Anti-ulcer effect of isoprenyl flavonoids. II. Synthesis and anti-ulcer activity of new chalcones related to sophoradin

Significance of Chalcone Scaffolds in Medicinal Chemistry

Chalcone is a simple naturally occurring α,β-unsaturated ketone with biological importance, which can also be easily synthesized in laboratories by reaction between two aromatic scaffolds. In plants, chalcones occur as polyphenolic compounds of different frameworks which are bioactive molecules that have been in traditional medicinal practice for many years. Chalcone-based lead molecules have been developed, possessing varied potentials such as antimicrobial, antiviral, anti-inflammatory, anticancer, anti-oxidant, antidiabetic, antihyperurecemic, and anti-ulcer effects. Chalcones contribute considerable fragments to give important heterocyclic molecules with therapeutic utilities targeting various diseases. These characteristic features have made chalcone a topic of interest among researchers and have attracted investigations into this widely applicable structure. This review highlights the extensive exploration carried out on the synthesis, biotransformations, chemical reactions, hybridization, and pharmacological potentials of chalcones, and aims to provide an extensive, thorough, and critical review of their importance, with emphasis on their properties, chemistry, and biomedical applications to boost future investigations into this potential scaffold in medicinal chemistry.

Synthesis, biological evaluation and molecular modeling studies of modulated benzyloxychalcones as potential acetylcholinesterase inhibitors

Acetylcholinesterase inhibitors (AChEIs) have become a significant target in the search for an efficient treatment of Alzheimer's disease. Chalcone-based compounds display a strong potency to hinder AChE. So, this study focused on the synthesis of a series of new chalcone derivatives with anti-cholinesterase potential and their structures were characterized based on spectroscopic methods including IR, 1H NMR, 13C NMR and HRMS. Chalcone derivatives were screened against AChE. Most of them exhibited potent inhibitory activity against AChE. Compound 11i showed the most potent activity toward acetylcholinesterase compared to the positive compound, Galantamine. Docking studies into the active site of the acetylcholinesterase enzyme ravealed the significant docking score of the synthesized compounds with docking score of -7.959 to -9.277 kcal/mol when compared to the co-crystallized ligand, Donepezil (-10.567 kcal/mol). The interaction's stability was further assessed using a conventional atomistic 100 ns dynamics simulation study, which revealed the conformational stability of representative compound 11i in the cavity of the acetylcholinesterase enzyme.Communicated by Ramaswamy H. Sarma.

Redefining Chalcone Synthesis: Aldol Adduct Elimination for the Rapid Access to Thienyl Chalcones

This paper introduces a unique and novel method for synthesizing thienyl chalcones using iron oxide nanoparticles (FeONPs) as a heterogeneous catalyst. It stands out as a rare example in the literature for the synthesis of these chalcones from 1,3-diketones and various aromatic aldehydes. The magnetic FeONPs employed as the catalyst bring several advantages, including their efficiency, affordability, and ecofriendly nature, making them an attractive choice for producing thiophene chalcones. One noteworthy aspect of this methodology is the utilization of mild reaction conditions, which greatly simplify the operational aspects of the reaction. Synthesized chalcones were confirmed through the application of various techniques, proton-NMR, 13C NMR, mass spectrometry, and single-crystal X-ray diffraction analysis. These analyses provide valuable insights into the chemical compositions and structural characteristics of the synthesized compounds. Significantly, this methodology is reported for the first time in the literature, indicating its novelty and contribution to the field of chalcone synthesis.

Photophysical and biological aspects of α, β-unsaturated ketones: Experimental and in silico approach

