New polyphenolic 5'-nucleotidase inhibitors isolated from the wine grape "Koshu" and their biological effects

New 5'-nucleotidase inhibitors designated as NPF-88BU-IA, NPF-88BU-IB, NPF-88BU-IIA and NPF-88BU-IIB, respectively, were isolated from the seeds and skin of the wine grape "Koshu". They were purified by solvent extraction, dialysis, and reversed-phase high performance liquid chromatography (HPLC). Their physico-chemical properties revealed these compounds to be polyphenolic substances. The average relative molecular masses of the four were estimated by gel permeation chromatography (GPC) analysis to be 7850, 5950, 11900, and 11300, respectively. They strongly inhibited 5'-nucleotidase activities from snake venom and rat liver membrane, and displayed significant therapeutic activity against Ehrlich ascites carcinoma. They also showed inhibitory effects on the growth of Streptococcus mutans MT8148(c), a primary cariogenic bacterium. Furthermore, these 5'-nucleotidase inhibitors inhibited the glucan formation from sucrose. These results suggest that the 5'-nucleotidase inhibitors can prevent the cause of caries of tooth.     

Phosphatase-inhibitory activity and activation of murine macrophages by new 5'-nucleotidase inhibitors, NPF-86IA, NPF-86IB, NPF-86IIA and NPF-86IIB

New 5'-nucleotidase-inhibitory polyphenols named NPF-86IA, NPF-86IB, NPF-86IIA and NPF-86IIB were isolated from the seeds of Areca catechu L. The ability of the inhibitors to precipitate gelatin was investigated by microturbidimetry. These inhibitors produced weak turbidity. As 5'-nucleotidase is a kind of phosphatase, we examined the effects of these inhibitors on alkaline and acidic phosphatases. While they showed moderate inhibitory effects on the activity of acidic phosphatases, they did not have any significant effect on the activity of alkaline phosphatase. Therefore, they showed a higher inhibitory effect on the 5'-nucleotidase than the other phosphatases, Murine macrophages were directly stimulated by the 5'-nucleotidase inhibitors.     

The inhibition of eugenol on glucan is essential for the biofilm eradication effect on caries-related biofilm in an artificial mouth model

This study aimed to evaluate the inhibitory effects of herbal extracts on caries-related bacteria, glucan and biofilm in?vitro. Sensitive tests of bacteria were carried out by broth dilution method on a 96-microwell plate. Glucan inhibition tests were carried out using the phenol sulphate method. A minimum biofilm inhibitory concentration (MBIC) test was performed in an artificial mouth model. The results of the MBIC of agents were 8, 16 and 32?mg?mL(-1) for eugenol, tannic acid and magnolol, respectively. For the results of glucan inhibition tests, over 63%, 28% and 27% inhibition occurred on insoluble glucan syntheses of Streptococcus sobrinus for eugenol, magnolol and tannic acid, respectively. Over 46%, 16% and 13% inhibition on soluble glucan syntheses for eugenol, magnolol and tannic acid, respectively, were also observed. In conclusion, the inhibition of eugenol on glucan is essential for the biofilm inhibition effect on caries-related biofilm in an artificial mouth model in?vitro.     

Effect of tea polyphenols on glucan synthesis by glucosyltransferase from Streptococcus mutans

In the course of our studies on the development of anti-plaque agents for prevention of dental caries, we investigated effects of some of tea preparations and their individual components on the glucan synthesis catalyzed by glucosyltransferase (GTF) from Streptococcus mutans. Extracts of green tea and black tea, and polyphenol mixtures showed appreciable inhibition in the synthesis of insoluble glucan. Among the components isolated from tea infusions, theaflavin and its mono- and digallates had potent inhibitory activities at concentrations of 1-10 mM against GTF. (+)-Catechin, (-)-epicatechin and their enantiomers had moderate inhibitory activities at these concentrations, while galloyl esters of (-)-epicatechin, (-)-epigallocatechin and (-)-gallocatechin had increased inhibitory activities.     

