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PubMed1998

Plant-derived leading compounds for chemotherapy of human immunodeficiency virus (HIV) infection.

Many compounds of plant origin have been identified that inhibit different stages in the replication cycle of human immunodeficiency virus (HIV): 1) virus adsorption: chromone alkaloids (schumannificine), isoquinoline alkaloids (michellamines), sulphated polysaccharides and polyphenolics, flavonoids, coumarins (glycocoumarin, licopyranocoumarin) phenolics (caffeic acid derivatives, galloyl acid derivatives, catechinic acid derivatives), tannins and triterpenes (glycyrrhizin and analogues, soyasaponin and analogues); 2) virus-cell fusion: lectins (mannose- and N-acetylglucosamine-specific) and triterpenes (betulinic acid and analogues); 3) reverse transcription; alkaloids (benzophenanthridines, protoberberines, isoquinolines, quinolines), coumarins (calanolides and analogues), flavonoids, phloroglucinols, lactones (protolichesterinic acid), tannins, iridoids (fulvoplumierin) and triterpenes; 4) integration: coumarins (3-substituted-4-hydroxycoumarins), depsidones, O-caffeoyl derivatives, lignans (arctigenin and analogues) and phenolics (curcumin); 5) translation: single chain ribosome inactivating proteins (SCRIP's); 6) proteolytic cleavage (protease inhibition): saponins (ursolic and maslinic acids), xanthones (mangostin and analogues) and coumarins; 7) glycosylation: alkaloids including indolizidines (castanospermine and analogues), piperidines (1-deoxynojirimicin and analogues) and pyrrolizidines (australine and analogues); 8) assembly/release: naphthodianthrones (hypericin and pseudohypericin), photosensitisers (terthiophenes and furoisocoumarins) and phospholipids. The target of action of several anti-HIV substances including alkaloids (O-demethyl-buchenavianine, papaverine), polysaccharides (acemannan), lignans (intheriotherins, schisantherin), phenolics (gossypol, lignins, catechol dimers such as peltatols, naphthoquinones such as conocurvone) and saponins (celasdin B, Gleditsia and Gymnocladus saponins), has not been elucidated or does not fit in the proposed scheme. Only a very few of these plant-derived anti-HIV products have been used in a limited number of patients suffering from AIDS viz. glycyrrhizin, papaverine, trichosanthin, castanospermine, N-butyl-1-deoxynojirimicin and acemannan.

Alkaloids↗
PubMed1995

Phenylethanoids in the herb of Plantago lanceolata and inhibitory effect on arachidonic acid-induced mouse ear edema.

The five phenylethanoids, acteoside (1), cistanoside F (2), lavandulifolioside (3), plantamajoside (4) and isoacteoside (5) were isolated from the herb of Plantago lanceolata L. (Plantaginaceae). Compounds 1, the major phenylethanoid in the herb of P. lanceolata L., and 4, the major phenylethanoid in the herb of P. asiatica L., showed inhibitory effects on arachidonic acid-induced mouse ear edema.

Animals↗
PubMed1994

Quercetin-induced benzophenanthridine alkaloid production in suspension cell cultures of Sanguinaria canadensis.

Addition of micromolar concentrations of quercetin or rutin to suspension cell cultures of Sanguinaria canadensis L. (bloodroot) induced the biosynthesis of sanguinarine and chelerythrine in a dose-dependent manner. In contrast, related compounds: baicalein, naringin, naringenin, catechin, caffeic acid and benzoic acid displayed very weak inductive activity. Of the two active flavonoids, quercetin was the most effective for inducing benzophenanthridine alkaloid biosynthesis, with doses of 100 microM increasing alkaloid production over 375% as compared to negative controls. Quercetin's inductive effects were similar to that of an elicitor derived from fungus Penicillium expansum (PE-elicitor). Suppression of quercetin and PE-induced alkaloid biosynthesis by low doses of actinomycin D (5 micrograms/ml, alpha-amanitin (20 micrograms/ml), or cycloheximide (1 microgram/ml) demonstrate a requirement for both RNA and de novo cytoplasmic protein synthesis and suggest that alterations in gene expression are involved in the inductive mechanism. Furthermore, quercetin-induced alkaloid biosynthesis was significantly reduced by pretreatment of the cells with the calcium chelator, EGTA (3 mM), or the calcium channel inhibitor, verapamil (100 microM), suggesting that this process was calcium dependent.

Alkaloids↗
PubMed1993

Bioactive compounds from the buds of Platanus orientalis and isolation of a new kaempferol glycoside.

