Natural Product Research Research Articles

Rationalising Optimal Dosing of Phytotherapeutics For Use In Children: Current Status - Potential Solutions - Actions Needed.

"Children are not small adults with respect to the treatment with medicinal products." This statement of the WHO was the basis for the initiative of the European Commission for the establishment of a paediatric regulation in 2007 to improve the health of children by facilitating the development of medicines for children and adolescents. Seventeen years later, in the field of herbal medicinal products, results are still sobering. Therefore, the Foundation Plants for Health, Society for Medicinal Plants and Natural Products Research, and German Society for Phytotherapy organised a symposium to assess the status quo for the paediatric use of herbal medicinal products (HMPs), to analyse the causes of the current situation, and to discuss strategies for establishing the proof of safe and efficacious HMPs for children.The current situation for HMPs and their use in children is not fulfilling the requirements of legislation. HMPs in paediatrics are effective and safe, but considering the needs of children is necessary. In European countries, the use, registration, and marketing of HMPs are different, depending on the respective national regulations and specific traditions. EU herbal monographs are the best common denominator for such procedures. Emerging safety discussions must be considered. New approaches with real-world data might be a solution. The regulatory framework is to be adapted. Defining rationalised dosing for HMPs can be achieved by the extrapolation of data from adults, by using existing clinical data for children, and by using RWD. Therefore, a strong need for revising restrictions for the use of HMPs in children and rationalising defined dosage regimes is obvious.

Exploring the phytochemical and biological properties of Salsola foetida: a promising wild plant from Southeastern Algeria

ABSTRACT This study presents an initial exploration of the phytochemical composition and biological properties of Salsola foetida, a wild plant native to southeastern Algeria. The investigation encompassed an analysis of the biochemical content, phytochemical profile, and bioactivity of the plant’s aerial parts. The biomass of S. foetida was found to comprise 51.2 ± 0.4% ash, with elemental analysis revealing the presence of carbon, oxygen, calcium, sodium, chlorine, magnesium, potassium, and sulfur. Carbohydrates were identified as the predominant constituents, surpassing the levels of proteins and lipids. Phytochemical screening, coupled with Fourier Transform Infrared (FT-IR) analysis, confirmed the presence of various secondary metabolites, including alkaloids and phenols. Reversed-phase high-performance liquid chromatography (RP-HPLC) analysis further delineated a spectrum of phenolic compounds, with rutin emerging as the predominant compound at 1.59 µg/ml. Quantification revealed a noteworthy phenolic content of 67.1 ± 0.2 µg GE/mg ED. The extract exhibited robust radical scavenging effects, with the radical 50% inhibitory concentration (IC50) being 61.8 ± 0.2 μg/ml, along with protective effects against H2O2-induced hemolysis and the ability to reduce ferric ions. Additionally, the extract demonstrated anti-inflammatory, antibacterial, and antidiabetic activities. Notably, it exhibited considerable sunscreen properties, boasting a sun protected factor (SPF) value of 21 ± 1. Overall, S. foetida presents promising antioxidant activity and a spectrum of potential biological activities, underscoring its significance as a novel antioxidant candidate for applications in animal nutrition, medicine, and natural product research.

Comprehensive analysis of different solvent extracts of Ferula communis L. fruit reveals phenolic compounds and their biological properties via in vitro and in silico assays

