Polyphenols composition from leaves of Cuphea spp. and inhibitor potential, in vitro, of angiotensin I-converting enzyme (ACE)

Extractive optimization of bioactive compounds in aerial parts of cuphea carthagenensis using Box-Behnken experimental design

Cuphea carthagenensis is known for its potential antioxidant and anti-inflammatory properties, attributed to triterpenes, flavonoids, and tannins. This study aimed to optimise the extraction process for aerial parts of C. carthagenensis using vortex extraction. A Box-Behnken experimental design coupled with response surface methodology was employed to evaluate the effects of three independent variables: sample-to-solvent ratio, velocity, and temperature. The optimised extract underwent phytochemical screening and assessment of its antimicrobial capacity. The highest extraction yields were obtained through maceration (22.84%) and ultrasound-assisted extraction (21.95%). However, the extract by vortex extraction exhibited significantly higher phenolic content (250.17 µgEAG gext-1) and antioxidant capacity. The optimal extraction conditions were identified as a sample-to-solvent ratio of 1:35, 12,000 rpm, and a temperature of 60 °C. The optimised extract was characterised by a predominance of glycosylated flavonoids and demonstrated moderate antibacterial activity, particularly against Streptococcus pyogenes, Staphylococcus epidermidis, and Bacillus subtilis.

Primary Antioxidant Power and Mpro SARS-CoV-2 Non-Covalent Inhibition Capabilities of Miquelianin

The antioxidant power of quercetin-3-O-glucuronide (miquelianin) has been studied, at the density functional level of theory, in both lipid-like and aqueous environments. In the aqueous phase, the computed pKa equilibria allowed the identification of the neutral and charged species present in solution that can react with the ⋅OOH radical. The Hydrogen Atom Transfer (HAT), Single Electron Transfer (SET) and Radical Adduct Formation (RAF) mechanisms were considered, and the individual, total and fraction corrected rate constants were obtained. Potential non-covalent inhibition of Mpro from SARS-CoV-2 by miquelianin has been also evaluated.

Detection of Various Traditional Chinese Medicinal Metabolites as Angiotensin-Converting Enzyme Inhibitors: Molecular Docking, Activity Testing, and Surface Plasmon Resonance Approaches

Angiotensin-converting enzyme 1 (ACE1) is a peptide involved in fluid and blood pressure management. It regulates blood pressure by converting angiotensin I to angiotensin II, which has vasoconstrictive effects. Previous studies have shown that certain compounds of natural origin can inhibit the activity of angiotensin-converting enzymes and exert blood pressure-regulating effects. Surface Plasmon Resonance (SPR) biosensor technology is the industry standard method for observing biomolecule interactions. In our study, we used molecular simulation methods to investigate the docking energies of various herbal metabolites with ACE1 proteins, tested the real-time binding affinities between various herbal metabolites and sACE1 by SPR, and analyzed the relationship between real-time binding affinity and docking energy. In addition, to further explore the connection between inhibitor activity and real-time binding affinity, several herbal metabolites' in vitro inhibitory activities were tested using an ACE1 activity test kit. The molecular docking simulation technique's results and the real-time affinity tested by the SPR technique were found to be negatively correlated, and the virtual docking technique still has some drawbacks as a tool for forecasting proteins' affinities to the metabolites of Chinese herbal metabolites. There may be a positive correlation between the enzyme inhibitory activity and the real-time affinity detected by the SPR technique, and the results from the SPR technique may provide convincing evidence to prove the interaction between herbal metabolites and ACE1 target proteins.

Soilless Cultivated Halophyte Plants: Volatile, Nutritional, Phytochemical, and Biological Differences