A new compound kaempferol 3-O-alpha-L-(2"-E-p-coumaroyl)-rhamnopyranoside, as well as the known flavonoids, kaempferol 3-O-beta-D-(6"-E-p-coumaroyl)-glucopyranoside, kaempferol 3-O-alpha-L-(2",3"-di-E-p-coumaroyl)-rhamnopyranoside, and caffeic acid were obtained from the methanolic extract of Platanus orientalis L. buds. All the compounds were isolated by column chromatography and identified using 1H-NMR, 2D-1H-NMR (COSY), 1H-13C-NMR, and CIDMS techniques. Cytotoxic and antimicrobial studies were carried out in vitro against human cell lines and against Gram-positive and Gram-negative organisms.

Anti-Infective Agents↗
PubMed2002

Phorbol 12-myristate 13-acetate up-regulates the transcription of MUC2 intestinal mucin via Ras, ERK, and NF-kappa B.

MUC2 is a secretory mucin normally expressed by goblet cells of the intestinal epithelium. It is overexpressed in mucinous type colorectal cancers but down-regulated in colorectal adenocarcinoma. Phorbol 12-myristate 13-acetate (PMA) treatment of colon cancer cell lines increases MUC2 expression, so we have undertaken a detailed analysis of the effects of PMA on the promoter activity of the 5'-flanking region of the MUC2 gene using stably and transiently transfected promoter reporter vectors. Protein kinase C inhibitors (bisindolylmaleimide, calphostin C) and inhibitors of mitogen-activated protein/extracellular signal regulated kinase kinase (MEK) (PD98059 and U0126) suppressed up-regulation of MUC2. Src tyrosine kinase inhibitor PP2, a protein kinase A inhibitor (KT5720), and a p38 inhibitor (SB 203580) did not affect transcription. Western blotting and reverse transcription-PCR analysis confirmed these results. In addition, co-transfections with mutants of Ras, Raf, and MEK showed that the induction of MUC2 promoter activity by PMA required these three signaling proteins. Our results demonstrate that PMA activates protein kinase C, stimulating MAP kinase through a Ras- and Raf-dependent mechanism. An important role for nuclear factor kappaB (NF-kappaB) was also demonstrated using the inhibitor caffeic acid phenethyl ester and electrophoretic mobility shift assays. Such identification of pathways involved in MUC2 up-regulation by PMA in the HM3 colon cancer cell line may serve as a model for the effects of cytokines and growth factors, which regulate MUC2 expression during the progression of colorectal cancer.

Binding Sites↗
PubMed2003

Phorbol ester-dependent activation of peroxiredoxin I gene expression via a protein kinase C, Ras, p38 mitogen-activated protein kinase signaling pathway.

The antioxidant protein peroxiredoxin (Prx) I is a thioredoxin peroxidase that is involved in the regulation of proliferation and differentiation of mammalian cells. Here, it is shown that Prx I gene expression was induced transcriptionally by the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) in cultured rat liver tissue macrophages and RAW264.7 monocytic cells. TPA-dependent induction of Prx I gene expression was mediated by two proximal activator protein-1 sites of the rat Prx I promoter region that were nuclear targets of c-Jun as determined by transfection studies with luciferase reporter gene constructs and electrophoretic mobility shift assays. The transcription factor Nrf2, however, was not involved in the regulation of Prx I promoter activity. Prx I gene induction by TPA was decreased by protein kinase C inhibitors and overexpressed dominant negative forms of Ras and MEKK1, but not Raf-1. The p38 MAPK inhibitor SB202190 and overexpression of dominant negative mutants of MAPK kinase 4 (MKK4), MKK6, and p38 inhibited the TPA-dependent induction of Prx I gene transcription. In contrast, inhibitors of the JNK, SP600125, and the NF-kappaB signaling pathway, caffeic acid phenethyl ester, respectively, as well as overexpressed dominant negative MKK7 and IkappaB, had no effect on the up-regulation of Prx I reporter gene activity by TPA. Cotransfection of wild-type p38alpha and p38beta, but not that of p38gamma and p38delta, increased Prx I promoter activity. The data indicate that a protein kinase C, Ras, MEKK1, p38 MAPK signaling pathway plays a major role for the transcriptional up-regulation of Prx I gene expression.

Animals↗
PubMed2002

Inhibitory effects of Choto-san (Diao-teng-san), and hooks and stems of Uncaria sinensis on free radical-induced lysis of rat red blood cells.

