Dihydrophenazine: a multifunctional new weapon that kills multidrug-resistant Acinetobacter baumannii and restores carbapenem and oxidative stress susceptibilities.

AIMS: The current work aims to fully characterize a new antimicrobial agent against Acinetobacter baumannii, which continues to represent a growing threat to healthcare settings worldwide. With minimal treatment options due to the extensive spread of resistance to almost all the available antimicrobials, the hunt for new antimicrobial agents is a high priority. METHODS AND RESULTS: An Egyptian soil-derived bacterium strain NHM-077B proved to be a promising source for a new antimicrobial agent. Bio-guided fractionation of the culture supernatants of NHM-077B followed by chemical structure elucidation identified the active antimicrobial agent as 1-hydroxy phenazine. Chemical synthesis yielded more derivatives, including dihydrophenazine (DHP), which proved to be the most potent against A. baumannii, yet it exhibited a marginally safe cytotoxicity profile against human skin fibroblasts. Proteomics analysis of the cells treated with DHP revealed multiple proteins with altered expression that could be correlated to the observed phenotypes and potential mechanism of the antimicrobial action of DHP. DHP is a multipronged agent that affects membrane integrity, increases susceptibility to oxidative stress, interferes with amino acids/protein synthesis, and modulates virulence-related proteins. Interestingly, DHP in subinhibitory concentrations re-sensitizes the highly virulent carbapenem-resistant A. baumannii strain AB5075 to carbapenems providing great hope in regaining some of the benefits of this important class of antibiotics. CONCLUSIONS: This work underscores the potential of DHP as a promising new agent with multifunctional roles as both a classical and nonconventional antimicrobial agent that is urgently needed.

Biosynthesis and Characterization of Aeonium arboreum-Derived Silver Nanoparticles: Antimicrobial Activity, Biofilm Inhibition, Antihemolytic Activity, and In Silico Studies.

Environmentally friendly biosynthesis of silver nanoparticles (AgNPs) from Aeonium arboreum (L.) Webb & Berthel is reported for the first time. The synthesized AgNPs were characterized using UV-Vis, FTIR, TEM, Zeta potential, and XRD analysis, revealing high stability (-29.1 mV), spherical shape, and an average size of 100 nm. The antimicrobial activity levels of both A. arboreum extract and biosynthesized AgNPs were evaluated against five uropathogens (Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans). Both the extract and the AgNPs exhibited significant efficacy, particularly against E. coli, with inhibition zones of 27 mm and 30 mm, respectively. LC-MS analysis tentatively identified 11 secondary metabolites in the extract, including quercetin-3-O-glucoside, quercetin-3-O-rhamnoside, myricetin 3-glucoside, and daphneresinol. In silico docking studies revealed promising binding affinities of these metabolites in relation to key enzymes involved in bacterial folate synthesis (dihydrofolate reductase (DHFR) and dihydropteroate synthase (DHPS)) and DNA replication (DNA gyrase). These findings demonstrate the potential of A. arboreum-based AgNPs and their associated metabolites as a novel therapeutic approach for combating urinary tract infections. Their antimicrobial, antihemolytic, and antibiofilm properties warrant further investigation.

LC-QToF chemical profiling of Euphorbia grantii Oliv. and its potential to inhibit LPS-induced lung inflammation in rats via the NF-κB, CY450P2E1, and P38 MAPK14 pathways.

Acute lung injury (ALI) is a life-threatening syndrome that causes high morbidity and mortality worldwide. The aerial parts of Euphorbia grantii Oliv. were extracted with methanol to give a total methanolic extract (TME), which was further fractionated into dichloromethane (DCMF) and the remaining mother liquor (MLF) fractions. Biological guided anti-inflammatory assays in vitro revealed that the DCMF showed the highest activity (IC50 6.9 ± 0.2 µg/mL and 0.29 ± 0.01 µg/mL) compared to. celecoxib (IC50 of 88.0 ± 1 µg/mL and 0.30 ± 0.01 µg/mL) on COX-1 and COX-2, respectively. Additionally, anti-LOX activity was IC50 = 24.0 ± 2.5 µg/mL vs. zileuton with IC50 of 40.0 ± 0.5 µg/mL. LC-DAD-QToF analysis of TME and the active DCMF resulted in the tentative identification and characterization of 56 phytochemical compounds, where the diterpenes were the dominated metabolites. An LPS-induced inflammatory model of ALI (10 mg/kg i.p) was used to assess the anti-inflammatory potential of DCMF in vivo at dose of 200 mg/kg and 300 mg/kg compared to dexamethasone (5 mg/kg i.p). Our treatments significantly reduced the pro-inflammatory cytokines (TNF-α, IL-1, IL-6, and MPO), increased the activity of antioxidant enzymes (SOD, CAT, and GSH), decreased the activity of oxidative stress enzyme (MDA), and reduced the expression of inflammatory genes (p38.MAPK14 and CY450P2E1). The western blotting of NF-κB p65 in lung tissues was inhibited after orally administration of the DCMF. Histopathological study of the lung tissues, scoring, and immunohistochemistry of transforming growth factor-beta 1 (TGF-ß1) were also assessed. In both dose regimens, DCMF of E. grantii prevented further lung damage and reduced the side effects of LPS on acute lung tissue injury.