In this work, four fluorinated α, β-unsaturated ketones named as 3-(3-bromophenyl)-1-(3-(trifluoromethyl)phenyl)prop-2-en-1-one (1), 3-(4-methoxyphenyl)-1-(3-(trifluoromethyl)phenyl) prop-2-en-1-one (2), 3-(3-bromo-5-chloro-2-hydroxyphenyl)-1-(3-(trifluoromethyl)phenyl) prop-2-en-1-one (3) and 3-(2-hydroxy-5-methylphenyl)-1-(3-(trifluoromethyl)phenyl)prop-2-en-1-one (4) were synthesized by Claisen-Schmidt reaction. The synthesized molecules were then characterized through ultraviolet-visible spectroscopy (UV-Vis), Fourier transform infrared (FTIR), 1 H-NMR, 13 C-NMR, and mass spectrometry. The antioxidant potential, Urease inhibition, and interaction of compounds 1-4 with Salmon sperm DNA were experimentally explored and supported by molecular docking studies. The synthesized compounds strongly interact with SS-DNA through intercalative mode. It was noticed that compound 1 served as potent Urease inhibitor while compound 4 as better antioxidant among synthesized compounds. Moreover, frontier molecular orbitals, nonlinear optical (NLO) properties, natural bond orbitals, molecular electrostatic potential, natural population analysis, and photophysical properties of synthesized compounds were accomplished through density functional theory and time-dependent density functional theory. The band gap of all the compounds have been worked out using Taucs method. In addition to that, a precise comparative account of UV and IR data obtained from theoretical and experimental findings showed good agreement between theoretical and experimental data. The findings of our studies reflected that compounds 1-4 possess better NLO properties than Urea standard and the band gap data also reflected their prospective use towards optoelectronic materials. The better NLO behavior of compounds was attributed to the noncentrosymmetric structure of synthesized compounds.

Synthesis and Photophysical, Electrochemical, and DFT Studies of Piperidyl and Pyrrolidinyl Chalcones

Small organic molecules with interesting optical and electrochemical properties find applications as organic luminescent materials. In this work, we report the synthesis of novel chalcones with D-A-D and D-A-D-A architecture, followed by their optical, electrochemical, and computational studies. The absorption band of these compounds occurs at 360-480 nm with emission maxima appearing around 513-552 nm. The large Stokes shifts (Δλ) for all compounds (90-132 nm) suggest intramolecular charge transfer (ICT) in the excited states. The molar absorptivity and fluorescence quantum yields were found to be in the range of 1.7-4.26 × 104 M-1 cm-1 and 0.29-0.39, respectively. The electrochemical parameters were determined by using cyclic voltammetry (CV). Density functional theory (DFT) calculations of all compounds were made by using B3LYP/G (d,p) functionals in chloroform and were found to have a good correlation with experimental results. Preliminary studies of absorption, photoluminescence, CV, and their theoretical correlation suggest that these compounds may be optimized for their applications in optoelectronics, sensing, and bioimaging.

A Review on Metal Ion Sensors Derived from Chalcone Precursor

Disclosure of new molecular probes as chromogenic and fluorogenic cation sensors is scientifically exigent work. Recently chalcone derivatives gained more attention because of their structural variability. A suitable donor and acceptor groups separated by delocalized π-orbitals display excellent chromogenic and fluorogenic properties because of intramolecular charge transfer (ICT). These designed molecular frameworks provide the coordination sites to the incoming metal ions results in small changes in the optical properties. In a typical sensing behavior, coordination leads to a large conjugation plane with the probe resulted in hypo/hyperchromic shifts or red/blue shifts. In this review, we tried to converge the reported chalcone-derived sensors and explored the design, synthesis, metal ion sensing mechanism, and practical application of the probes. We expect that this review gives a basic outline for researchers to explore the field of chalcone-based sensors further.

Synthesis, Structural Characterizations, and Quantum Chemical Investigations on 1-(3-Methoxy-phenyl)-3-naphthalen-1-yl-propenone

In the present study, 1-(3-methoxy-phenyl)-3-naphthalen-1-yl-propenone (MPNP) is synthesized and characterized by several experimental techniques such as Fourier transform-infrared spectroscopy (FT-IR), FT-Raman, NMR and UV-vis spectral methods. The similar techniques are also investigated by the computational method using Gaussian software. The density functional theory (DFT) method is used to obtain the optimized structure using the B3LYP/6-311++G(d,p) basis set. This optimization procedure of the molecule gives the minimum energy confirmation of the structure. The computed geometrical parameters are compared with experimental data. The experimental FT-IR and FT-Raman spectra of MPNP are obtained in the regions 4000-400 and 4000-50 cm-1 respectively. The detailed vibrational assignments of the molecule are obtained with the support of potential energy distribution. The theoretical NMR (1H and 13C) analysis is conducted by the GIAO method for its structural characterization and compared with experimental chemical shifts. The experimental UV-vis spectrum is obtained in the dimethyl sulfoxide solvent and compared with the theoretically computed spectrum by the time-dependent DFT method. In addition to these studies, other analyses such as nonlinear optical, natural bonds orbital, frontier molecular orbital, molecular electrostatic potential, and NCI have been conducted to understand the nature of the molecule. The title molecule is docked and also the drug-likeness, ADMET studies were carried out. The RBD domain bound to the ACE2 receptor during the fusion makes spike glycoprotein an elusive therapeutic target in SARS-CoV-2 infection.