The present study is designed to test our hypothesis that the ingestion of Uncaria sinensis (US), the main medicinal plant of Choto-san (Diao-teng-san, CS), would protect red blood cell (RBC) membrane from free radical-induced oxidation if polyphenolics in US could be absorbed and circulated in blood. When incubated with RBC suspension, Choto-san extract (CSE) and Uncaria sinensis extract (USE) exhibited strong protection for RBC membrane against hemolysis induced by 2,2-azo-bis (2-amidinopropane) dihydrochloride (AAPH), an azo free-radical initiator. The inhibitory effect was dose-dependent at concentrations of 50 to 1000 microg/mL. Ingestion of 200 mg of USE was associated with a significant decrease in susceptibility of RBC to hemolysis in rats. Furthermore, caffeic acid, an antioxidative hydroxycinnamic acid, was identified in rat plasma after administration of URE.

Amidines↗
PubMed1997

Whole-grain consumption and chronic disease: protective mechanisms.

Dietary guidance recommends consumption of whole grains to reduce the risk of chronic diseases including cancer and cardiovascular disease. Epidemiologic studies support the belief that whole grains are protective against cancers, especially gastrointestinal cancers such as gastric and colonic, and cardiovascular disease. Components in whole grains that may be protective are diverse and include compounds that affect the gut environment, i.e., dietary fiber, resistant starch, and other undigestible compounds in whole grains, compounds that function as antioxidants such as trace minerals and phenolic compounds, and compounds that are phytoestrogens with potential hormonal effects. Many of the protective compounds in whole grains are also in fruits and vegetables, but some plant compounds are more concentrated in whole grains, such as phenolic compounds including ferulic and caffeic acid. Other potential mechanistic effects of whole grains include binding of carcinogens and modulation of glycemic index. Clearly, the range of protective substances in whole grains is impressive, and advice to consume additional whole grains is justifiable.

Acute Disease↗
PubMed2004

Detoxification of olive mill wastewater using superabsorbent polymers.

The detoxification of agro-industrial effluents using superabsorbent polymers is a new and innovative process. Olive mill wastewater constitutes a major environmental problem in Mediterranean countries due to the large volumes generated, the seasonality of the industry, and the high content of polyphenols and organic matter. The application of superabsorbent polymers allows olive mill wastewater to be used as a fertilizer, as it is immobilized, increasing the biological activity that decreases its phytotoxicity, thus making its water, organic matter and mineral content usable for plant nutrition. Various parameters that characterise olive mill wastewater were evaluated after absorption in 2 different superabsorbent polymers (SAP1 and SAP2). The organic matter was equally distributed in both phases, while there was a concentration of protein and sodium in solution. The K:Na ratio decreased from 70:1 to 2:1. The polyphenol desorption from the gel into solution was found to follow Fick's law. The mass transfer coefficients were 0.147 min(-1) and 0.0085 min(-1) for SAP1 and SAP2, respectively. Phytotoxicity tests were carried out with SAP2. Olive mill wastewater in SAP2 with polyphenol concentrations up to 200 mg l(-1) revealed no phytotoxicity, and even stimulated Lepidium sativum growth, while olive mill wastewater without superabsorbent polymer revealed growth inhibition for all concentrations tested. Caffeic acid degradation by the immobilised biomass followed zero order kinetics. Degradation constants of 0.087 mg l(-1) min(-1) gSAP2(-1) and 1.156 mg l(-1) min(-1) gSAP2(-1) were found. Fungi that developed in the plant growth medium were identified as Aspergillus sp. and Penicillium sp.

Adsorption↗
PubMed2005

Antioxidant and free radical scavenging activities of some leafy vegetables.

Some leafy vegetables were studied for their nutritional composition, antioxidant and free radical scavenging activities. The aerial parts of Coriandrum sativum, Spinacia oleracea, Trigonella corniculata and Trigonella foenum-graecum showed lower inhibitory concentration values (4.1-7.9 mg/ml), efficiency concentration values (178-321 mg/mg DPPH) and higher values of anti-radical power (0.31-0.51) as compared with their seeds. Thermal treatment reduced the total phenolic contents, antioxidant and free radical scavenging activities. The leaves of C. sativum were found with good amounts of caffeic acid, ferulic acid, gallic acid and chlorogenic acid.

Antioxidants↗
PubMed2001

Iridoid and phenylethanoid glycosides from Phlomis longifolia var. longifolia.