α-Glucosidase, butyrylcholinesterase and acetylcholinesterase inhibitory activities of phenolic compounds from Carthamus tinctorius L. flowers: In silico and in vitro studies.

Chemical investigation of Carthamus tinctorius L. flowers resulted in isolation of seven metabolites that were identified as; p-Hydroxybenzoic acid (1), trans hydroxy cinnamic acid (2), kaempferol-6-C-glucoside (3), astragalin (4), cartormin (5), kaempferol-3-O-rutinoside (6), and kaempferol-3-O-sophoroside (7). Virtual screening of the isolated compounds against human intestinal α-glucosidase, acetylcholinesterase, and butyrylcholinesterase was carried out. Additionally, the antioxidant activity of the bioactive compounds was assessed. Compounds 1 and 5 exhibited moderate binding affinities to acetylcholinesterase (binding energy -5.33 and -4.18 kcal/mol, respectively), compared to donepezil (-83.33kcal/mol). Compounds 1-7 demonstrated weak affinity to butyrylcholinesterase. Compounds 2 and 4 displayed moderate binding affinity to human intestinal α-glucosidase,compared to Acarbose (reference compound), meanwhile compound 2 exhibited lower affinity. Molecular dynamic studies revealed that compound 4 formed a stable complex with the binding site throughout a 100 ns simulation period. The in-vitro results were consistent with the virtual experimental results, as compounds 1 and 5 showed mild inhibitory effects on acetylcholinesterase (IC50s 150.6 and 168.7 µM, respectively). Compound 4 exhibited moderate α-glucosidase inhibition with an IC50 of 93.71 µM. The bioactive compounds also demonstrated notable antioxidant activity in ABTS [2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)], ORAC (oxygen radical-absorbance capacity), and metal chelation assays, suggesting their potential in improving dementia in Alzheimer's disease (AD) and mitigating hyperglycemia.

Feature-Based Molecular Networking for the Exploration of the Metabolome Diversity of Common Egyptian Centaurea Species in Relation to Their Cytotoxic Activity.

Centaurea is a genus compromising over 250 herbaceous flowering species and is used traditionally to treat several ailments. Among the Egyptian Centaurea species, C. lipii was reported to be cytotoxic against multidrug-resistant cancer cells. In this context, we aimed to explore the metabolome of C. lipii and compare it to other members of the genus in pursuance of identifying its bioactive principles. An LC-MS/MS analysis approach synchronized with feature-based molecular networks was adopted to offer a holistic overview of the metabolome diversity of the Egyptian Centaurea species. The studied plants included C. alexandrina, C. calcitrapa, C. eryngioides, C. glomerata, C. lipii, C. pallescens, C. pumilio, and C. scoparia. Their constitutive metabolome showed diverse chemical classes such as cinnamic acids, sesquiterpene lactones, flavonoids, and lignans. Linking the recorded metabolome to the previously reported cytotoxicity identified sesquiterpene lactones as the major contributors to this activity. To confirm our findings, bioassay-guided fractionation of C. lipii was adopted and led to the isolation of the sesquiterpene lactone cynaropicrin with an IC50 of 1.817 µM against the CCRF-CEM leukemia cell line. The adopted methodology highlighted the uniqueness of the constitutive metabolome of C. lipii and determined the sesquiterpene lactones to be the responsible cytotoxic metabolites.

SIRT1/Nrf2/NF-κB Signaling Mediates Anti-Inflammatory and Anti-Apoptotic Activities of Oleanolic Acid in a Mouse Model of Acute Hepatorenal Damage.