Development of chalcone-based derivatives for sensing applications

The sensing of various analytes including metal ions and anions is at an incredible speed due to their widespread use in biological processes. Various small molecular species have been reported for the detection of various analytes, with the advantage of low cost and high sensitivity. Among various classes of organic molecules, chalcones are suitable candidates for the design of new chemosensors for targeted ions. In this review, using extensive examples of chalcone-based chemosensors, we explore the design, mechanism, and performance of various chemosensors for the detection of different ions. We believe that this review will provide new insight for researchers in related areas to develop chemosensors for various targeted ions.

Data of preparation and evaluation of supramolecular hydrogel based on cellulose for sustained release of therapeutic substances with antimicrobial and wound healing properties

The data article refers to the paper “supramolecular hydrogel based on cellulose for sustained release of therapeutic substances with antimicrobial and wound healing properties”[1]. The dataset includes the synthesis and characterization of (E)-1,3-bis(4-(allyloxy)phenyl)prop‑2-en-1-one (3) (crosslinking agent). Moreover, the multiwall carbon nanotubes (MWCNTs) synthesis and functionalization (MWCNTs-COOH) are described. The formulation obtained by adding multiwalled carbon nanotubes-COOH with the crosslinked cellulose-chalcone hydrogel is abbreviated as MWCNTsCCH, and the same formulation loaded with therapeutic substances (TS) is named MWCNTsCCH-TS. The MWCNTsCCH database such as components and their amounts, swelling degree, thermogravimetric analysis, and cytotoxicity evaluation are depicted. Finally, to elucidate the mechanism of therapeutic substances release, the obtained averages of the release profiles were fitted through mathematical models.

Supplementation with Angelica keiskei inhibits expression of inflammatory mediators in the gastric mucosa of Helicobacter pylori-infected mice

Oxidative stress is involved in the pathogenesis of Helicobacter pylori-associated gastric ulceration and carcinogenesis. The oxidant-sensitive transcription factor, nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB), regulates expression of inflammatory mediators such as interferon γ (IFN-γ), cyclooxygenase 2 (COX-2), and inducible nitric oxide synthase (iNOS). These inflammatory mediators increased in gastric mucosal tissues from patients infected with H pylori. Angelica keiskei (AK), a green leafy vegetable, is rich in carotenoids and flavonoids and shows antioxidant and anti-inflammatory activities. Therefore, we hypothesized that AK may protect the gastric mucosa of H pylori-infected mice against inflammation. We determined lipid peroxide abundance, myeloperoxidase activity, expression levels of inflammatory mediators (IFN-γ, COX-2, and iNOS), NF-κB-DNA binding activity, and histologic changes in gastric mucosal tissues. The antioxidant N-acetylcysteine served as the positive control treatment. Supplementation with AK suppressed increases in lipid peroxide abundance, myeloperoxidase activity, induction of inflammatory mediators (IFN-γ, COX-2, and iNOS), activation of NF-κB, and degradation of nuclear factor of κ light polypeptide gene enhancer in B-cells inhibitor α in gastric mucosal tissue from H pylori-infected mice. Inhibition of H pylori-induced alterations by AK was similar to that by N-acetylcysteine. Taken together, these results suggest that supplementation with AK may prevent H pylori-induced gastric inflammation by inhibiting NF-κB-mediated induction of inflammatory mediators in the gastric mucosa of patients infected with H pylori.

Protective effects of (1-(4-hydroxy-phenyl)-3-m-tolyl-propenone chalcone in indomethacin-induced gastric erosive damage in rats

Background

Non-steroidal anti-inflammatory drugs (NSAIDs) can result in peptic ulcer disease (PUD) which is a common condition worldwide. The aim of this study was to evaluate the antiulcer properties of (1-(4-hydroxy-phenyl)-3-m-tolyl-propenone) (HPTP) chalcone in rats using indomethacin as ulcerogenic agent.

