Antifungal stilbenoids from Stemona collinsae

Recent Advances in the Development of Antifungal Agents: Beyond Azoles, Polyenes, and Echinocandins

The escalating incidence of antimicrobial resistance to antifungal agents, alongside the emergence of drug-resistant fungal strains, constitutes a significant threat to a potential global fungal pandemic. In response, researchers are intensifying efforts to identify novel antifungal compounds through diverse methodologies. Emerging strategies focus on innovative therapeutic targets that may reduce the risk of resistance development while offering broad-spectrum efficacy against fungal infections. Additionally, these approaches present potential cost-effectiveness and accelerated development timelines. This review systematically categorizes a range of novel antifungal compounds, including antifungal peptides, cationic amphiphiles, small molecules, polymers, and repurposed drugs, based on their efficacy in inhibiting fungal growth and associated virulence factors. These compounds exhibit notable antimicrobial activity across in silico, in vitro, and in vivo systems against various pathogenic fungal strains, with several showing substantial promise for clinical application. Furthermore, the review highlights the limitations of standard antifungals and elucidates the mechanisms by which fungal strains develop resistance. This work aims to engage researchers in the distinctive field of fungal biology and foster the exploration of new antifungal strategies.

Stilbenes Against Alzheimer's Disease: A Comprehensive Review of Preclinical Studies of Natural and Synthetic Compounds Combined with the Contributions of Developed Nanodrug Delivery Systems

This review covers preclinical studies of stilbene derivative compounds (both natural and synthetic) with potential preventive and therapeutic effects against Alzheimer's disease (AD). AD is a worldwide neurodegenerative disease characterized by the destruction of nerve cells in the brain and the loss of cognitive function due to aging. Stilbenes are a unique class of natural phenolic compounds distinguished by a C6-C2-C6 (1,2-diphenylethylene) structure and two aromatic rings connected by an ethylene bridge. Stilbenes' distinct features make them an intriguing subject for pharmacological research and development. Several preclinical studies have suggested that stilbenes may have neuroprotective effects by reducing Aβ generation and oligomerization, enhancing Aβ clearance, and regulating tau neuropathology through the prevention of aberrant tau phosphorylation and aggregation, as well as scavenging reactive oxygen species. Synthetic stilbene derivatives also target multiple pathways involved in neuroprotection and have demonstrated promising biological activity in vitro. However, some properties of stilbenes, such as sensitivity to physiological conditions, low solubility, poor permeability, instability, and low bioavailability, limit their usefulness in clinical applications. To address this issue, current investigations have developed new drug delivery systems based on stilbene derivative molecules. This review aims to shed light on the development of next-generation treatment strategies by examining in detail the role of stilbenes in Alzheimer's pathophysiology and their therapeutic potential.

Mechanisms and Origins of Regioselectivity in Rare-Earth-Catalyzed C-H Functionalization of Anisoles and Thioanisoles

The direct catalytic C-H functionalization of aromatic compounds such as anisoles and thioanisoles is of great interest and significance. However, achieving precise regioselectivity remains a major challenge. In this study, we conducted comprehensive density functional theory calculations to explore the mechanisms of rare-earth-catalyzed regioselective C-H alkylation, borylation, and silylation of anisole and thioanisole. The results reveal that in cationic C-H alkylation systems, the alkene insertion step follows a substrate-assisted mechanism, in which an additional substrate molecule acts as a ligand to facilitate the transformation. In neutral C-H borylation and silylation systems, although mononuclear hydride species readily dimerize into binuclear hydride species due to thermodynamic stability, the catalytic process predominantly proceeds via a mononuclear pathway. Furthermore, the origins of regioselectivity were thoroughly elucidated. A detailed analysis of electronic and steric effects in related transition states reveals that, for anisole, regioselectivity is primarily governed by ring strain. Since α-C(sp3)-H activation involves the formation of a highly strained three-membered ring, the reaction preferentially occurs at the ortho-C(sp2)-H site, forming a less strained four-membered ring. In contrast, for thioanisole, electronic effects play a decisive role, driving C-H activation at the more negatively charged α-C(sp3) site due to stronger metal-carbon interactions.