Although giant fennel is recognized as a “superfood” rich in phytochemicals with antioxidant activity, research into the antibacterial properties of its fruits has been relatively limited, compared to studies involving the root and aerial parts of the plant. In this study, seven solvents—acetone, methanol, ethanol, ethyl acetate, chloroform, water, and hexane—were used to extract the chemical constituents of the fruit of giant fennel (Ferula communis), a species of flowering plant in the carrot family Apiaceae. Specific attributes of these extracts were investigated using in silico simulations and in vitro bioassays. High-performance liquid chromatography equipped with a diode-array detector (HPLC–DAD) identified 15 compounds in giant fennel extract, with p-coumaric acid, 3-hydroxybenzoic acid, sinapic acid, and syringic acid being dominant. Among the solvents tested, ethanol demonstrated superior antioxidant activity and phenolic and flavonoid contents. F. communis extracts showed advanced inhibition of gram-negative pathogens (Escherichia coli and Proteus mirabilis) and variable antifungal activity against tested strains. Molecular docking simulations assessed the antioxidative, antibacterial, and antifungal properties of F. communis, facilitating innovative therapeutic development through predicted compound–protein interactions. In conclusion, the results validate the ethnomedicinal use and potential of F. communis. This highlights its significance in natural product research and ethnopharmacology.

Artificial intelligence and natural product research.

Artificial intelligence and natural product research.

Integration of Wnt-inhibitory activity and structural novelty scoring results to uncover novel bioactive natural products: new Bicyclo[3.3.1]non-3-ene-2,9-diones from the leaves of Hymenocardia punctata.

In natural products (NPs) research, methods for the efficient prioritization of natural extracts (NEs) are key for discovering novel bioactive NPs. In this study a biodiverse collection of 1,600 NEs, previously analyzed by UHPLC-HRMS2 metabolite profiling was screened for Wnt pathway regulation. The results of the biological screening drove the selection of a subset of 30 non-toxic NEs with an inhibitory IC50 ≤ 5μg/mL. To increase the chance of finding structurally novel bioactive NPs, Inventa, a computational tool for automated scoring of NEs based on structural novelty was used to mine the HRMS2 analysis and dereplication results. After this, four out of the 30 bioactive NEs were shortlisted by this approach. The most promising sample was the ethyl acetate extract of the leaves of Hymenocardia punctata (Phyllanthaceae). Further phytochemical investigations of this species resulted in the isolation of three known prenylated flavones (3, 5, 7) and ten novel bicyclo[3.3.1]non-3-ene-2,9-diones (1, 2, 4, 6, 8-13), named Hymenotamayonins. Assessment of the Wnt inhibitory activity of these compounds revealed that two prenylated flavones and three novel bicyclic compounds showed interesting activity without apparent cytotoxicity. This study highlights the potential of combining Inventa's structural novelty scores with biological screening results to effectively discover novel bioactive NPs in large NE collections.

Characterization of Chemical Interactions between Clinical Drugs and the Oral Bacterium, Corynebacterium matruchotii, via Bioactivity-HiTES.

In the field of natural product research, the rediscovery of already-known compounds is one of the significant issues hindering new drug development. Recently, an innovative approach called bioactivity-HiTES has been developed to overcome this limitation, and several new bioactive metabolites have been successfully characterized by this method. In this study, we applied bioactivity-HiTES to Corynebacterium matruchotii, the human oral bacterium, with 3120 clinical drugs as potential elicitors. As a result, we identified two cryptic metabolites, methylindole-3-acetate (MIAA) and indole-3-acetic acid (IAA), elicited by imidafenacin, a urinary antispasmodic drug approved by the Japanese Pharmaceuticals and Medical Devices Agency (PMDA). MIAA showed weak antibacterial activity against a pulmonary disease-causing Mycobacterium conceptionense with an IC50 value of 185.7 μM. Unexpectedly, we also found that C. matruchotii metabolized fludarabine phosphate, a USFDA-approved anticancer drug, to 2-fluoroadenine which displayed moderate antibacterial activity against both Bacillus subtilis and Escherichia coli, with IC50 values of 8.9 and 20.1 μM, respectively. Finally, acelarin, a prodrug of the anticancer drug gemcitabine, was found to exhibit unreported antibacterial activity against B. subtilis with an IC50 value of 33.6 μM through the bioactivity-HiTES method as well. These results indicate that bioactivity-HiTES can also be applied to discover biotransformed products in addition to finding cryptic metabolites in microbes.

Withanone as an Emerging Anticancer Agent and Understanding Its Molecular Mechanisms: Experimental and Computational Evidence.