Results

None of the rats showed symptoms of kidney and liver toxicity during the term of the study. Administration of HPTP had decreased the acidity, increased gastric wall mucus and flattening of gastric mucosa and reducing erosive gastric damage area. HPTP also showed dose dependent increase in SOD, GPx activity and PGE₂ level and decrease MDA. H & E stain showed decreased infiltration of leucocytes with edema of submucosal layer. PAS staining showed intense uptake of magenta color of gastric wall mucus in rats fed with HPTP, and immunohistochemical staining of gastric mucosa revealed over-expression of HSP70 protein, down-expression of Bax protein and over expression of TGF-β in rats administered with HPTP.

Conclusion

This study has revealed that chalcone1-(4-hydroxy-phenyl)-3-m-tolyl-propenone can serve as a safe and effective antiulcer agent as it has been proved to increase pH and gastric wall mucus, increase GPx, SOD, PGE₂, and decrease MDA level, ultimately, it has also contributes towards the over-expression of HSP protein andTGF-β, and down-expression of Bax protein.

Electronic supplementary material

The online version of this article (doi:10.1186/s12917-014-0303-7) contains supplementary material, which is available to authorized users.

Panacea seed "Nigella": A review focusing on regenerative effects for gastric ailments

Nigella sativa (NS) or black cumin is a dark, thin, and crescent-shaped, seeded shrub belonging to the Ranunculaceae family commonly growing on Mediterranean coasts in Saudi Arabia, northern Africa and Asia. They have amazing curative and therapeutic features that make them one of the most popular, safe, non-detrimental, and cytoprotective medicinal plant that can be used for prevention and treatment of many complicated diseases. Originally, N. sativa was used to treat migraines and allergy, and researches have shown its effectiveness in destroying cancer cells as well. The gastro protective effect of NS oil and its constituents has also been reported earlier; however, the complete perception on etiology and pathogenesis of gastric ulcer is not yet clear. Herein, we attempt to unveil some of the potential mechanisms exhibited by NS in preventing problems related to gastric ulcers. Gastric ailments like ulcers and tumors are the most common disorders of the gastro-intestinal tract in the present day life of the industrialized world. Gastric ulcer being a multifaceted problem exhibits complex etiology and is the fourth most common cause of cancer mortality. Drug interactions and toxicity are the main hindrances in chemotherapy. The existing merits and demerits of modern-day drugs make us turn toward the plant kingdom which may provide a valuable resource of novel potent natural compounds for pharmaceuticals or alternately, as dietary supplements. In this context, the revered phytotherapeutic N. sativa comes as a promising savior in today’s times. This review aims to summarize, both the functional and disease-related effects in the area of gastroenterology.

Herbal Remedy: An Alternate Therapy of Nonsteroidal Anti-Inflammatory Drug Induced Gastric Ulcer Healing

Nonsteroidal anti-inflammatory drugs (NSAIDs) are one of the most commonly used therapeutic drug groups used worldwide for curing an array of health problems like pain, inflammation, cardiovascular complications, and many other diseases, but they may cause different side effects including gastroduodenal disorders. So, there is a growing interest and need to search for nontoxic, antiulcer formulations from medicinal plants to treat NSAIDs induced gastric ulcer. Extensive research has reported on many natural plants like Camellia sinensis, Phyllanthus emblica, Myristica malabarica, Piper betle, Picrorhiza kurroa, and so forth, and their active constituents reduced NSAIDs induced gastric ulcer via their antioxidative as well as immunomodulatory activity. Therefore, use of herbal formulations in daily life may prevent NSAIDs induced gastric ulceration and other side effects.

2'-Carb-oxy-meth-oxy-4,4'-bis-(3-methyl-but-2-en-yloxy)chalcone

In the title compound, C₂₇H₃₀O₆, also known as sofalcone, an anti-ulcer agent used for the protection of gastric mucosa­, the two benzene rings form a dihedral angle of 6.78 (11)°. Inter­molecular O—H⋯O hydrogen bonds link the mol­ecules into centrosymmetric dimers, which are further linked by weak C—H⋯O inter­actions into ribbons propagated in [20]. Finally, π–π inter­actions between the benzene rings [centroid–centroid distance = 3.583 (13) Å] stabilize the crystal packing.