Background and objectives: Oleanolic acid (OA) is a penta-cyclic triterpene with diverse bioactivities such as anticarcinogenic, antiviral, antimicrobial, hepatoprotective, anti-atherosclerotic, hypolipidemic, and gastroprotective. However, its effects on hepatorenal damage remain unclear. The protective activity of OA, separated from Viscum schimperi (Loranthaceae), against TAA (thioacetamide)-produced acute hepatic and renal damage was explored. Materials and Methods: Mice were treated with OA for 7 days before TAA (200 mg/kg, i.p.). Serum indices of hepatorenal injury, pathological lesions, molecular biological indexes, and inflammatory/apoptotic genes were estimated. Results: The tissues of both organs were greatly affected by the TAA injection. That was evident through increased serum markers of hepato-renal injury as well as remarkable histopathological lesions. TAA-induced injury was associated with oxidative and inflammatory responses in both organs as there was an elevation of oxidative stress parameters (4-HNE (4-hydroxy-nonenal), MDA (malondialdehyde), NOx (nitric oxide)), decline of antioxidants (reduced glutathione (GSH), superoxide dismutase (SOD), and total antioxidant capacity (TAC)), and an increase in the gene expression/level of inflammatory mediators (interleukins (1ß&6)). The inflammatory response was linked to a significant activation of NF-κB (nuclear-factor kappa-B)/TNF-α (tumor-necrosis factor-alpha) signaling. The inflammatory response in both organs was accompanied by apoptotic changes, including a rise in the gene expression and level of apoptotic parameters (caspase-3 and Bax) along with a decline in Bcl-2 (anti-apoptotic parameter) gene expression and level. These pathogenic events were found to be closely related to the suppression of the antioxidant signaling pathway, Nrf2 (nuclear-factor erythroid 2-related factor-2)/SIRT1 (sirtuin-1)/HO-1 (heme-oxygenase 1). On the other hand, OA significantly ameliorated TAA-induced injury in both organs. On the other hand, OA counterpoised the inflammatory response as it ameliorated NF-κB/TNF-α signaling and cytokine release. OA enhanced Nrf2/SIRT1/HO-1 signaling and counteracted apoptotic damage. Conclusions: OA showed anti-inflammation and antiapoptotic capacities that effectively suppressed TAA-induced acute hepatorenal damage.

Natural Reno-Protective Agents against Cyclosporine A-Induced Nephrotoxicity: An Overview.

CA (cyclosporine A) is a powerful immunosuppressing agent that is commonly utilized for treating various autoimmune illnesses and in transplantation surgery. However, its usage has been significantly restricted because of its unwanted effects, including nephrotoxicity. The pathophysiology of CA-induced kidney injury involves inflammation, apoptosis, tubular injury, oxidative stress, and vascular injury. Despite the fact that exact mechanism accountable for CA's effects is inadequately understood, ROS (reactive oxygen species) involvement has been widely proposed. At present, there are no efficient methods or drugs for treating CA-caused kidney damage. It is noteworthy that diverse natural products have been investigated both in vivo and in-vitro for their possible preventive potential in CA-produced nephrotoxicity. Various extracts and natural metabolites have been found to possess a remarkable potential for restoring CA-produced renal damage and oxidative stress alterations via their anti-apoptosis, anti-inflammatory, and antioxidative potentials. The present article reviews the reported studies that assess the protective capacity of natural products, as well as dietary regimens, in relation to CA-induced nephrotoxicity. Thus, the present study presents novel ideas for designing and developing more efficient prophylactic or remedial strategies versus CA passive influences.

Phytochemical profile, enzyme inhibition activity and molecular docking analysis of Feijoa sellowiana O. Berg.

