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Isolation of mitraphylline from Uncaria tomentosa (Willd. ex Schult.) DC. barks and development of spectrophotometric method for total alkaloids determination in Cat's Claw samples
Author(s) -
Gouvêa Marcos Martins,
Pusceddu Breno Henrique,
Pereira Netto Annibal Duarte,
Peregrino Carlos Augusto de Freitas,
Macedo Elizabeth Valverde,
Mourão Samanta Cardozo,
Marques Flávia Ferreira de Carvalho
Publication year - 2019
Publication title -
phytochemical analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 72
eISSN - 1099-1565
pISSN - 0958-0344
DOI - 10.1002/pca.2891
Subject(s) - chemistry , chromatography , repeatability , high performance liquid chromatography , mass spectrometry , extraction (chemistry) , analytical chemistry (journal)
The usual quality control for Uncaria tomentosa (Willd. ex Schult.) DC. barks requires highly specific analytical standards and methods based on high‐performance liquid chromatography (HPLC), which impacts the costs of the analytical process and the final products. Objective To obtain an analytical reference standard of mitraphylline by isolation from U. tomentosa barks and develop a spectrophotometric method for determination of total alkaloids in samples of U. tomentosa . Methodology An alkaloid‐enriched extract was obtained by acid–base partition and mitraphylline was selectively precipitated using an 80:20 v/v toluene/hexane solution. The compound was characterised by HPLC‐UV/DAD (diode‐array detector), mass spectrometry, UV‐visible, infrared (IR) and 1 H‐ and 13 C‐nuclear magnetic resonance (NMR) spectroscopy. Sample preparation for the spectrophotometric method consisted of an extraction with boiling methanol (3 × 10 mL, 15 min), followed by a strong cation exchange solid phase extraction (SCX‐SPE) clean‐up. Results Mitraphylline with a purity of 98% was isolated in 0.05% m/m yield. All characterisation results were in agreement with previous published data. The spectrophotometric method showed linear range between 0.40 and 20 μg/mL; limits of detection and quantification of 0.15 and 0.49 μg/mg, respectively; dispersion of results lower than 5% for repeatability and intermediate precision; statistically proven accuracy by comparison with reference values obtained by Soxhlet and an HPLC‐UV/DAD method; and robustness in relation to sample mass extracted and extraction time. Conclusion The methods developed to obtain mitraphylline analytical standard from U. tomentosa barks and to determine total alkaloids by spectrophotometry provided a cheaper and faster quality control alternative for U. tomentosa samples.