Pinosylvin: A Multifunctional Stilbenoid with Antimicrobial, Antioxidant, and Anti-Inflammatory Potential

Stilbenoids are a category of plant compounds exhibiting notable health-related benefits. After resveratrol, perhaps the most well-known stilbenoid is pinosylvin, a major phytochemical constituent of most plants characterised by the pine spines among others. Pinosylvin and its derivatives have been found to exert potent antibacterial and antifungal effects, while their antiparasitic and antiviral properties are still a subject of ongoing research. The antioxidant properties of pinosylvin are mostly based on its scavenging of free radicals, inhibition of iNOS and protein kinase C, and promotion of HO-1 expression. Its anti-inflammatory properties are based on a variety of mechanisms, such as COX-2 inhibition, NF-κB and TRPA1 activation inhibition, and reduction in IL-6 levels. Its anticancer properties are partly associated with its antioxidant and anti-inflammatory potential, although a number of other mechanisms are described, such as apoptosis induction and matrix metalloproteinase inhibition. A couple of experiments have also suggested a neuroprotective potential. A multitude of ethnomedical and ethnobotanical effects of pinosylvin-containing plants are reported, like antimicrobial, antioxidant, anti-inflammatory, hepatoprotective, and prokinetic actions; many of these are corroborated by recent research. The advent of novel methods of artificial pinosylvin synthesis may facilitate its mass production and adoption as a medical compound. Finally, pinosylvin may be a tool in promoting environmentally friendly pesticide and insecticide policies and be used in land remediation schemes.

Assessing the efficacy of Stemona collinsiae roots extract against third-stage larvae of Gnathostoma spinigerum and its safety profiles

Gnathostomiasis, caused by the advanced third-stage larvae of Gnathostoma spinigerum, demands novel treatment avenues. The ethanolic root extract of Stemona collinsiae has been postulated to have anthelminthic properties, suggesting its potential as an alternative remedy. In this study, S. collinsiae roots were collected, identified, and extracted with 95 % ethanol. The crude extracts were standardized using didehydrostemofoline as chemical marker. The efficacy of the S. collinsiae root extract against third-stage larvae of G. spinigerum and its toxicity to Wistar rats were evaluated. Both in vitro and in vivo tests were performed, where the in vitro tests assessed the anthelminthic potential of S. collinsiae extract against G. spinigerum larvae, while in vivo tests examined the extract's efficacy against G. spinigerum larvae in infected Wistar rats and the efficacy was compared with albendazole. Parallelly, Wistar rats underwent acute and sub-chronic toxicity tests to establish the safe dosage of the extract. The in vitro tests showcased significant anthelminthic activity, marked by discernible morphological alterations in the exposed larvae. Acute toxicity proved fatal at 2000 mg/kg body weight, while a dose of 300 mg/kg proved non-toxic. Using the Globally Harmonized Classification System, an LD50 of 500 mg/kg was determined. In vivo trials revealed a pronounced decline in G. spinigerum larvae among rats treated with the S. collinsiae extract. The larvae were also observed to be encysted post-treatment, while those treated with albendazole were not encysted. The S. collinsiae extract, with its noteworthy in vitro efficacy and favorable safety metrics in rodents, can be a potential anthelminthic agent. The diminished inflammatory response compared to albendazole hints at S. collinsiae being a safer gnathostomiasis treatment alternative. The promising results in these preliminary trials warrant a deeper investigation to determine the root extract's optimal dosing, suitable delivery methods, and its broader clinical implications.

Current perspectives and difficulties in the design of acaricides and repellents from plant-derived compounds for tick control

Ticks and tick-borne diseases have gained increasing attention in recent years due to their impact on public health and significant losses in livestock production. The use of synthetic compounds for tick control is becoming problematic, mainly due to the resistance to commercially available products as well as their toxicity. Therefore, new alternative control methods are required. For this purpose, plant-derived extracts may be considered as effective repellents and/or acaricides. The present literature review focuses on studies evaluating the acaricidal and repellent activity of plant-derived extracts and plant secondary metabolites. We also noted recent advances in protein-ligand-docking simulation to examine the possible toxic effect of natural chemical compounds on ticks. In conclusion, plant-derived repellents/acaricides can be effective against ticks, especially in rural areas and livestock farms.

