Thiophenes-Naturally Occurring Plant Metabolites: Biological Activities and In Silico Evaluation of Their Potential as Cathepsin D Inhibitors

Singlet oxygen signalling and its potential roles in plant biotic interactions

Singlet oxygen (SO) is among the most potent reactive oxygen species, and readily oxidizes proteins, lipids and DNA. It can be generated at the plant surface by phototoxins in the epidermis, acting as a direct defense against pathogens and herbivores (including humans). SO can also accumulate within mitochondria, peroxisomes, cytosol and the nucleus through multiple enzymatic and nonenzymatic processes. However, the majority of research on intracellular SO generation in plants has focused on transfer of light energy to triplet oxygen by photopigments from the chloroplast. SO accumulates in response to diverse stresses that perturb chloroplast metabolism, and while its high reactivity limits diffusion distances, it participates in retrograde signalling through the EXECUTER1 sensor, generation of carotenoid metabolites and possibly other unknown pathways. SO thereby reprogrammes nuclear gene expression and modulates hormone signalling and programmed cell death. While SO signalling has long been known to regulate plant responses to high-light stress, recent literature also suggests a role in plant interactions with insects, bacteria and fungi. The goals of this review are to provide a brief overview of SO, summarize evidence for its involvement in biotic stress responses and discuss future directions for the study of SO in defense signalling.

Beneath the rind: A review on the remarkable health benefits and applications of the wood apple fruit

Limonia acidissima Groff, commonly referred to as the Wood apple, is a tropical fruit belonging to Rutaceae family. Indigenous to Sri Lanka, India, and Myanmar, it is extensively cultivated throughout Southeast Asia. This fruit holds a profound historical significance in traditional medicine due to its exceptional nutritional and therapeutic attributes. Wood apple pulp is significantly abundant in β-carotene, a precursor to vitamin A, and contains a substantial amount of vitamin B, including riboflavin and thiamine, as well as trace amounts of ascorbic acid (vitamin C). Moreover health-benefitting properties associated with L. acidissima, such as, antioxidant, hepatoprotective, antimicrobial, neuroprotective, antidiabetic, anti-inflammatory, anti-spermatogenic, analgesic, antiulcer, and antihyperlipidemic properties, are attributed to a diverse range of phytochemicals. These encompass polyphenolic compounds, saponins, phytosterols, tannins, triterpenoids, coumarins, amino acids, tyramine derivatives, and vitamins. From the findings of the various studies, it was observed that wood apple fruit shows significant anticancer activity by inhibiting the proliferation of cancer. Furthermore, wood apple finds wide-ranging commercial applications in the formulation of ready-to-serve beverages, syrups, jellies, chutneys, and various other food products. In summary, this review highlights the nutritional and phytochemical constituents of wood apple, depicts its antioxidant, anti-inflammatory, and anti-diabetic capabilities, and explores its potential in value-added product development. Nevertheless, it is crucial to acknowledge that the molecular mechanisms supporting these properties remain an underexplored domain. To ensure the safe integration of wood apple fruit into the realms of the food, cosmetics, and pharmaceutical sectors, rigorous clinical trials, including toxicity assessments, are required. These endeavors hold the potential to promote innovation and contribute significantly to both research and industrial sectors.

Insights into the anti-infective effects of Pluchea indica (L.) Less and its bioactive metabolites against various bacteria, fungi, viruses, and parasites

ETHNOPHARMACOLOGICAL RELEVANCE

Pluchea indica (L.) Less (family Asteraceae) is popularly consumed as a medicinal vegetable and used in ethnomedicine to treat various diseases including gastrointestinal problems such as dysentery and leucorrhoea, which are due to bacterial, fungal or parasitic infections. There have been numerous studies on the antimicrobial effects of the plant due to these ethnomedicine use.

AIM OF THIS REVIEW

This review is comprehensively discussed the information on the anti-infective properties of P. indica and its secondary metabolites, and highlight the potential of the plant as a new source of anti-infective agents.

MATERIALS AND METHODS

Scientific databases such as Scopus, Google Scholar, ScienceDirect, PubMed, Wiley Online Library, and ACS Publications were used to gather the relevant information on the ability of P. indica to fight infections, with the leaves and roots receiving most of the attention.

