Overlay molecule spectra mestrenova
ex Havil., Uncaria hirsuta Havil., Uncaria sinensis (Oliv.) Havil., Uncaria macrophylla Wall., and Uncaria sessilifructus Roxb. This herbal medicine is mainly derived from the dried hook-bearing stems of five Uncaria species (Rubiaceae), including Uncaria rhynchophylla (Miq.) Miq. (1,2) Currently, Gou-Teng is officially documented in the Chinese Pharmacopoeia (2020 edition) for the treatment of hyperpyrexia, epilepsy, pre-eclampsia, and hypertension. Uncariae Ramulus Cum Uncis, known as “Gou-Teng” in Chinese, is a commonly used herbal medicine that has been widely used in China and other Asian countries, such as Japan, for thousands of years. Moreover, qNMR represents a feasible alternative to high-performance liquid chromatography-based methods for the quality control of TCMs. The proposed qNMR method was demonstrated to be a powerful tool for quantifying the alkaloids in traditional Chinese medicines (TCMs) due to its unique advantages of high precision, rapid analysis, and nonrequirement of standard compounds for calibration curve preparation. The accuracy determined at three concentrations was within ±4.4% in terms of relative error. The intra- and interday relative standard deviation across three validation runs over the entire concentration range is less than 2.51%. The lower limit of quantification is 25 μg/mL. The method is linear in the concentration range of 25–400 μg/mL. Validation of the quantitative method was also performed in terms of specificity, linearity, sensitivity, accuracy, and precision. The highly deshielded signal of NH was at δ H 10–11 in the aprotic solvent DMSO- d 6, which enables satisfactory separation of the signals to be integrated. This method was performed on a 600 MHz NMR spectrometer with optimized acquisition parameters for performing quantitative experiments within 14 min. In the present study, a rapid, accurate, and precise method was developed for the simultaneous quantitation of four characteristic components, namely, rhynchophylline ( 1), isorhynchophylline ( 2), corynoxeine ( 3), and isocorynoxeine ( 4), through 1H NMR spectrometry techniques. Quantitative determination of monoterpenoid indole alkaloids is critical for controlling its quality. Uncariae Ramulus Cum Uncis, known as “Gou-Teng” in Chinese, is derived mainly from the dried hook-bearing stems of Uncaria rhynchophylla.