Despite decades of research and effort, treating cancer is still a challenging task. Current conventional treatments are still unsatisfactory to fully eliminate and prevent re-emergence or relapses, and targeted or personalised therapy, which are more effective in managing cancer, may be unattainable or inaccessible for some. In the past, research in natural products have yielded some of the most commonly used cancer treatment drugs known today. Hence it is possible more are awaiting to be discovered. Withanone, a common withanolide found in the Ayurvedic herb Withania somnifera, has been claimed to possess multiple benefits capable of treating cancer. This review focuses on the potential of withanone as a safe cancer treatment drug based on the pharmacokinetic profile and molecular mechanisms of actions of withanone. Through these in silico and in vitro studies discussed in this review, withanone showspotent anticancer activities and interactions with molecular targets involved in cancer progression. Furthermore, some evidences also show the selective killing property of withanone, which highlights the safety and specificity of withanone in targeting cancer cell. By compiling these evidences, this review hopes to spark interest for future research to be conducted in more extensive studies involving withanone to generate more data, especially involving in vivo experiments and toxicity evaluation of withanone.

Applications of Liquid Chromatography-Tandem Mass Spectrometry in Natural Products Research: Tropane Alkaloids as a Case Study.

Although many drugs utilized today are synthetic in origin, natural products still provide a rich source of novel chemical diversity and bioactivity, and can yield promising leads for resistant or emerging diseases. The challenge, however, is twofold: not only must researchers find natural products and elucidate their structures, but they must also identify what is worth isolating and assaying (and what is already known - a process known as dereplication). With the advent of modern analytical instrumentation, the pace of natural product discovery and dereplication has accelerated. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) has become an especially valuable technique for identifying and classifying chemical structures. Tropane alkaloids (TAs) are plant-derived compounds of great medicinal and toxicological significance. In this study, we developed an LC-MS/MS-based screening workflow utilizing the multiple MS/MS configurations available on a triple-quadrupole (QQQ) mass spectrometer to annotate and classify TA structures based on their distinct fragmentation patterns. By using a combination of data-dependent (DD) product ion scans, precursor ion scans (PrIS), and neutral loss scans (NLS), we applied this method to TA-rich extracts of the nightshades Datura stramonium and Datura metel. This method is rapid, sensitive, and was successfully employed for both preliminary dereplication of complex TA-containing samples and for the discovery of a novel candidate for isolation, purification (and eventual bioassay).

Basics and Fundamentals of Natural Product Research

Historical evidence shows that plant-derived agents have had therapeutic relevance in the lives of humans providing different classes of drugs. Many natural products and synthetically modified natural product derivatives have been successfully developed for clinical use to treat human diseases. Drug discovery from medicinal plants continues to provide new and important leads against various pathologies targets including cancer, malaria, cardiovascular diseases and neurological disorders. Proper sample preparation can increase the extraction efficiency of biologically active compounds. Extraction is the separation of the pharmacologically active, chemical distinct non-matrix components of a plant, microbial, or animal material from the matric (structural) parts. Natural extracts are often extremely complex and contain many unknown compounds. In this situation, the use of an effect-related analytical approach is a real relief. Information about biological effects of natural complex materials in humans, is a necessity for natural product research to be meaningful and useful. This brings to the fore effect-directed analysis which identifies or isolates substances of biological relevance. Data bases and books were consulted for information contained in this review. This review discusses the fundamentals of natural product research from a wide range of methods of preparing plant material, extraction, concentration, separation, isolation, pharmacological activity screening, toxicity profiling, virtual screening, and data analysis

Antibiotic Skeletal Diversification via Differential Enoylreductase Recruitment and Module Iteration in trans-Acyltransferase Polyketide Synthases.