RESULTS

Anti-bacterial, anti-mycobacterial, anti-malarial, and anti-viral activities have been the most exploited. Most studies were carried out on the crude extracts of the plant and in most studies the bioactive extracts were not standardized or chemically characterized. Several studies have reported the anti-infective activity of several bioactive components of P. indica including caffeoylquinic acids, terpenoid glycosides, thiophenes, and kaempferol.

CONCLUSIONS

The strong anti-infective effect and underlying mechanisms of the compounds provide insights into the potential of P. indica as a source of new leads for the development of anti-infective agents for use in food and pharmaceutical industries.

Unlocking Therapeutic Potential: Comprehensive Extraction, Profiling, and Pharmacological Evaluation of Bioactive Compounds from Eclipta alba (L.) Hassk. for Dermatological Applications

Herbal medicine has been studied as an alternate approach to modern medicine as it is more cost-effective and accessible via natural sources. Eclipta alba (E. alba, L.) Hassk. is a weed plant abundantly distributed throughout different regions of the world and contains abundant bioactive compounds used for various skin conditions. In this review, we aimed to gather information from the literature about the extraction, separation, and identification of these bioactive compounds and their potential in skin diseases. Relevant studies published before August 2023 were identified and selected from electronic databases, including Scopus, SciFinder, ScienceDirect, Google Scholar, and Wiley Library, using the following keywords: Eclipta alba, Eclipta prostrata, phytochemicals, extraction, separation, isolation, identification, characterization, pharmacological activity, and skin conditions. Up-to-date extraction, separation, and identification methods of bioactive compounds from E. alba and their skin-related pharmacological activities are discussed in this review. As there are limitations regarding extraction, separation, and identification methods, and in-depth mechanistic and human studies of the skin-related pharmacological activities of bioactive compounds, these gaps are areas for future research to expand our understanding and broaden the potential applications of this medicinal weed plant, including the development of cosmeceutical and skincare products, anti-inflammatory agents, and formulations for dermatological treatments.

Ethnomedicinal uses, phytochemistry, and pharmacological relevance of Justicia procumbens (Oriental Water Willow) - A promising traditional plant

ETHNOPHARMACOLOGICAL RELEVANCE

Justicia procumbens L. (JP) (Oriental Water Willow, Shrimp plant, Acanthaceae) is a herbaceous plant that is commonly found in India, Taiwan, Australia, Southern China, Vietnam, and Korea. The plant has been primarily used to treat fever, asthma, edema, cough, jaundice, urinary tract infection, and sore throat, as well as for snake bites and as a fish-killer. In the present review, the reported phyto-chemical, ethno-pharmacological, biological, and toxicological studies on J. procumbens were summarized. Special focus had been given to its reported lignans, regarding their isolation, characterization, quantitative estimation, and biosynthesis.

MATERIALS AND METHODS

A survey of the literature was done using assorted databases and publishers; Scopus, Sci-Finder, Web of Science, PubMed, GoogleScholar, ScienceDirect, Wiley, Taylors&Francis, Bentham, Thieme, and Springer.

RESULTS

Currently, 95 metabolites have been separated fromJ. procumbens. Lignans and their glycosides were reported as main phyto-constituents of J. procumbens. Various methods are mentioned for quantitative estimation of these lignans. These phyto-constituents possessed wide pharmacological effectiveness, such as antiplatelet aggregation, antimicrobial, antitumor, and antiviral.

CONCLUSIONS

Many of the stated effects are harmonious with the reported traditional uses of this plant. This data could further support J. procumbens's utilization as a herbal remedy and drug lead. However, further study of J. procumbens toxicity, as well as preclinical and clinical investigation is required to ensure the safe usage of J. procumbens.