Flavonoids with gastroprotective activity

Peptic ulcers are a common disorder of the entire gastrointestinal tract that occurs mainly in the stomach and the proximal duodenum. This disease is multifactorial and its treatment faces great difficulties due to the limited effectiveness and severe side effects of the currently available drugs. The use of natural products for the prevention and treatment of different pathologies is continuously expanding throughout the world. This is particularly true with regards to flavonoids, which represent a highly diverse class of secondary metabolites with potentially beneficial human health effects that is widely distributed in the plant kingdom and currently consumed in large amounts in the diet. They display several pharmacological properties in the gastroprotective area, acting as anti-secretory, cytoprotective and antioxidant agents. Besides their action as gastroprotectives, flavonoids also act in healing of gastric ulcers and additionally these polyphenolic compounds can be new alternatives for suppression or modulation of peptic ulcers associated with H. pylori. In this review, we have summarized the literature on ninety-five flavonoids with varying degrees of antiulcerogenic activity, confirming that flavonoids have a therapeutic potential for the more effective treatment of peptic ulcers.

Effects of Dietary Angelica keiskei on Serum and Liver Lipid Profiles, and Body Fat Accumulations in Rats

Angelica keiskei (Ashitaba) is a perennial plant belonging to the Umbelliferae family. Recently, much attention has been focused on Ashitaba products as a so-called health food for the breakdown of cellulite among various physiological benefits of Ashitaba. The current study was carried out to investigate the physiological efficacy of dietary Ashitaba on serum and liver lipid profiles and body fat accumulation in rats. Rats were fed a high-fat diet with various amounts of Ashitaba for 28 d. Perirenal adipose tissue weights of rats fed the x 10 (170 mg/100 g BW) Ashitaba diet were significantly higher (p < 0.05) than those of the control group. Serum triacylglycerol concentrations of rats fed the x 100 (1,700 mg/100 g BW) Ashitaba diet were significantly higher (p < 0.05) than those of the x 1 (17 mg/100 g BW) group. Fecal weights and bile acid excretions of rats fed the x 10 or x 100 Ashitaba diet were significantly higher (p < 0.05) than those of the control group. However, there were no significant differences in the body weight gain, epididymal adipose tissue weight, serum cholesterol or liver lipid concentrations or other biochemical profiles in the serum. Furthermore, even the excessive ingestion of Ashitaba had no significant pathological impact on the liver or kidney. These results indicate that the large intake of Ashitaba products may supply dietary fiber and thus improve gastrointestinal condition through the increased excretion of feces containing high level of bile acids, although even excessive intake of Ashitaba for a short period of 28 d did not show any impact on the decrease in body fat or modification of lipid profiles in this study.

The biochemistry and medical significance of the flavonoids

Flavonoids are plant pigments that are synthesised from phenylalanine, generally display marvelous colors known from flower petals, mostly emit brilliant fluorescence when they are excited by UV light, and are ubiquitous to green plant cells. The flavonoids are used by botanists for taxonomical classification. They regulate plant growth by inhibition of the exocytosis of the auxin indolyl acetic acid, as well as by induction of gene expression, and they influence other biological cells in numerous ways. Flavonoids inhibit or kill many bacterial strains, inhibit important viral enzymes, such as reverse transcriptase and protease, and destroy some pathogenic protozoans. Yet, their toxicity to animal cells is low. Flavonoids are major functional components of many herbal and insect preparations for medical use, e.g., propolis (bee's glue) and honey, which have been used since ancient times. The daily intake of flavonoids with normal food, especially fruit and vegetables, is 1-2 g. Modern authorised physicians are increasing their use of pure flavonoids to treat many important common diseases, due to their proven ability to inhibit specific enzymes, to simulate some hormones and neurotransmitters, and to scavenge free radicals.

The acetone soluble fraction from bark extract of Stryphnodendron adstringens (Mart.) coville inhibits gastric acid secretion and experimental gastric ulceration in rats

The acetone soluble fraction from a crude methanol extract of Stryphnodendron adstringens stem bark (AFSAB) was evaluated in acute (ethanol, indomethacin and hypothermic restraint-stress) and chronic (acetic acid) models of gastric ulceration and on basal and bethanechol-stimulated gastric acid secretion in rats. Rats pretreated orally with AFSAB at doses of 400 and 800 mg/kg showed significant decreases of gastric lesion scores in ethanol (62% and 98%) and hypothermic restraint-stress (89% and 88%) models but exerted no significant influence on indomethacin-induced acute or acetic acid-induced chronic ulceration. In pylorus-ligated rats, AFSAB significantly decreased the basal as well as bethanechol-stimulated gastric secretory volume and the total acidity with an elevated pH value. AFSAB failed to modify the gastric mucus and the gastric wall nonprotein-sulphydryl content. These results point to a possible antisecretory effect of AFSAB which account for the observed antiulcer activity in ethanol and hypothermic restraint-stress induced models of acute gastric ulceration.

