UHPLC-HRMS/MS on untargeted metabolomics: a case study with Copaifera (Fabaceae)

Untargeted metabolomics is a powerful tool in chemical fingerprinting. It can be applied in phytochemistry to aid species identification, systematic studies and quality control of bioproducts. This approach aims to produce as much chemical information as possible, without focusing on any specific chemical class, thus, requiring extensive chemometric effort. This study aimed to evaluate the feasibly of an untargeted metabolomics method in phytochemistry by a study case of the Copaifera genus (Fabaceae). This genus contains significant medicinal species used worldwidely. Copaifera exploitation issues include a lack of chemical data, ambiguous species identification methods and absence of quality control for its bioproducts. Different organs of five Copaifera species were analysed by UHPLC-HRMS/MS, GNPS platform and chemometric tools. Untargeted metabolomics enabled the identification of 19 chemical markers and 29 metabolites, distinguishing each sample by species, plant organs, and biome type. Chemical markers were classified as flavonoids, terpenoids and condensed tannins. The applied method provided reliable information about species chemodiversity using fast workflow with little sampling size. The untargeted approach by UHPLC-HRMS/MS proved to be a promising tool for species identification, pharmacological prospecting and in the future for the quality control of extracts used in the manufacture of bioproducts.

Identification and characterization of quinoline alkaloids from the root bark of Dictamnus dasycarpus and their metabolites in rat plasma, urine and feces by UPLC/Qtrap-MS and UPLC/Q-TOF-MS

Quinoline alkaloids are the main bioactive and potentially toxic constituents in the root bark of Dictamnus dasycarpus Turcz. (BXP), a widely used traditional Chinese medicine for the treatment of skin inflammation, eczema and rubella. However, the comprehensive analysis of the chemical components and metabolites of quinoline alkaloids remain unclear. In this study, an integrated strategy by combining UPLC/Q-TOF-MS and UPLC/Qtrap-MS was established to comprehensively profile the quinoline alkaloids from BXP and their metabolites in rat plasma, urine and feces. Q-TOF-MS (MS^E mode), Qtrap-MS (EMS, MIM, pMRM and NL mode) were performed for acquiring more precursor ions and clearer precursor product ions. A step-by-step manner based on the diagnostic fragment ions (DFIs), in-house database, ClogP value and dipole moment (μ) was proposed to overcome the complexities due to the similar fragmentation behaviors of the quinoline alkaloids. As a result, a total of 73 quinoline alkaloids were unambiguously or tentatively identified. Among them, 4 furoquinolines, 10 dihydrofuroquinolines, 2 pyranoquinolinones, 4 dihydropyranoquinolinones and 9 quinol-2-ones were characterized in BXP for the first time. Moreover, a total of 98 BXP-related constituents (including 57 prototypes and 41 metabolites) were detected in rat plasma, urine and feces. The metabolic pathways included phase I reactions (O-demethylation, hydroxylation and 2,3-olefinic epoxidation) and phase II reactions (conjugation with glucuronide, sulfate and N-acetylcysteine). In conclusion, the integrated strategy with the proposed stepwise manner is suitable for rapid identifying and characterizing more extensive quinoline alkaloids of BXP in vitro and in vivo. Moreover, the results will be helpful for revealing the pharmacological effective substances or toxic substances of BXP and provide a solid basis for further research.

Synthesis of Degraded Limonoid Analogs as New Antibacterial Scaffolds against Staphylococcus aureus

Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA) have become serious infections in humans and ruminants. S. aureus strains are showing rapid changes to develop resistance in traditional antibiotic-containing systems. In the continuous fierce fight against the emergent multi-drug resistant bacterial strains, straightforward and scalable synthetic procedures to produce new active molecules are in demand. Analysis of molecular properties points to degraded limonoids as promising candidates. In this article, we report a simple synthetic approach to obtain degraded limonoid analogs as scaffolds for new antibacterial molecules. The minimum inhibitory concentrations against S. aureus were evaluated for the stereoisomer mixtures by the broth microdilution method. Analysis of results showed that the acetylated derivatives were the most active of them all.

Decoding active components in a formulation of multiple herbs for treatment of psoriasis based on three cell lines fishing and liquid chromatography-mass spectrometry analysis

Chinese medicine formula (CMF) usually contains multiple herbs and its components are very complicated, which therapeutic effects are derived from the integrative activity of multiple components. Therefore, the screening of bioactive compounds in the formula is necessary, though it is very difficult, not only for elucidating the therapeutic components but also for developing the quality control method. In this work, three cell lines fishing combined with LC-MS analysis was developed for screening the potential bioactive compounds in Fuzhengzhiyanghefuzhiyang decoction (FZHFZY), a CMF for the treatment of psoriasis in clinic. Nineteen potential active compounds were discovered and thirteen of them were identified as rehmannioside D, melittoside or rehmannioside A, tufulingoside, neoastilbin, astilbin, neoisoastilbin, isoastilbin, engeletin, isoengeletin, spinosin, cnidimoside A, rutaevin and limonin, respectively. The effects of identified components were also analyzed in vitro. The results showed that IL-1β expression of RAW 264.7 cells treated with spinosin and melittoside as well as the TNF-α level of RAW 264.7 cells treated with rehmannioside D and melittoside were not significantly different compared with lipopolysaccharide (LPS)-treated cells. Though all identified potential active components had no apoptosis effect to HaCaT cells, rehmannioside D, rehmannioside A, astilbin and neoisoastilbin could significantly suppress HUVEC cells migration compared with control. These results indicated that the target cell fishing combined with LC-MS analysis is a useful tool for screening bioactive compounds from complicated CMF, and the identified active components may mainly contribute to the therapeutic effects of FZHFZY.

