Molecular Networking-Based Metabolome, In Vitro Antidiabetic and Anti-Inflammatory Effects of Breonadia salicina (Vahl) Hepper & J.R.I. Wood.

Breonadia salicina (Vahl) Hepper & J.R.I. Wood is widely distributed throughout Africa. It is used ethnobotanically to treat various diseases. However, the metabolic profile of the Breonadia species is not well characterized and the metabolites that are responsible for the bioactivity of this plant remain unknown. Therefore, there is a need to determine the phytochemical and bioactivity profile to identify metabolites that contribute to the antidiabetic, anti-inflammatory and antiproliferation activity, including the genotoxicity and cytotoxic effects, of Breonadia salicina. The study is aimed at exploring the metabolomic profile antidiabetic, anti-inflammatory and antiproliferation activity, as well as the genotoxicity and cytotoxicity effects, of constituents of B. salicina. The compounds in the B. salicina extract were analyzed by ultra-performance liquid chromatography with quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS), and the resultant data were further analyzed using a molecular networking approach. The crude stem bark and root extracts showed the highest antidiabetic activity against α-amylase at the lowest test concentration of 62.5 µg/mL, with 74.53 ± 0.74% and 79.1 ± 1.5% inhibition, respectively. However, the crude stem bark and root extracts showed the highest antidiabetic activity against α-glucosidase at the lowest test concentration of 31.3 µg/mL, with 98.20 ± 0.15% and 97.98 ± 0.22% inhibition, respectively. The crude methanol leaf extract showed a decrease in the nitrite concentration at the highest concentration of 200 µg/mL, with cell viability of 90.34 ± 2.21%, thus showing anti-inflammatory activity. No samples showed significant cytotoxic effects at a concentration of 10 µg/mL against HeLa cells. Furthermore, a molecular network of Breonadia species using UPLC-QTOF-MS with negative mode electrospray ionization showed the presence of organic oxygen compounds, lipids, benzenoids, phenylpropanoids and polyketides. These compound classes were differentially distributed in the three different plant parts, indicating the chemical differences between the stem bark, root and leaf extracts of B. salicina. Therefore, the identified compounds may contribute to the antidiabetic and anti-inflammatory activity of Breonadia salicina. The stem bark, root and leaf extracts of B. salicina yielded thirteen compounds identified for the first time in this plant, offering a promising avenue for the discovery of new lead drugs for the treatment of diabetes and inflammation. The use of molecular networking produced a detailed phytochemical overview of this Breonadia species. The results reported in this study show the importance of searching for bioactive compounds from Breonadia salicina and provide new insights into the phytochemical characterization and bioactivity of different plant parts of Breonadia salicina.

Effects of seasonal variation on phytochemicals contributing to the antimalarial and antitrypanosomal activities of Breonadia salicina using a metabolomic approach.

This study involves the investigation of various plant parts of Breonadia salicina (Vahl) Hepper and J.R.I. Wood across multiple consecutive seasons. It aims to delve into the phytochemistry of these different plant parts and establish connections between the findings and their biological activities. This comprehensive approach employs metabolomics techniques, with the ultimate goal of exploring the potential for drug development. Samples were collected in Fondwe, a village in Limpopo (South Africa), based on local reports of the efficacy of this plant used by traditional healers in the area. The antimalarial and antitrypanosomal activities of samples collected over the seasons were determined with the parasite lactate dehydrogenase (pLDH) and specific Trypanosoma brucei assays, respectively. Consequently, a total of 24 compounds were tentatively identified through ultra-performance liquid chromatography with quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS). Chemical profiles of the different plant parts of Breonadia salicina collected in different seasons produced contrasting metabolic profiles. Chemometric analysis of the UPLC-QTOF-MS data enabled us to determine the chemical variability of the crude stem bark, root and leaf extracts (n = 48) collected over four consecutive seasons by evaluating the metabolomics fingerprinting of the samples using an untargeted approach. Principal component analysis (PCA), hierarchical cluster analysis (HCA), and partial least squares discriminant analysis (PLS-DA) indicated the existence of two key clusters that are linked to the root, stem bark, and leaves. The stem and root chemistry differed from that of the leaves. Seasonal variations were noted in each plant part, with autumn and winter samples closely grouped compared to spring and summer samples in the methanol leaf extracts. Biochemometric analysis could not relate specific compounds to the antimalarial and antitrypanosomal activities of the active extracts, underscoring the intricate interactions among the secondary metabolites. This study further confirms the optimal plant parts to collect in each season for the most effective antimalarial and antitrypanosomal activities.

Recent advances of bifunctional catalysts for zinc air batteries with stability considerations: from selecting materials to reconstruction.