New substances against human immunodeficiency virus: sulfated 5'-nucleotidase inhibitory polyphenols.

Two sulfated polyphenols, NF-86II-S-13.3 and NF-86II-S-6.2, were synthesized from NF-86II without sulfur their inhibitory effect on human immunodeficiency virus (HIV) infection in vitro was examined, using cytopathic effect and an antigen expression assay system in MT-4 cells. NF-86II-S-13.3 (sulfur content, 13.3%) completely inhibited the cytopathic effect of HIV and the HIV-specific antigen expression in MT-4 cells at concentrations of more than 6.3 micrograms/ml. The effect of NF-86II-S-6.2 (sulfur content, 6.2%) was much weaker than that of NF-86IIS-13.3. On the other hand, NF-86II without sulfur did not show any activity at all.     

Antimicrobial and anti-adhesive potential of a biosurfactant Rufisan produced by Candida lipolytica UCP 0988

In the last years, researches developed with biosurfactants for application in the medical area have been revealing the promising biological activities of these biomolecules. In this work the antimicrobial and anti-adhesive properties of a biosurfactant Rufisan isolated from the yeast Candida lipolytica UCP 0988, growth in a medium supplemented with ground nut refinery residue was determined against several microorganisms. The biosurfactant was able to reduce the water surface tension from 70 to 25.3 mN/m and showed a critical micelle concentration (CMC) of 0.03%. The biosurfactant was isolated after 72 h of fermentation and was tested in concentrations varying from 0.75 to 12 mg/l. The highest antimicrobial activities were observed against Streptococcus agalactiae, Streptococcus mutans, Streptococcus mutans NS, Streptococcus mutans HG, Streptococcus sanguis 12, Streptococcus oralis J22 at a concentration superior to the biosurfactant critical micelle concentration. Moreover, the biosurfactant showed anti-adhesive activity against most of the microorganisms tested. As far as we know, this is the first compilation of data on antimicrobial and anti-adhesive activities of a biosurfactant obtained from a Candida strain against such a broad group of microorganisms. The results obtained in this work showed that the biosurfactant from C. lipolytica is a potential antimicrobial and/or anti-adhesive agent for several biomedical applications.     

Isolation of the new anacardic acid 6-[16'Z-nonadecenyl]-salicylic acid and evaluation of its antimicrobial activity against Streptococcus mutans and Porphyromonas gingivalis

A new anacardic acid, 6-[16'Z-nonadecenyl]-salicylic acid (1), along with seven known compounds, 6-[8'Z-pentadecenyl] salicylic acid (15:1 anacardic acid) (2), 6-nonadecenyl salicylic acid (anacardic acid 19:0) (3), 6-pentadecyl salicylic acid (anacardic acid 15:0) (4), masticadienonic acid (5), 3α-hydroxymasticadienonic acid (6), 3-epi-oleanolic acid (7) and β-sitosterol, were isolated from the bark of Amphipterygium adstringens using a bioassay-guided fractionation method. The structure of the new compound (1) was elucidated by spectroscopic data interpretation. The known compounds (2-7) were identified by comparison of their spectroscopic data with reported values in the literature. Compounds 1-4 exhibited antibacterial activity against Streptococcus mutans and Porphyromonas gingivalis with minimum inhibitory concentrations ranging from 7 to 104?μg?mL and from 12 to 126?μg?mL, respectively.     

Inhibition Effects of Dilute-Acid Prehydrolysate of Corn Stover on Enzymatic Hydrolysis of Solka Floc