Microorganisms are remarkable chemists capable of assembling complex molecular architectures that penetrate cells and bind biomolecular targets with exquisite selectivity. Consequently, microbial natural products have wide-ranging applications in medicine and agriculture. How the "blind watchmaker" of evolution creates skeletal diversity is a key question in natural products research. Comparative analysis of biosynthetic pathways to structurally related metabolites is an insightful approach to addressing this. Here, we report comparative biosynthetic investigations of gladiolin, a polyketide antibiotic from Burkholderia gladioli with promising activity against multidrug-resistant Mycobacterium tuberculosis, and etnangien, a structurally related antibiotic produced by Sorangium cellulosum. Although these metabolites have very similar macrolide cores, their C21 side chains differ significantly in both length and degree of saturation. Surprisingly, the trans-acyltransferase polyketide synthases (PKSs) that assemble these antibiotics are almost identical, raising intriguing questions about mechanisms underlying structural diversification in this important class of biosynthetic assembly line. In vitro reconstitution of key biosynthetic transformations using simplified substrate analogues, combined with gene deletion and complementation experiments, enabled us to elucidate the origin of all the structural differences in the C21 side chains of gladiolin and etnangien. The more saturated gladiolin side chain arises from a cis-acting enoylreductase (ER) domain in module 1 and in trans recruitment of a standalone ER to module 5 of the PKS. Remarkably, module 5 of the gladiolin PKS is intrinsically iterative in the absence of the standalone ER, accounting for the longer side chain in etnangien. These findings have important implications for biosynthetic engineering approaches to the creation of novel polyketide skeletons.

A validated, precise TLC-densitometry method for simultaneous quantification of mahanimbine and koenimbine in marketed herbal formulations

BackgroundMurraya koenigii (L.) Spreng. (Rutaceae) is an important medicinal plant in natural products research for its diverse pharmacological activities. Carbazole alkaloids were the major classes of phytoconstituents obtained from different parts of this plant, such as leaves, stems, and roots. Mahanimbine and koenimbine are two important carbazole alkaloids obtained from the M. koenigii plant and are known for their anti-cancer, anti-oxidant, anti-diarrhoeal agents, etc. Standardization plays a vital role in the herbal drug industry for maintaining the quality, purity, safety, and efficacy of herbal formulations, and hyphenated analytical techniques like HPTLC, HPLC, GC–MS, and LC–MS were utilized for this purpose. In the present study, a specific, simple, and rapid semi-automated TLC method was developed to quantify mahanimbine and koenimbine in some marketed herbal formulations, and the same was validated based on (ICH)-Q2-(R1) guidelines.ResultsThis study revealed that the powder formulation (F3) contains the highest amount of mahanimbine (62.32 µg), but the tablet formulation (F1) contains both mahanimbine (41.19 µg) and koenimbine (143.6 µg).ConclusionA simple, specific, and reproducible semi-automated TLC method was developed and validated successfully as per (ICH)-Q2-(R1) guidelines and can be utilized for analysing marketed herbal formulations containing M. koenigii powder/extracts.

MAR4 Streptomyces: A Unique Resource for Natural Product Discovery.

Marine-derived Streptomyces have long been recognized as a source of novel, pharmaceutically relevant natural products. Among these bacteria, the MAR4 clade within the genus Streptomyces has been identified as metabolically rich, yielding over 93 different compounds to date. MAR4 strains are particularly noteworthy for the production of halogenated hybrid isoprenoid natural products, a relatively rare class of bacterial metabolites that possess a wide range of biological activities. MAR4 genomes are enriched in vanadium haloperoxidase and prenyltransferase genes, thus accounting for the production of these compounds. Functional characterization of the enzymes encoded in MAR4 genomes has advanced our understanding of halogenated, hybrid isoprenoid biosynthesis. Despite the exceptional biosynthetic capabilities of MAR4 bacteria, the large body of research they have stimulated has yet to be compiled. Here we review 35 years of natural product research on MAR4 strains and update the molecular diversity of this unique group of bacteria.

Natural products and derivatives as Japanese encephalitis virus antivirals.