Feijoa sellowiana leaves and fruits have been investigated as a source of diverse bioactive metabolites. Extract and eight metabolites isolated from F. sellowiana leaves were evaluated for their enzymatic inhibitory activity against α-glucosidase, amylase, tyrosinase, acetylcholinestrerase and butyrylcholinesterase both in vitro and in silico. Feijoa leaves' extract showed strong antioxidant activity and variable levels of inhibitions against target enzymes with a strong anti-tyrosinase activity (115.85 mg Kojic acid equivalent/g). Additionally, α-tocopherol emerged as a potent inhibitor of AChE and BChE (5.40 & 10.38 mmol galantamine equivalent/g, respectively). Which was further investigated through molecular docking and found to develop key enzymatic interactions in AChE and BChE active sites. Also, primetin showed good anti BChE (11.70 mmol galantamine equivalent/g) and anti-tyrosinase inhibition (90.06 mmol Kojic acid equivalent/g) which was also investigated by molecular docking studies. Highlights Isolation of eight bioactive constituents from Feijoa sellowiana leaves. In vitro assays using different enzymatic drug targets were investigated. In silico study was performed to define compound interactions with target proteins. Feijoa leaf is an excellent source of anti-AChE and antityrosinase bioactives.

Natural Peroxisome Proliferator-Activated Receptor γ (PPARγ) Activators for Diabetes.

CONTEXT: Metabolic syndrome (MetS) represents a worldwide problem. Drugs used in MetS target different symptoms, like excessive body weight, insulin resistance, hyperglycemia, dyslipidemia, or hypertension. Peroxisome proliferator-activated receptors (PPAR) regulate the gene expression involved in lipid metabolism, inflammation, and adipogenesis. Activation of PPARγ has become a target of interest to counter hyperglycemia linked with MetS and type 2 diabetes (T2DM). OBJECTIVE: The current review intended to summarize reported research on medicinal plants, or their bioactive constituents, with PPARγ-activating potential. DESIGN: The research team searched the literature up to 2016 using electronic databases- ScienceDirect, PubMed, Google-Scholar, SpringerLink, Scopus, and Wiley-for publications on medicinal plants with promising PPARγ modulators using keywords diabetes mellitus, natural products, peroxisome proliferator-activated receptors, metabolic syndrome, adipogenesis. SETTING: This study was conducted in the Department of Natural Products and Alternative Medicine, Faculty of Pharmacy, King Abdulaziz University, Jeddah, Saudi Arabia, Department of Pharmacognosy, Faculty of Pharmacy, Cairo University, Cairo, Egypt, and Department of Pharmacognosy and Pharmaceutical Chemistry, College of Pharmacy, Taibah University, Al Madinah, Al Munawwarah, Saudi Arabia. RESULTS: Several natural products were considered to be good ligands for PPARγ. The PPARγ agonistic activity of over 100 plants covered in this review was supported by experimental evidence. Some of the plants and their constituents had been studied for their possible mechanisms of action. CONCLUSIONS: Findings discussed in this review highlighted PPARγ's role as an organizer of lipid metabolism and glucose homeostasis, thus supporting its function as a target for antidiabetic agents. The discovery that some natural compounds and plants could activate PPARγ opens up the prospect for future development of strategies to take advantage of its therapeutic potential in diabetes. Therefore, the current review could provide significant information for biotechnological or pharmaceutical applications in targeted drug delivery and design.

Bioassay Guided Isolation and Docking Studies of a Potential ß-Lactamase Inhibitor from Clutia myricoides.

Infectious diseases are the second major cause of death worldwide, and the ability to resist multiple classes of antibiotics is the key factor in enabling pathogenic organisms to survive and spread in the nosocomial environment. Unfortunately, the available ß-lactamase inhibitors are not efficient against ß-lactamase B, C, and D which necessitates discovering either broad spectrum ß-lactamase inhibitors or new ß-lactam antibiotics resistant to bacterial enzymes. In this regard, products of natural origin have prompted the disclosure of new compounds and medicinal leads. Chloroform fraction of Clutia myricoides (Soa'bor) showed a pronounced activity against extended-spectrum ß-lactamase (ESBL) strains. Bio-guided fractionation resulted in isolation of two new compounds; 2-methoxy chrysophanol (2) and Saudin-I (5) in addition to three known compounds that were identified as chrysophanol (1), stigmasterol (3) and ß-sitosterol (4). Antibacterial and anti ESBL activities of the isolated compounds were performed. No antibacterial activities were detected for any of the tested compounds. Meanwhile, compound 2 showed promising anti ESBL activity. Compound 2 has shown an obvious activity against K. pneumoniae ATCC 700603 with a marked enlargement of inhibition zones (>5mm) in combination with third generation cephalosporin antibiotics. To further understand the mechanism of action of compound 2, molecular docking was carried out against CTX-M-27 ESBL. The results showed binding site interactions strikingly different from its analogue, compound 1, allowing compound 2 to be active against ESBL. These results proposed the concomitant use of these active compounds with antibiotics that would increase their efficiency. Nevertheless, the interaction between this active compound and antibiotics should be taken into consideration. Therefore, in order to evaluate the safety of this active compound, further in vitro and in vivo toxicity assays must be carried out.