The use of halophyte plants appears as a potential solution for degraded soil, food safety, freshwater scarcity, and coastal area utilization. These plants have been considered an alternative crop soilless agriculture for sustainable use of natural resources. There are few studies carried out with cultivated halophytes using a soilless cultivation system (SCS) that report their nutraceutical value, as well as their benefits on human health. The objective of this study was to evaluate and correlate the nutritional composition, volatile profile, phytochemical content, and biological activities of seven halophyte species cultivated using a SCS (Disphyma crassifolium L., Crithmum maritimum L., Inula crithmoides L., Mesembryanthemum crystallinum L., Mesembryanthemum nodiflorum L., Salicornia ramosissima J. Woods, and Sarcocornia fruticosa (Mill.) A. J. Scott.). Among these species, results showed that S. fruticosa had a higher content in protein (4.44 g/100 g FW), ash (5.70 g/100 g FW), salt (2.80 g/100 g FW), chloride (4.84 g/100 g FW), minerals (Na, K, Fe, Mg, Mn, Zn, Cu), total phenolics (0.33 mg GAE/g FW), and antioxidant activity (8.17 µmol TEAC/g FW). Regarding the phenolic classes, S. fruticosa and M. nodiflorum were predominant in the flavonoids, while M. crystallinum, C. maritimum, and S. ramosissima were in the phenolic acids. Moreover, S. fruticosa, S. ramosissima, M. nodiflorum, M. crystallinum, and I. crithmoides showed ACE-inhibitory activity, an important target control for hypertension. Concerning the volatile profile, C. maritimum, I. crithmoides, and D. crassifolium were abundant in terpenes and esters, while M. nodiflorum, S. fruticosa, and M. crystallinum were richer in alcohols and aldehydes, and S. ramosissima was richer in aldehydes. Considering the environmental and sustainable roles of cultivated halophytes using a SCS, these results indicate that these species could be considered an alternative to conventional table salt, due to their added nutritional and phytochemical composition, with potential contribution for the antioxidant and anti-hypertensive effects.

The Genus Cuphea P. Browne as a Source of Biologically Active Phytochemicals for Pharmaceutical Application and Beyond—A Review

Cuphea P. Browne (Lythraceae) is a monophyletic taxon comprising some 240–260 species that grow wild in the warm, temperate, and tropical regions of South and Central America and the southern part of North America. They have been valued as traditional medicinal remedies for numerous indications, including treating wounds, parasitic infections, hypertension, digestive disorders, cough, rheumatism, and pain. Modern pharmacological research provides data that support many of these traditional uses. Such a wide array of medicinal applications may be due to the exceptionally rich phytochemical profile of these plants, which includes bioactive compounds classified into various metabolite groups, such as polyphenols, triterpenes, alkaloids, and coumarins. Furthermore, Cuphea seed oils, containing medium-chain fatty acids, are of increasing interest in various industries as potential substitutes for coconut and palm oils. This review aims to summarize the results of phytochemical and pharmacological studies on Cuphea plants, with a particular focus on the therapeutic potential and molecular mechanisms of the action of polyphenolic compounds (especially flavonoids and tannins), which have been the subject of many recently published articles.

Alchemilla viridiflora Rothm.: the potent natural inhibitor of angiotensin I-converting enzyme

Alchemilla viridiflora Rothm., Rosaceae is a herbaceous plant widespread in central Greece, Bulgaria, North Macedonia and Serbia with Kosovo. Liquid chromatography-mass spectrometry analysis leads to the identification of 20 compounds in methanol extract, mainly ellagitannins and flavonoid glycosides. Given that various plant extracts have traditionally been used to treat hypertension and that some of the analyzed methanol extract constituents have beneficial cardiovascular effects, we hypothesized that some of these effects are achieved by inhibiting angiotensin I-converting enzyme (ACE). The dose-dependent ACE inhibitory activities of A. viridiflora and miquelianin were observed with an IC₅₀ of 2.51 ± 0.00 µg/mL of A. viridiflora extract compared to the IC₅₀ of 5.4139 ± 0.00 µM for miquelianin. The contribution of the single compounds to the tested activity was further analyzed through the in silico experimental approach. Computational docking results showed that tiliroside, ellagic acid pentose and galloyl-hexahydroxydiphenoyl-glucose exhibited even better binding affinity for the ACE active site than miquelianin, for which ACE activity was confirmed by an in vitro assay.

Four almost unexplored species of Brazilian Connarus (Connaraceae): Chemical composition by ESI-QTof-MS/MS-GNPS and a pharmacologic potential

INTRODUCTION

Species of Connaraceae are globally used in traditional medicines. However, several of these have not been studied regarding their chemical composition, and some are even at risk of extinction without proper studies. Therefore, the chemical composition and pharmacological potential of Connarus blanchetii Planch., Connarus nodosus Baker, Connarus regnellii G. Schellenb., and Connarus suberosus Planch., which were previously unknown, were analyzed.

