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PubMed1994

Development of bioactive functions in hydrangeae dulcis folium. III. On the antiallergic and antimicrobial principles of hydrangeae dulcis folium. (1). Thunberginols A, B, and F.

From the less polar fraction of Hydrangeae Dulcis Folium, the fermented and dried leaves of Hydrangea macrophylla Seringe var. thunbergii Makino, Eight antiallergic and antimicrobial principles were isolated together with several known compounds. Among the newly isolated bioactive constituents, the chemical structures of thunberginols A, B, and F have been determined on the basis of chemical and physicochemical evidence. Thunberginols A, B, and F were found to exhibit more potent antiallergic activity than phyllodulcin, hydrangenol, disodium cromoglycate (DSCG), and tranilast. In addition, these thunberginols showed antimicrobial activity against oral bacteria.

Animals↗
PubMed1999

1,2,3,4-tetrahydroisoquinoline derivatives; lipophilicity evaluation vs. 5-HT1A receptor affinity.

Retention parameters (log k') of 1,2,3,4-tetrahydroisoquinoline derivatives--a new class of 5-HT1A receptor ligands--were determined on the basis of reversed-phase HPLC experiments. Good correlations were found between the log k' values and the calculated log Pc, van der Waals volume of the R substituent (VR) as well as the 5-HT1A receptor affinity (Ki) of the investigated compounds. It was demonstrated that hydrophobic forces played a pivotal role in stabilizing the ligand-receptor bioactive complex for that group of compounds.

Animals↗
PubMed2002

Comparative anxiolytic activity profile of various preparations of Passiflora incarnata linneaus: a comment on medicinal plants' standardization.

OBJECTIVES: Mother tincture preparation of Passiflora incarnata from five reputable manufacturers of homeopathic medicines were compared to the bioactive fraction of methanol extract of P. incarnata (standard) for their anxiolytic activity in mice using the elevated plus-maze model of anxiety. MATERIALS AND METHODS: The extracts of P. incarnata were further subdivided in four doses, i.e., 100, 200, 300, and 400 mg/kg, suspended in a vehicle, and administered orally to groups of mice. Methanol extract of P. incarnata (125 mg/kg, orally) was taken as a standard. Anxiolytic activity was measured using the elevated plus-maze model. All treatments were given orally. Forty-five (45) minutes after the treatments, mice were placed on the center of the elevated plus-maze and the number of entries in open arms were measured for 5 minutes. SUBJECTS: Studies were performed with Swiss albino mice. RESULTS: The dried mother tincture preparations exhibited maximum anxiolytic activity at 300 mg/kg (SBL); 400 mg/kg (DWSI and DWSG); 200 mg/kg (DRCG), and nil (BHL) respectively, with reference to anxiolytic activity exhibited by the methanol extract of aerial parts of P. incarnata (125 mg/kg). CONCLUSIONS: To ensure uniformity and consistency of the biologic effects exhibited by plant-derived phytopharmaceuticals, uniform standards are required globally. The monographs on P. incarnata mention standardization of the plant using any known flavonoid as the chemical marker and the marker compound was not the one responsible for the plants multifarious biologic effects. The recent report of a trisubstituted benzoflavone compound (BZF) as the main bioactive phytoconstituent of P. incarnata made it feasible to resort to biologic standardization of this plant using BZF as the biomarker compound. The biologic standardization would ensure bioequivalence of the medicinal preparations of P. incarnata. These studies also recommend the incorporation of leaf constants, ash values, extractive values, thin layer chromatography profile (vital "fingerprints" specific for a plant), and the quantitative assay by determining the bioactive BZF moiety in pharmacopoeias in order to ensure uniform biologic results and standards of P. incarnata because the plant currently has tremendous usefulness. The herbal pharmacopoeias, which are still in their "infancy," can be strengthened by incorporating the appropriate bioactive constituents that need to be identified by using modern technological procedures. Once the appropriate bioactive constituent(s) are established and authenticated, their qualitative and quantitative assay procedures can be developed. Reporting the vital fingerprint parameters of the plant and incorporation of assay procedures of the bioactive phytomoiety in the official monographs of medicinal plants, will certainly strengthen the herbal pharmacopoeias. This is perhaps the most important scientific approach that would ensure uniform standards and bioequivalence of plant-medicines - a need to revive faith in the healing potentials of plant-derived medicines.

Administration, Oral↗
PubMed2006

Synthesis and herbicidal activity of novel 3-aminocarbonyl-2-oxazolidinethione derivatives containing a substituted pyridine ring.

A series of 3-aminocarbonyl-2-oxazolidinethione derivatives containing a substituted pyridine ring were designed and synthesized. The structures of all of the title compounds were characterized by 1H NMR, 13C NMR, IR, and HRMS. Their agricultural bioactivities were evaluated, and some of these compounds exhibited good herbicidal activities against Echinochloa crusgalli, Sorghum vulgare, Digitaria sanguinalis, Eclipta prostrasta, Cucumis sativus, and Brassica campestris, which were associated mainly with their steric properties and lipophilicities based on the structure-activity relationship discussion.