Synthetic and biological activity evaluation studies on novel 1,3-diarylpropenones

Fourteen novel C-prenylated and O-allylated 1,3-diarylpropenones (chalcones) were synthesized by Claisen-Schmidt condensation reaction of C-prenylated/O-allylated acetophenones with appropriate aldehydes; twelve of these model chalcones were screened in an assay based on the confrontation of invasive human MCF-7/6 mammary carcinoma cells with fragments of normal embryonic chick heart in vitro. Out of the twelve chalcones tested, three were found to exhibit potent anti-invasive activity. Some of these chalcones and their precursor acetophenones were also tested for inhibition of initiation of lipid peroxidation in rat liver microsomes; a prenylated acetophenone carrying two methoxy groups and two free phenolic hydroxy functions was found to be a potential antioxidant.

The plant kingdom as a source of anti-ulcer remedies

Phytogenic agents have traditionally been used by herbalists and indigenous healers for the prevention and treatment of peptic ulcer. This article reviews the anti-acid/anti-peptic, gastro-protective and/or anti-ulcer properties of the most commonly employed herbal medicines and their identified active constituents. Botanical compounds with anti-ulcer activity include flavonoids (i.e. quercetin, naringin, silymarin, anthocyanosides, sophoradin derivatives) saponins (i.e. from Panax japonicus and Kochia scoparia), tannins (i.e. from Linderae umbellatae), gums and mucilages (i.e. gum guar and myrrh). Among herbal drugs, liquorice, aloe gel and capsicum (chilli) have been used extensively and their clinical efficacy documented. Also, ethnomedical systems employ several plant extracts for the treatment of peptic ulcer. Despite progress in conventional chemistry and pharmacology in producing effective drugs, the plant kingdom might provide a useful source of new anti-ulcer compounds for development as pharmaceutical entities or, alternatively, as simple dietary adjuncts to existing therapies.

Lipase-catalysed regio- and enantioselective deacetylation of 2,4-diacetoxyphenyl alkyl ketones

Porcine pancreatic lipase in tetrahydrofuran catalyses the deacetylation of 2,4-diacetoxyphenyl alkyl ketones in a highly regioselective fashion. The strategy of regioselective deacetylation of diacetoxyphenyl alkyl ketones has also resulted in the enantiomeric resolution of a racemic diacetoxyphenyl alkyl ketone, i.e. (+/-)-2,4-diacetoxyphenyl (1-ethyl)pentyl ketone, a precursor for the synthesis of an antifungal coumarin, 7-acetoxy-4-(1-ethyl)pentyl-3-phenyl-2H-1-benzopyran-2-one.

Modifications of the alpha,beta-double bond in chalcones only marginally affect the antiprotozoal activities

Methods for selective alkylation of chalcones in the alpha- or beta-position and for selective reduction of the alpha,beta-double bond have been developed. The antiparasitic potencies of the alpha,beta-double bond modified chalcones only differ marginally from the potencies of the parent chalcones indicating that the propenone residue only functions as a spacer between the two benzene rings, which are the true pharmacophore.

Lipase-catalysed selective deacetylation of phenolic/enolic acetoxy groups in peracetylated benzyl phenyl ketones

Highly chemo- and regioselective de-esterification has been observed in the deacetylation of peracetylated enolic forms of polyphenolic benzyl phenyl ketones by lipase from porcine pancreas (PPL) suspended in tetrahydrofuran (THF). The enzyme selectively deacetylates the enolic acetoxy over the phenolic acetoxy group(s) and continuation of the reaction resulted, in addition the regioselective deacetylation of acetoxy function para to the nuclear carbonyl group.

Biotransformations in the regioselective deacetylation of polyphenolic peracetates in organic solvents

Regioselectivity has been observed in the deacetylation of peracetates of polyphenolic aromatic ketones by lipases from porcine pancreas (PPL) and Candida cyclindracea (CCL) suspended in organic solvents. The deacetylation of acetoxyl groups at positions para and meta to the carbonyl (ketonic) group is favoured over the one at the ortho position.