GDU-952, a novel AhR agonist ameliorates skin barrier abnormalities and immune dysfunction in DNFB-induced atopic dermatitis in mice

The aryl hydrocarbon receptor (AhR) is widely expressed in the skin. It controls immune-mediated skin responses to various external environmental signals, promote terminal differentiation of epidermal keratinocytes and participates the maintenance of the skin barrier function. As a therapeutic target, AhR activation modulates many diseases progression driven by immune/inflammatory processes such as atopic dermatitis (AD) and psoriasis. In this study, we revealed that GDU-952 is a novel AhR agonist, which is able to decreases IgE serum levels, to inhibit pro-inflammatory cytokines such as IL-6 and TNF-α and to induce immunoregulatory effects through restoring Th1/Th2 immune balance and promoting CD4+FOXP3+regulatory T (Treg) populations in AD skin lesions. Furthermore, GDU-952 can strengthen the skin barrier function through upregulating epidermal differentiation-related and tight junction proteins. This may alleviate AD symptoms, such as dermatitis scores, epidermal hyperplasia and mast cell infiltration. These results offer a rationale for further preclinical/clinical studies to evaluate the possible use of GDU-952 in the management of AD.

Assessments of Alpha-Amylase Inhibitory Potential of Tagetes Flavonoids through In Vitro, Molecular Docking, and Molecular Dynamics Simulation Studies

Diabetes is a chronic fast-growing metabolic disorder that is characterized by high blood glucose levels. Tagetes minuta L. has been used as a traditional remedy for various illnesses for many years, and, furthermore, its oil is used in the perfume and flavor industries. T. minuta contains various metabolites, such as flavonoids, thiophenes, terpenes, sterols, and phenolics, with varied bioactivities. Flavonoids can inhibit carbohydrate-digesting enzymes, such as alpha-amylase, which is a convenient dietary strategy for controlling hyperglycemia. In the current investigation, the isolated flavonoids quercetagetin-6-O-(6-O-caffeoyl-β-D-glucopyranoside), quercetagetin-7-O-β-D-glucopyranoside, quercetagetin-6-O-β-D-glucopyranoside, minutaside A, patuletin-7-O-β-D-glucopyranoside, quercetagetin-7-methoxy-6-O-β-D-glucopyranoside, tagenols A and B, quercetagetin-3,7-dimethoxy-6-O-β-D-glucopyranoside, patuletin, quercetin-3,6-dimethyl ether, and quercetin-3-methyl ether from T. minuta were assessed for their alpha-amylase inhibition (AAI) efficacy using an in vitro assay, as well as molecular docking, dynamics simulation, and ADMET analyses. Our findings show that quercetagetin-6-O-(6-O-caffeoyl-β-D-glucopyranoside) (1), quercetagetin-7-O-β-D-glucopyranoside (2), quercetagetin-6-O-β-D-glucopyranoside (3), minutaside A (4), patuletin-7-O-β-D-glucopyranoside (5), and quercetagetin-7-methoxy-6-O-β-D-glucopyranoside (6) had a notable AAI capacity (IC₅₀s ranged from 7.8 to 10.1 μM) compared to acarbose (IC₅₀ 7.1 μM). Furthermore, these compounds with the highest binding affinity among the tested flavonoids revealed high docking scores for AA (ranging from -12.171 to 13.882 kcal/mol) compared to that of acarbose (-14.668 kcal/mol). In MDS, these compounds were observed to show maximum stability and the greatest binding free energy, suggesting that they may contend with native ligands. In addition, the ADMET analysis showed that these active compounds had a broad span of drug-like, pharmacokinetic, and physicochemical features and did not possess any considerable undesired effects. The current results suggest the potential of these metabolites as AAI candidates. However, further in vivo and mechanistic studies are warranted to specify the efficacy of these metabolites.

Higher-order [8+2]-cycloadditions of tropothione with levoglucosenone (LGO) and structurally similar exo-cyclic enones derived from cyrene

Levoglucosenone (LGO) and structurally similar exo-cyclic enones derived from cyrene (dihydrolevoglucosenone) react with tropothione following the higher-order [8 + 2]-cycloaddition pathway. Reactions were performed at room temperature in CH₂Cl₂ solutions in absence of any activating reagent. Whereas reaction of tropothione with LGO occurred with complete stereoselectivity, leading to a single, sterically favored exo cycloadduct, identified as polycylic thiophene derivative, reactions performed with exo-cyclic enones yielded in some instances mixtures of two isomeric exo and endo cycloadducts, derived from spiro-tetrahydrothiophene as major and minor components, respectively, of the studied reaction mixtures. Exo and endo [8 + 2] cycloadducts differ in absolute configuration at the newly created chiral centers. Structures of exo and endo cycloadducts were confirmed by single crystal X-ray diffraction analysis.

