Probing the Antiallergic and Anti-inflammatory Activity of Biflavonoids and Dihydroflavonols from Dietes bicolor

Robustaflavone as a novel scaffold for inhibitors of native and auto-proteolysed human neutrophil elastase

Human neutrophil elastase (HNE) plays a key role in initiating inflammation in the cardiopulmonary and systemic contexts. Pathological auto-proteolysed two-chain (tc) HNE exhibits reduced binding affinity with inhibitors. Using AutoDock Vina v1.2.0, 66 flavonoid inhibitors, sivelestat and alvelestat were docked with single-chain (sc) HNE and tcHNE. Schrodinger PHASE v13.4.132 was used to generate a 3D-QSAR model. Molecular dynamics (MD) simulations were conducted with AMBER v18. The 3D-QSAR model for flavonoids with scHNE showed r2 = 0.95 and q2 = 0.91. High-activity compounds had hydrophobic A/A2 and C/C2 rings in the S1 subsite, with hydrogen bond donors at C5 and C7 positions of the A/A2 ring, and the C4' position of the B/B1 ring. All flavonoids except robustaflavone occupied the S1'-S2' subsites of tcHNE with decreased AutoDock binding affinities. During MD simulations, robustaflavone remained highly stable with both HNE forms. Principal Component Analysis suggested that robustaflavone binding induced structural stability in both HNE forms. Cluster analysis and free energy landscape plots showed that robustaflavone remained within the sc and tcHNE binding site throughout the 100 ns MD simulation. The robustaflavone scaffold likely inhibits both tcHNE and scHNE. It is potentially superior to sivelestat and alvelestat and can aid in developing therapeutics targeting both forms of HNE.

Discovery of anti-inflammatory natural flavonoids: Diverse scaffolds and promising leads for drug discovery

Natural products have been utilized for medicinal purposes for millennia, endowing them with a rich source of chemical scaffolds and pharmacological leads for drug discovery. Among the vast array of natural products, flavonoids represent a prominent class, renowned for their diverse biological activities and promising therapeutic advantages. Notably, their anti-inflammatory properties have positioned them as promising lead compounds for developing novel drugs combating various inflammatory diseases. This review presents a comprehensive overview of flavonoids, highlighting their manifold anti-inflammatory activities and elucidating the underlying pathways in mediating inflammation. Furthermore, this review encompasses systematical classification of flavonoids, related anti-inflammatory targets, involved in vitro and in vivo test models, and detailed statistical analysis. We hope this review will provide researchers engaged in active natural products and anti-inflammatory drug discovery with practical information and potential leads.

Beneficial effects of flavonoids on cardiovascular diseases by influencing NLRP3 inflammasome

Cardiovascular diseases (CVDs) are a leading cause of global mortality and have a high incidence rate worldwide. The function of inflammasomes in CVDs has received a lot of attention recently, and the nucleotide-binding domain and leucine-rich repeat protein 3 (NLRP3) inflammasome may be a new target for the prevention and treatment of CVDs. Flavonoids, which are found in food and plant extracts, inhibited inflammation in CVDs by regulating the NLRP3 inflammasome. CB-Dock was used to investigate whether 34 flavonoids from natural products acted on NLRP3 inflammasome. In brief, the PDB format of NLRP3 was selected as a protein file, and 34 flavonoids in SDF format were selected as the ligand file, and then input to CB-Dock for molecular docking. The docking results showed that epigallocatechin-3-gallate (EGCG), amentoflavone, baicalin, scutellarin, vitexin, silibinin, and puerarin had good binding affinities to NLRP3, which could be used as NLRP3 inhibitors, and aid in the discovery of lead compounds for the design and development of CVDs.

Chemical characterization of the polyphenolic rich fraction of Thunbergia erecta and its therapeutic potential against doxorubicin and cyclophosphamide-induced cognitive impairment in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Thunbergia erecta (Benth.) was traditionally used as anxiolytic, sedative and antidepressant.

AIM OF THE STUDY

The study aimed to characterize T. erecta leaf ethyl acetate fraction of alcohol extract (TEAF) and evaluate its neuroprotective effect on doxorubicin and cyclophosphamide-induced chemobrain.

MATERIALS AND METHODS

Chemical profiling of TEAF was done using (Liquid chromatography coupled with mass (LC-ESI-MS/MS). In vivo chemobrain model was performed by cognitive impairment induced by doxorubicin and cyclophosphamide. Behavioral assessments included moris water maze, y maze, novel object recognition task and passive avoidance tests. Histological examination and oxidative stress markers were investigated. Protein expression of HMDGB1/RAGE/pNF-κB pathway markers was done using western blotting. All results were applied to hippocampus and prefrontal cortex of rats. Molecular docking was done within the active sites of Human Receptor for Advanced Glycation Endproducts (RAGE) using Discovery studio software.