Antiulcerogenicity of the flavonoid fraction from Bidens aurea: comparison with ranitidine and omeprazole

Effects of the flavonoid fraction of Bidens aurea (Aiton) Sherff on gastric ulceration induced by restraint and cold were studied in rats. Mucosal damage was evaluated histomorphometrically and the results were compared with those of omeprazole and ranitidine. The effects of these agents on the quantity and quality of the gastric mucus were also determined histologically and biochemically. Oral treatment with the ether fraction of the flavonoid extract gave the highest level of gastric protection. Mucus content was increased and accompanied by a proportional increase in proteins and hexosamines. There was also a marked increase of the periodic acid-Shiff (PAS) area (neutral glycoprotein) and the alcian blue (AB) area (sulphated glycoprotein). The groups which received ranitidine and omeprazole did not overcome the inhibition of the mucus secretion induced in this experimental model.

Inhibition of gastric H+,K(+)-ATPase by the anti-ulcer agent, sofalcone

Effects of the anti-ulcer agent, sofalcone, on gastric H+,K(+)-ATPase were studied as well as those of other chalcone derivatives, chalcone and sophoradin. These drugs inhibited pig gastric H+,K(+)-ATPase in a dose-dependent manner. They were 5-10-fold less inhibitory toward Na+,K(+)-ATPase than H+,K(+)-ATPase. The potencies of these drugs on the inhibition of enzymes were as follows: sophoradin greater than sofalcone greater than chalcone. Kinetic studies showed that the inhibition of H+,K(+)-ATPase by sofalcone was competitive with respect to ATP and was non-competitive with respect to K+. Sofalcone also inhibited H+,K(+)-ATPase mediated proton transport and reduced the phosphoenzyme level. These results suggest that sofalcone inhibits gastric H+,K(+)-ATPase competitively with ATP at the ATP site and thereby blocks the phosphorylation of the enzyme. This may be the cause of the anti-secretory activity of sofalcone.

Inhibition of gastric H+, K(+)-ATPase by chalcone derivatives, xanthoangelol and 4-hydroxyderricin, from Angelica keiskei Koidzumi

Two chalcone derivatives, xanthoangelol (1) and 4-hydroxyderricin (II) isolated from Angelica keiskei Koidzumi, inhibited pig gastric H+, K(+)-ATPase with IC50 values of 1.8 and 3.3 microM, respectively. The inhibition by I or II was competitive with respect to ATP and was non-competitive with respect to K+ I and II also inhibited K+, stimulated p-nitrophenyl phosphatase, with IC50 values of 1.3 and 3.5 microM, respectively. Proton transport in-vitro was inhibited by I or II, in a dose-dependent manner, 1 at 100 mg kg-1, i.p. significantly inhibited acid secretion and the formation of stress-induced gastric lesions. These results suggest that the antisecretory effect of 1 is due to the inhibition of gastric H+, K(+)-ATPase.

Inhibition of 15-hydroxy prostaglandin dehydrogenase and increase of prostaglandin E2: effect of sofalcone on rat gastric mucosa

The effect of sofalcone, an anti-ulcer agent, on gastric mucosal prostaglandin (PG) metabolism was studied. Gastric mucosal PGE2 was determined in rats in which PGE2 synthesis was inhibited by preadministration of indomethacin. Oral administration of sofalcone at doses of 200 and 400 mg/kg significantly inhibited the PG metabolizing enzyme, 15-hydroxy-PG-dehydrogenase (15-OH-PG-DH) activity and increased PGE2 contents in the rat gastric mucosa. The inhibition of 15-OH-PG-DH activity was accompanied by an increase of PGE2 contents up to 6 hours after the administration of sofalcone. These changes, however, were not observed 12 hours after its administration. Intraperitoneally administered sofalcone also inhibited 15-OH-PG-DH activity and increased PGE2 content. The inhibition of 15-OH-PG-DH activity by sofalcone was noncompetitive and uncompetitive against substrates NAD and PGE1, respectively. These results suggest that the increase of the gastric PGE2 level is mainly due to the inhibition of 15-OH-PG-DH activity, and this increase in PGE2 may be involved in the anti-ulcer effect of sofalcone.

Anti-ulcer action of Panax japonicus rhizome

Using HCl/ethanol-induced ulcer in rats as a screening model, an anti-ulcer effect was observed for a methanol extract of Panax japonicus rhizome, saponin fractions and chikusetsusaponin III. Results suggest that the gastric mucous membrane-protective effect of the methanol extract is likely to be due to the crude saponin fraction and chikusetsusaponin III.