Search for Snail Repellents: Antimollusc Activities from Stemona parviflora and Six Other Chinese Stemona Species

Snails are important agricultural pests difficult to control, but data regarding molluscicidal assays are scant. Stemona alkaloids are typical secondary metabolites for the taxa and have been broadly investigated for their pharmacological and toxicological effects. This makes it possible for us to further develop the toxicities of these compounds to snails. In this work, we tested the antifeedant properties of leaves from seven Chinese Stemona species against the land snail species Bradybaena ravida in choice and non-choice feeding assays. The tested leaves Stemona parviflora exhibited the most deterrent effects, and a further phytochemical investigation of aerial parts led to the identification of 16 alkaloids. Among them, three novel alkaloids could be identified. The alkaloidal fraction and single alkaloids were further assayed against this snail species, and the results suggest a cocktail effect because the impact of the alkaloidal fraction was higher than the effects caused by single alkaloids. The study can promote the search process of natural antimollusc products from plants to control snails.

Larvicidal activity of Stemona collinsiae root extract against Musca domestica and Chrysomya megacephala

Musca domestica and Chrysomya megacephala, considered synanthropic insects, are medically important flies, as they transmit vector-borne diseases to humans and animals. In Thailand, Stemona (Stemonaceae) plants have been traditionally used as insecticides. This study was designed to determine the larvicidal activity of S. collinsiae root extract against M. domestica and C. megacephala larvae. A 70% ethanol crude extract from S. collinsiae roots was tested against the third-instar larvae of both species using direct and indirect contact methods. The development and mortality rates of the insects were observed, and the LC values were calculated. The extract caused irregular development in both species, shown as segmental puparia that could not emerge as adult flies. The LC50 values of the extract against M. domestica tested by direct and indirect contact methods were 0.0064 ± 0.0005 mg/larva and 0.0165 ± 0.0002 mg/cm2/larva, respectively. In the case of C. megacephala, the LC50 value determined by the indirect contact method was 1.0500 ± 0.0001 mg/cm2/larva. The ethanolic root extract of S. collinsiae was able to kill the larvae of both species after dermal administration. It is of interest to develop S. collinsiae root extract as a natural fly control biopesticide.

Regioselective C-H alkylation of anisoles with olefins by cationic imidazolin-2-iminato scandium(iii) alkyl complexes

A new type of rare-earth alkyl complexes supported by monoanionic imidazolin-2-iminato ligands were synthesised and structurally characterised by X-ray diffraction and NMR analyses. The utility of these imidazolin-2-iminato rare-earth alkyl complexes in organic synthesis was demonstrated by their performance in highly regioselective C-H alkylation of anisoles with olefins. With as low as 0.5 mol% catalyst loading, various anisole derivatives without ortho-substitution or 2-methyl substituted anisoles reacted with several alkenes under mild conditions, producing the corresponding ortho-Csp2-H and benzylic Csp3-H alkylation products in high yield (56 examples, 16-99% yields). Control experiments revealed that rare-earth ions, ancillary imidazolin-2-iminato ligands, and basic ligands were crucial for the above transformations. Based on deuterium-labelling experiments, reaction kinetic studies, and theoretical calculations, a possible catalytic cycle was provided to elucidate the reaction mechanism.

Rhodium-Catalyzed Intramolecular Cyclization to Synthesize 2-Aminobenzofurans via Carbene Metathesis Reactions

Herein, we report a new method of synthesizing of 2-aminobenzofuran 3-enes via the formal C-S insertion reaction of alkyne-tethered diazo compounds. Metal carbene, as a kind of active synthetic intermediate, plays a very important role in organic synthesis. Through the carbene/alkyne metathesis strategy, a new donor carbene is produced in situ as a key intermediate, which has different reactions from the donor receptor carbene.