RESULTS

Twenty-one phytoconstituents, mostly polyphenolics, were characterized in TEAF of which eleven compounds were tentatively identified for the first time from T. erecta leaves where rosmarinic acid (11) represents the most prevailing compound. TEAF resulted in a marked dose-dependent amelioration of the histopathological changes evidenced by normal histological structure demonstrated in the hypocampal gesture of rats. TEAF demonstrated an enhanced memory and learning functioning in the different behavioral tests assessed especially at 200 mg/kg. It showed significant long-term spatial memory enhancement manifested by 50.32% increase in probe trial relative to chemobrain-induced group. It showed pronounced antioxidant activity evidenced by the significant elevation of prefrontal cortical and hippocampal reduced glutathione levels by 2.45 and 2.65 folds, respectively relative to the chemobrain-induced group. The pronounced reduction in hydrogen peroxide (1.24-1.93 folds) and malondialdehyde levels (1.42-2.60 folds) with significant elevation of catalase activity (12.65-31.47%) induced by TEAF supported its potent antioxidant activity. TEAF reversed the inflammatory cytokines release induced by chemotherapy via its interference with HMGB1/RAGE pathway suppressing the expression of HMBG1, RAGE, p65 (NF-kB), and IL-1β. In silico studies showed that rosmarinic acid displayed the best fitting at the active site of RAGE (ΔG = -40.39 kcal/mol).

CONCLUSIONS

Thunbergia erecta can act as a promising remedy for chemobrain that further consolidates its traditional importance.

Metabolic profiling, antioxidant, and enzyme inhibition potential of Iris pseudacorus L. from Egypt and Japan: A comparative study

Genus Iris comprises numerous and diverse phytoconstituents displaying marked biological activities. The rhizomes, and aerial parts of Iris pseudacorus L. cultivars from Egypt and Japan were subjected to comparative metabolic profiling using UPLC-ESI-MS/MS. The antioxidant capacity was determined using DPPH assay. In vitro enzyme inhibition potential against α-glucosidase, tyrosinase and lipase was evaluated. In silico molecular docking was conducted on the active sites of human α-glucosidase and human pancreatic lipase. Forty-three compounds were tentatively identified including flavonoids, isoflavonoids, phenolics and xanthones. I. pseudacorus rhizomes extracts (IPR-J and IPR-E) exhibited the highest radical scavenging activity with IC₅₀ values of 40.89 µg/mL and 97.97 µg/mL, respectively (Trolox IC₅₀ value was 14.59 µg/mL). Moreover, IPR-J and IPR-E exhibited promising α-glucosidase inhibitory activity displaying IC₅₀ values of 18.52 µg/mL, 57.89 µg/mL, respectively being more potent as compared to acarbose with IC₅₀ value of 362.088 µg/mL. All extracts exerted significant lipase inhibitory activity exhibiting IC₅₀ values of 2.35, 4.81, 2.22 and 0.42 µg/mL, respectively compared to cetilistat with IC₅₀ value of 7.47 µg/mL. However, no tyrosinase inhibitory activity was observed for all I. pseudacorus extracts up to 500 µg/mL. In silico molecular modelling revealed that quercetin, galloyl glucose, and irilin D exhibited the highest fitting scores within the active sites of human α-glucosidase and pancreatic lipase. ADMET prediction (absorption, distribution, metabolism, excretion, and toxicity) showed that most of the phytoconstituents exhibited promising pharmacokinetic, pharmacodynamics and tolerable toxicity properties. According to our findings, I. pseudacorus might be considered as a valuable source for designing novel phytopharmaceuticals.

Perplexing Polyphenolics: The Isolations, Syntheses, Reappraisals, and Bioactivities of Flavonoids, Isoflavonoids, and Neoflavonoids from 2016 to 2022

Flavonoids, isoflavonoids, neoflavonoids, and their various subcategories are polyphenolics-an extensive class of natural products. These compounds are bioactive and display multiple activities, including anticancer, antibacterial, antiviral, antioxidant, and neuroprotective activities. Thus, these compounds can serve as leads for therapeutic agents or targets for complex synthesis; they are coveted and routinely isolated, characterized, biologically evaluated, and synthesized. However, data regarding the compounds' sources, isolation procedures, structural novelties, bioactivities, and synthetic schemes are often dispersed and complex, a dilemma this review aims to address. To serve as an easily accessible guide for researchers wanting to apprise themselves of the latest advancements in this subfield, this review summarizes seventy-six (76) articles published between 2016 and 2022 that detail the isolation and characterization of two hundred and forty-nine (249) novel compounds, the total and semisyntheses of thirteen (13) compounds, and reappraisals of the structures of twenty (20) previously reported compounds and their bioactivities. This article also discusses new synthetic methods and enzymes capable of producing or modifying flavonoids, isoflavonoids, or neoflavonoids.