Antiulcer and gastroprotective effects of solon, a synthetic flavonoid derivative of sophoradin. Role of endogenous prostaglandins

Solon is a synthetic isoprenyl flavonoid derived from sophoradin which is isolated from the root of an ancient Chinese plant. Solon was administered orally or intraperitoneally to rats. It inhibited dose dependently gastric ulcers produced by acidified aspirin, water immersion and restraint stress. Solon was also gastroprotective for the stomach as it reduced dose dependently the gastric necrotic lesions induced by absolute ethanol given orally. The degree of gastroprotection decreased with time, the optimal effects occurring 60-90 min after oral administration. Pretreatment with indomethacin partly prevented the gastroprotective effects of Solon. When given alone to fasted rats, Solon increased dose dependently the mucosal content of prostaglandins (PG), suggesting that the protective effects of this drug may be mediated at least in part by endogenous PG.

Effect of 2'-carboxymethoxy-4,4'-bis(3-methyl-2-butenyloxy)chalcone (SU-88) on prostaglandin metabolism in hog gastric mucosa

SU-88 [2'-carboxymethoxy-4,4'-bis(3-methyl-2-butenyloxy)chalcone] inhibited the activity of the prostaglandin (PG)-metabolizing enzyme, 15-hydroxy-PG-dehydrogenase (15-OH-PG-DH), in a cytoplasmic fraction of gastric mucosa. This compound had no effect on the PG synthetase of bovine seminal vesicle microsomes and lactate dehydrogenase in rat liver. The 15-OH-PG-DH activity of gastric mucosa was not influenced by a specific inhibitor of alcohol dehydrogenase, 4-methylpyrazole. Carbenoxolone (CBX) also inhibited 15-OH-PG-DH activity. The IC50 values for SU-88 and CBX were approximately 20 and 40 microM respectively. SU-88 inhibited 15-OH-PG-DH activity uncompetitively or competitively according to whether PGE1 or NAD was used as substrate. CBX inhibited competitively the activity of this enzyme for both substrates. After the addition of SU-88 or CBX to the incubation medium of gastric mucosa, the PGE2 level of the medium was increased significantly while that of the tissue remained unchanged. These results indicate that SU-88 specifically inhibited 15-OH-PG-DH activity and suggest that 15-OH-PG-DH activity regulates the level of PGs in gastric mucosa and may have an anti-ulcer influence.

Effect of 2'-carboxymethoxy-4,4'-bis(3-methyl-2-butenyloxy) chalcone (sofalcone) on chronic gastric ulcers in rats

The anti-ulcer effect of sofalcone, an isoprenyl chalcone derivative, on acetic acid-induced gastric ulcers in rats was studied histologically and histochemically. After administrations of sofalcone at 50 and 200 mg/kg twice daily for 10 days, contraction of the ulcer, mucosal regeneration, accelerated development of the collagen fibers in the granulation tissue at the base of the ulcer, and increase of acid mucopolysaccharides, an alcian blue stain-positive substance covering the regenerated mucosa, were noted. The healing effect of sofalcone was balanced in mucosal regeneration and connective tissue proliferation (formation of the collagen fibers). Sofalcone of 50 mg/kg showed a greater healing effect than gefarnate at the same dose and had a similar healing effect as L-glutamine at 200 mg/kg.

Cytoprotective effect of SU-88, an anti-ulcer agent, in the rat

The gastric cytoprotective action of SU-88, an anti-ulcer agent, was studied in rats. SU-88 dose-dependently prevented the formation of gastric lesions induced by absolute ethanol as observed by PGE2. The efficacy of SU-88 when given i.p. was more potent than the p.o. administration. Indomethacin (5mg/kg, p.o.) given 30 min prior to SU-88 dosing blocked this protective effect, whereas it was not affected when indomethacin was given 30 min after the SU-88 dosing. Cimetidine, on the other hand, failed to exert a protective effect against the ethanol-induced lesions and caused a significant increase in the lesions induced by 0.6N HCI. Pretreatment with SU-88 prior to cimetidine resulted in a marked reduction in the lesions. SU-88 was found to increase the synthesis of gastric glycoproteins and to prevent the reduction of glycoprotein synthesis caused by the administration of absolute ethanol. However, no increase in the synthesis was observed 5 min after the SU-88 dosing, although the lesion was significantly suppressed at that time. These findings indicate that SU-88 possesses a cytoprotective effect and that this effect seems to be mediated by the increase in endogenous PG.