Dilute-acid pretreatment liquor (PL) produced at NREL through a continuous screw-driven reactor was analyzed for sugars and other potential inhibitory components. Their inhibitory effects on enzymatic hydrolysis of Solka Floc were investigated. When the PL was mixed into the enzymatic hydrolysis reactor at 1:1 volume ratio, the glucan and xylan digestibility decreased by 63% and 90%, respectively. The tolerance level of the enzyme for each inhibitor was determined. Of the identified degradation components, acetic acid was found to be the strongest inhibitor for cellulase activity, as it decreased the glucan yield by 10% at 1 g/L. Among the sugars, cellobiose and glucose were found to be strong inhibitors to glucan hydrolysis, whereas xylose is a strong inhibitor to xylan hydrolysis. Xylo-oligomers inhibit xylan digestibility more strongly than the glucan digestibility. Inhibition by the PL was higher than that of the simulated mixture of the identifiable components. This indicates that some of the unidentified degradation components, originated mostly from lignin, are potent inhibitors to the cellulase enzyme. When the PL was added to a simultaneous saccharification and co-fermentation using Escherichia coli KO11, the bioprocess was severely inhibited showing no ethanol formation or cell growth.     

Effect of lectins from Diocleinae subtribe against oral Streptococci

Surface colonization is an essential step in biofilm development. The ability of oral pathogens to adhere to tooth surfaces is directly linked with the presence of specific molecules at the bacterial surface that can interact with enamel acquired pellicle ligands. In light of this, the aim of this study was to verify inhibitory and antibiofilm action of lectins from the Diocleinaesubtribe against Streptococcus mutans and Streptococcus oralis. The inhibitory action against planctonic cells was assessed using lectins from Canavaliaensi formis (ConA), Canavalia brasiliensis (ConBr), Canavalia maritima (ConM), Canavalia gladiata (CGL) and Canavalia boliviana (ConBol). ConBol, ConBr and ConM showed inhibitory activity on S. mutans growth. All lectins, except ConA, stimulated significantly the growth of S. oralis. To evaluate the effect on biofilm formation, clarified saliva was added to 96-well, flat-bottomed polystyrene plates, followed by the addition of solutions containing 100 or 200 μg/mL of the selected lectins. ConBol, ConM and ConA inhibited the S. mutans biofilms. No effects were found on S. oralis biofilms. Structure/function analysis were carried out using bioinformatics tools. The aperture and deepness of the CRD (Carbohydrate Recognition Domain) permit us to distinguish the two groups of Canavalia lectins in accordance to their actions against S. mutans and S. oralis. The results found provide a basis for encouraging the use of plant lectins as biotechnological tools in ecological control and prevention of caries disease.     

Evaluation of carbonic anhydrase and paraoxonase inhibition activities and molecular docking studies of highly water-soluble sulfonated phthalocyanines

The investigation of carbonic anhydrase and paraoxonase enzyme inhibition properties of water-soluble zinc and gallium phthalocyanine complexes ( 1 and 2 ) are reported for the first time. The binding of p-sulfonylphenoxy moieties to the phthalocyanine structure favors excellent solubilities in water, as well as providing an inhibition effect on carbonic anhydrase (CA) I and II isoenzymes and paraoxonase (PON1) enzyme. According to biological activity results, both complexes inhibited hCA I, hCA II, and PON1. Whereas 1 and 2 showed moderate hCA I and hCA II (off-target cytosolic isoforms) inhibitory activity (Ki values of 26.09 µM and 43.11 µM for hCA I and 30.95 µM and 33.19 µM for hCA II, respectively), they exhibited strong PON1 (associated with high-density lipoprotein [HDL]) inhibitory activity (Ki values of 0.37 µM and 0.27 µM, respectively). The inhibition kinetics were analyzed by Lineweaver–Burk double reciprocal plots. It revealed that 1 and 2 were noncompetitive inhibitors against PON1, hCA I, and hCA II. These complexes can be more advantageous than other synthetic CA and PON inhibitors due to their water solubility. Docking studies were carried out to examine the interactions between hCA I, hCA II, and PON1 inhibitors and metal complexes at a molecular level and to predict binding energies.     

Studies on aldose reductase inhibitors from natural products. IV. Constituents and aldose reductase inhibitory effect of Chrysanthemum morifolium, Bixa orellana and Ipomoea batatas.