With the growing depletion of traditional fossil energy resources and ongoing enhanced awareness of environmental protection, research on electrochemical energy storage techniques like zinc-air batteries is receiving close attention. A significant amount of work on bifunctional catalysts is devoted to improving OER and ORR reaction performance to pave the way for the commercialization of new batteries. Although most traditional energy storage systems perform very well, their durability in practical applications is receiving less attention, with issues such as carbon corrosion, reconstruction during the OER process, and degradation, which can seriously impact long-term use. To be able to design bifunctional materials in a bottom-up approach, a summary of different kinds of carbon materials and transition metal-based materials will be of assistance in selecting a suitable and highly active catalyst from the extensive existing non-precious materials database. Also, the modulation of current carbon materials, aimed at increasing defects and vacancies in carbon and electron distribution in metal-N-C is introduced to attain improved ORR performance of porous materials with fast mass and air transfer. Finally, the reconstruction of catalysts is introduced. The review concludes with comprehensive recommendations for obtaining high-performance and highly-durable catalysts.

A Separator with Double Coatings of Li4 Ti5 O12 and Conductive Carbon for Li-S Battery of Good Electrochemical Performance.

The market demand for energy pushes researchers to pay a lot of attention to Li-S batteries. However, the 'shuttle effect', the corrosion of lithium anodes, and the formation of lithium dendrites make the poor cycling performances (especially under high current densities and high sulfur loading) of Li-S batteries, which limit their commercial applications. Here, a separator is prepared and modified with Super P and LTO (abbreviation SPLTOPD) through a simple coating method. The LTO can improve the transport ability of Li+ cations, and the Super P can reduce the charge transfer resistance. The prepared SPLTOPD can effectively barrier the pass-through of polysulfides, catalyze the reactions of polysulfides into S2- , and increase the ionic conductivity of the Li-S batteries. The SPLTOPD can also prevent the aggregation of insulating sulfur species on the surface of the cathode. The assembled Li-S batteries with the SPLTOPD can cycle 870 cycles at 5 C with the capacity attenuation of 0.066% per cycle. When the sulfur loading is up to 7.6 mg cm-2 , the specific discharge capacity at 0.2 C can reach 839 mAh g-1 , and the surface of lithium anode after 100 cycles does not show the existence lithium dendrites or a corrosion layer. This work provides an effective way for the preparation of commercial separators for Li-S batteries.

In situ bridging nanotwinned all-solid-state Z-scheme g-C3N4/CdCO3/CdS heterojunction photocatalyst by metal oxide for H2 evolution.

Nanotwin and all-solid-state (ASS) Z-scheme heterojunction engineering are two widely used strategies for improving photocatalytic activity in H2 production. However, both strategies fail to produce a satisfactory effect when used alone due to their own limitations. Hence, combining nanotwin and ASS Z-scheme heterojunction engineering is expected to improve photocatalytic activity effectively. Herein, we report a nanotwinned ASS Z-scheme g-C3N4/CdCO3/CdS (CN/CC/CS) photocatalyst synthesized for the first time by in situ bridging of (CN) and (CS) with a (CC) conductor. The growth and ripening of CN/CC/CS are limited by thiourea (Tu) and CN. CN/CC/CS can improve charge carrier separation and transfer kinetics due to the synergetic advantages of its nanotwin structure, ASS Z-scheme junction, N-Cd chemically bonded interfaces, in situ intimate contact, and hierarchical architecture. The visible-light-driven H2 production rate of CN/CC/CS is 345% of that of CN/CS. This work proposes a new method for rationally designing novel materials with improved photocatalytic activity by combining heterojunction and defect engineering.

Agar Acts as Cathode Microskin to Extend the Cycling Life of Zn//α-MnO2 Batteries.

The Zn/MnO2 battery is a promising energy storage system, owing to its high energy density and low cost, but due to the dissolution of the cathode material, its cycle life is limited, which hinders its further development. Therefore, we introduced agar as a microskin for a MnO2 electrode to improve its cycle life and optimize other electrochemical properties. The results showed that the agar-coating layer improved the wettability of the electrode material, thereby promoting the diffusion rate of Zn2+ and reducing the interface impedance of the MnO2 electrode material. Therefore, the Zn/MnO2 battery exhibited outstanding rate performance. In addition, the agar-coating layer promoted the reversibility of the MnO2/Mn2+ reaction and acted as a colloidal physical barrier to prevent the dissolution of Mn2+, so that the Zn/MnO2 battery had a high specific capacity and exhibited excellent cycle stability.

An Artificial Polyacrylonitrile Coating Layer Confining Zinc Dendrite Growth for Highly Reversible Aqueous Zinc-Based Batteries.