Ethnobotanical Uses, Phytochemical Composition, Biosynthesis, and Pharmacological Activities of Carpesium abrotanoides L. (Asteraceae)

Carpesium abrotanoides L. (Asteraceae) is a medicinal plant with immense therapeutic importance and bioactivities. It is commonly encountered in various Asian regions. It has numerous ethnomedicinal uses for curing diverse ailments such as toothache, stomach ulcer, boils, tonsillitis, bronchitis, bacterial infection, bruises, swelling, virus infection, fever, and amygdalitis, as well as an anthelmintic versus round-, tape-, hook-, and pinworms. Different classes of phytoconstituents such as sesquiterpenes, sesquiterpene dimers, monoterpenes, and nitrogenous compounds have been reported from this plant. These phytoconstituents have proved to possess anti-inflammatory, cytotoxic, antimicrobial, and insecticidal capacities. The present review aims to summarize all published data on C. abrotanoides including traditional uses, phytoconstituents, bioactivities, and toxicological aspects, as well as the synthesis and biosynthesis of its metabolites through an extensive survey on various databases and various publishers. These reported data could draw the attention of various natural-metabolite-interested researchers and medicinal chemists towards the development of this plant and/or its metabolites into medicine for the prevention and treatment of certain illnesses. Despite the diverse traditional uses of C. abrotanoides, there is a need for scientific evidence to support these claims. Clinical trials are also required to further assure these data and validate this plant utilization in treating several diseases.

Exploring the Activity of Fungal Phenalenone Derivatives as Potential CK2 Inhibitors Using Computational Methods

Cancer represents one of the most prevalent causes of global death. CK2 (casein kinase 2) activation boosted cancer proliferation and progression. Therefore, CK2 inhibition can have a crucial role in prohibiting cancer progression and enhancing apoptosis. Fungi have gained vast interest as a wealthy pool of anticancer metabolites that could particularly target various cancer progression-linked signaling pathways. Phenalenones are a unique class of secondary metabolites that possess diverse bioactivities. In the current work, the CK2 inhibitory capacity of 33 fungal phenalenones was explored using computational studies. After evaluating the usefulness of the compounds as enzyme inhibitors by ADMET prediction, the compounds were prepared for molecular docking in the CK2-α1 crystal structure (PDB: 7BU4). Molecular dynamic simulation was performed on the top two scoring compounds to evaluate their binding affinity and protein stability through a simulated physiological environment. Compound 19 had a superior binding affinity to the co-crystallized ligand (Y49). The improved affinity can be attributed to the fact that the aliphatic chain makes additional contact with Asp120 in a pocket distant from the active site.

New Alpha-Amylase Inhibitory Metabolites from Pericarps of Garcinia mangostana

Two new benzophenones: garcimangophenones A (6) and B (7) and five formerly reported metabolites were purified from the pericarps EtOAc fraction of Garcinia mangostana ((GM) Clusiaceae). Their structures were characterized by various spectral techniques and by comparing with the literature. The α-amylase inhibitory (AAI) potential of the isolated metabolites was assessed. Compounds 7 and 6 had significant AAI activity (IC50 9.3 and 12.2 µM, respectively) compared with acarbose (IC50 6.4 µM, reference α-amylase inhibitor). On the other hand, 5 had a moderate activity. Additionally, their activity towards the α-amylase was assessed utilizing docking studies and molecular dynamics (MD) simulations. The docking and predictive binding energy estimations were accomplished using reported crystal structure of the α-amylase (PDB ID: 5TD4). Compounds 7 and 6 possessed highly negative docking scores of −11.3 and −8.2 kcal/mol, when complexed with 5TD4, respectively while acarbose had a docking score of −16.1 kcal/mol, when complexed with 5TD4. By using molecular dynamics simulations, the compounds stability in the complexes with the α-amylase was analyzed, and it was found to be stable over the course of 50 ns. The results suggested that the benzophenone derivative 7 may be potential α-amylase inhibitors. However, further investigations to support these findings are required.