Encephalartos villosus Lem. Displays a Strong In Vivo and In Vitro Antifungal Potential against Candida glabrata Clinical Isolates

Recently, Candida glabrata has been recognized as one of the most common fungal species that is highly associated with invasive candidiasis. Its spread could be attributed to its increasing resistance to antifungal drugs. Thus, there is a high need for safer and more efficient therapeutic alternatives such as plant extracts. Here, we investigated the antifungal potential of Encephalartos villosus leaves methanol extract (EVME) against C. glabrata clinical isolates. Tentative phytochemical identification of 51 metabolites was conducted in EVME using LC–MS/MS. EVME demonstrated antifungal activity with minimum inhibitory concentrations that ranged from 32 to 256 µg/mL. The mechanism of the antifungal action was studied by investigating the impact of EVME on nucleotide leakage. Additionally, a sorbitol bioassay was performed, and we found that EVME affected the fungal cell wall. In addition, the effect of EVME was elucidated on the efflux activity of C. glabrata isolates using acridine orange assay and quantitative real-time PCR. EVME resulted in downregulation of the expression of the efflux pump genes CDR1, CDR2, and ERG11 in the tested isolates with percentages of 33.33%, 41.67%, and 33.33%, respectively. Moreover, we investigated the in vivo antifungal activity of EVME using a murine model with systemic infection. The fungal burden was determined in the kidney tissues. Histological and immunohistochemical studies were carried out to investigate the effect of EVME. We noticed that EVME reduced the congestion of the glomeruli and tubules of the kidney tissues of the rats infected with C. glabrata. Furthermore, it decreased both the proinflammatory cytokine tumor necrosis factor-alpha and the abnormal collagen fibers. Our results reveal, for the first time, the potential in vitro (by inhibition of the efflux activity) and in vivo (by decreasing the congestion and inflammation of the kidney tissues) antifungal activity of EVME against C. glabrata isolates.

Promising Antifungal Activity of Encephalartos laurentianus de Wild against Candida albicans Clinical Isolates: In Vitro and In Vivo Effects on Renal Cortex of Adult Albino Rats

Candida albicans can cause various infections, especially in immunocompromised patients. Its ability to develop resistance to the current antifungal drugs as well as its multiple virulence factors have rendered the problem even more complicated. Thus, in the present investigation, we elucidated an in vitro and in vivo antifungal activity of Encephalartos laurentianus methanol extract (ELME) against C. albicans clinical isolates for the first time. A phytochemical identification of 64 compounds was conducted in ELME using LC-MS/MS. Interestingly, ELME exhibited antifungal activity with MIC values that ranged from 32–256 µg/mL. Furthermore, we investigated the antibiofilm activity of ELME against the biofilms formed by C. albicans isolates. ELME displayed antibiofilm activity using a crystal violet assay as it decreased the percentages of cells, moderately and strongly forming biofilms from 62.5% to 25%. Moreover, the antibiofilm impact of ELME was elucidated using SEM and fluorescent microscope. A significant reduction in the biofilm formation by C. albicans isolates was observed. In addition, we observed that ELME resulted in the downregulation of the biofilm-related tested genes (ALS1, BCR1, PLB2, and SAP5) in 37.5% of the isolates using qRT-PCR. Besides, the in vivo antifungal activity of ELME on the kidney tissues of rats infected with C. albicans was investigated using histological and immunohistochemical studies. ELME was found to protect against C. albicans induced renal damage, decrease desmin and inducible nitric oxide synthase, increase alkaline phosphatase, and increase infected rats’ survival rate. Additionally, the cytotoxicity of ELME was elucidated on Human Skin Fibroblast normal cells using MTT assay. ELME had an IC50 of 31.26 µg/mL. Thus, we can conclude that ELME might be a promising future source for antifungal compounds.

Insights on the neuroprotective effects of Salvia officinalis L. and Salvia microphylla Kunth in memory impairment rat model

Salvia species have a traditional longstanding culinary use mostly consumed in the Mediterranean diet as a common spice added to food. Salvia is commonly consumed as an herbal tea for...

Three new dihydroflavonols with free radical scavenging activity from Ribes himalense Royle ex Decne

Ribes himalense Royle ex Decne, a small shrub, is widely used as a Tibetan medicine in Chinese folk. In this study, three novel 1,1-diphenyl-2-picrylhydrazyl inhibitors named Rihimaside A, Rihimaside B, and Rihimaside C, as well as one known 1,1-diphenyl-2-picrylhydrazyl inhibitor, dihydromyricetin, were isolated from the leaves and stems of Ribes himalense Royle ex Decne using online high performance liquid chromatography-1,1-diphenyl-2-picrylhydrazyl activity screening system combined with medium and high-pressure liquid chromatography. All four 1,1-diphenyl-2-picrylhydrazyl inhibitors are dihydroflavonols. The 1,1-diphenyl-2-picrylhydrazyl scavenging activity and IC₅₀ values of three novel 1,1-diphenyl-2-picrylhydrazyl inhibitors were determined using 1,1-diphenyl-2-picrylhydrazyl methods. Rihimaside A, Rihimaside B, and Rihimaside C exhibited IC₅₀ values of 9.58 μg/mL, 12.57 μg/mL and 387 μg/mL, respectively.