Phenolics from Barleria cristata var. Alba as carcinogenesis blockers against menadione cytotoxicity through induction and protection of quinone reductase.

BACKGROUND: There are increasing interests in natural compounds for cancer chemoprevention. Blocking agents represent an important class of chemopreventive compounds. They prevent carcinogens from undergoing metabolic activation and thereby suppressing their interaction with cellular macromolecular targets. METHODS: The effect of phenolic compounds isolated from Barleria cristata var. alba as chemopreventive agent was evaluated. The ethyl acetate fraction of B. cristata was subjected to different chromatographic techniques for isolation of its major phenolic compounds. The isolated compounds were evaluated for their potential to induce the cancer chemopreventive enzyme marker NAD(P)H quinonereductase 1 (NQO1) in murine Hepa-1c1c7 cell model. RESULTS: The ethyl acetate fraction of B. cristata var. alba yielded five known compounds identified as verbascoside (1), isoverbascoside (2), dimethoxyverbascoside (3), p-hydroxy benzoic acid (4), and apigenin-7-O-glucoside (5). Among the tested compounds, isoverbascoside (2) was shown to potently induce the activity of the enzyme in a dose -dependent manner. As a functional assay for detoxification, compound 2 was the strongest to protect Hepa-1c1c7 against the toxicity of menadione, a quinone substrate for NQO1. CONCLUSION: This effect seemed to be attributed to the compound's potential to induce both the catalytic activity and protein expression of NQO1 as revealed by enzyme assay and Western blotting, respectively.

Anticancer Profiling for Coumarins and Related O-Naphthoquinones from Mansonia gagei against Solid Tumor Cells In Vitro.

Napthoquinones and coumarins are naturally occurring compounds with potential anticancer activity. In the current study, two O-naphthoquinons (mansonone-G and mansonone-N) and six coumarins (mansorin-A, mansorin-B, mansorin-C, mansorins-I, mansorin-II, and mansorin-III) were isolated from the heartwood of Mansonia gagei family Sterculariaceae. Isolated compounds were examined for their potential anticancer activity against breast (MCF-7), cervix (HeLa), colorectal (HCT-116) and liver (HepG2) cancer cells using Sulfarhodamine-B (SRB) assay. Mansorin-II and mansorin-III showed relatively promising cytotoxic profile in all cell lines under investigation with inhibitory concentrations (IC50s) in the range of 0.74 µM to 36 µM and 3.95 µM to 35.3 µM, respectively. In addition, mansorin-B, mansorin-C, mansorin-II and mansorin-III significantly increased cellular entrapment of the P-glycoprotein (P-gp) substrate, doxorubicin, in colorectal cancer cells expressing the P-gp pump. The inhibitory effect of the isolated compounds on P-gp pump was examined using human recombinant P-gp molecules attached to ATPase subunit. Mansorin-B and mansonone-G were found to inhibit the P-gp attached ATPase subunit. On the other hand, mansorin-C, mansorin-III and mansorin-II inhibited P-gp pump via dual action (P-gp related ATPase subunit inhibition and P-gp substrate binding site occupation). However, mansorin II was examined for its potential chemomodulatory effect to paclitaxel (PTX) against colorectal cancer cells (HCT-116 and CaCo-2). Mansorin-II significantly reduced the IC50 of PTX in HCT-116 cells from 27.9 ± 10.2 nM to 5.1 ± 1.9 nM (synergism with combination index of 0.44). Additionally, Mansorin-II significantly reduced the IC50 of PTX in CaCo-2 cells from 2.1 ± 0.8 µM to 0.13 ± 0.03 µM (synergism with combination index of 0.18). Furthermore, cell cycle analysis was studied after combination of mansorin-II with paclitaxel using DNA flow cytometry analysis. Synergism of mansorin-II and PTX was reflected in increasing apoptotic cell population in both HCT-116 and CaCo-2 cells compared to PTX treatment alone. Combination of mansorin-II with PTX in CaCo-2 cells significantly increased the cell population in G2/M phase (from 2.9 ± 0.3% to 7.7 ± 0.8%) with reciprocal decrease in G0/G1 cell fraction from 52.1 ± 1.1% to 45.5 ± 1.0%. Similarly in HCT-116 cells, mansorin-II with PTX significantly increased the cell population in G2/M phase (from 33.4 ± 2.8% to 37.6 ± 1.3%) with reciprocal decrease in the S-phase cell population from 22.8 ± 1.7% to 20.2 ± 0.8%. In conclusion, mansorin-II synergizes the anticancer effect of paclitaxel in colorectal cancer cells, which might be partially attributed to enhancing its cellular entrapment via inhibiting P-gp efflux pump.

