Microwave-assisted extraction in combination with HPLC-UV for quantitative analysis of six bioactive oxoisoaporphine alkaloids in Menispermum dauricum DC

The basic chemical substances of total alkaloids of Menispermi Rhizoma and their anti-inflammatory activities

Menispermi Rhizoma is the dried rhizome of Menispermum dauricum DC. (Menispermaceae), which commonly used to treat sore throat, enteritis, and dysentery in traditional Chinese medicine. To clarify the chemical basis of the total alkaloids of M. Rhizoma, HPLC was used to analyze total alkaloids, and then representative chemical constituents were separated by tracking. Nineteen compounds, including two new alkaloids (1R-methymenidaurine A-α-N-oxide (1) and 1R-7'-hydroxymethyl-menidaurine A (2)), thirteen known alkaloids, and four known flavonoids were isolated and identified using spectroscopic methods. Meanwhile, seven characteristic peaks were identified from the total alkaloids using HPLC analysis. Furthermore, compounds 1-18 were screened in vitro for their inhibitory effect against nitric oxide production in BV-2 microglia cells stimulated by lipopolysaccharide. Among them, six compounds showed weak inhibition, and the IC50 values of compounds 1 and 2 were 56.87 ± 1.61 and 53.67 ± 1.52 mM, respectively.

Research Progress on Chemical Constituents and Pharmacological Activities of Menispermi Rhizoma

Menispermi Rhizoma, the rhizome of Menispermum dauricum DC., is a traditional Chinese medicine, which has the effect of clearing away heat and detoxification, dispelling wind, and relieving pain. It is often used in the treatment of sore throat, enteritis, dysentery, and rheumatism. The chemical constituents of M. Rhizoma mainly include alkaloids, phenolic acids, quinones, cardiotonic glycosides, and so on. Modern pharmacological studies have proved that M. Rhizoma has the effects of anti-tumour, anti-inflammation, anti-oxidation, bacteriostasis, cardio-cerebrovascular protection, anti-depression and anti-Alzheimer’s disease. In recent years, the chemical constituents of M. Rhizoma have been found continuously, and the pharmacological studies have deepened gradually. This paper reviews the research progress on the chemical composition and pharmacological effects of M. Rhizoma, to provide a basis for further research and development of its medicinal value.

Recent advances in proteomics and metabolomics in plants

Over the past decade, systems biology and plant-omics have increasingly become the main stream in plant biology research. New developments in mass spectrometry and bioinformatics tools, and methodological schema to integrate multi-omics data have leveraged recent advances in proteomics and metabolomics. These progresses are driving a rapid evolution in the field of plant research, greatly facilitating our understanding of the mechanistic aspects of plant metabolisms and the interactions of plants with their external environment. Here, we review the recent progresses in MS-based proteomics and metabolomics tools and workflows with a special focus on their applications to plant biology research using several case studies related to mechanistic understanding of stress response, gene/protein function characterization, metabolic and signaling pathways exploration, and natural product discovery. We also present a projection concerning future perspectives in MS-based proteomics and metabolomics development including their applications to and challenges for system biology. This review is intended to provide readers with an overview of how advanced MS technology, and integrated application of proteomics and metabolomics can be used to advance plant system biology research.

Isoquinoline alkaloid dimers with dopamine D1 receptor activities from Menispermum dauricum DC

A phytochemical investigation on chemical constituents from the rhizomes of Menispermum dauricum DC. identified eight undescribed dimeric alkaloids with structurally diverse monomeric isoquinoline. Alkaloid structures were elucidated by a combination of spectroscopic data analyses and time-dependent density functional theory (TDDFT) ECD calculation. The isolates were evaluated for inhibitory effect on dopamine D1 receptor and compound 1 exhibited potent D1 receptor antagonistic activity with an IC₅₀ value of 8.4 ± 2.0 μM.

4-Hydroxyl-oxoisoaporphine, one small molecule as theranostic agent for simultaneous fluorescence imaging and photodynamic therapy as type II photosensitizer

Oxoisoaporphine (OA) is a plant phototoxin isolated from Menispermaceae, however, its weak fluorescence and low water solubility impede it for theranostics. We developed here 4-hydroxyl-oxoisoaporphine (OHOA), which has good singlet oxygen-generating ability (0.06), strong fluorescence (0.72) and improved water solubility. OHOA displays excellent fluorescence for cell imaging and exhibits light-induced cytotoxicity against cancer cell. In vitro model of human cervical carcinoma (HeLa) cell proved that singlet oxygen generated by OHOA triggered photosensitized oxidation reactions and exert toxic effect on tumor cells. The MTT assay using HeLa cells verified the low cytotoxicity of OHOA in the dark and high phototoxicity. Confocal experiment indicates that OHOA mainly distributes in mitochondria and western blotting demonstrated that OHOA induces cell apoptosis via the mitochondrial pathway in the presence of light. Our molecule provides an alternative choice as a theranostic agent against cancer cells which usually are in conflict with each other for most traditional theranostic agents.

A sensitive HPLC-FLD method for the quantification of 6-O-demethylmenisporphine isolated from Menispermi Rhizoma in rat plasma

Background

To investigate the pharmacokinetics of 6-O-demethylmenisporphine, an oxoisoaporphine alkaloid with significant anti-tumor activities and isolated from Menispermi Rhizoma, a novel and sensitive HPLC assay was established for 6-O-demethylmenisporphine quantification in rat plasma.