Flavonoids as inhibitors of human neutrophil elastase

Elastase is a proteolytic enzyme belonging to the family of hydrolases produced by human neutrophils, monocytes, macrophages, and endothelial cells. Human neutrophil elastase is known to play multiple roles in the human body, but an increase in its activity may cause a variety of diseases. Elastase inhibitors may prevent the development of psoriasis, chronic kidney disease, respiratory disorders (including COVID-19), immune disorders, and even cancers. Among polyphenolic compounds, some flavonoids and their derivatives, which are mostly found in herbal plants, have been revealed to influence elastase release and its action on human cells. This review focuses on elastase inhibitors that have been discovered from natural sources and are biochemically characterised as flavonoids. The inhibitory activity on elastase is a characteristic of flavonoid aglycones and their glycoside and methylated, acetylated and hydroxylated derivatives. The presented analysis of structure-activity relationship (SAR) enables the determination of the chemical groups responsible for evoking an inhibitory effect on elastase. Further study especially of the in vivo efficacy and safety of the described natural compounds is of interest in order to gain better understanding of their health-promoting potential.

Potential of Sorghum Polyphenols to Prevent and Treat Alzheimer's Disease: A Review Article

Alzheimer's disease (AD) is characterized by the excessive deposition of extracellular amyloid-beta peptide (Aβ) and the build-up of intracellular neurofibrillary tangles containing hyperphosphorylated tau proteins. This leads to neuronal damage, cell death and consequently results in memory and learning impairments leading to dementia. Although the exact cause of AD is not yet clear, numerous studies indicate that oxidative stress, inflammation, and mitochondrial dysfunction significantly contribute to its onset and progression. There is no effective therapeutic approach to stop the progression of AD and its associated symptoms. Thus, early intervention, preferably, pre-clinically when the brain is not significantly affected, is a better option for effective treatment. Natural polyphenols (PP) target multiple AD-related pathways such as protecting the brain from Aβ and tau neurotoxicity, ameliorating oxidative damage and mitochondrial dysfunction. Among natural products, the cereal crop sorghum has some unique features. It is one of the major global grain crops but in the developed world, it is primarily used as feed for farm animals. A broad range of PP, including phenolic acids, flavonoids, and condensed tannins are present in sorghum grain including some classes such as proanthocyanidins that are rarely found in others plants. Pigmented varieties of sorghum have the highest polyphenolic content and antioxidant activity which potentially makes their consumption beneficial for human health through different pathways such as oxidative stress reduction and thus the prevention and treatment of neurodegenerative diseases. This review summarizes the potential of sorghum PP to beneficially affect the neuropathology of AD.

Phytochemical discrimination of Pinus species based on GC-MS and ATR-IR analyses and their impact on Helicobacter pylori

INTRODUCTION

The leaves and cones of Pinus plants as well as their essential oils have been used in traditional medicine for the treatment of several ailments.

OBJECTIVES

Phytochemical discrimination of Pinus species and investigation of their anti-Helicobacter pylori activity in vitro and in silico.

MATERIALS AND METHODS

Gas chromatography-mass spectrometry (GC-MS) and attenuated total reflectance infrared (ATR-IR) metabolic profiling of the essential oils of Pinus species. Principal component analysis (PCA) and hierarchal cluster analysis (HCA) were applied for discrimination and segregation of Pinus species.

RESULTS

GC-MS revealed the presence of 76 constituents, where monoterpenes represented the major class with the dominance of α-pinene (72%) followed by β-pinene (16%) for P. canariensis. β-Pinene was the dominant component in P. pinea (24%) followed by terpinolene (11%). α-Pinene (17%) and caryophyllene (12%) were the major components in P. halepensis, while, 3-carene (33%) and α-pinene (17%) represented the major constituents of P. roxburghii oil. By applying PCA and HCA on GC-MS and ATR-IR data analysis, ATR-IR displayed much better discrimination for Pinus species. The pine oils showed promising inhibitory effects on Helicobacter pylori. Furthermore, in silico molecular modelling was carried out where the calculated free binding energies of phytochemicals identified ranged from -33.71 to -19.67 kcal/mol for urease and -41.18 to -16.57 kcal/mol for shikimate kinase. This suggests favourable binding of pine essential oil components to both enzymes, thus explaining their potential inhibitory activity on H. pylori.

CONCLUSION

GC-MS and ATR-IR based metabolic analyses could discriminate between Pinus species. Pine essential oils can be used as promising therapeutic drugs to protect against H. pylori infection.

Structural characterization of prenylated compounds from Broussonetia kazinoki and their antiosteoclastogenic activity

An undescribed 1,3-diphenylpropane derivative, kazinol V and six undescribed prenylated flavonoids, broussonols F-H and broussonols K-M were isolated from the roots of Broussonetia kazinoki Siebold, together with 12 known compounds. This is the first report of the isolation and structure determination of broussonol I from a natural source. The chemical structure of the undescribed compounds was determined using conventional NMR and HRMS data. Absolute configurations were assigned using time-dependent density functional theory calculations and Electronic Circular Dichroism (ECD) spectroscopy. The isolated compounds were screened for their effects on RANKL-induced osteoclast formation using RAW264.7 cells. Among them, broussonols F, G, and K showed strong, dose-dependent antiosteoclastogenic activities. Broussonol K exhibited the most potent inhibitory activity and possessed bone resorption suppressive activity.