Aqueous rechargeable zinc-metal-based batteries are an attractive alternative to lithium-ion batteries for grid-scale energy-storage systems because of their high specific capacity, low cost, eco-friendliness, and nonflammability. However, uncontrollable zinc dendrite growth limits the cycle life by piercing the separator, resulting in low zinc utilization in both alkaline and mild/neutral electrolytes. Herein, a polyacrylonitrile coating layer on a zinc anode produced by a simple drop coating approach to address the dendrite issue is reported. The coating layer not only improves the hydrophilicity of the zinc anode but also regulates zinc-ion transport, consequently facilitating the uniform deposition of zinc ions to avoid dendrite formation. A symmetrical cell with the polymer-coating-layer-modified Zn anode displays dendrite-free plating/stripping with a long cycle lifespan (>1100 h), much better than that of the bare Zn anode. The modified zinc anode coupled with a Mn-doped V2 O5 cathode forms a stable rechargeable full battery. This method is a facile and feasible way to solve the zinc dendrite problem for rechargeable aqueous zinc-metal batteries, providing a solid basis for application of aqueous rechargeable Zn batteries.

Nanomaterials for the electrochemical nitrogen reduction reaction under ambient conditions.

As an important chemical product and carbon-free energy carrier, ammonia has a wide range of daily applications in several related fields. Although the industrial synthesis method using the Haber-Bosch process could meet production demands, its huge energy consumption and gas emission limit its long-time development. Therefore, the clean and sustainable electrocatalytic N2 reduction reaction (NRR) operating under conditions have attracted great attention in recent years. However, the chemical inertness of N2 molecules makes it difficult for this reaction to proceed. Therefore, rationally designed catalysts need to be introduced to activate N2 molecules. Here, we summarize the recent progress in low-dimensional nanocatalyst development, including the relationship between the structure and NRR performance from both the theoretical and experimental perspectives. Some insights into the development of NRR electrocatalysts from electronic control aspects are provided. In addition, the theoretical mechanisms, reaction pathways and credibility studies of the NRR are discussed. Some challenges and future prospects of the NRR are also pointed out.

In Vitro Studies on Antioxidant and Anti-Parasitic Activities of Compounds Isolated from Rauvolfia caffra Sond.

As part of an ongoing study of natural products from local medicinal plants, the methanol extract of stem bark of Rauvolfia caffra Sond was investigated for biological activity. Column chromatography and preparative thin-layer chromatography were used to isolate lupeol (1), raucaffricine (2), N-methylsarpagine (3), and spegatrine (4). The crude extract, fractions and isolated compounds were tested for anti-oxidant, antitrypanosomal and anti-proliferation activities. Two fractions displayed high DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging activity and reducing power with IC50 (The half maximal inhibitory concentration) and IC0.5 values of 0.022 ± 0.003 mg/mL and 0.036 ± 0.007 mg/mL, and 0.518 ± 0.044 mg/mL and 1.076 ± 0.136 mg/mL, respectively. Spegatrine (4) was identified as the main antioxidant compound in R. caffra with IC50 and IC0.5 values of 0.119 ± 0.067 mg/mL and 0.712 ± 0 mg/mL, respectively. One fraction displayed high antitrypanosomal activity with an IC50 value of 18.50 µg/mL. However, the major constituent of this fraction, raucaffricine (2), was not active. The crude extract, fractions and pure compounds did not display any cytotoxic effect at a concentration of 50 µg/mL against HeLa cells. This study shows directions for further in vitro studies on the antioxidant and antitrypanosomal activities of Rauvolfia caffra Sond.

Isolation, Chemical Profile and Antimalarial Activities of Bioactive Compounds from Rauvolfia caffra Sond.

In this study, the chemical profile of a crude methanol extract of Rauvolfia caffra Sond was determined by ultra-performance liquid chromatography-mass spectrometry (UPLC-MS). Column chromatography and preparative thin layer chromatography were used to isolate three indole alkaloids (raucaffricine, N-methylsarpagine and spegatrine) and one triterpenoid (lupeol). The antiplasmodial activity was determined using the parasite lactate dehydrogenase (pLDH) assay. The UPLC-MS profile of the crude extract reveals that the major constituents of R. caffra are raucaffricine (m/z 513.2) and spegatrine (m/z 352.2). Fraction 3 displayed the highest antiplasmodial activity with an IC50 of 6.533 µg/mL. However, raucaffricine, isolated from the active fraction did not display any activity. The study identifies the major constituents of R. caffra and also demonstrates that the major constituents do not contribute to the antiplasmodial activity of R. caffra.

Bioactive compounds from the endophytic fungus Fusarium proliferatum.

The crude extract of an endophytic fungus isolated from Syzygium cordatum and identified as Fusarium proliferatum showed 100% cytotoxicity against the brine shrimp Artemia salina at 100 µg/mL. Seven coloured, biologically active metabolites - including ergosta-5,7,22-trien-3ß-ol, nectriafurone-8-methyl ether, 9-O-methyl fusarubin, bostrycoidin, bostrycoidin-9-methyl ether and 8-hydroxy-5,6-dimethoxy-2-methyl-3-(2-oxo-propyl)-1,4-naphthoquinone- were isolated from the extract.

