Simultaneous identification and quantification of polymethoxyflavones, coumarin and phenolic acids in Ageratum conyzoides by UPLC-ESI-QToF-MS and UPLC-PDA

Analysis of Pyrrolizidine Alkaloids in Stingless Bee Honey and Identification of a Botanical Source as Ageratum conyzoides

Stingless bee honeys (SBHs) from Australian and Malaysian species were analysed using ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) for the presence of pyrrolizidine alkaloids (PAs) and the corresponding N-oxides (PANOs) due to the potential for such hepatotoxic alkaloids to contaminate honey as a result of bees foraging on plants containing these alkaloids. Low levels of alkaloids were found in these SBHs when assessed against certified PA standards in targeted analysis. However, certain isomers were identified using untargeted analysis in a subset of honeys of Heterotrigona itama which resulted in the identification of a PA weed species (Ageratum conyzoides) near the hives. The evaluation of this weed provided a PA profile matching that of the SBH of H. itama produced nearby, and included supinine, supinine N-oxide (or isomers) and acetylated derivatives. These PAs lacking a hydroxyl group at C7 are thought to be less hepatoxic. However, high levels were also observed in SBH (and in A. conyzoides) of a potentially more toxic diester PA corresponding to an echimidine isomer. Intermedine, the C7 hydroxy equivalent of supinine, was also observed. Species differences in nectar collection were evident as the same alkaloids were not identified in SBH of G. thoracica from the same location. This study highlights that not all PAs and PANOs are identified using available standards in targeted analyses and confirms the need for producers of all types of honey to be aware of nearby potential PA sources, particularly weeds.

The aqueous extracts of Ageratum conyzoides inhibit inflammation by suppressing NLRP3 inflammasome activation

ETHNOPHARMACOLOGICAL RELEVANCE

Ageratum conyzoides L. (Asteraceae), a well-known and widely distributed traditional tropical medicinal herb, has been used to treat diverse diseases. Our preliminary research has shown that aqueous extracts of A. conyzoides leaf (EAC) have anti-inflammatory activity. However, the detailed underlying anti-inflammatory mechanism of EAC is still unclear.

AIM OF THE STUDY

To determine the anti-inflammatory mechanism of action of EAC.

MATERIALS AND METHODS

The major constituents of EAC were identified by ultra-performance liquid chromatography (UPLC) combined with quadrupole-time-of-flight mass/mass spectrometry (UPLC-Q-TOF-MS/MS). LPS and ATP were used to activate the NLRP3 inflammasome in two types of macrophages (RAW 264.7 and THP-1 cells). The cytotoxicity of EAC was measured by the CCK8 assay. The levels of inflammatory cytokines and NLRP3 inflammasome-related proteins were detected by ELISA and western blotting (WB), respectively. The oligomerization of NLRP3 and ASC and the resulting inflammasome complex formation were observed by immunofluorescence. The intracellular reactive oxygen species (ROS) level was measured by flow cytometry. Finally, an MSU-induced peritonitis model was established to evaluate the anti-inflammatory effects of EAC in vivo.

RESULTS

Twenty constituents were identified in the EAC. Kaempferol 3,7-diglucoside, 1,3,5-tricaffeoylquinic acid, and kaempferol 3,7,4'-triglucoside were found to be the most potent ingredients. EAC significantly reduced the levels of IL-1β, IL-18, TNF-α, and caspase-1 in the two types of activated macrophages, implying that EAC can inhibit the activation of the NLRP3 inflammasome. A mechanistic study revealed that EAC inhibited NLRP3 inflammasome activation by blocking NF-κB signalling pathway activation and scavenging the level of intracellular ROS to prevent NLRP3 inflammasome assembly in macrophages. Furthermore, EAC attenuated the in vivo expression of inflammatory cytokines by suppressing NLRP3 inflammasome activation in a peritonitis mouse model.

CONCLUSION

Our results demonstrated that EAC inhibited inflammation by suppressing NLRP3 inflammasome activation, highlighting that this traditional herbal medicine might be used to treat NLRP3 inflammasome-driven inflammatory diseases.