Hinokiflavone and Related C-O-C-Type Biflavonoids as Anti-cancer Compounds: Properties and Mechanism of Action

Biflavonoids are divided in two classes: C-C type compounds represented by the dimeric compound amentoflavone and C-O-C-type compounds typified by hinokiflavone (HNK) with an ether linkage between the two connected apigenin units. This later sub-group of bisflavonyl ethers includes HNK, ochnaflavone, delicaflavone and a few other dimeric compounds, found in a variety of plants, notably Selaginella species. A comprehensive review of the anticancer properties and mechanism of action of HNK is provided, to highlight the anti-proliferative and anti-metastatic activities of HNK and derivatives, and HNK-containing plant extracts. The anticancer effects rely on the capacity of HNK to interfere with the ERK1-2/p38/NFκB signaling pathway and the regulation of the expression of the matrix metalloproteinases MMP-2 and MMP-9 (with a potential direct binding to MMP-9). In addition, HNK was found to function as a potent modulator of pre-mRNA splicing, inhibiting the SUMO-specific protease SENP1. As such, HNK represents a rare SENP1 inhibitor of natural origin and a scaffold to design synthetic compounds. Oral formulations of HNK have been elaborated to enhance its solubility, to facilitate the compound delivery and to enhance its anticancer efficacy. The review shed light on the anticancer potential of C-O-C-type biflavonoids and specifically on the pharmacological profile of HNK. This compound deserves further attention as a regulator of pre-mRNA splicing, useful to treat cancers (in particular hepatocellular carcinoma) and other human pathologies.

Discovery of potential pharmacodynamic ingredients of Dang-Gui-Si-Ni decoction based on absorbed ingredients and molecular docking

ETHNOPHARMACOLOGICAL RELEVANCE

The Dang-Gui-Si-Ni (DGSN) decoction as a classic prescription has been widely used for thousands of years in the clinical practice of traditional Chinese medicine (TCM). Especially in recent years, the potential efficacy of TCM for the treatment of Raynaud's syndrome has attracted great attention as there are still no specific remedies for this disease. However, the active constituents and underlying mechanisms responsible for the therapeutic benefits are not well understood, which makes it difficult to ensure quality control or to design research and drug development strategies. To identify the potential pharmacodynamic ingredients (PPIs) of TCM will help to achieve suitable process control procedures for industrial production and large-scale manufacturing.

AIM OF THE STUDY

In the present study, we propose a multi-dimensional qualitative analysis method combining water-decoction spectra, in-vitro intestinal absorption spectra, in-vivo plasma spectra, and molecular docking of components to quickly identify the PPIs for the DGSN decoction of TCM.

MATERIALS AND METHODS

Water-based decoctions of DGSN were prepared in accordance with the clinical use registered in ancient books. Ultra-high-performance liquid chromatography-quadrupole-time of flight mass spectrometry (UHPLC-Q/TOF-MS) coupled with computerized modelling activity screening was used to quickly identify the PPIs of the DGSN decoction. Bioactive compounds absorbed in vitro were identified using the everted intestinal sac model from rats and compounds absorbed in vivo were confirmed in portal vein blood samples obtained following oral administration in rats. Molecular docking validation experiments were adopted to predict the binding activity to coagulation factors I, II, VII, X, and IX. The active components were further confirmed by pharmacodynamics analysis. The anticoagulant activity of the DGSN decoction was verified using rat models.

RESULTS

Thirty-one compounds were identified in the DGSN decoction. According to the in vivo experiments, 22 compounds that could be absorbed in vivo were detected by the everted intestinal sac model in rats. This model greatly reduces the scope of PPIs and is easy to perform. Ten compounds were detected in the portal vein blood in rats. The compounds detected in plasma provide stronger evidence supporting the PPIs. Molecular docking in vitro experiments indicated that 7 compounds exhibited better binding activity with coagulation factors I, II, VII, X, and IX. The animal experiments confirmed that the DGSN decoction could improve the microcirculation, providing indirect proof of anticoagulant activity suggested by the molecular docking studies. Finally, based on the multi-dimensional methods, 9 potential compounds present in the DGSN decoction were identified as PPIs (i.e., ferulic acid, paeoniflorin, albiflorin, chlorogenic acid, cryptochlorogenic acid, liquiritin, liquiritin apioside, cinnamaldehyde and glycyrrhizic acid).

CONCLUSION

Overall, this study combined the water-decoction spectra, intestinal absorption spectra in vitro, plasma spectra in vivo, and molecular docking studies to establish a multi-dimensional qualitative analysis method of the DGSN decoction. Meanwhile, 9 compounds in DGSN decoction were identified as PPIs using this method, and are proposed for application as quality standards for complex TCM prescriptions.