Phenylpropanoid Derivatives from the Tuber of Asparagus cochinchinensis with Anti-Inflammatory Activities

Three undescribed phenylpropanoid derivatives, including two new bibenzyl constituents (1-2), one new stilbene constituent (3), together with five known compounds stilbostemin F (4), dihydropinosylvin (5), 2-(4-hydroxyphenyl)ethyl benzoate (6), 1-(4-hydroxybenzoyl)ethanone (7), and 4-hydroxy-3-prenylbenzoic acid (8), were isolated from the tuber of Asparagus cochinchinensis. The structures of 1-8 were elucidated according to UV, IR, HRMS, 1D and 2D-NMR methods together with the published literature. All of the isolated compounds were assessed for anti-inflammatory activity by acting on lipopolysaccharide (LPS)-induced RAW 264.7 macrophage cells in vitro. The results showed that compounds 2 and 5 were found to inhibit the production of nitric oxide (NO) with the IC₅₀ value of 21.7 and 35.8 µM, respectively. In addition, further studies found that compound 2 demonstrated concentration-dependent suppression of the protein expression of iNOS and exerted anti-inflammatory activity via the NF-κB signalling pathway. The present data suggest that phenylpropanoid derivatives from the tuber of A. cochinchinensis might be used as a potential source of natural anti-inflammatory agents.

Stilbenes: Source plants, chemistry, biosynthesis, pharmacology, application and problems related to their clinical Application-A comprehensive review

Stilbenes are some of the important phenolic compounds originating from plant families like Vitaceae, Leguminaceae, Gnetaceae, and Dipterocarpaceae. Structurally, they have a C6-C2-C6 skeleton, usually with two isomeric forms. Stilbenes are biosynthesized due to biotic and abiotic stresses such as microbial infections, high temperatures, and oxidation. This review aims to provide a comprehensive overview of stilbenes' botanical sources, chemistry, biosynthetic pathways, pharmacology, and clinical applications and challenges based on up-to-date data. All included studies were collected from PubMed, ScienceDirect, Google Scholar, and CNKI, and the presented data from these indexed studies were analyzed and summarized. A total of 459 natural stilbene compounds from 45 plant families and 196 plant species were identified. Pharmacological studies also show that stilbenes have various activities such as anticancer, antimicrobial, antioxidant, anti-inflammatory, anti-degenerative diseases, anti-diabetic, neuroprotective, anti-aging, and cardioprotective effects. Stilbene synthase (STS) is the key enzyme involved in stilbene biosynthetic pathways. Studies on the therapeutic application of stilbenes pinpoint that challenges such as low bioavailability and isomerization are the major bottlenecks for their development as therapeutic drugs. Although the medicinal uses of several stilbenes have been demonstrated in vivo and in vitro, studies on the development of stilbenes deserve more attention in the future.

Pharmacological Properties to Pharmacological Insight of Sesamin in Breast Cancer Treatment: A Literature-Based Review Study

The use of dietary phytochemical rather than conventional therapies to treat numerous cancers is now a well-known approach in medical science. Easily available and less toxic dietary phytochemicals present in plants should be introduced in the list of phytochemical-based treatment areas. Sesamin, a natural phytochemical, may be a promising chemopreventive agent aiming to manage breast cancer. In this study, we discussed the pharmacological properties of sesamin that determine its therapeutics opportunity to be used in breast cancer treatment and other diseases. Sesamin is available in medicinal plants, especially in Sesamum indicum, and is easily metabolized by the liver. To better understand the antibreast cancer consequence of sesamin, we postulate some putative pathways related to the antibreast cancer mechanism: (1) regulation of estrogen receptor (ER-α and ER-β) activities, (2) suppressing programmed death-ligand 1 (PD-L1) overexpression, (3) growth factor receptor inhibition, and (4) some tyrosine kinase pathways. Targeting these pathways, sesamin can modulate cell proliferation, cell cycle arrest, cell growth and viability, metastasis, angiogenesis, apoptosis, and oncogene inactivation in various in vitro and animal models. Although the actual tumor intrinsic signaling mechanism targeted by sesamin in cancer treatment is still unknown, this review summarized that this phytoestrogen suppressed NF-κB, STAT, MAPK, and PIK/AKT signaling pathways and activated some tumor suppressor protein in numerous breast cancer models. Cotreatment with γ-tocotrienol, conventional drugs, and several drug carriers systems increased the anticancer potentiality of sesamin. Furthermore, sesamin exhibited promising pharmacokinetics properties with less toxicity in the bodies. Overall, the shreds of evidence highlight that sesamin can be a potent candidate to design drugs against breast cancer. So, like other phytochemicals, sesamin can be consumed for better therapeutic advantages due to having the ability to target a plethora of molecular pathways until clinically trialed standard drugs are not available in pharma markets.