The hot water extracts of Chrysanthemum morifolium, Bixa orellana and Ipomoea batatas, were found to have potent inhibitory activity towards lens aldose reductase (AR). Ellagic acid (4) was isolated from C. morifolium and I. batatas, isoscutellarein (7) from B. orellana and 3,5-dicaffeoylquinic acid (10) from I. batatas, respectively, as potent inhibitors.     

Antibacterial compounds from Siraitia grosvenorii leaves

Luo Han Guo (LHG) fruits (Siraitia grosvenorii Swingle) have been used as traditional medicine in China for centuries to treat sore throats and coughs. However, LHG leaves are seldom used and minimal scientific information is available on them. In our recent study on the leaves of S. grosvenorii, the bioactive compounds β-amyrin (2), aloe emodin (5), aloe-emodin acetate (6), 5α,8α-epidioxy-24(R)-methylcholesta-6,22-dien-3β-ol (7) and p-hydroxyl benzyl acid (8), accompanied by n-hexadecaoic acid (1), 12-methyltetradecanoic acid (3), β-sitosterol (4) and daucosterol (9) were first obtained. Their structures have been identified on the basis of spectroscopic studies. The activities of these compounds were evaluated in?vitro against the growth of oral bacterial species Streptococcus mutans, Actinobacillus actinomycetemcomitans, Fusobacterium nucleatum and the yeast Candida albicans, and their minimum inhibition concentrations were determined. Furthermore, the activity against S. mutans is likely to be due to the inhibition of glucosyltransferase. The experimental data provide important information on bioactive phytochemicals in the leaf of S. grosvenorii, which shows that the leaf can be a new resource as an antibacterial agent.     

Antibacterial activity of 15-deoxygoyazensolide isolated from the stems of Minasia alpestris (Asteraceae) against oral pathogens

This work reports the isolation of the sesquiterpene lactone 15-deoxygoyazensolide from the stems of Minasia alpestris and the evaluation of its antimicrobial activity against the following oral pathogens: Enterococcus faecalis, Streptococcus salivarius, Streptococcus sobrinus, Streptococcus mutans, Streptococcus mitis, Streptococcus sanguinis, and Lactobacillus casei. Despite the cytotoxicity and genotoxicity of other sesquiterpene lactones of the furanoheliangolide-type, our results revealed that this compound exhibits low antibacterial activity against the evaluated oral pathogens; however, an interesting selectivity against E. faecalis (minimum inhibitory concentration [MIC]=40 μg mL(-1)) and S. sobrinus (MIC=60 μg mL(-1)) was observed.     

Evaluation of ent-kaurenoic acid derivatives for their anticariogenic activity

Ent-kaur-16(17)-en-19-oic acid (kaurenoic acid, KA) is a tetracyclic diterpene prototype for natural anticaries agents. Six KA derivatives were prepared and their antimicrobial activity against the main microorganisms involved in the caries process evaluated. The sodium salt of KA (KA-Na) was the most active, displaying very promising MIC values for most pathogens. Time-kill assays against the primary causative agent of caries (Streptococcus mutans) indicated that KA and KA-Na only inhibited growth in the first 12 h, suggesting a bacteriostatic effect. After this period (12-24 h), their bactericidal effect was clearly noted. KA and KA-Na showed no synergy when combined with the gold standard anticariogenic (chlorhexidine dihydrochloride, CHD) in the checkerboard assays against S. mutans.     