Baicalein 5,6-Dimethyl Ether Prevents Memory Deficits in the Scopolamine Zebrafish Model by Regulating Cholinergic and Antioxidant Systems

Baicalein 5,6-dimethyl ether, a bioactive flavonoid isolated for the first time from Alnus rugosa, was explored for its capability to relieve memory deficits and decrease oxidative stress. We examined the neuropharmacological effects of baicalein 5,6-dimethyl ether on scopolamine (Sco)-induced zebrafish (Danio rerio) anxiety, amnesia, and brain oxidative stress and attempted to elucidate the underlying mechanisms. Anxiety-like behavior, exploratory behavior, and memory performance were measured using novel tank-diving test (NTT), Y-maze, and novel object recognition (NOR) tests. For 10 days, baicalein 5,6-dimethyl ether (1, 3, and 5 µg/L) was administered through immersion, whereas Sco (100 μM) was delivered 30 min before behavioral tests. Treatment with baicalein 5,6-dimethyl ether reduced anxiety and memory impairment, and increased exploratory behavior in specific tests, along with significant protection from neuronal oxidative stress in the brain tissue of Sco-treated zebrafish. Antioxidant and anti-acetylcholinesterase (AChE) activities of baicalein 5,6-dimethyl ether in the Sco-induced zebrafish were further confirmed using in vivo assays. In Sco-treated zebrafish, baicalein 5,6-dimethyl ether regulated cholinergic function by inhibiting AChE activity. Baicalein 5,6-dimethyl ether may be a promising candidate compound for treating anxiety and amnesia by restoring cholinergic activity and reducing brain oxidative stress, according to our findings.

Anti-Allergic, Anti-Inflammatory and Anti-Hyperglycemic Activity of Chasmanthe aethiopica Leaf Extract and Its Profiling Using LC/MS and GLC/MS

This study aims to comprehensively explore the phytoconstituents as well as investigate the different biological activities of Chasmanthe aethiopica (Iridaceae) for the first time. Metabolic profiling of the leaf methanol extract of C. aethiopica (CAL) was carried out using HPLC-PDA-ESI-MS/MS. Twenty-nine compounds were annotated belonging to various phytochemical classes including organic acids, cinnamic acid derivatives, flavonoids, isoflavonoids, and fatty acids. Myricetin-3-O-rhamnoside was the major compound identified. GLC/MS analysis of the n-hexane fraction (CAL-A) resulted in the identification of 45 compounds with palmitic acid (16.08%) and methyl hexadecanoic acid ester (11.91%) representing the major constituents. CAL-A exhibited a potent anti-allergic activity as evidenced by its potent inhibition of β-hexosaminidase release triggered by A23187 and IgE by 72.7% and 48.7%, respectively. Results were comparable to that of dexamethasone (10 nM) in the A23187 degranulation assay showing 80.7% inhibition for β-hexosaminidase release. Both the n-hexane (CAL-A) and dichloromethane (CAL-B) fractions exhibited potent anti-inflammatory activity manifested by the significant inhibition of superoxide anion generation and prohibition of elastase release. CAL showed anti-hyperglycemic activity in vivo using streptozotocin-induced diabetic rat model by reducing fasting blood glucose levels (FBG) by 53.44% as compared with STZ-treated rats along with a substantial increase in serum insulin by 22.22%. Molecular modeling studies indicated that dicaffeoylquinic acid showed the highest fitting with free binding energies (∆G) of -47.24 and -60.50 Kcal/mol for human α-amylase and α-glucosidase, respectively confirming its anti-hyperglycemic activity. Thus, C. aethiopica leaf extract could serve as an effective antioxidant natural remedy combating inflammation, allergy, and hyperglycemia.

Identification of tetragocarbone C and sideroxylin as the most potent anti-inflammatory components of Syncarpia glomulifera

In contrast to ancient Western and Asian cultures, medicinal plants of the Aboriginal and Torres Strait Islanders in Australia have not been as intensively studied for their molecular composition and molecular bioactivity. Syncarpia glomulifera subsp. glomulifera is a species in the plant family Myrtaceae. The resin of the plant has been traditionally used by the D'harawal people of Western Sydney to heal inflamed sores and ulcers. Hence, the anti-inflammatory activity of its leaf extract was investigated in RAW 264.7 macrophage and N11 microglia cell lines to isolate and identify the most active compounds. One new compound, tetragocarbone C, and three known compounds, tetragocarbone B, sideroxylin, and lumaflavanone A showed potent anti-inflammatory activity by downregulating nitric oxide and TNF-α production in LPS and IFN-γ stimulated cells. Except for the less potent tetragocarbone B, all compounds had an IC₅₀ value (for nitric oxide downregulation) of <10 μg/mL and moderate cytotoxicity in both cell lines. The molecular targets along pro-inflammatory signaling pathways were further investigated in RAW 264.7 cells. All four compounds suppressed phosphorylation of ERK, c-Jun, and limited the phosphorylation of STAT-1 and STAT-3 in response to LPS and IFN-γ activation. The four compounds also suppressed NF-κB activation by preventing the translocation of the p65 subunit into the nucleus. Collectively, these findings suggest that the compounds isolated from Syncarpia glomulifera, especially tetragocarbone C and sideroxylin are promising anti-inflammatory agents, and could be further investigated for the treatment of diseases characterized by chronic inflammation.