Saudi plants as a source of potential ß-lactamase inhibitors.

This study was performed to assess the potential ß-lactamase inhibitory properties of nineteen crude Saudi plant extracts belonging to eight families against extended spectrum ß-lactamase (ESßL) strains of Klebsiella pneumoniae and other medically important pathogens. A total of 276 microbial isolates of pathogenic bacteria were used in this study; only 15 of them showed decreased sensitivity to one or several of ceftazidime, aztreonam, cefotaxime or ceftriaxone, which are deemed to be possible producers of ESßL. Antibacterial activities of plant extracts were carried out against ESßL positive isolates by the disc diffusion method. The potential ESßL suppressing activities of plant extracts and prepared fractions, (chloroform and methanol), with or without antibiotic were studied by disc diffusion method. Results revealed that selected plant extracts showed no antibacterial activity against tested strains; meanwhile, only Echinops viscosus, Pulicaria arabica, Tephrosia nubica, Chrozophora oblongifolia, and Clutia myricoides showed pronounced ESßL inhibitory activities. The extracts were quantified for phenolic compounds and their antioxidant properties. Bio-guided fractionation of the active extracts revealed that the chloroform fraction of C. myricoides possess a promising ESßL inhibitory activity. The separation and the structural elucidation of the active compounds from C. myricoides will offer beneficial leads for developing ß-lactamase inhibitors.

Phenolics Isolated from Aframomum meleguta Enhance Proliferation and Ossification Markers in Bone Cells.

Osteoporosis is a serious health problem characterized by decreased bone mineral density and deterioration of bone microarchitecture. Current antiosteoporotic agents exhibit a wide range of adverse effects; meanwhile, phytochemicals are effective and safer alternatives. In the current work, nine compounds belonging to hydroxyphenylalkane and diarylheptanoid groups were isolated from Aframomum meleguea seeds and identified as 6-gingerol (1), 6-paradol (2), 8-dehydrogingerdione (3), 8-gingerol (4), dihydro-6-paradol (5), dihydrogingerenone A (6), dihydrogingerenone C (7), 1,7-bis(3,4-dihydroxy-5-methoxyphenyl)heptane-3,5-diyl diacetate (8), and 1-(3,4-dihydroxy-5-methoxyphenyl)-7-(3,4-dihydroxyphenyl)heptane-3,5-diyl diacetate (9). The structures of isolated compounds were established by NMR and mass spectral data, in addition to referring to literature data. Exposure of MCF-7, MG-63, and SAOS-2 cells to subcytotoxic concentrations of the compounds under investigation resulted in accelerated proliferation. Among them, paradol was selected for further detailed biochemical analysis in SAOS-2 cells. DNA flowcytometric analysis of cell cycle distribution revealed that paradol did not induce any significant change in the proliferation index of SAOS-2 cells. Assessment of osteogenic gene expression revealed that paradol enhanced the expression of osteocyte and osteoblast-related genes and inhibited osteoclast and RUNX suppressor genes. Biochemically, paradol enhanced alkaline phosphatase activity and vitamin D content and decreased the osteoporotic marker acid phosphatase. In conclusion, paradol, which is a major constituents of A. melegueta seeds, exhibited potent proliferative and ossification characteristics in bone cells.

Sesquiterpene Lactones from Cynara cornigera: Acetyl Cholinesterase Inhibition and In Silico Ligand Docking.