Japanese encephalitis virus (JEV) causes acute Japanese encephalitis (JE) in humans and reproductive disorders in pigs. There are ~68 000 cases of JE worldwide each year, with ~13 600-20 400 deaths. JE infections have a fatality rate of one-third, and half of the survivors experience permanent neurological sequelae. The disease is prevalent throughout the Asia-Pacific region and has the potential to spread globally. JEV poses a serious threat to human life and health, and vaccination is currently the only strategy for long-term sustainable protection against JEV infection. However, licensed JEV vaccines are not effective against all strains of JEV. To date, there are no drugs approved for clinical use, and the development of anti-JEV drugs is urgently needed. Natural products are characterized by a wide range of sources, unique structures, and low prices, and this paper provides an overview of the research and development of anti-JEV bioactive natural products.

Endolichenic Fungi: A Promising Medicinal Microbial Resource to Discover Bioactive Natural Molecules-An Update.

Lichens are some of the most unique fungi and are naturally encountered as symbiotic biological organisms that usually consist of fungal partners (mycobionts) and photosynthetic organisms (green algae and cyanobacteria). Due to their distinctive growth environments, including hot deserts, rocky coasts, Arctic tundra, toxic slag piles, etc., they produce a variety of biologically meaningful and structurally novel secondary metabolites to resist external environmental stresses. The endofungi that live in and coevolve with lichens can also generate abundant secondary metabolites with novel structures, diverse skeletons, and intriguing bioactivities due to their mutualistic symbiosis with hosts, and they have been considered as strategically significant medicinal microresources for the discovery of pharmaceutical lead compounds in the medicinal industry. They are also of great importance in the fundamental research field of natural product chemistry. In this work, we conducted a comprehensive review and systematic evaluation of the secondary metabolites of endolichenic fungi regarding their origin, distribution, structural characteristics, and biological activity, as well as recent advances in their medicinal applications, by summarizing research achievements since 2015. Moreover, the current research status and future research trends regarding their chemical components are discussed and predicted. A systematic review covering the fundamental chemical research advances and pharmaceutical potential of the secondary metabolites from endolichenic fungi is urgently required to facilitate our better understanding, and this review could also serve as a critical reference to provide valuable insights for the future research and promotion of natural products from endolichenic fungi.

Implications of confounding from unmodeled interactions between explanatory variables when using latent variable regression models to make inferences.

With linear dependency between the explanatory variables, partial least squares (PLS) regression is commonly used for regression analysis. If the response variable correlates to a high degree with the explanatory variables, a model with excellent predictive ability can usually be obtained. Ranking of variable importance is commonly used to interpret the model and sometimes this interpretation guides further experimentation. For instance, when analyzing natural product extracts for bioactivity, an underlying assumption is that the highest ranked compounds represent the best candidates for isolation and further testing. A problem with this approach is that in most cases the number of compounds is larger than the number of samples (and usually much larger) and that the concentrations of the compounds correlate. Furthermore, compounds may interact as synergists or as antagonists. If the modelling process does not account for this possibility, the interpretation can be thoroughly wrong since unmodelled variables that strongly influence the response will give rise to confounding of a first order PLS model and send the experimenter on a wrong track. We show the consequences of this by a practical example from natural product research. Furthermore, we show that by including the possibility of interactions between explanatory variables, visualization using a selectivity ratio plot may provide model interpretation that can be used to make inferences.

Natural Products Dereplication: Databases and Analytical Methods.

The development of efficient methods for dereplication has been critical in the re-emergence of the research in natural products as a source of drug leads. Current dereplication workflows rapidly identify already known bioactive secondary metabolites in the early stages of any drug discovery screening campaign based on natural extracts or enriched fractions. Two main factors have driven the evolution of natural products dereplication over the last decades. First, the availability of both commercial and public large databases of natural products containing the key annotations against which the biological and chemical data derived from the studied sample are searched for. Second, the considerable improvement achieved in analytical technologies (including instrumentation and software tools) employed to obtain robust and precise chemical information (particularly spectroscopic signatures) on the compounds present in the bioactive natural product samples. This chapter describes the main methods of dereplication, which rely on the combined use of large natural product databases and spectral libraries, alongside the information obtained from chromatographic, UV-Vis, MS, and NMR spectroscopic analyses of the samples of interest.