Anti-neuroinflammatory activity of 6,7-dihydroxy-2,4-dimethoxy phenanthrene isolated from Dioscorea batatas Decne partly through suppressing the p38 MAPK/NF-κB pathway in BV2 microglial cells

ETHNOPHARMACOLOGICAL RELEVANCE

The rhizome of Dioscorea batatas Decne (called Chinses yam) widely distributed in East Asian countries including China, Japan, Korea and Taiwan has long been used in oriental folk medicine owing to its tonic, antitussive, expectorant and anti-ulcerative effects. It has been reported to have anti-inflammatory, antioxidative, cholesterol-lowering, anticholinesterase, growth hormone-releasing, antifungal and immune cell-stimulating activities.

AIM OF THE STUDY

Neuroinflammation caused by activated microglia contributes to neuronal dysfunction and neurodegeneration. In the present study, the anti-neuroinflammatory activity of 6,7-dihydroxy-2,4-dimethoxy phenanthrene (DHDMP), a phenanthrene compound isolated from Dioscorea batatas Decne, was examined in microglial and neuronal cells.

MATERIALS AND METHODS

A natural phenanthrene compound, DHDMP, was isolated from the peel of Dioscorea batatas Decne. The anti-neuroinflammatory capability of the compound was examined using the co-culture system of BV2 murine microglial and HT22 murine neuronal cell lines. The expression levels of inflammatory mediators and cytoprotective proteins in the cells were quantified by enzyme-linked immunosorbent assay and Western blot analysis.

RESULTS

DHDMP at the concentrations of ≤1 μg/mL did not exhibit a cytotoxic effect for BV2 and HT22 cells. Rather DHDMP effectively restored the growth rate of HT22 cells, which was reduced by co-culture with lipopolysaccharide (LPS)-treated BV2 cells. DHDMP significantly decreased the production of proinflammatory mediators, such as nitric oxide, tumor necrosis factor-α, interleukin-6, inducible nitric oxide synthase, and cyclooxygenase-2 in BV2 cells. Moreover, DHDMP strongly inhibited the nuclear translocation of nuclear factor κB (NF-κB) and phosphorylation of p38 mitogen-activated protein kinase (MAPK) in BV2 cells. The compound did not affect the levels and phosphorylation of ERK and JNK. Concurrently, DHDMP increased the expression of heme oxygenase-1 (HO-1), an inducible cytoprotective enzyme, in HT22 cells.

CONCLUSIONS

Our findings indicate that DHDMP effectively dampened LPS-mediated inflammatory responses in BV2 microglial cells by suppressing transcriptional activity of NF-κB and its downstream mediators and contributed to HT22 neuronal cell survival. This study provides insight into the therapeutic potential of DHDMP for inflammation-related neurological diseases.

Oral toxicity of various Stemona collinsiae crude extracts against nymph and adult stages of American cockroach, Periplaneta americana (Dictyoptera: Blattodea)