Qualitative and Quantitative Analysis of Ukrainian Iris Species: A Fresh Look on Their Antioxidant Content and Biological Activities

The major groups of antioxidant compounds (isoflavonoids, xanthones, hydroxycinnamic acids) in the rhizome methanol extracts of four Ukrainian Iris sp. (Iris pallida, Iris hungarica, Iris sibirica, and Iris variegata) were qualitatively and quantitatively analyzed using HPLC-DAD and UPLC-MS/MS. Gallic acid, caffeic acid, mangiferin, tectoridin, irigenin, iristectorigenin B, irisolidone, 5,6-dihydroxy-7,8,3',5'-tetramethoxyisoflavone, irisolidone-7-O-β-d-glucopyranoside, germanaism B, and nigricin were recognized by comparing their UV/MS spectra, chromatographic retention time (tR) with those of standard reference compounds. I. hungarica and I. variegata showed the highest total amount of phenolic compounds. Germanaism B was the most abundant component in the rhizomes of I. variegata (7.089 ± 0.032 mg/g) and I. hungarica (6.285 ± 0.030 mg/g). The compound analyses showed good calibration curve linearity (r² > 0.999) and low detection and quantifications limit. These results validated the method for its use in the simultaneous quantitative evaluation of phenolic compounds in the studied Iris sp. I. hungarica and I. variegata rhizomes exhibited antioxidant activity, as demonstrated by the HPLC-ABTS system and NRF2 expression assay and anti-inflammatory activity on respiratory burst in human neutrophils. Moreover, the extracts showed anti-allergic and cytotoxic effects against cancer cells. Anti-coronavirus 229E and lipid formation activities were also evaluated. In summary, potent antioxidant marker compounds were identified in the examined Iris sp.

Anti-inflammatory, hepatoprotective and antioxidant activity of ellagitannin isolated from Melaleuca styphelioides

Ellagitannins have a marked antioxidant effect and can prevent liver injury induced by free radicals. An undescribed ellagitannin named styphelioidin was isolated from Melaleuca styphelioides Sm. The structure of styphelioidin was elucidated by using various spectroscopic methods. The hepatoprotective activity of styphelioidin (25, 50, and 100 μM) was tested using the CCl₄-challenged HepG2 cell model by measuring alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels in HepG2 cells treated with styphelioidin for 1 h followed by 40 mM CCl₄. Glutathione (GSH), superoxide dismutase activity (SOD) and lipid peroxidation (MDA) were evaluated to determine the mechanisms of the hepatoprotective activity. Styphelioidin significantly reduced the levels of ALT, AST, and MDA at all tested concentrations. Moreover, it conferred a marked increase in the GSH levels and the SOD activity compared to the CCl₄-treated groups. Styphelioidin also exerted DPPH· radical-scavenging effects with an IC₅₀ value of 3.67 μM. Results indicated the hepatoprotective therapeutic potential of styphelioidin comparable to silymarin. Moreover, anti-inflammatory activity was assessed and styphelioidin inhibited fMLF/CB-induced elastase release in human neutrophils with IC₅₀ 2.51 μM. Cell-free experiments with human neutrophil elastase indicated a direct enzymatic inhibitory effect of styphelioidin on the enzyme activity (IC₅₀ 2.58 μM). The potential of styphelioidin to interact with human neutrophil elastase binding sites was further confirmed by molecular docking of styphelioidin into human neutrophil elastase crystal structure using AutoDock 4.2. Styphelioidin represents a potent hepatoprotective and antioxidant agent with effects on ALT, AST, MDA, GSH, and SOD comparable to silymarin. The beneficial anti-elastase properties hold the potential for drug development against elastase-related inflammatory diseases. This study highlights a promising natural hepatoprotective and anti-inflammatory candidate derived from M. styphelioides.

Robustaflavone induces G0/G1 cell cycle arrest and apoptosis in human umbilical vein endothelial cells and exhibits anti-angiogenic effects in vivo

We investigated the anti-angiogenic and pro-apoptotic effects of robustaflavone (RF), a naturally occurring biflavonoid, on human umbilical vein endothelial cells (HUVECs). RF inhibited HUVEC proliferation and showed cytotoxicity that inhibited HUVEC viability. RF-induced apoptosis was characterized by flow cytometry and caspase 3 analysis. We found that RF increased the number of sub-G1 cells and terminal deoxynucleotidyl transferase dUTP nick end-labeled cells. Additionally, RF induced caspase 3 and poly (ADP-ribose) polymerase activation. Potential molecular targets were identified using a human apoptosis antibody array. RF upregulated Bax, Bad, cleaved caspase 3, p21, and phosphorylated p53 levels. RF induced mitochondrial membrane potential loss and the release of cytochrome c and apoptosis-inducing factor. Cell cycle arrest at G0/G1 phase and the downregulation of Cdk4, Cdk6, and cyclin D1 expression were induced by RF. In vivo anti-angiogenic effects were investigated using a tumor allograft animal model and a Matrigel plug assay. RF reduced the volumes and weights of CT-26 cell-derived tumors. The blood vessel density was significantly decreased in RF-treated tumors. RF also inhibited VEGF-A-stimulated blood vessel formation in vivo in Matrigel plugs. These results suggest that RF can potentially inhibit angiogenesis-dependent tumor growth and metastasis.