Promoter engineering of natural product biosynthetic gene clusters in actinomycetes: concepts and applications.

Covering 2011 to 2022Low titers of natural products in laboratory culture or fermentation conditions have been one of the challenging issues in natural products research. Many natural product biosynthetic gene clusters (BGCs) are also transcriptionally silent in laboratory culture conditions, making it challenging to characterize the structures and activities of their metabolites. Promoter engineering offers a potential solution to this problem by providing tools for transcriptional activation or optimization of biosynthetic genes. In this review, we summarize the 10 years of progress in promoter engineering approaches in natural products research focusing on the most metabolically talented group of bacteria actinomycetes.

Empowering natural product science with AI: leveraging multimodal data and knowledge graphs.

Artificial intelligence (AI) is accelerating how we conduct science, from folding proteins with AlphaFold and summarizing literature findings with large language models, to annotating genomes and prioritizing newly generated molecules for screening using specialized software. However, the application of AI to emulate human cognition in natural product research and its subsequent impact has so far been limited. One reason for this limited impact is that available natural product data is multimodal, unbalanced, unstandardized, and scattered across many data repositories. This makes natural product data challenging to use with existing deep learning architectures that consume fairly standardized, often non-relational, data. It also prevents models from learning overarching patterns in natural product science. In this Viewpoint, we address this challenge and support ongoing initiatives aimed at democratizing natural product data by collating our collective knowledge into a knowledge graph. By doing so, we believe there will be an opportunity to use such a knowledge graph to develop AI models that can truly mimic natural product scientists' decision-making.

The Chemical Ecology of Plant Natural Products.

Plants are excellent chemists with an impressive capability of biosynthesizing a large variety of natural products (also known as secondary or specialized metabolites) to resist various biotic and abiotic stresses. In this chapter, 989 plant natural products and their ecological functions in plant-herbivore, plant-microorganism, and plant-plant interactions are reviewed. These compounds include terpenoids, phenols, alkaloids, and other structural types. Terpenoids usually provide direct or indirect defense functions for plants, while phenolic compounds play important roles in regulating the interactions between plants and other organisms. Alkaloids are frequently toxic to herbivores and microorganisms, and can therefore also provide defense functions. The information presented should provide the basis for in-depth research of these plant natural products and their natural functions, and also for their further development and utilization.

Molecular understanding of the therapeutic potential of melanin inhibiting natural products.

With the development of society and the improvement of people's living standards, there is an increasing demand for melanin-inhibiting products that prioritize health, safety, and efficacy. Therefore, the development of natural products that can safely and efficiently inhibit melanin synthesis is of great social significance and has significant market potential. In this paper, by reviewing the literature reported in recent years, we summarized the natural products with inhibition of melanin synthesis effects that have been put into or not yet put into the market, and classified them according to the chemical groups of their compounds or the extraction methods of the natural products. Through the summary analysis, we found that these compounds mainly include terpenoids, phenylpropanoids, flavonoids and so on, while the natural product extracts mainly include methanol extracts, ethanol extracts, and aqueous extracts. Their main inhibition of melanin synthesis mechanisms include: (1) direct inhibition of tyrosinase activity; (2) down-regulation of the α-MSH-MC1R, Wnt, NO, PI3K/Akt and MAPK pathways through the expression of MITF and its downstream genes TYR, TRP-1, and TRP-2; (3) antioxidant; (4) inhibition of melanocyte growth through cytotoxicity; (5) inhibition of melanosome production and transport. This paper provides an in-depth discussion on the research progress of whitening natural products and their market value. The aim is to offer guidance for future research and development of natural skin whitening products.