Gerhard Prinsloo

Medicinal plants remain vital to drug discovery due to their diverse secondary metabolites. Anonidium mannii, an underutilized plant traditionally used for fever, diabetes, cancers, and infections, was evaluated for its pharmacological and metabolomic profiles using hexane, chloroform, and butanol-water extracts. Antibacterial activity against six pathogenic bacteria, antioxidant potential (2,2-diphenyl-1-picrylhydrazyl (DPPH) assay), and cytotoxicity on Vero and HepG2 cells (MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay) were assessed. Chemical profiling employed integrated LC-MS and GC-MS. The butanol-water extract exhibited strong antibacterial effects (MIC: 0.62-5.0 mg/mL) and potent antioxidant activity (IC₅₀: 0.44 ± 0.05 µg/mL), while the hexane extract showed notable selectivity toward HepG2 cells (SI: 1.99). LC-MS revealed bioactive metabolites, including flavonoids and caffeoylquinic acids, most reported here for the first time in A. mannii. GC-MS tentatively identified several bioactive hydrocarbons and esters with known anticancer properties. These results provide evidence of antibacterial, antioxidant, and cytotoxic activities in A. mannii leaf extracts, consistent with its traditional uses.

Sea cucumbers are soft-bodied marine invertebrates revered for their potent health benefits derived from biologically active molecules. However, research has primarily focused on commercially valuable species, such as Apostichopus japonicus, leading to their overexploitation as well as neglect of other species that may also contain valuable metabolites and nutritional value. This study presents the first untargeted metabolomic comparison of two southern African sea cucumber species, Holothuria cinerascens and Pseudocnella sykion, using proton nuclear magnetic resonance and ultra-performance liquid chromatography quadrupole time-of-flight high-resolution mass spectrometry. These species were selected due to their limited prior study and their overlapping habitats along the KwaZulu-Natal coastline. Despite their shared geographical locality, they exhibit distinct metabolic profiles. H. cinerascens displayed elevated levels of metabolites involved in osmoregulation (betaine), energy and amino acid metabolism (xylose, glucose, alanine, glutamate, glutamine, lysine and taurine) and defence metabolites, including the presence of several triterpene glycosides, whereas P.sykion notably contained rosmarinic acid and higher proline levels. These differences probably reflectgenetic, ecological and reproductive variations between the species. Even though it provides insightsinto sea cucumber metabolism, this study also underscores the challenges in holothurian metabolomics,including the scarcity of holothurian-specific annotations in metabolite databases and the absence of thesespecies in the Dictionary of Marine Natural Products. By establishing the baseline metabolic compositionsof these understudied species, this work provides a foundation for targeted metabolomics to elucidate theirmetabolic pathways, discover novel bioactive compounds, expand aquaculture practices, foster economicopportunities and advance sustainable resource management and conservation efforts.

Maize is an important crop worldwide with approximately 1200 million tons consumed and a market size worth $143 billion. Environmental stress influence production of crops and mitigating these ensures optimum production. Dicarboxylic acids are known as emulsifying agents that mitigate various stresses in plants. Previous reports have shown that mixtures of dicarboxylic acids like azelaic and sebacic acid are equally important for plants and have improved plant resistance to stress by directly or indirectly affecting metabolic components. In this study, maize plants in their six‐leaf (V6) growth stage were sprayed with a mixture of dicarboxylic acids (photon) to investigate the effect of priming on the metabolic profile of maize. A nontargeted ¹ H‐NMR‐based metabolic approach was used to determine the metabolic responses of maize sprayed with photon and grown under the same conditions. Leaf samples were collected at various time points (1 h, 2 h, 12 h, 24 h, 1 week, 2 weeks, and 3 weeks) after application of photon. Orthogonal partial least squares–discriminant analysis (OPLS‐DA) revealed various metabolites that were involved in tolerance to plant stress. A significant increase in salicylic acid (SA) and azelaic acid (AzA) was observed in photon‐treated samples compared to the controls, and it was also responsible for an increase in amino acids (GABA, alanine, and asparagine) and sugars (sucrose, maltose, and trehalose). In addition, malate and aconitate accumulated after 2 h of treatment and were found to be present in higher concentrations in the treated maize leaf extracts. Since SA was identified as one of the major compounds in treated plants, the enzymatic antioxidants (SOD, CAT, and SOD) were further evaluated. Limited SOD and CAT activity at concentrations ranging from 16.63 to 3.91 µg/mL was detected. The POD showed the lowest activity with no significant differences between photon‐treated and untreated extracts. The results indicate that maize plants treated with photon showed appreciable changes in various metabolites, although no significant priming effect on antioxidant enzyme activities was detected. Therefore, the priming effect is proposed to involve the SAR in maize.