From the aerial parts of Phlomis longifolia var. longifolia four iridoid glucosides, shanzhiside methyl ester (1), 5-deoxypulchelloside I (2), lamalbide (3), phlomiol (4) and three phenylethanoid glycosides, verbascoside (5), forsythoside B (6), leucosceptoside A (7) along with the caffeic acid ester, chlorogenic acid (8) were isolated. The structures of the isolated compounds were established by spectroscopic (UV, IR, 1D- and 2D-NMR, FABMS) and chemical evidence. The structure elucidation of the iridoid compounds 2 and 3 are discussed in detail.

Chromatography, Liquid↗
PubMed2003

Comparison of antioxidant activity between aromatic indolinonic nitroxides and natural and synthetic antioxidants.

In view of the possible employment of nitroxide compounds in various fields, it is important to know how they compare with other synthetic antioxidant compounds currently used in several industries and with naturally occurring antioxidants. To address this issue, the antioxidant activity of two aromatic indolinonic nitroxides synthesized by us was compared with both commercial phenolic antioxidants (BHT and BHA) and with natural phenolic antioxidants (alpha-hydroxytyrosol, tyrosol, caffeic acid, alpha-tocopherol). DPPH radical scavenging ability and the inhibition of both lipid and protein oxidation induced by the peroxyl-radical generator, AAPH, were evaluated. The results obtained show that overall: (i) the reduced forms of the nitroxide compounds are better scavengers of DPPH radical than butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BLT) but less efficient than the natural compounds; (ii) the nitroxides inhibit both linolenic acid micelles and bovine serum albumin (BSA) oxidation to similar extents as most of the other compounds in a concentration-dependent fashion. Since the aromatic nitroxides tested in this study are less toxic than BHT, these compounds may be regarded as potential, alternative sources for several applications. The mechanisms underlying the antioxidant activity of nitroxides were further confirmed by UV-Vis absorption spectroscopy experiments and macroscale reactions in the presence of radicals generated by thermolabile azo-compounds. Distribution coefficients in octanol/buffer of the nitroxides and the other compounds were also determined as a measure of lipophilicity.

Animals↗
PubMedDate not supplied

Mast cell degranulation alters lymphatic contractile activity through action of histamine.

OBJECTIVE: Mast cells reside in most tissues and in close association with blood vessels and nerves, areas where lymphatic vessels are also present. Mast cells and lymphatic vessels are two important players in the development of the inflammatory process. This study was designed to examine the effects of mast cell degranulation on the contractile activity of mesenteric lymphatic vessels. METHODS: Lymphatic vessel contractile activity was assessed in vitro by video microscopy of the mesentery of cow's milk-sensitized guinea pigs upon application of beta-lactoglobulin and compared to the response measured in sham animals. RESULTS: Application of 5-10 microM beta-lactoglobulin increased lymphatic vessel constriction frequency and decreased constriction amplitude (n = 12). This effect was not seen in sham-treated animals (n = 16) and was not due to an increased number of mast cells in the mesentery of the milk-sensitized animals, as revealed by histological examination. Two known mast cell-derived mediators, histamine and thromboxane A2, via stable mimetic U46619 also altered lymphatic pumping in a similar manner, but only pretreatment with the histamine H1 receptor antagonist pyrilamine (1 microM) could reduce the beta-lactoglobulin-induced response. The thromboxane A2 receptor antagonist, SQ 29548, and the 5-lipoxygenase inhibitor, caffeic acid, were without significant effect. CONCLUSION: In the in vitro mesenteric preparation, mast cell degranulation altered lymphatic contractile activity via the release of a mediator suggested to be histamine and the subsequent activation of H1 receptors. This action could potentially interfere with the expected ability of lymphatic vessels to reduce edema during inflammation.

Animals↗
PubMed2007

Characterization of ionically bound peroxidases from apple (Mallus pumilus) fruits.

Ionically bound peroxidases (POD) were salt extracted from the pulp of four Indian apple varieties, i.e., Golden delicious HP, Golden delicious JK, Red delicious, and Royal delicious. They were precipitated with chilled ethanol. Thermal treatments of partially purified enzymes were given from 40-70 degrees C for 30 minutes. Golden delicious HP peroxidase showed thermostability at 60 degrees C, while three other peroxidases were observed at 50 degrees C. Phenolic compounds (i.e., caffeic acid, ferulic acids, p-coumaric acid, protocatechuic acid) and metal ions (i.e., Cu2+ and Fe2+) activated all apple peroxidases. However, Mn2+ inhibited the peroxidases from Golden delicious HP, Golden delicious JK, and Red delicious, and a substantial increase was observed in Royal delicious peroxidase. Mg2+ inhibited the peroxidases from Golden delicious HP and Red delicious, but marginal activation was reported in peroxidases from Golden delicious JK and Royal delicious. Zn2+ established stimulation in Golden delicious HP and Golden delicious JK peroxidases, but inhibition was observed in peroxidases in Red delicious and Royal delicious.. Methionine, proline, tryptophan, and valine stimulated all four apple peroxidases, but cysteine showed inhibition in Golden delicious JK.