The Free Radical Scavenging Property of the Leaves, Branches, and Roots of Mansoa hirsuta DC: In Vitro Assessment, 3D Pharmacophore, and Molecular Docking Study

In this work, a metabolic profile of Mansoa hirsuta was investigated, and in vitro assays and theoretical approaches were carried out to evaluate its antioxidant potential. The phytochemical screening detected saponins, organic acids, phenols, tannins, flavonoids, and alkaloids in extracts of leaves, branches, and roots. Through LC-MS analysis, the triterpenes oleanolic acid (m/z 455 [M-H]⁻) and ursolic acid (m/z 455 [M-H]⁻) were identified as the main bioactive components. The extracts of the leaves, branches, and roots revealed moderate antioxidant potential in the DPPH test and all extracts were more active in the ABTS test. The leaf extracts showed better antioxidant capacity, displaying IC₅₀ values of 43.5 ± 0.14, 63.6 ± 0.54, and 56.1 ± 0.05 µg mL⁻¹ for DPPH, ABTS, and kinetics assays, respectively. The leaf extract showed higher total flavonoid content (TFC) (5.12 ± 1.02 mg QR/g), followed by branches (3.16 ± 0.88 QR/g) and roots (2.04 ± 0.52 QR/g/g). The extract of the branches exhibited higher total phenolic content (TPC) (1.07 ± 0.77 GAE/g), followed by leaves (0.58 ± 0.30 GAE/g) and roots (0.19 ± 0.47 GAE/g). Pharmacophore and molecular docking analysis were performed in order to better understand the potential mechanism of the antioxidant activity of its major metabolites.

Turning Waste into Beneficial Resource: Implication of Ageratum conyzoides L. in Sustainable Agriculture, Environment and Biopharma Sectors

The annual herb, Ageratum conyzoides L. (Asteraceae), is distributed throughout the world. Although invasive, it can be very useful as a source of essential oils, pharmaceuticals, biopesticides, and bioenergy. However, very limited information exists on the molecular basis of its different utility as previous investigations were mainly focused on phytochemical/biological activity profiling. Here we have explored various properties of A. conyzoides that may offer environmental, ecological, agricultural, and health benefits. As this aromatic plant harbors many important secondary metabolites that may have various implications, biotechnological interventions such as genomics, metabolomics and tissue-culture can be indispensable tools for their mass-production. Further, A. conyzoides acts as a natural reservoir of begomoviruses affecting a wide range of plant species. As the mechanisms of disease spreading and crop infection are not fully clear, whole-genome sequencing and various advanced molecular technologies including RNAi, CRISPER/Cas9, multi-omics approaches, etc., may aid to decipher the molecular mechanism of such disease development and thus, can be useful in crop protection. Overall, improved knowledge of A. conyzoides is not only essential for developing sustainable weed control strategy but can also offer potential ways for biomedicinal, environment, safe and clean agriculture applications.

Development and Validation of a Reversed Phase High Performance Liquid Chromatography-Photodiode Array Detection Method for Simultaneous Identification and Quantification of Coumarin, Precocene-I, β-Caryophyllene Oxide, α-Humulene, and β-Caryophyllene in Ageratum Conyzoides Extracts and Essential Oils from Plants

BACKGROUND

Ageratum conyzoides is an aromatic plant. It is considered as an invasive and cosmopolite weed, widely spread in tropical and subtropical regions. Phytochemicals such as benzopyrenes, flavonoids, and terpenoids are reported from A. conyzoides.

OBJECTIVE

Development and validation of a reversed-phase HPLC-photodiode array (PDA) detection method for simultaneous identification and quantification of coumarin, precocene-I, β-caryophyllene oxide, α-humulene, and β-caryophyllene in extracts of A. conyzoides and essential oils was carried out.

METHODS

Separation of analytes was achieved on a RP-18 (250 mm × 4.6 mm, 5 µm) column using a solvent system comprising of a mixture of acetonitrile and water with 0.05% trifluoroacetic acid in gradient elution mode at ambient temperature with flow rate of 1 mL/min.

RESULTS

The retention time of coumarin, precocene-I, β-caryophyllene oxide, α-humulene, and β-caryophyllene was 4.38, 12.86, 20.10, 33.34, and 35.11 min, respectively. Limits of detection for coumarin, precocene-I, β-caryophyllene oxide, α-humulene, and β-caryophyllene were 2.5, 2.5, 2.5, 0.025, and 2.5 µg/mL, respectively. Similarly, LOQ were 10, 10, 10, 0.10, and 10 µg/mL for coumarin, precocene-I, β-caryophyllene oxide, α-humulene, and β- caryophyllene, respectively. Repeatabilities (RSD, %) values for intraday and interday precision for coumarin, precocene-I, β-caryophyllene oxide, α-humulene, and β-caryophyllene was 0.765-2.086 and 0.886-2.128; 0.879-1.672 and 0.979-1.825; 0.696-2.418 and 0.768-2.592; 1.728-2.362 and 1.965-2.378; 1.615-2.897 and 1.658-2.906, respectively.

CONCLUSIONS

The separation of five analytes was achieved within 50 min. The developed and validated HPLC-PDA method was successfully applied for identification and quantification of above five analytes in A. conyzoides extracts and essential oils. The method could be used for meeting the characterization criteria of phytoformulations.