OBJECTIVE

This work aims to investigate the pharmacological potential of these four Connarus species. The chemical composition of different extracts was determined by high-resolution mass spectrometry (HRMS), with subsequent analysis by the GNPS platform and competitive fragmentation modeling (CFM).

MATERIALS AND METHODS

Leaf extracts (C. blanchetii, C. nodosus, C. regnellii, and C. suberosus) and bark extracts (C. regnellii and C. suberosus) were obtained by decoction, infusion, and maceration. LC/HRMS data were submitted to the GNPS platform and evaluated using CFM in order to confirm the structures.

RESULTS

The HRMS-GNPS/CFM analysis indicated the presence of 23 compounds that were mainly identified as phenolic derivatives from quercetin and myricetin, of which 21 are unedited in the Connarus genus. Thus, from the analyses performed, we can identify different compounds with pharmacological potential, as well as the most suitable forms of extraction.

CONCLUSION

Using HRMS-GNPS/CFM, 21 unpublished compounds were identified in the studied species. Therefore, our combination of data analysis techniques can be used to determine their chemical composition.

Impact of Drying Processes on the Nutritional Composition, Volatile Profile, Phytochemical Content and Bioactivity of Salicornia ramosissima J. Woods

Salicornia ramosissima J. Woods is a halophyte plant recognized as a promising natural ingredient and will eventually be recognized a salt substitute (NaCl). However, its shelf-life and applicability in several food matrices requires the use of drying processes, which may have an impact on its nutritional and functional value. The objective of this study was to evaluate the effect of oven and freeze-drying processes on the nutritional composition, volatile profile, phytochemical content, and bioactivity of S. ramosissima using several analytical tools (LC-DAD-ESI-MS/MS and SPME-GC-MS) and bioactivity assays (ORAC, HOSC, and ACE inhibition and antiproliferative effect on HT29 cells). Overall, results show that the drying process changes the chemical composition of the plant. When compared to freeze-drying, the oven-drying process had a lower impact on the nutritional composition but the phytochemical content and antioxidant capacity were significantly reduced. Despite this, oven-dried and freeze-dried samples demonstrated similar antiproliferative (17.56 mg/mL and 17.24 mg/mL, respectively) and antihypertensive (24.56 mg/mL and 18.96 mg/mL, respectively) activities. The volatile composition was also affected when comparing fresh and dried plants and between both drying processes: while for the freeze-dried sample, terpenes corresponded to 57% of the total peak area, a decrease to 17% was observed for the oven-dried sample. The oven-dried S. ramosissima was selected to formulate a ketchup and the product formulated with 2.2% (w/w) of the oven-dried plant showed a good consumer acceptance score. These findings support the use of dried S. ramosissima as a promising functional ingredient that can eventually replace the use of salt.

Understanding the Gastrointestinal Protective Effects of Polyphenols using Foodomics-Based Approaches

Plant polyphenols are rich sources of natural anti-oxidants and prebiotics. After ingestion, most polyphenols are absorbed in the intestine and interact with the gut microbiota and modulated metabolites produced by bacterial fermentation, such as short-chain fatty acids (SCFAs). Dietary polyphenols immunomodulatory role by regulating intestinal microorganisms, inhibiting the etiology and pathogenesis of various diseases including colon cancer, colorectal cancer, inflammatory bowel disease (IBD) and colitis. Foodomics is a novel high-throughput analysis approach widely applied in food and nutrition studies, incorporating genomics, transcriptomics, proteomics, metabolomics, and integrating multi-omics technologies. In this review, we present an overview of foodomics technologies for identifying active polyphenol components from natural foods, as well as a summary of the gastrointestinal protective effects of polyphenols based on foodomics approaches. Furthermore, we critically assess the limitations in applying foodomics technologies to investigate the protective effect of polyphenols on the gastrointestinal (GI) system. Finally, we outline future directions of foodomics techniques to investigate GI protective effects of polyphenols. Foodomics based on the combination of several analytical platforms and data processing for genomics, transcriptomics, proteomics and metabolomics studies, provides abundant data and a more comprehensive understanding of the interactions between polyphenols and the GI tract at the molecular level. This contribution provides a basis for further exploring the protective mechanisms of polyphenols on the GI system.