Euryops pectinatus L. Flower Extract Inhibits P-glycoprotein and Reverses Multi-Drug Resistance in Cancer Cells: A Mechanistic Study

Euryops pectinatus is a South African ornamental plant belonging to family Asteraceae. The present work evaluates the cytotoxic activity and phytochemical profile of the flower extract. Metabolite profiling was performed using HPLC-PDA-ESI-MS/MS. Total phenolics and flavonoids content were assessed. Cytotoxicity was evaluated against 6 different cancer cell lines using MTT assay. The possible underlying mechanism was proposed. We analyzed whether the extract could overcome the resistance of multidrug-resistant cancer cells for doxorubicin. The effect of combination of E. pectinatus with doxorubicin was also studied. Additionally, the potential inhibitory activity of the identified phytochemicals to PB1 protein was analyzed using in silico molecular docking. Twenty-five compounds were tentatively identified. Total phenolic and flavonoid contents represented 49.41 ± 0.66 and 23.37 ± 0.23 µg/mg dried flower extract, respectively. The extract showed selective cytotoxicity against Caco2 cells but its main effect goes beyond mere cytotoxicity. It showed strong inhibition of P-glycoprotein, which helps to overcome multidrug resistance to classical chemotherapeutic agents. In silico molecular docking showed that dicaffeoyl quinic acid, kaempferol-O-rutinoside, rutin, and isorhamnetin-O-rutinoside exhibited the most potent inhibitory activity to PB1 involved in tumor progression. Euryops pectinatus flower heads could have promising selective cytotoxicity alone or in combination with other chemotherapeutic agents to counteract multidrug resistance.

Anti-inflammatory, antiallergic and COVID-19 protease inhibitory activities of phytochemicals from the Jordanian hawksbeard: identification, structure–activity relationships, molecular modeling and impact on its folk medicinal uses

On Wednesday 11th March, 2020, the world health organization (WHO) announced novel coronavirus (COVID-19, also called SARS-CoV-2) as a pandemic.

Total synthesis of wikstrol A and wikstrol B

The first total synthesis of wikstrol A and wikstrol B was achieved by employing aldol reaction, Sharpless asymmetric dihydroxylation, regioselective iodination, Sonogashira coupling, and rhodium-catalyzed oxidative coupling as key steps. The structure of the key intermediate for wikstrol A was confirmed via its derivative by single-crystal X-ray analysis.

Evaluation of the anti-inflammatory properties of the active constituents in Ginkgo biloba for the treatment of pulmonary diseases

Ginkgo biloba has long been used in ancient China for the treatment of cough, asthma, and other lung diseases. However, the active constituents in G. biloba for pulmonary disease treatment remain unclear. The objective of this study was to evaluate the anti-inflammatory active constituents in G. biloba and clarify their associated molecular mechanisms. The biological effects of different G. biloba extracts were evaluated in an ovalbumin-induced allergic mouse model. Anti-inflammatory compounds were present in the ethyl acetate phase of the extract, which were analysed by HPLC-MS. Biflavones were identified as the main compounds, which were further evaluated by docking calculations. Leukocyte elastase showed a high fit score with ginkgetin, one of the identified biflavones. The lowest binding free energy was -6.69 kcal mol-1. The effects of biflavones were investigated in vivo and in vitro. Ginkgetin markedly suppressed the abnormal expression of the Akt and p38 pathways in human neutrophil elastase (HNE)-stimulated A549 cells. Biflavones also decreased MUC5AC mRNA expression in HNE-stimulated A549 cells and the allergic mouse model. Inflammatory cells (neutrophils) and cytokines (IL-8) also decreased in mice treated with biflavones. The results suggest that G. biloba biflavones could inhibit the activity of leukocyte elastase. This in turn implicates G. biloba as a functional food for the treatment of airway inflammation.

Rhamnocitrin isolated from Prunus padus var. seoulensis: A potent and selective reversible inhibitor of human monoamine oxidase A

Three flavanones and two flavones were isolated from the leaves of Prunus padus var. seoulensis by the activity-guided screening for new monoamine oxidase (MAO) inhibitors. Among the compounds isolated, rhamnocitrin (5) was found to potently and selectively inhibit human MAO-A (hMAO-A, IC₅₀ = 0.051 µM) and effectively inhibit hMAO-B (IC₅₀ = 2.97 µM). The IC₅₀ value of 5 for hMAO-A was the lowest amongst all natural flavonoids reported to date, and the potency was 20.2 times higher than that of toloxatone (1.03 µM), a marketed drug. In addition, 5 reversibly and competitively inhibited hMAO-A and hMAO-B with K_i values of 0.030 and 0.91 µM, respectively. Genkwanin (4) was also observed to strongly inhibit hMAO-A and hMAO-B (IC₅₀ = 0.14 and 0.35 µM, respectively), and competitively inhibit hMAO-A and hMAO-B (K_i = 0.097 and 0.12 µM, respectively). Molecular docking simulation reveals that the binding affinity of 5 with hMAO-A (-18.49 kcal/mol) is higher than that observed with hMAO-B (0.19 kcal/mol). Compound 5 interacts with hMAO-A at four possible residues (Asn181, Gln215, Thr336, and Tyr444), while hMAO-B forms a single hydrogen bond at Glu84. These findings suggest that compound 5 as well as 4 can be considered as novel potent and reversible hMAO-A and/or hMAO-B inhibitors or useful lead compounds for future development of hMAO inhibitors in neurological disorder therapies.