The use of botanicals and herbal products is increasing globally, especially in developed countries, but their active ingredients are often poorly defined and inconsistently regulated. Moreover, the chemical composition of plants is usually influenced by internal factors (such as genetics, phenology, and age) and external influences (such as environmental conditions). These influences can significantly alter chemical profiles, which is critical for plants used in food, cosmetics, and medicine. Growing concern over harmful compounds in these products highlights the variability in their levels. Specifically, some compounds in plants are known to have genotoxic or carcinogenic effects, and their concentrations can vary greatly depending on these factors. This paper reviews how factors like water stress, soil nutrients, geographic location, and plant development affect the presence of hazardous substances in plants. While genetic factors like chemotypes and cultivars are well-studied, less is known about how environmental and developmental conditions affect chemically uniform plants. Overall, the current work emphasizes the unpredictability of these effects and underscores the need for further research to compare the levels of hazardous compounds in plants against established human safety thresholds, to better assess exposure risks in food, cosmetic and herbal products.

Sea cucumbers, marine invertebrates increasingly recognised for their valuable biomolecules, are in growing demand due to the rising preference for marine products as safer, less toxic, and environmentally friendly alternatives to synthetic or terrestrial counterparts. Metabolomics analysis provides a comprehensive approach for investigating the metabolic dynamics of marine organisms, enabling the discovery of their nutritional and biochemical potential. This study aimed to perform an untargeted metabolomics analysis of Thyone aurea body tissue and crude storage-ethanol extracts using ¹H NMR. Additionally, full-scan UPLC-QTOF-MS was used to confirm the NMR-metabolomics annotation and to provide more information on the chemical profile of T. aurea. Both the analytical techniques were used to assess the extent of metabolite leaching during solvent storage and its methodological implications for compound profiling. The analysis revealed distinct metabolite patterns between the tissue and extract, particularly for amino acids, triterpene glycosides, aliphatic organosulphates, and carboxylic acids. Overall, both the body tissue and storing-ethanol extracts demonstrated high metabolite potential and variability, emphasising the role of solvent storage in influencing metabolic profiles. These findings suggest that the chemical composition of sea cucumber samples can be significantly impacted by storage conditions, which must be carefully considered during metabolite profiling. Further research is warranted to elucidate the metabolic pathways of T. aurea and to expand our understanding of sea cucumbers more broadly. This study contributes to the growing field of marine metabolomics and establishes a foundation for future research on a wider range of lesser-studied, potentially endemic sea cucumber species.

Burkea africana is a tree found in savannah and woodland in southern Africa, as well as northwards into tropical African regions as far as Nigeria and Ethiopia. It is used as fuel wood, medicinally to treat various conditions, such as toothache, headache, migraine, pain, inflammation, and sexually transmitted diseases, such as gonorrhoea, but also an ornamental tree. The current study investigated the possible symbiotic relationship between B. africana trees and the C. forda caterpillars and the mutual role played in ensuring the survival of B. africana trees/seedlings in harsh natural conditions and low-nutrient soils. Deoxyribonucleic acid isolation and sequencing results revealed that the fungal species Pleurostomophora richardsiae was highly predominant in the leaves of B. africana trees and present in the caterpillars. The second most prominent fungal species in the caterpillars was Aspergillus nomius. The latter is known to be related to a Penicillium sp. which was found to be highly prevalent in the soil where B. africana trees grow and is suggested to play a role in enhancing the effective growth of B. africana trees in their natural habitat. To support this, a phylogenetic analysis was conducted, and a tree was constructed, which shows a high percentage similarity between Aspergillus and Penicillium sp. The findings of the study revealed that B. africana trees not only serve as a source of feed for the C. forda caterpillar but benefit from C. forda caterpillars which, after dropping onto the soil, is proposed to inoculate the soil surrounding the trees with the fungus A. nomius which suggests a symbiotic and/or synergistic relationship between B. africana trees and C. forda caterpillars.