Stemona collinsiae exhibits insecticidal resistance against various pests and insect vectors. However, insecticidal activity of S. collinsiae roots has not been tested for some insect vectors, including the American cockroach, Periplaneta americana. The synanthropic insect P. americana is a reservoir of pathogenic and non-pathogenic microorganisms and a cause of infectious diseases and cockroach allergy. This important vector transmits microorganisms to animals and humans to cause vector-borne diseases. This research involved detection of the nymphicidal and adulticidal activities of S. collinsiae root extracts against P. americana through oral administration. The effects of hexane, dichloromethane, ethanol, and water crude extracts were tested on final instar nymphs and adult P. americana. After P. americana ingested bait containing hexane and dichloromethane crude extracts, signs of toxicity occurred, such as hind leg shaking, whole-body tremor, immobility, abdomen swelling, and death. At 48 h, the nymphs and adult P. americana that ingested dichloromethane crude extract-containing bait showed corrected mortality of 65%-100% and 20%-100%, respectively. Whereas none of the nymphs and adult P. americana that ingested the water crude extract-containing bait died (0% corrected mortality). When we dissected alimentary canals of the dead P. americana that had ingested dichloromethane and hexane crude extract-containing baits, the foreguts were found to be swollen. TLC analysis showed the dichloromethane and hexane crude extracts contained the alkaloid didehydrostemofoline and unknown fluorescent substances. Phytochemicals from crude extracts were detected in extracts of dissected alimentary canals using thin-layer chromatography, and didehydrostemofoline alkaloid and unknown fluorescent substances were found in cockroaches that ingested dichloromethane- and hexane-containing baits. The cause of death of P. americana may be attributed to alkaloids and synergistic effects of other substances in S. collinsiae root extract. Mechanisms of action might include several pathways involved in nervous system function. Thus, dichloromethane and hexane crude extracts can be developed as alternative active ingredients in a natural insecticide for cockroach control.

Biomimetic Carbene Cascades Enabled Imine Derivative Migration from Carbene-Bearing Thiocarbamates

Inspired by the body circulation of Omeprazole (irreversible proton pump inhibitor), we disclose the carbene-triggered cascades for the synthesis of 2-aminobenzofuran derivatives from N-sulfonyl-1,2,3-triazoles or benzothioazole-bearing thiocarbamates, which represents an unprecedented imine derivative migration process. Furthermore, the desulfurizing reagent-free Barton-Kellogg-type reactions starting from N-sulfonyl-1,2,3-triazoles have also been achieved for the first time, and elemental sulfur is confirmed as a byproduct during this transformation. Both experimental data and DFT calculations further thoroughly explained the unique reactivity.

The traditional uses, phytochemistry, and pharmacology of Stemona species: A review

ETHNOPHARMACOLOGICAL RELEVANCE

Plants of genus Stemona (Stemonaceae) have been long used locally and traditionally in many South and East Asian counties to relieve cough, dispel phlegm, prevent asthma, control pests, diminish inflammation, decrease pain, and treat some cutaneous diseases.

AIM OF STUDY

This review provided comprehensive and up-to-date information about botanic characterization and distribution, ethnopharmacology, secondary metabolites, pharmacological activities, and toxicology of plants of genus Stemona to explore the scientific potential and future therapeutic potential of the plants.

MATERIALS AND METHODS

This article conducted a literature review on information about the Stemona species in multiple electronic databases, including PubMed, Web of Science, Wiley, Science Direct, Elsevier, Google Scholar, ACS publications, SpringerLink, and China National Knowledge Internet. Information was also derived from other literature sources (e.g. Chinese Pharmacopoeia, 2015 edition, Chinese herbal classic books, PhD and MSc thesis). Plant names were validated by "The Plant List" (www.theplantlist.org). All studies of the genus Stemona were included in this review until March 2020.

RESULTS

Our comprehensive analysis of the scientific literatures indicated that many Stemona species are popular and valuable herbal medicines with therapeutic potentials to treat various ailments. Phytochemical analyses identified alkaloids and stilbenoids as the major bioactive substances of Stemona species. Numerous studies have shown that the extracts and secondary metabolites isolated from these plants have a wide range of pharmacological activities, including insecticidal and antifeedant, antitussive, anti-inflammatory, anticancer, antimicrobial, and antivirus activities.

CONCLUSION

Though plants of genus Stemona have been put to enormous traditional uses, the pharmacological studies conducted were insufficient. Therefore, more secondary metabolites need to be studied for more detailed pharmacological studies. Further studies are also required to establish the mechanisms which mediate the plants' bioactivities in relation to the medicinal uses as well as investigate any potential toxicity for future clinical studies.