Antioxidant activity of peptide-based angiotensin converting enzyme inhibitors

Angiotensin converting enzyme (ACE) inhibitors are important for the treatment of hypertension as they can decrease the formation of vasopressor hormone angiotensin II (Ang II) and elevate the levels of vasodilating hormone bradykinin. It is observed that bradykinin contains a Ser-Pro-Phe motif near the site of hydrolysis. The selenium analogues of captopril represent a novel class of ACE inhibitors as they also exhibit significant antioxidant activity. In this study, several di- and tripeptides containing selenocysteine and cysteine residues at the N-terminal were synthesized. Hydrolysis of angiotensin I (Ang I) to Ang II by ACE was studied in the presence of these peptides. It is observed that the introduction of L-Phe to Sec-Pro and Cys-Pro peptides significantly increases the ACE inhibitory activity. On the other hand, the introduction of L-Val or L-Ala decreases the inhibitory potency of the parent compounds. The presence of an L-Pro moiety in captopril analogues appears to be important for ACE inhibition as the replacement of L-Pro by L-piperidine 2-carboxylic acid decreases the ACE inhibition. The synthetic peptides were also tested for their ability to scavenge peroxynitrite (PN) and to exhibit glutathione peroxidase (GPx)-like activity. All the selenium-containing peptides exhibited good PN-scavenging and GPx activities.     

靶向VEGFR受体抑制剂齐墩果酸衍生物的合成及初步抗肿瘤活性研究

以天然产物齐墩果酸为母体,设计合成齐墩果酸衍生物,采用计算机辅助药物设计,对C-3、C-28位结构改造,设计合成12个未见文献报道的靶向VEGFR受体抑制剂; 采用噻唑蓝(MTT)法,用人肝癌细胞(HepG2)和乳腺癌细胞(MCF-7)对其进行初步体外抗肿瘤活性筛选;其结构经1H-NMR、13C-NMR谱确证。活性测试得出化合物I7、II1与阳性对照药相比有较强抑制作用,其抗肿瘤活性高于母体OA,分子对接结果显示I7和II1 与 VEGFR 受体具有较好的结合能力,值得进一步研究。     

Synthesis of Sulfonamides Incorporating Piperidinyl-Hydrazidoureido and Piperidinyl-Hydrazidothioureido Moieties and Their Carbonic Anhydrase I,II, IX and XII Inhibitory Activity

Here we report a small library of hydrazinocarbonyl-ureido and thioureido benzenesulfonamide derivatives, designed and synthesized as potent and selective human carbonic anhydrase inhibitors (hCAIs). The synthesized compounds were evaluated against isoforms hCA I, II, IX and XII using acetazolamide (AAZ) as standard inhibitor. Several urea and thiourea derivatives showed inhibitory activity at low nanomolar levels with selectivity against the cytosolic hCA II isoform, as well as the transmembrane, tumor-associated enzymes hCA IX and XII. The thiourea derivatives showed enhanced potency as compared to urea analogues. Additionally, eight compounds 5g, 5m, 5o, 5q, 6l, 6j, 6o and 6u were selected for docking analysis on isoform I, II, IX, XII to illustrate the potential interaction with the enzyme to better understand the activity against the different isoforms.     

New fungal metabolite geranylgeranyltransferase inhibitors with antifungal activity

Geranylgeranyltransferase I (GGTase I) catalyzes the post-translational transfer of lyophilic diterpenoid geranylgeranyl to the cysteine residue of proteins terminating with a CaaX motif such as Rho1p and Cdc42p. It has been shown that GGTase I activity is essential for viability of Saccharomyces cerevisiae and hence its inhibition is a potential antifungal target. From natural product screening, a number of azaphilones including one novel analog were isolated as broad-spectrum inhibitors of GGTase I. Isolation, structure elucidation, GGTase I inhibitory activities and antifungal activities of these compounds are described.     

美丽红豆杉二萜的研究 II: 一个新的紫杉烷二萜的结构

报导了从美丽红豆杉茎皮中分到的两个紫杉烷二萜化合物: 经高分辨核磁共振和COSY测定其结构为红豆杉素J(taxinine J)和2-去乙酰氧基-红豆杉素J(2-deacetoxytaxinine J), 后者系一新化合物, 药理结果表明: 二个化合物对肝癌细胞具有不同程度抑制作用.     

Aldose reductase inhibitors from natural sources

This review covers aldose reductase inhibitors (ARIs) isolated from natural sources. Compounds in the review are grouped according to the source from which they have been isolated: terrestrial, marine, or microorganism and the in vitro inhibitory activity of the compounds is also showed. The literature, both journals and patents, up to June 2002 is reviewed and 86 references are cited.