Phytochemistry by design: a case study of the chemical composition of Ocotea guianensis optimized extracts focused on untargeted metabolomics analysis

Untargeted metabolomics aim to provide a global chemical fingerprint of biological matrices. This research field can be used in phytochemical screenings for bioactive species or in the identification of species. Despite its importance in providing a global chemical profile, little research has focused on the optimization of the extraction methods, as each type of matrix requires a specific procedure. Therefore, we propose to evaluate the effect of different extraction features in an ultrasound-assisted extraction for the untargeted metabolomic study of an Ocotea species, a genus of great economical interest but little chemical exploitation. Method optimization was performed in a full factorial 2232 design, evaluating the solvent composition, extraction temperature, sample particle size and sample : solvent ratio effects in the metabolomic response. The effect of these parameters on the quality of the untargeted metabolomic profiles was studied by analysis of the extraction yield as well as the chromatographic and spectrometric profiles. Most substances identified were glycosylated flavonoids and aporphinic alkaloids. The application of 70% ethanol enhanced the extraction of several specialized metabolites. Statistical analysis of extraction yield and chemical profiles indicates that high temperatures and low proportion between sample and extracting solvent reduce the quality and modify the chemical profile, both qualitatively and quantitatively. The use of 70% ethanol as the extracting solvent, 1 : 12 sample : solvent ratio, 40 °C as the extraction temperature and particle size of 0.595 mm were the optimized conditions to produce a comprehensive chemical profile for Ocotea guianensis.

The Chemistry and Pharmacology of Citrus Limonoids

Citrus limonoids (CLs) are a group of highly oxygenated terpenoid secondary metabolites found mostly in the seeds, fruits and peel tissues of citrus fruits such as lemons, limes, oranges, pumellos, grapefruits, bergamots, and mandarins. Represented by limonin, the aglycones and glycosides of CLs have shown to display numerous pharmacological activities including anticancer, antimicrobial, antioxidant, antidiabetic and insecticidal among others. In this review, the chemistry and pharmacology of CLs are systematically scrutinised through the use of medicinal chemistry tools and structure-activity relationship approach. Synthetic derivatives and other structurally-related limonoids from other sources are include in the analysis. With the focus on literature in the past decade, the chemical classification of CLs, their physico-chemical properties as drugs, their biosynthesis and enzymatic modifications, possible ways of enhancing their biological activities through structural modifications, their ligand efficiency metrics and systematic graphical radar plot analysis to assess their developability as drugs are among those discussed in detail.

Medicinal uses, phytochemistry and pharmacology of the genus Dictamnus (Rutaceae)

ETHNOPHARMACOLOGICAL RELEVANCE

Seven species from the genus Dictamnus are distributed throughout Europe and North Asia and only two species grow in China. One is Dictamnus dasycarpus Turcz., which could be found in many areas of China and has been recorded in Chinese Pharmacopoeia. The other is Dictamnus angustifolius G. Don ex Sweet, which is only present in Xinjiang province and has been used as an alternative for Dictamnus dasycarpus in the local for the treatment of rheumatism, bleeding, itching, jaundice, chronic hepatitis and skin diseases. The present paper reviewed the traditional uses, phytochemistry, pharmacology and toxicology of the genus Dictamnus.

MATERIALS AND METHODS

Information on the Dictamnus species was collected from classic books about Chinese herbal medicine and globally accepted scientific databases including PubMed, Elsevier, ASC, Scopus, Google Scholar, Web of Science, CNKI and others.

RESULTS

About 170 chemical compounds, which include quinoline alkaloids, limonoids, sesquiterpenes, coumarins, flavonoids and steroids, have been isolated from the genus Dictamnus. The characteristic and active constituents of Dictamnus species are considered to be quinoline alkaloids and limonoids, which exhibited a broad spectrum of biological activities such as anti-cancer, anti-inflammation, anti-microbe, anti-platelet-aggregation, vascular-relaxation, anti-insect, anti-HIV, anti-allergy and neuroprotection. Moreover, quinoline alkaloids and limonoids could be used as quality control markers to distinguish different species from the genus Dictamnus. However, there were also some reports on the toxic hepatitis and phototoxic effect of Dictamnus species, and the related research needs to be further studied.

CONCLUSION

In this review, we summarized the chemical constituents, pharmacology, quality control and toxicology of the species from genus Dictamnus. Phytochemical investigations indicated that quinoline alkaloids and limonoids were the major bioactive components with potential cytotoxic, neuroprotective, anti-inflammatory, antimicrobial, anti-platelet-aggregation and vascular relaxing activities. These two kinds of compounds have attracted great interests in the past few years and may have great potential to be new drug lead compounds.

Limonoids from the root bark of Dictamnus angustifolius: potent neuroprotective agents with biometal chelation and halting copper redox cycling properties

Ten limonoids were isolated from the root bark ofDictamnus angustifolius. Their metal chelating properties, the abilities to halt copper redox cycling, cell viabilities and neuroprotection studies against oxidative stress were evaluated.