Stilbenoids from the roots of Stemona tuberosa

Two new stilbenoids, stemobenoids A (1) and B (2), together with three known compounds were obtained from the roots of Stemona tuberosa. The structures of the new compounds were established by extensive spectroscopic analysis, including HRMS, 1D and 2D NMR data. Compounds 1 and 2 displayed potent quinone reductase inducing activity in Hepa 1c1c7 cells.

Antioxidation of 2-phenylbenzofuran derivatives: structural-electronic effects and mechanisms

Stilbenoid-type 2-phenylbenzofuran derivatives, which are widely distributed in nature, are now promising antioxidant agents. In the present study, a quantum computational approach principally based on the DFT/B3LYP method with the 6-311++G(d,p) basis set was used to shed light on free radical scavenging for the isolated compounds stemofurans A-K and S-W. On the basis of the findings and from a thermodynamic perspective, the antioxidant activity of all studied compounds in the gaseous phase was mostly controlled by the O-H bond dissociation enthalpy (BDE), consistent with the hydrogen atom transfer (HAT) mechanism. The solvent effect was investigated, and the hydroxyl radicals of these studied compounds possessed the lowest proton affinity (PA) enthalpy and the sequential proton loss electron transfer (SPLET) pathway occurred in water, methanol and acetone. The studied compounds interacted with DPPH radicals, which is kinetic evidence of the involvement of two intermediates and one transition state. From both thermodynamics and kinetics perspectives, it can be proposed that stemofuran U is likely to be a leader compound in antioxidant drug development due to the presence of a 4'-OH moiety. Regarding the structure-bioactivity relationship, methylation can lead to a decrease in BDE.

A phytochemical investigation of Stemona parviflora roots reveals several compounds with nematocidal activity

Twelve undescribed compounds including six phenanthrene derivatives (parviphenanthrines A-F), two stilbene derivatives (parvistilbines A-B), three esters (parviesters A-C), and one sesquiterpenoid (parvidiol A) were isolated from the roots of Stemona parviflora, together with twenty-two known ones. The structures of the undescribed compounds were elucidated based on the analyses of their spectroscopic data. The absolute configuration of parviphenanthrine A was determined by the quantum ECD calculations. Parviphenanthrines A and E, stemanthrene A, stilbostenin E, 4-hydroxy-benzenepropanol-α-benzoate, and (E)-4-hydroxycinnamic acid methyl ester showed nematocidal activity against Meloidogyne incognita with IC₅₀ values of 14.02 ± 0.32, 2.51 ± 0.13, 17.10 ± 0.65, 2.05 ± 0.07, 4.22 ± 0.31, and 1.07 ± 0.05 μM, respectively.

Aryl benzofuran derivatives from the stem bark of Calpocalyx dinklagei attenuate inflammation

Calpocalyx dinklagei Harms (Fabaceae) is a tropical medicinal tree, which is indigenous to Western Africa. A phytochemical study of this local plant species from its stem bark has led to the isolation of two previously undescribed aryl benzofuran derivatives, named dinklagein A and B, together with eight known compounds. Their chemical structures were elucidated by use of extensive spectroscopic methods (IR, HREI-MS and 1D and 2D NMR). Among all isolates, dinklagein A displayed remarkably potent inhibitory activity against the production of nitric oxide (NO) in the lipopolysaccharide (LPS) induced RAW264.7 macrophages. SAR and molecular docking investigations on iNOS and previously undescribed compounds (dinklagein A and B) supported experimental data. Furthermore, dinklagein A dose dependently suppressed the LPS-stimulated iNOS expression at both mRNA and protein level. It also attenuated IL-1β release, mRNA expressions of IL-1β and COX-2 at low doses. These results suggest that dinklagein A can be developed as natural, multi-target agent against several inflammatory diseases.

Total synthesis of natural products containing benzofuran rings

In this review, various approaches for the construction of benzofurans as an important moiety in different natural products during the total synthesis of the natural of products are underscored.