Methods

Peak responses were detected by a highly selective and sensitive fluorescence detector with 426-nm excitation and 514-nm emission wavelengths. Curcumin was employed as the internal standard (IS). A Capcell Pak C18 column (150 mm × 4.6 mm i.d., 5 μm) and an isocratic elution procedure with a flow rate of 1.0 mL/min were used to exclude the endogenous interfering substance. Acetonitrile-water (68:32, v/v) containing 1% formic acid was employed as mobile phase. A 7-point calibration curve that covered the concentration range of 10–2500 ng/mL was constructed.

Results

A good linearity was observed with a correlation coefficient (r) of 0.9993. The lower limit of quantification for 6-O-demethylmenisporphine was 10 ng/mL. The mean recoveries of analyte in rat plasma exceeded 80.5%. The precision at four concentration levels was within 11.3% and the accuracy ranged from − 7.6 to 6.7%.

Conclusion

Using this new HPLC-FLD method, the investigation of plasma samples from rats following oral dosing of neat compound and Menispermi Rhizoma extract was successfully conducted. The results will provide a reference for the evaluation of preclinical safety of 6-O-demethylmenisporphine.

Pharmacokinetics, tissue distribution and excretion of 6-O-demethylmenisporphine, a bioactive oxoisoaporphine alkaloid from Menispermi Rhizoma, as determined by a HPLC-MS/MS method

6-O-demethylmenisporphine, a major active oxoisoaporphine alkaloid isolated from Menispermi Rhizoma, has been confirmed to possess significant bioactivities, including anti-cancer and anti-hypoxia effects. However, few researches on quantifying 6-O-demethylmenisporphine in biosamples have been performed. In this research, a sensitive HPLC-MS/MS approach for determining 6-O-demethylmenisporphine in various biological matrices (plasma, tissue, urine, bile and feces) of rat has been constructed. Carbamazepine was chosen as the internal standard (IS). All biosamples were prepared using a simple one-step acetonitrile precipitation. A Capcell Pak C18 column coupled with an isocratic mobile phase consisted of acetonitrile (0.1% formic acid)-water (90:10, v/v), was employed to separate 6-O-demethylmenisporphine from endogenous interferences. Peak responses were detected by multiple reaction monitoring (MRM) transitions with m/z 308.0 → 264.9 for 6-O-demethylmenisporphine and m/z 237.0 → 194.1 for IS in positive-ion mode. The approach exhibited perfect linearity over a range of 5-2000 ng/mL for plasma and 2-1000 ng/mL for various tissue, urine, bile and feces. The lower limit of quantification (LLOQ) for analyte among different biological samples ranged from 2 ng/mL to 5 ng/mL. The newly established method was simple, efficient and sensitive, which was successfully applied to investigate the absorption, distribution, and excretion of 6-O-demethylmenisporphine after oral dosing to rats. The results indicated that 6-O-demethylmenisporphine could be well absorbed into blood circulation and widely distributed in various tissues after oral dosing, the oral bioavailability was up to 51.52%. Meanwhile, it was widely metabolized in vivo and eliminated as the metabolites, the unconverted form was excreted mainly by feces route. The bioavailability, tissue distribution and excretion characteristics of 6-O-demethylmenisporphine were firstly revealed, which will provide references for further development of 6-O-demethylmenisporphine as an anti-tumor drug candidate.

Sample Preparation Focusing on Plant Omics

Because of strong impact of omics in many fields, and the complexity of the samples when focusing on areas such as genomics, (metallo)proteomics, metabolomics, among others, it is easy to rationalize the great importance that sample preparation has for achieving reliable results, mainly considering plant science. Then, this chapter points out applications of the sample preparation focusing on such areas, and a diversity of strategies, techniques, and procedures is highlighted and commented.

Rapid determination of oxindole alkaloids in cat's claw by HPLC using ionic liquid-based microwave-assisted extraction and silica monolithic column

Cat's claw is a large woody vine with hook-like thorns, and has been traditionally used to treat inflammatory disorders in South and Central America. In this study, a rapid, validated high-performance liquid chromatographic (HPLC) method using a silica monolithic column was developed for the simultaneous determination of oxindole alkaloids, namely rhynchophylline, pteropodine, isomitraphylline and isopteropodine, in cat's claw. The ionic liquid-based microwave-assisted extraction (ILMAE), considered as an environmentally friendly and powerful tool, was first applied in the extraction of oxindole alkaloids. To optimize the HPLC method, the stationary phases, pH values of mobile phase and flow rates were investigated. The validated HPLC method using a Monolithic RP_18e column (100 × 4.6 mm) enables these analytes to be separated almost twice as fast as with a conventional particulate column (~16 vs ~30 min) with limits of quantification and detection of 0.5 and 0.15 μg/mL, respectively. The ILMAE conditions were optimized by the Taguchi orthogonal array design. In comparison with conventional water boiling extraction, ILMAE offers almost four times higher yields within an extremely short extraction time. The developed HPLC coupled with ILMAE method could be efficient and practical for rapid determination of oxindole alkaloids in cat's claw.