. The white tea has a great potential on the skin for cosmetics and the for better skin physiology. Tea polyphenols, particularly catechin derivatives, are powerful antioxidants that benefit human health. Because of their potential to scavenge free radicals and thereby prevent oxidative stress, antioxidant components have piqued interest. In this context, several studies have revealed antiaging activity of white tea, as it involved in preventing aging and other age-related disorders. White tea delays the process of aging and improves the longevity of life. This manuscript provides a summary of various bioactive components present in white tea along with the different alkaloids, enriched with (-)-epicatechin (EC), (-)-epigallocatechin (EGC) and (-)-epigallocatechin 3-gallate (EGCG), which are responsible for their health-promoting and antiaging properties.

Isolation of N-Ethyl-2-pyrrolidinone-Substituted Flavanols from White Tea Using Centrifugal Countercurrent Chromatography Off-Line ESI-MS Profiling and Semi-Preparative Liquid Chromatography

N-Ethyl-2-pyrrolidinone-substituted flavanols (EPSF) are marker compounds for long-term stored white teas. However, due to their low contents and diasteromeric configuration, EPSF compounds are challenging to isolate. In this study, two representative epimeric EPSF compounds, 5′′′R- and 5′′′S-epigallocatechin gallate-8-C N-ethyl-2-pyrrolidinone (R-EGCG-cThea and S-EGCG-cThea), were isolated from white tea using centrifugal partition chromatography (CPC). Two different biphasic solvent systems composed of 1. n-hexane – ethyl acetate – methanol – water (1:5:1:5, v/v/v/v) and 2. n-hexane – ethyl acetate – acetonitrile – water (0.7:3.0:1.3:5.0, v/v/v/v) were used for independent pre-fractionation experiments; 500 mg in each separation of white tea ethyl acetate partition were fractionated. The suitability of the two solvent systems was pre-evaluated by electrospray mass-spectrometry (ESI-MS/MS) analysis for metabolite distribution and compared to the results of the CPC experimental data using specific metabolite partition ratio KD values, selectivity factors α, and resolution factors RS. After size-exclusion and semi-preparative reversed-phase liquid chromatography, 6.4 mg of R-EGCG-cThea and 2.9 mg of S-EGCG-cThea were recovered with purities over 95%. Further bioactivity evaluation showed that R- and S-EGCG-cThea possessed in vitro inhibition effects on α-glucosidase with IC50 of 70.3 and 161.7 μM, respectively.

Tea and Chicory Extract Characterization, Classification and Authentication by Non-Targeted HPLC-UV-FLD Fingerprinting and Chemometrics

Tea is a widely consumed drink in the world which is susceptible to undergoing adulterations to reduce manufacturing costs and rise financial benefits. The development of simple analytical methodologies to assess tea authenticity, as well as to detect and quantify frauds, is an important matter considering the rise of adulteration issues in recent years. In the present study, untargeted HPLC-UV and HPLC-FLD fingerprinting methods were employed to characterize, classify, and authenticate tea extracts belonging to different varieties (red, green, black, oolong, and white teas) by partial least squares-discriminant analysis (PLS-DA), as well as to detect and quantify adulteration frauds when chicory was used as the adulterant by partial least squares (PLS) regression, to ensure the authenticity and integrity of foodstuffs. Overall, PLS-DA showed a good classification and grouping of the tea samples according to the tea variety and, except for some white tea extracts, perfectly discriminated from the chicory ones. One hundred percent classification rates for the PLS-DA calibration models were achieved, except for green and oolong tea when HPLC-FLD fingerprints were employed, which showed classification rates of 96.43% and 95.45%, respectively. Good predictions were also accomplished, also showing, in almost all the cases, a 100% classification rate for prediction, with the exception of white tea and oolong tea when HPLC-UV fingerprints were employed that exhibited a classification rate of 77.78% and 88.89%, respectively. Good PLS results for chicory adulteration detection and quantitation were also accomplished, with calibration, cross-validation, and external validation errors beneath 1.4%, 6.4%, and 3.7%, respectively. Acceptable prediction errors (below 21.7%) were also observed, except for white tea extracts that showed higher errors which were attributed to the low sample variability available.

Development of thin-layer chromatographic method for determination of caffeine in black, green, and white tea

Caffeine is naturally present in tea and coffee giving the pleasant and stimulant effect. Several different types of teas, black, green, and white teas bought in market were analysis for caffeine content. The boiled sample tea was filtered through filter paper. Lead(II) acetate was used to separate tannins from caffeine followed by filtration through filter paper with a black ribbon. The liquid-liquid extraction was carried out using dichloromethane (3×5 mL) and sodium sulfate as a drying agent. The TLC method was performed on Merck precoated silica gel plates 5×10 cm (60F254, 200 μm) using either methanol or dichloromethane as solvents and the mobile phases were glacial acetic acid and ethyl acetate (95:5, v/v), while the second one was consisted of ethyl acetate and ethanol (80:20, v/v), respectfully. The Rf values were 0.36 and 0.86 for the first and the second mobile phase, respectively, in comparison to the standard caffeine. The values for pH of boiled sample teas were in the range from 4.85 to 5.80. The most abundant tea sample for caffeine was determined in green tea bought in the grocery store for health nutrition (2.04 %). The yield for tea samples from green market, white tea and two tea black samples were 0.06, 0.71, 0.07, and 0.05%, respectively. The developed TLC method can be used for determination of caffeine content in tea samples.