Synthesis and antifungal activity of novel indole-replaced streptochlorin analogues

Based on examples of the successful applications in drug discovery of bioisosterism, a series of streptochlorin analogues in which indole has been replaced by other heterocycles has been designed and synthesized, as a continuation of our studies aimed at the discovery of novel streptochlorin analogues with improved antifungal activity. Biological testing showed that most of the indole-replaced streptochlorin analogues were inactive, though compound 6f had a broad spectrum of antifungal activity with significant activity against Alternaria solani. The SAR study demonstrated that indole ring is an essential moiety for the antifungal activity of streptochlorin analogues, promoting the idea of indole ring as a framework that might be exploited in the future.

Potential pancreatic lipase inhibitory activity of phenolic constituents from the root bark of Morus alba L

Detailed phytochemical investigation from the root bark of Morus alba resulted in the isolation of eleven new compounds, including seven 2-arylbenzofuran derivatives (morusalfurans A-G), three flavonoids (morusalnols A-C), and one geranylated stilbene (morusibene A), as well as 22 known compounds. The structures of the identified compounds were elucidated based on a comprehensive analysis of spectroscopic data and Mosher's method. Compounds 2, 3, 6-8, 11, 23, 24, and 29 showed potent inhibition of PL in comparison with the positive control treatment (orlistat, IC50=0.012μM), with IC50 values ranging from 0.09 to 0.92μM.

A facile one-pot synthesis of 2,3-diarylated benzo[b]furans via relay NHC and palladium catalysis

An efficient one-pot synthesis of 2,3-diarylated benzo[b]furans was realized through the relay catalysis of N-Heterocyclic Carbene (NHC) and palladium from substituted 2'-bromodiphenylbromomethanes and aryl aldehydes. The easy availability of the starting materials, good compatibility of catalysts, convergent assembly and concomitant modification of the target scaffold, and potential utilization value of the products make this strategy attractive in organic synthesis.

Hydrazone–palladium catalyzed annulation of 1-cinnamyloxy-2-ethynylbenzene derivatives

The annulation of 1-cinnamyloxy-2-ethynylbenzene derivatives using a hydrazone–palladium catalyst system proceeded smoothly and gave the corresponding 2-substituted-3-cinnamylbenzofurans in good-to-excellent yields.

Fluorination of 2-substituted benzo[b]furans with Selectfluor™

An efficient protocol was developed to access 3-fluoro-2-hydroxy-2-substituted benzo[b]furans with Selectfluor™ as the fluorinating reagent in MeCN and water. By utilizing SOCl₂/Py as the dehydrating agent, the compounds above were readily converted to 3-fluorinated, 2-substituted benzo[b]furans in high yields.

Palladium-catalyzed tandem reaction of 2-hydroxyarylacetonitriles with sodium sulfinates: one-pot synthesis of 2-arylbenzofurans

Palladium-catalyzed desulfinative addition and intramolecular annulation tandem reactions of 2-hydroxyarylacetonitriles with sodium sulfinates for one-pot synthesis of 2-arylbenzofurans.

Cytotoxic deoxybenzoins and diphenylethylenes from Arundina graminifolia

Eight new C-4-alkylated deoxybenzoins (1-8), three new diphenylethylenes (9-11), and five known diphenylethylenes were isolated from Arundina graminifolia. The structures of 1-11 were elucidated by spectroscopic methods including extensive 1D and 2D NMR techniques. Compounds 9-11 are the first naturally occurring diphenylethylenes possessing a hydroxyethyl unit. Compounds 1-11 were evaluated for cytotoxicity against five human tumor cell lines. Compounds 4, 5, and 9-11 showed significant cytotoxicity against five cancer cell lines, with IC50 values ranging from 1.8 to 8.7 μM.

Natural stilbenoids: distribution in the plant kingdom and chemotaxonomic interest in Vitaceae

Stilbenoids, a family of polyphenols known for the complexity of their structure and for their diverse biological activities, occur with a limited but heterogeneous distribution in the plant kingdom. The most prominent stilbene containing plant family, the Vitaceae, represented by the famous wine producing grape vines Vitis vinifera L., is one of the richest sources of novel stilbenes currently known, together with other families, such as Dipterocarpaceae, Gnetaceae and Fabaceae. This review focuses on the distribution of stilbenes and 2-arylbenzofuran derivatives in the plant kingdom, the chemical structure of stilbenes in the Vitaceae family and their taxonomic implication.