Comparative Study of Fourteen Alkaloids from Uncaria rhynchophylla Hooks and Leaves Using HPLC-Diode Array Detection-Atmospheric Pressure Chemical Ionization/MS Method

Abstract

The purpose of the study is to compare alkaloid profile of Uncaria rhynchophylla hooks and leaves. Ten oxindole alkaloids and four glycosidic indole alkaloids were identified using HPLC-diode array detection (DAD) or LC-atmospheric pressure chemical ionization (APCI)-MS method, and a HPLC-UV method for simultaneous quantification of major alkaloids was validated. The hooks are characterized by high levels of four oxindole alkaloids rhynchophylline (R), isorhynchophylline (IR), corynoxeine (C) and isocorynoxeine (IC), while the leaves contained high level of two glycosidic indole alkaloids vincoside lactam (VL) and strictosidine (S). The presented methods have proven its usefulness in chemical characterization of U. rhynchophylla hooks and leaves.Key words oxindole alkaloid; glycosidic alkaloid; Uncaria rhynchophylla; alkaloid profile; HPLC; LCatmospheric pressure chemical ionization-MS China has an abundant resource of Uncaria rhynchophylla (MIQ.) JACKS. The hooks on this plant are used in the treatment of infantile convulsion, headache, dizziness, hypertension and stroke in Traditional Chinese Medicine and Japanese Kampo Medicine. 1,2) In addition, the leaves, as a candidate part of the hooks, 3) are used in the manufacture of an antihypertensive remedy in China. 4) Oxindole alkaloids such as rhynchophylline (R) and isorhynchophylline (IR) are major components of U. rhynchophylla, 5) responsible for the cardiocerebral vascular effects, including hypotension, 6) vasodilation, 7) anti-platelet aggregation 8) and protective effect against neuronal damage. 9)Concerning quality assessment of U. rhynchophylla hooks, HPLC-UV method may be practical for determination of oxindole alkaloids due to the characteristic absorption of indole ring at 245 nm and 290 nm.10) The alkaloid profile of the hooks was studied using HPLC-UV technique in the previous literatures.11) LC-MS technique is able to provide both analytical separation and structural determination of unknown bioactive compounds, which was applied to chemically characterize the oxindole alkaloids from Uncaria tormentosa 12) and the metabolites of R and IR. 13,14) Yamanaka et al. determined ten tertiary alkaloids in various parts of U. rhynchophylla, indicating that the alkaloid profile of the leaves is similar to that of the hooks.15) Recently, we reported the isolation of several oxindole alkaloids and glycosidic indole alkaloids from U. rhynchophylla leaves, together with their inhibitory effects on microglial activation. R, IR, corynoxeine (C), isocorynoxeine (IC), strictosidine (S) and vincoside lactam (VL) are found to be potently active. [16][17][18] However, the chemical analysis of S and VL of U. rhynchophylla has not been reported yet.In the present study, ten oxindole alkaloids and four glycosidic alkaloids from U. rhynchophylla hooks and leaves were identified by HPLC-diode array detection (DAD) and LC-MS technologies. Moreover, an accurate and sufficiently sensitive HPLC-UV method was validated to simultaneously determine these alkaloids. Utilizing opt...

Metabolic Profile of Isocorynoxeine in Rats Obtained by Ultra-High Performance Liquid Chromatography/Quadrupole Time-of-Flight Mass Spectrometry

“…C, corynoxeine-N-oxide (C-NO), 18,19-dehydrocorynoxinic acid (DCA), 18,19-dehydrocorynoxinic acid B (DCAB), isocorynoxeine-N-oxide (IC-NO), IC, IR and R were isolated from the CHCl 3 extract of U. rhynchophylla [1,8,20] were isolated from the urine of rats administered IC orally [14]. The identification of these compounds was confirmed by spectral analysis including UV, 1D and 2D NMR, mass spectrometry (MS) and circular dichroism experiments (CD).…”

“…These alkaloids exhibit wide beneficial effects on the cardiovascular and cardiocerebral vascular systems, such as a protective effect on ischemiainduced neuronal damage in the rat hippocampus [4], inhibitory effect on 5-HT 2A receptor function in the mouse brain [5], vasodilator action [6] and antagonist effect on angiotensin II-induced proliferation rat vascular smooth muscle cells [7]. IC is one of the major oxindole alkaloids in herbal medicine [8] and also shows a protective effect on glutamate-induced neuronal damage in cultured cerebellar granule cells from rat [9], the inhibitory activities on the 5-HT 2A receptor in mouse brain [5] and lipopolysaccharide (LPS)-induced NO release in primary cultured rat cortical microglia [10].…”

Qualitative and Quantitative Analyses of Alkaloids in <i>Uncaria</i> Species by UPLC-ESI-Q-TOF/MS

“…RIN, CNX, CNXB were also riched in UMW (0.739-0.857 mg/g for RIN, 0.366-0.394 mg/g for CNX, trace-0.197 mg/g for CNXB) than other four U. species (trace-0.321 mg/g for RIN, trace for CNX, trace for CNXB). Several studies on HPLC analysis of the URM have been reported, [12][13][14] and most of them focused on chemical profiling of alkaloids. However, there were large variations in the content of these bioactive alkaloids in the U. species samples according to the species and different geographic locations, which may be responsible for the different therapeutic efficacies of these herbal plants.…”

“…Several holistic chemical profiling methods of the URM have been reported, such as the screening and identification of six oxindole alkaloids and four indole alkaloids in various parts of URM by HPLC, 12) the quantification of ten oxindole alkaloids and four glycosidic alkaloids using HPLC-UV and LC-MS technologies, 13) and the profiling of the alkaloids using HPLC-DAD-quadrupole time-of-flight mass spectrometry (Q-TOF/MS) method. 14) However, in these literature, the identification or quantification of the URCU from other four botanical origins were still not fully understood.…”

Effective Separation and Simultaneous Determination of Corynoxeine and Its Metabolites in Rats by High-Performance Liquid Chromatography with Tandem Mass Spectrometry and Application to Pharmacokinetics and In Vivo Distribution in Main Organs

“…1), has been of interest, especially using high-performance liquid chromatography with tandem mass spectrometry (LC-MS). [1][2][3][4][5] The plentiful pharmacological activities and in vivo identification in biosystems of COR have been investigated. [6][7][8][9][10][11][12][13] We have reported that after oral administration, COR was hydroxylated into 11-hydroxycorynoxeine (M1) and 10-hydroxycorynoxeine (M2), which successively glucuronidated into 11-hydroxycorynoxeine 11-O-β-D-glucuronide (M3) and 10-hydroxycorynoxeine 10-O-β-D-glucuronide (M4), respectively.…”