Wild artichoke (Cynara cornigera), a thistle-like perennial belonging to the Asteraceae family, is native to the Mediterranean region, northwestern Africa, and the Canary Islands. While the pleasant, albeit bitter, taste of the leaves and flowers is attributed to the sesquiterpene lactones cynaropicrin and cynarin, a comprehensive phytochemical investigation still needs to be reported. In this study seven sesquiterpene lactones were isolated from an aqueous methanol plant extract, including a new halogenated metabolite (1), the naturally isolated compound sibthorpine (2), and five metabolites isolated for the first time from C. cornigera. Structures were established by spectroscopic methods, including HREIMS, (1 )H, (13 )C, DEPT, (1 )H-(1 )H COSY, HMQC, and HMBC-NMR experiments as well as by X-ray analysis. The isolated bioactive nutrients were analyzed for their antioxidant and metal chelating activity. Compound 1 exhibited a potent metal chelating activity as well as a high antioxidant capacity. Moreover, select compounds were effective as acetyl cholinesterase inhibitors presenting the possibility for such compounds to be examined for anti-neurodegenerative activity. A computational pharmacophore elucidation and docking study was performed to estimate the pharmacophoric features and binding conformation of isolated compounds in the acetyl cholinesterase active site.

Antiproliferative Scalarane-Based Metabolites from the Red Sea Sponge Hyrtios erectus.

Two new sesterterpenes analogs, namely, 12-acetoxy,16-epi-hyrtiolide (1) and 12ß-acetoxy,16ß-methoxy,20α-hydroxy-17-scalaren-19,20-olide (2), containing a scalarane-based framework along with seven previously reported scalarane-type sesterterpenes (3-9) have been isolated from the sponge Hyrtios erectus (order Dictyoceratida) collected from the Red Sea, Egypt. The structures of the isolated compounds were elucidated on the basis of their spectroscopic data and comparison with reported NMR data. Compounds 1-9 exhibited considerable antiproliferative activity against breast adenocarcinoma (MCF-7), colorectal carcinoma (HCT-116) and hepatocellular carcinoma cells (HepG2). Compounds 3, 5 and 9 were selected for subsequent investigations regarding their mechanism of cell death induction (differential apoptosis/necrosis assessment) and their influence on cell cycle distribution.

Phenolics from Garcinia mangostana alleviate exaggerated vasoconstriction in metabolic syndrome through direct vasodilatation and nitric oxide generation.

BACKGROUND: Exaggerated vasoconstriction plays a very important role in the hypertension, a major component of metabolic syndrome (MetS). In the current work, the potential protective effect of methanol extract of fruit hulls of Garcinia mangostana L. on the exaggerated vasoconstriction in MetS has been investigated. In addition, the bioactive fraction and compounds as well as the possible mechanism of action have been illustrated. METHODS: The effect of methanol extract of G. mangostana (GMT) fruit hulls on the vascular reactivity of aorta isolated from animals with MetS was investigated through bioassay-guided fractionation procedures. GMT was partitioned with chloroform (I) and the remaining mother liquor was fractionated on a Diaion HP-20 with H2O, 50 and 100 % methanol to give fractions II, III, and IV, respectively. The effect of total extract (GMT), bioactive fraction and the bioactive compounds on the vasoconstriction were examined in aortae isolated from animals with MetS by incubation for 30 min before exposing aortae to cumulative concentrations of phenylephrine (PE). The direct relaxant effect was also examined by adding cumulative concentrations of the bioactive fraction and its bioactive compounds to PE precontracted vessels. In addition, aortic nitric oxide (NO) and reactive oxygen species (ROS) production was investigated. RESULTS: Bioassay-guided fractionation of GMT revealed isolation of garcimangosone D (1), aromadendrin-8-C-ß-D-glucopyranoside (2), 2,4,3'-trihydroxy benzophenone-6-O-ß-D-glucopyranoside (3), maclurin-6-O-ß-D-glucopyranoside (rhodanthenone) (4), epicatechin (5), and 2,3',4,5',6-pentahydroxy benzophenone (6). Only compounds 2, 4, and 5 significantly alleviated the exaggerated vasoconstriction of MetS aortae and in the same time showed significant vasodilation of PE pre-contracted aortae. To further illustrate the mechanism of action, the observed vasodilation was completely blocked by the nitric oxide (NO) synthase inhibitor, Nω-nitro-L-arginine methyl ester hydrochloride and inhibited by guanylate cyclase inhibitor, methylene blue. However, vasodilation was not affected by the potassium channel blocker, tetraethylammonium or the cyclooxygenase inhibitor, indomethacin. In addition, compounds 2, 4, and 5 stimulated NO generation from isolated aortae to levels comparable with acetylcholine. Furthermore, 4 and 5 inhibited reactive oxygen species generation in MetS aortae. CONCLUSION: The phenolic compounds 2, 4, and 5 ameliorated the exaggerated vasoconstriction in MetS aortae through vasodilatation-NO generation mechanism.