Polyphenolic Composition and in Vitro Antihypertensive and Anti-Inflammatory Effects of Cuphea lindmaniana and Cuphea urbaniana

The present study investigates the chemical composition, anti-inflammatory, and antihypertensive activities, in vitro, from extracts of Cuphea lindmaniana and Cuphea urbaniana leaves. The extraction was performed ultrasound-assisted, and UHPLC/MS analysis was in positive mode ionization. The anti-inflammatory activity of the extracts and miquelianin were assayed at concentrations 0.001-10 μg/mL by chemotaxis on rat polymorphonuclear neutrophils. The antihypertensive activity was performed by angiotensin-converting enzyme (ACE) inhibition. From the nineteen proposed compounds, six of them are described for the first time in this genus. The extracts displayed antichemotactic effect with a reduction of 100 % of the neutrophil migration, in vitro, in most concentrations. The ACE-inhibition presented results ranging from 19.58 to 22.82 %. In conclusion, C. lindmaniana and C. urbaniana extracts contain a rich diversity of flavonoids and display in vitro anti-inflammatory and antihypertensive potential. Thus, this study could serve as a scientific baseline for further investigation, on developmental novel products with therapeutic actions.

Phenolic compounds from an Algerian medicinal plant (Pallenis spinosa): simulated gastrointestinal digestion, characterization, and biological and enzymatic activities

Pallenis spinosa is a medicinal plant which is used in folk medicine as curative or preventive remedies for various diseases. Individual phenolic compounds from the methanolic extracts of its flowers, leaves and stem were determined by the high performance liquid chromatography method (HPLC) and total phenolic contents (TPC) were evaluated by Folin-Ciocalteu assay. The stability and bioactivity (antioxidant activity, micellar cholesterol solubility, α-amylase, and angiotensin converting enzymes (ACE) inhibitory effects) of these extracts in the gastrointestinal environment was determined before and after their protection in hydroxypropylmethylcellulose (HPMC) capsules. HPLC analysis revealed the presence of thirteen phenolic compounds with nine flavonoids and four phenolic acids. Except for kaempferol, the twelve other compounds have not been previously detected in the aerial part of the studied plant. Quantification of phenolics by HPLC and Folin Ciocalteu methods revealed that the highest TPC was detected in the flower extracts (104.31 ± 0.80 and 145.73 ± 0.48 mg EGA per g of extract, respectively). Leaf extracts displayed the best antioxidant capacity against the two tested radicals DPPH and ABTS (IC50 = 1.24 ± 0.03 and 0.94 ± 0.02 mg mL-1, respectively), FRAP assay (IC50 = 0.50 ± 0.02 mg mL-1), α-amylase inhibitory (IC50 = 1.25 ± 0.00 mg mL-1) and angiotensin activity with an inhibitory percent of 30.10 ± 0.12%. The best activity shown by stem extracts was against micellar cholesterol solubility (67.57 ± 0.00%). A strong decrease in TPC and their bioactivity was observed after the gastrointestinal digestion (GID) in non encapsulated extracts. These results showed that P. spinosa is a good source of phenolic compounds and GID affects significantly their composition, content and bioactivity.

Inhibition of biofilm and quorum sensing-regulated virulence factors in Pseudomonas aeruginosa by Cuphea carthagenensis (Jacq.) J. F. Macbr. Leaf extract: An in vitro study

ETHNOPHARMCOLOGICAL RELEVANCE

Microbial biofilm formation, a quorum sensing (QS) regulated process, is one of the major causes of nosocomial and chronic infections, foodborne diseases, and associated deaths. Various approaches have been used to eradicate the menace of biofilm. Ethnomedicinal plants as potent antibiofilm agents are gaining a lot of interest in an era where the drug resistance is increasing and the availability of potent antibiotics is no longer promised. In this context, the methanol extract of Cuphea carthagenensis (CCMD), an ethno-medicinal and culinary herb, was evaluated as an antibiofilm and anti-QS agent against Pseudomonas aeruginosa.

AIM OF THE STUDY

The aim of the study is to evaluate the antibiofilm and anti-QS activity of an ethnomedicinal plant against a strong biofilm forming microorganism, P. aeruginosa.