Amino Acids↗
PubMed2005

The inhibition effect of some n-alkyl dithiocarbamates on mushroom tyrosinase.

Three new n-alkyl dithiocarbamate compounds, as sodium salts, C4H9NHCS2Na (I), C6H13NHCS2Na (II) and C8H17NHCS2Na (III), were synthesized and examined for inhibition of both cresolase and catecholase activities of mushroom tyrosinase (MT) from a commercial source of Agaricus bisporus in 10 mM phosphate buffer pH 6.8, at 293K using UV spectrophotometry. Caffeic acid and p-coumaric acid were used as natural substrates for the enzyme for the catecholase and cresolase reactions, respectively. Lineweaver-Burk plots showed different patterns of mixed and competitive inhibition for catecholase and cresolase reactions, respectively. These new synthetic compounds can be classified as potent inhibitors of MT due to Ki values of 0.8, 1.0 and 1.8 microM for cresolase inhibitory activity, and also 9.4, 14.5 and 28.1 microM for catecholase inhibitory activity for I, II and III, respectively. They showed a greater potency in the inhibitory effect towards the cresolase activity of MT. Both substrate and inhibitor can be bound to the enzyme with negative cooperativity between the binding sites (alpha > 1) and this negative cooperativity increases with increasing length of the aliphatic tail in these compounds. The inhibition mechanism is presumably related to the chelating of the binuclear coppers at the active site and the different Ki values may be related to different interaction of the aliphatic chains of I, II and III with the hydrophobic pocket in the active site of the enzyme.

Agaricales↗
PubMed2002

Signals involved in mycobacteria-induced CXCL-8 production by human monocytes.

CXC chemokine-interleukin-8 (IL-8) (CXCL-8) is a potent proinflammatory chemotactic factor that induces important immune responses for antimycobacterial defenses. However, little is known about the biochemical mechanisms by which the mycobacterial antigens upregulate the release of CXCL-8 from human monocytes. In this study, the mechanisms through which Mycobacterium bovis BCG induces CXCL-8 secretion in human monocytes were investigated. We found that M. bovis BCG induced the production of high levels of CXCL-8 by human monocytes. M. bovis-induced CXCL-8 secretion was unaffected by the protein kinase C (PKC) inhibitor bisindolylmaleimide. In contrast, preincubation of the monocytes with the protein tyrosine kinase (PTK) inhibitor genistein resulted in dose-dependent suppression of mycobacteria-induced CXCL-8 secretion. These results were further supported by the fact that treatment of monocytes with herbimycin-A, another well-described inhibitor of PTK activity with a different mechanism of action, significantly diminished the effect of M. bovis on CXCL-8 secretion. In addition, the specificity of this inhibition was demonstrated by the inability of herbimycin-A to block in a significant manner IL-1 beta induction of CXCL-8. Herbimycin-A significantly blocked tyrosine phosphorylation of p59(hck) in response to M. bovis. Finally, two specific NF-kappa B inhibitors, sulfasalazine and caffeic acid phenetyl ester (CAPE), strongly inhibited the production of CXCL-8 by human monocytes infected with M. bovis. These results show intracellular signaling pathways and a transcription factor involved in the M. bovis-mediated upregulation of CXCL-8 biosynthesis and release by human monocytes.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMedDate not supplied

Chemosensitization and radiosensitization of tumors by plant polyphenols.

The treatment of cancer with chemotherapeutic agents and radiation has two major problems: time-dependent development of tumor resistance to therapy (chemoresistance and radioresistance) and nonspecific toxicity toward normal cells. Many plant-derived polyphenols have been studied intently for their potential chemopreventive properties and are pharmacologically safe. These compounds include genistein, curcumin, resveratrol, silymarin, caffeic acid phenethyl ester, flavopiridol, emodin, green tea polyphenols, piperine, oleandrin, ursolic acid, and betulinic acid. Recent research has suggested that these plant polyphenols might be used to sensitize tumor cells to chemotherapeutic agents and radiation therapy by inhibiting pathways that lead to treatment resistance. These agents have also been found to be protective from therapy-associated toxicities. How these polyphenols protect normal cells and sensitize tumor cells to treatment is discussed in this review.

Animals↗