A New Bioactive Metabolite Isolated from the Red Sea Marine Sponge Hyrtios erectus.

Chemical investigation of the lipophilic fraction of Hyrtios erectus, a Red Sea sponge, yielded a new pentacyclic nitrogen-containing scalarane; 24-methoxypetrosaspongia C (1), together with the previously reported scalaranes sesterstatin 3 (2), 12-deacetyl-12-epi-scalaradial (3) and 12-deacetyl-12,18-di-epi-scalaradial (4). The compounds were identified using HRESIMS, 1D and 2D NMR experiments. The isolated compounds showed growth inhibitory activity against hepatocellular carcinoma (HepG2), colorectal carcinoma (HCT-116) and breast adenocarcinoma cells (MCF-7).

Phenolics from Garcinia mangostana Inhibit Advanced Glycation Endproducts Formation: Effect on Amadori Products, Cross-Linked Structures and Protein Thiols.

Accumulation of Advanced Glycation Endproducts (AGEs) in body tissues plays a major role in the development of diabetic complications. Here, the inhibitory effect of bioactive metabolites isolated from fruit hulls of Garcinia mangostana on AGE formation was investigated through bio-guided approach using aminoguanidine (AG) as a positive control. Including G. mangostana total methanol extract (GMT) in the reaction mixture of bovine serum albumin (BSA) and glucose or ribose inhibited the fluorescent and non-fluorescent AGEs formation in a dose dependent manner. The bioassay guided fractionation of GMT revealed isolation of four bioactive constituents from the bioactive fraction; which were identified as: garcimangosone D (1), aromadendrin-8-C-glucopyranoside (2), epicatechin (3), and 2,3',4,5',6-pentahydroxybenzophenone (4). All the tested compounds significantly inhibited fluorescent and non-fluorescent AGEs formation in a dose dependent manner whereas compound 3 (epicatechin) was found to be the most potent. In search for the level of action, addition of GMT, and compounds 2-4 inhibited fructosamine (Amadori product) and protein aggregation formation in both glucose and ribose. To explore the mechanism of action, it was found that addition of GMT and only compound (3) to reaction mixture increased protein thiol in both glucose and ribose while compounds 1, 2 and 4 only increased thiol in case of ribose. In conclusion, phenolic compounds 1-4 inhibited AGEs formation at the levels of Amadori product and protein aggregation formation through saving protein thiol.

Gingerol Synergizes the Cytotoxic Effects of Doxorubicin against Liver Cancer Cells and Protects from Its Vascular Toxicity.

Hydroxyphenylalkanes and diarylheptanoids possess potential therapeutic value in different pathophysiological conditions, such as malignancy. In the current study, naturally isolated hydroxyphenylalkane and diarylheptanoid compounds were investigated for potential chemo-modulatory effects in addition to potential vascular protective roles with doxorubicin. Diarylheptanoids showed stronger antioxidant effects, in comparison to hydroxyphenylalkanes, as demonstrated by DPPH assay and amelioration of CCl4-induced disturbed intracellular GSH/GSSG balance. Shogaol and 4'-methoxygingerol showed considerable cytotoxic effects against HCT116, HeLa, HepG2 and MCF7 cells, with IC50 values ranging from 3.1 to 19.4 µM. Gingerol significantly enhanced the cytotoxic profile of doxorubicin against HepG2 and Huh7, cells decreasing its IC50s by 10- and 4-fold, respectively. Cell cycle distribution was studied using DNA cytometry. Doxorubicin alone induced cell accumulation at S-phase and G2/M-phase, while in combination with gingerol it significantly induced cell cycle arrest at the G2/M-phase. Additionally, the vascular protective effect of gingerol against doxorubicin (10 µM) was examined on isolated aortic rings. Co-incubation with 6-gingerol (30 µM) completely blocked the exaggerated vasoconstriction and impaired vascular relaxation induced by doxorubicin. In conclusion, despite its relatively weak antioxidant properties, gingerol protected from DOX-induced vascular damage, apparently not through a ROS scavenging mechanism. Besides, gingerol synergized the cytotoxic effects of DOX against liver cancer cells without influencing the cellular pharmacokinetics.