The genus Pluchea: phytochemistry, traditional uses, and biological activities.

In this review, literature data on phytochemical and biological investigations on the genus Pluchea are compiled. Pluchea is a genus of flowering plants in the Asteraceae family and comprises ca. 80 species distributed mainly in Northern and Southern America, Africa, Asia, and Australia. Sesquiterpenoids and flavonoids are the main constituents of this genus. Compounds isolated from plants of the Pluchea genus display a variety of biological properties, viz., anticancer, antileishmanial, immunosuppressive, antioxidant, anti-acetylcholinesterase, antimicrobial, trypanocidal, hepatoprotective, cytotoxic, larvicidal, anti-ulcer, anti-inflammatory, and antinociceptive activities.

Isolation and relative stereochemistry of lippialactone, a new antimalarial compound from Lippia javanica.

The aerial parts of Lippia javanica were investigated for biologically active chemical compounds present in them. Chromatographic separation of the ethyl acetate extract of the aerial parts yielded a new antimalarial α-pyrone, lippialactone (2). Lippialactone is active against the chloroquine-sensitive D10 strain of Plasmodium falciparum with an IC50 value of 9.1 µg/mL, and is also mildly cytotoxic. The relative stereochemistry of lippialactone was determined by molecular modeling based on the determination of the relative configuration by quantum mechanical GIAO (13)C chemical shift calculations.

Chemistry and biology of genus Vismia.

CONTEXT: Many herbal remedies have been employed in the treatment and management of various human ailments since the beginning of human civilization. Vismia is an extensive genus of the family Hypericaceae and consists of small trees inhabiting the tropical and subtropical regions of South and Central America. Within the framework of an International Cooperative Biodiversity Groups project, three Vismia species were studied for their potential anticancer activity. OBJECTIVES: This review is an extensive study of the available scientific literature published and comprises of the ethnopharmacological, phytochemical and therapeutic potential of genus of plants under the umbrella Vismia. METHODS: The present review includes 134 natural products with 47 references compiled from the major databases, viz., Chemical Abstracts, Science Direct, SciFinder, PubMed, Dr. Dukes Phytochemical and Ethnobotany, CIMER, and InteliHealth. RESULTS: An exhaustive survey of the accessed literature revealed that flavonoids, flavanols, xanthones, anthraones, anthraquinones, benzophenones, lignans, steroids, monoterpenes and triterpenes constituted the major classes of phytoconstituents of this genus. Pharmacological reports revealed that it is used for skin diseases such as dermatitis, leprosy, syphilis, herpes, scabies and eczemas, and as an anticancer for human breast, CNS, and lung cancer cell lines. CONCLUSION: Genus Vismia plants seem to hold great potential for an in-depth investigation towards discovering biological activities, especially for the treatment of cancers affecting our society. Through this review, the authors hope to attract the attention of natural product researchers throughout the world to focus on the unexplored potential of Vismia plants, with the view of developing new formulations with an improved therapeutic value.

Phomosines H-J, novel highly substituted biaryl ethers, isolated from the endophytic fungus Phomopsis sp. from Ligustrum vulgare.

From the endophytic fungus Phomosis sp., four known phomosines A-D (1-4) and three new phomosines H-J (5-7) have been isolated. The structures of the new compounds were determined on the basis of their spectroscopic data analysis (1H, 13C, 1H-1H COSY, HMQC, and HMBC NMR, as well as mass spectrometry). The structures of phomosine H (5) and J (7) were also confirmed by semisynthesis from phomosine A (1). The remaining four known compounds [phomosines A-D (1-4)] were identified by comparing their spectroscopic data with those reported in the literature. The four known metabolites were biologically active. Of the novel metabolites, only 6 was antifungal and antibacterial.

Composition and antimicrobial activities of volatile components of Lippia javanica.

The volatile oil of Lippia javanica was prepared by hydrodistillation of leaves, flowers and stems, and characterized by GC-MS. The major component was 3-methyl-6-(1-methylethylidene)-cyclohex-2-en-1-one. The oil was tested for antimicrobial activity on cultures of Escherichia coli, Bacillus subtilis and Staphylococcus aureus, and found to inhibit E. coli and S. aureus at 1% dilution. The oil was also active against Plasmodium falciparum in micromolar concentrations.

2,4-trans-,7 4'-dihydroxy-4-methoxyflavan from Cassia abbreviata.

2,4-Trans-7,4'-dihydroxy-4-methoxyflavan has been characterised from Cassia abbreviata.