METHODS

Antibiofilm activity of CCMD was demonstrated at different concentrations by Tissue Culture Plate, Test Tube method and other microscopic techniques. The effect of CCMD on QS and QS-related virulence factors viz. Pyocyanin, exopolymeric substance matrix (EPS), total protease, elastase, pyoverdin and swimming motility in P. aeruginosa were also evaluated. Antioxidant activity (DPPH & FRAP), total phenolic and flavonoid content were also checked. In order to determine the composition of the extract HPLC analysis was also performed.

RESULTS

In vitro study demonstrated a significant inhibition of biofilm formation (81.88 ± 2.57%) as well as production of QS-dependent virulence factors in P. aeruginosa. The extract also inhibited violacein production (83.31 ± 2.77%) in Chromobacterium violaceum which correlates with the reduction in QS-mediated virulence factors. The extract showed 64.79% ± 0.83% DPPH scavenging activity and reduction of ferricyanide complex (Fe³⁺) to the ferrous form (Fe²⁺) in DPPH and FRAP assay, respectively. Furthermore, the extract showed thermal stability and does not have any growth inhibitory effect on P. aeruginosa. The HPLC analysis demonstrated the presence of ellagic acid, ascorbic acid and hippuric acid in the extract.

CONCLUSION

This work is the first to demonstrate that C. carthagenensis can attenuate biofilm formation and QS-mediated virulence factors of P. aeruginosa. Further investigation is required to use this ethnomedicinal plant (CCMD) as an important source of antibiofilm agents.

Anti-COVID-19 drug candidates: A review on potential biological activities of natural products in the management of new coronavirus infection

Background and aim

The novel coronavirus disease (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is now become a worldwide pandemic bringing over 71 million confirmed cases, while the specific drugs and vaccines approved for this disease are still limited regarding their effectiveness and adverse events. Since virus incidences are still on rise, infectivity and mortality may also rise in the near future, natural products are highly considered to be valuable sources for the discovery of new antiviral drugs against SARS-CoV-2. This present review aims to comprehensively summarize the up-to-date scientific literatures on biological activities of plant- and mushroom-derived compounds relevant to mechanistic targets involved in SARS-CoV-2 infection and inflammatory-associated pathogenesis, including viral entry, replication and release, and the renin-angiotensin-aldosterone system (RAAS).

Experimental procedure

Data were retrieved from a literature search available on PubMed, Scopus and Google Scholar databases and collected until the end of May 2020. The findings from in vitro cell and non-cell based studies were considered, while the results of in silico studies were excluded.

Results and conclusion

Based on the previous findings in SARS-CoV studies, except in silico molecular docking analysis, herein, we provide a total of 150 natural compounds as potential candidates for development of new anti-COVID-19 drugs with higher efficacy and lower toxicity than the existing therapeutic agents. Several natural compounds have showed their promising actions on multiple therapeutic targets, which should be further explored. Among them, quercetin, one of the most abundant of plant flavonoids, is proposed as a lead candidate with its ability on the virus side to inhibit SARS-CoV spike protein-angiotensin-converting enzyme 2 (ACE2) interaction, viral protease and helicase activities, as well as on the host cell side to inhibit ACE activity and increase intracellular zinc level.

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Relevant and up-to-date publications in natural products with anti-COVID-19 potential.

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Emphasis on the potential of anti-COVID-19 plant/mushroom-based medicine.

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Twenty four proposed natural compounds for the anti-COVID-19 drug candidates.

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Quercetin emerged as the most promising compound acting on multiple therapeutic targets.

