ABSTRACT
OBJECTIVE: To establish the quantification method for free amino acids including threonine, alanine, lysine and tyrosine in the inner part of Poria cocos. METHODS: AQC (6-quinolyl-N-hydroxy-succinimidyl-carboxylate) was used as deriving reagent, and pre-column derivatization combined with ultra-high performance chromatography was applied to quantify threonine, alanine, lysine and tyrosine in 24 batches of the inner part of Poria cocos from Yunnan, Hubei and Anhui provinces. The experimental data were analyzed by partial least squares discriminant analysis (PLS-DA) using Simca-p+11 software. RESULTS: Alanine existed in every batch of sample, and its content ranged from 16.97-69.92 μg·g-1 in samples collected from different origins. Threonine, lysine and tyrosine were not found in some samples. The PLS-DA result showed that the samples from Yunnan and Anhui provinces clustered well. While the amino acid contents in the samples from Hubei province varied greatly. CONCLUSION: AQC combined with pre-column derivatization is a convenient, rapid and sensitive method to quantify the free amino acids in Poria.
ABSTRACT
To find novel functional beverages from folk teas, 33 species of frequently used non-Camellia tea (plants other than Camellia) were collected and compared with Camellia tea (green tea, pu-erh tea and black tea) for the first time. Data are reported here on the quantities of 20 free amino acids (FAAs) and three purine alkaloids (measured by UHPLC), total polyphenols (measured by Folin-Ciocalteu assay), and antioxidant activity (DPPH). The total amounts of FAAs in non-Camellia tea (0.62-18.99 mg/g) are generally less than that of Camellia tea (16.55-24.99 mg/g). However, for certain FAAs, the quantities were much higher in some non-Camellia teas, such as γ-aminobutyric acid in teas from Ampelopsis grossedentata, Isodon serra and Hibiscus sabdariffa. Interestingly, theanine was detected in tea from Potentilla fruticosa (1.16±0.81 mg/g). Furthermore, the content of polyphenols in teas from A. grossedentata, Acer tataricum subsp. ginnala are significantly higher than those from Camellia tea; teas from I. serra, Pistacia chinensis and A. tataricum subsp. ginnala have remarkable antioxidant activities similar to the activities from green tea (44.23 μg/mL). Purine alkaloids (caffeine, theobromine and theophylline) were not detected in non-Camellia teas. The investigation suggest some non-Camellia teas may be great functional natural products with potential for prevention of chronic diseases and aging, by providing with abundant polyphenols, antioxidants and specific FAAs.
ABSTRACT
A simple, sensitive and reproducible high-performance liquid chromatography (HPLC) method has been validated for determining concentrations of glutamate, glycine, and alanine in human plasma. Proteins in plasma were precipitated with perchloric acid, followed by derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC). Simultaneous analysis of glutamate, glycine, and alanine is achieved using reversed-phase HPLC conditions and ultraviolet detection. Excellent linearity was observed for these three amino acids over their concentration ranges with correlation coefficients (r)>0.999. The intra- and inter-day precision were below 10%. This method utilizes quality control samples and demonstrates excellent plasma recovery and accuracy. The developed method has been successfully applied to measure plasma glutamate, glycine, and alanine in twenty volunteers.