Metabolomic analysis among ten traditional "Arnica" (Asteraceae) from Brazil

ETHNOPHARMACOLOGICAL RELEVANCE

Extracts of several Asteraceae species in Brazil are popularly used as anti-inflammatory. Some of these species are popularly recognizes as "arnica" because of the morphological and sensorial analogy with the traditional European Arnica montana. These used species in Brazil were identified as Calea uniflora Less, Chaptalia nutans (L.) Polák, Lychnophora ericoides Mart. Lychnophora pinaster Mart. Lychnophora salicifolia Mart. Porophyllum ruderale (Jacq.) Cass, Pseudobrickellia brasiliensis (Spreng.) R. M. King & H. Rob. Sphagneticola trilobata (L.) Pruski and Solidago chilensis Meyen. However, the comparative chemical profile of these so-called "arnicas" has never been reported in the literature.

AIM OF THE STUDY

This work aimed to compare the main plants recognized as "arnica" in Brazil by using metabolomic analysis, based on UPLC-ESI-QTof-MS² data and multivariate statistical analysis.

MATERIALS AND METHODS

The metabolites profiling of 10 "arnica" species were established by UPLC-ESI-QTof-MS². Three tinctures of each species (dry leaves) were produced and one aliquot of each tincture was injected and analyzed three times by UPLC-ESI-QTof-MS². Data were acquired both in negative and positive modes and processed by MassLynx®, MarkerLynx® and Matlab® softwares. Principal component analysis (PCA) was used to reduce dimensionality and data redundancy; hierarchical trees helped to identify and eliminate contaminated or misplaced injections/samples. To achieve the objectives both hierarchical and k-means clustering techniques were employed to group similar samples or species.

RESULTS

Diagnostic analysis of MS data allowed the identification of 54 metabolites. The identification was supported with the use of an external standard, fragmentation pattern and data from the literature. The main classes of identified compounds included phenolic acids, coumarin, flavonoids, heterosides, terpenoids and nitrogen compounds. Cluster analysis revealed that Sphagneticola trilobata, Solidago chilensis and Lychnophora pinaster have some chemical features similar to those of Arnica montana. In contrast, the same statistical analysis also showed that Pseudobrickellia brasiliensis, Porophyllum ruderale and Chaptalia nutans are chemically diverse from Arnica montana. The variability of the samples relied principally on nitrogenated compounds (confidence level 4) found in P. brasiliensis and P. ruderale, three phenolic compounds (level 2) detected in P. brasiliensis and in C. nutans and triterpenes (level 3) found in L. salicifolia and L. pinaster.

CONCLUSIONS

In summary, the mass spectrometry technique in conjunction with multivariate statistical analysis proved to be an excellent tool to identify correlated compounds, as well as to verify the chemical similarity among evaluated species. This methodology was successfully used to establish important correlations in medicinal preparations of so-called "arnicas" used in Brazil.

Phytochemical Analysis, Anti-inflammatory, and Antioxidant Activities of Dendropanax dentiger Roots

Dendropanax dentiger root is a traditional medicinal plant in China and used to treat inflammatory diseases for centuries, but its phytochemical profiling and biological functions are still unknown. Thus, a rapid, efficient, and precise method based on ultra high-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UHPLC-Q-TOF-MS/MS) was applied to rapidly analyse the phytochemical profiling of D. dentiger with anti-inflammatory and antioxidant activities in vitro. As a result, a total of 78 chemical compositions, including 15 phenylpropanoids, 15 alkaloids, 14 flavonoids, 14 fatty acids, 7 phenols, 4 steroids, 4 cyclic peptides, 3 terpenoids, and 2 others, were identified or tentatively characterized in the roots of D. dentiger. Moreover, alkaloid and cyclic peptide were reported from D. dentiger for the first time. In addition, the ethanol crude extract of D. dentiger roots exhibited remarkable anti-inflammatory activity against cyclooxygenase- (COX-) 2 inhibitory and antioxidant activities in vitro. This study is the first to explore the phytochemical analysis and COX-2 inhibitory activity of D. dentiger. This study can provide important phytochemical profiles and biological functions for the application of D. dentiger roots as a new source of natural COX-2 inhibitors and antioxidants in pharmaceutical industry.

[Examination of Extraction Conditions of Chlorogenic Acid and Its Content in Domestic Phellodendron amurense Leaves]

Phellodendron amurense is a broad-leaved tree; its outer bark and cork layers are removed and used as a crude medicinal agent known as Phellodendri Cortex. These trees are cultivated for approximately 15 to 20 years, harvested by felling, and processed by separating the outer and inner bark. Conventionally, parts other than the inner bark (i.e., fruit, leaves, and heartwood) remain unused. However, the revenue earned from by-products could contribute to continued cultivation of Phellodendron amurense. Herein, we examined the extraction condition and investigated the content of chlorogenic acid in the leaves of domestic Phellodendron amurense, which possesses antioxidant activity.