Syzygium gratum Extract Alleviates Vascular Alterations in Hypertensive Rats

Background and Objectives: Syzygium gratum (SG) is a local vegetable and widely consumed in Thailand. Previously, a strong antioxidative effect of SG extract has been reported. The effects of SG extract on hypertension have remained unknown. The effect of SG aqueous extract on blood pressure and vascular changes were examined in L-NAME-induced hypertensive rats (LHR), and its potential active constituents were also explored. Materials and Methods: Male Sprague Dawley rats were allocated to control, L-NAME (40 mg/kg/day), L-NAME + SG (100, 300, 500 mg/kg/day), or captopril (5 mg/kg/day) groups. The components of SG extract were analyzed. Results: The analysis of aqueous SG extract was carried out using HPLC-Mass spectroscopy, and phenolic compounds could be identified as predominant components which might be responsible for its antihypertensive effects observed in the LHR model (p < 0.05). Additionally, SG extract also improved vascular responses to acetylcholine and decreased vascular remodeling in LHR (p < 0.05). Enhancements of eNOS expression and plasma nitric oxide metabolite levels, and attenuation of angiotensin converting enzyme (ACE) activity and plasma angiotensin II levels were observed in the LHR group treated with SG. Moreover, SG exhibited strong antioxidant activities by reducing vascular superoxide generation and systemic malondialdehyde in LHRs. Captopril suppressed high blood pressure and alleviated vascular changes and ACE activity in LHRs, similar to those of the SG extract (p < 0.05). Conclusion: Our results suggest that the SG extract exhibited antihypertensive effects, which is relevant to alleviation of vascular dysfunction and vascular remodeling of LHRs. These effects might be mediated by phenolic compounds to inhibit ACE activity and scavenge reactive oxygen species in LHR.

Discovery and Development of Inflammatory Inhibitors from 2-Phenylchromonone (Flavone) Scaffolds

Flavonoids are compounds based on a 2-phenylchromonone scaffold. Flavonoids can be divided into flavonoids, flavonols, dihydroflavones, anthocyanins, chalcones and diflavones according to the oxidation degree of the central tricarbonyl chain, the connection position of B-ring (2-or 3-position), and whether the tricarbonyl chain forms a ring or not. There are a variety of biological activities about flavonoids, such as anti-inflammatory activity, anti-oxidation and anti-tumor activity, and the antiinflammatory activity is apparent. This paper reviews the anti-inflammatory activities and mechanisms of flavonoids and their derivatives reported in China and abroad from 2011 till date (2011-2020), in order to find a good drug scaffold for the study of anti-inflammatory activities.

Cuphea spp.: antichemotactic study for a potential anti-inflammatory drug

Cuphea genus (Lythraceae) popularly known in Brazil as "sete-sangrias", it's described as antimicrobial, anti-inflammatory, diuretic and antihypertensive mainly. Investigating the chemotactic ability plays an important role in the identification of new anti-inflammatory agents. Thus, this research aims to assay the antichemotactic activity of hydroethanolic extracts of C. calophylla, C. carthagenensis, C. glutinosa, and C. racemosa as well as the compounds miquelianin and myricitrin. The antichemotactic activity of the hydroethanolic extracts, miquelianin, and myricitrin were assayed at concentrations 0.001 to 10 µg/mL in the lipopolysaccharide-induced chemotaxis on rat polymorphonuclear neutrophils. All the assayed samples displayed antichemotactic activity with reduction of the neutrophil migration in the range of 4.46-100%, and an IC₅₀ value in the range of 0.30-1.24 µg/mL. Thus, this study demonstrates that the extracts hydroethanolic of Cuphea species, miquelianin, and myricitrin display a significant antichemotactic activity. Therefore, in future studies, extracts from Cuphea spp. could be used as anti-inflammatory drugs.

Untargeted Metabolomics of Fermented Rice Using UHPLC Q-TOF MS/MS Reveals an Abundance of Potential Antihypertensive Compounds

Enzyme treatment and fermentation of cereals are known processes that enhance the release of bound bioactive compounds to make them available for bioactivity. In this study, we tested the angiotensin converting enzyme (ACE) inhibitory ability of destarched rice, Prozyme 2000p treated destarched rice (DP), and fermented DP samples. Prozyme 2000p treatment increased the ACE inhibitory ability from 15 ± 5% to 45 ± 3%. Fermentation of the Prozyme 2000p treated samples with Enterococcus faecium EBD1 significantly increased the ACE inhibitory ability to 75 ± 5%, while captopril showed an ACE inhibition of 92 ± 4%. An untargeted metabolomics approach using Ultra-high-performance liquid tandem chromatography quadrupole time of flight mass spectrometry revealed the abundance of vitamins, phenolic compounds, antioxidant peptides, DPP IV inhibitory peptides, and antihypertensive peptides in the fermented samples which may account for its strong ACE inhibition. Although fermented DP had decreased fatty acid levels, the amount of essential amino acid improved drastically compared to destarched rice. Our results show that fermenting Prozyme-treated destarched rice with Enterococcus faecium EBD1 generates abundant bioactive compounds necessary for developing antihypertensive functional foods.