Herbicides↗
PubMed2004

Geranyl N-dimethylallylanthranilate, a new compound from Esenbeckia yaaxhokob.

Through a bioactivity-guided fractionation from the acetone extract of the leaves from Esenbeckia yaaxhokob geranyl N-dimethylallylanthranilate ( 1), the first natural N- and O-prenylated anthranilate, was isolated in addition of the known natural products caryophyllene beta-oxide, caryolane-5beta,9beta-diol, spathulenol ( 2), friedeline, friedelanol, decaprenol, flindersiamine ( 3) and beta-sitosterol. The antimicrobial activities of the extract, fractions and pure compounds were evaluated against two Gram (+) and four Gram (-) bacteria. Compounds 1 and 2 exhibited moderated antimicrobial activity against Staphyloccocus aureus, while 3 was active against S. aureus and Streptococcus faecalis.

Anti-Infective Agents↗
PubMed2005

Neuroprotective and antioxidant activity of compounds from the aerial parts of Dioscorea opposita.

Bioactivity-guided fractionation of an ethanol extract of the aerial parts of Dioscorea opposita afforded a new compound, 6,7-dihydroxy-2-methoxy-1,4-phenanthrenedione (1), and four known compounds, chrysoeriol 4'-O-beta-D-glucopyranoside (2), chrysoeriol 7-O-beta-D-glucopyranoside (3), alternanthin (4), and daucosterol. The structure of 1 was established on the basis of the interpretation of its 1D and 2D NMR spectrascopic data. Compounds 1-4 exhibited both promising neuroprotective effects and discernible to moderate antioxidant activities in vitro.

Antioxidants↗
PubMed2006

3D-QSAR analysis of antimalarial farnesyltransferase inhibitors based on a 2,5-diaminobenzophenone scaffold.

With annual death tolls in the millions and emerging resistance to existing drugs, novel therapies are needed against malaria. Wiesner et al. recently developed a novel class of antimalarials derived from farnesyltransferase inhibitors based on a 2,5-diaminobenzophenone scaffold. The compounds displayed a wide range of activity, including submicromolar, against the multi-drug resistant Plasmodium falciparum strain Dd2. In order to investigate quantitatively the local physicochemical properties involved in the interaction between drug and biotarget, we used the 3D-QSAR methods CoMFA and CoMSIA to study some of the series, including the screened lead compound 2,5-bis-acylaminobenzophenone, 28 cinnamic acid derivatives, 29 N-(3-benzoyl-4-tolylacetylaminophenyl)-3-(5-aryl-2-furyl)acrylic acid amides, and 34 N-(4-substituted-amino-3-benzoylphenyl)-[5-(4-nitrophenyl)-2-furyl]acrylic acid amides. We found that steric, electrostatic, and hydrophobic properties of substituent groups play key roles in the bioactivity of the series of compounds, while hydrogen bonding interactions show no obvious impact. We built several highly predictive 3D-QSAR models, including a CoMSIA one composed of steric, electrostatic, and hydrophobic fields, with r(2)=0.94, q(2)=0.63, and r(pred)(2)=0.63. The results provide insight for optimization of this class of antimalarials for better activity and may prove helpful for further lead optimization.

Animals↗
PubMed1994

Amperometric biosensor for phenols based on a tyrosinase-graphite-epoxy biocomposite.

A new biocomposite, based on the incorporation of the enzyme tyrosinase into a graphite-epoxy resin matrix, was used for the effective biosensing of phenolic compounds. The enzyme retains its bioactivity on confinement in the epoxy resin environment. This renewable (polishable) and rigid bioprobe offers convenient quantification for various phenolic substrates. The fast response (steady-state time = 25 s) accrues from the close proximity of the enzyme and graphite sites. The influence of various experimental variables was explored for optimum biosensing performance. Flow-injection monitoring of phenolic compounds at a rate of 50 samples h-1 yielded a detection limit of 1 x 10(-6) mol l-1 and a relative standard deviation of 1.4% (n = 40).

Biosensing Techniques↗
PubMedDate not supplied

Conformational analysis and pharmacophore design for selected 1-(2-pyrimidinyl)piperazine derivatives with sedative-hypnotic activity.

The conformational of selected 1-(2-pyrimidinyl)piperazine derivatives with high sedative-hypnotic activity was analysed and the model bioactive conformations were suggested. Subsequently, the pharmacophores of analysed compounds were designed. It was suggested that the pharmacophore of bioactive derivatives should be composed of 11 features that characterise the binding model of pyrimidinylpiperazine ligands to the binding site at the hypothetic receptor. This 11 feature pharmacophore was compared to three other pharmacophores designed for the selected anxiolytics (benzodiazepines and buspirone analogues) and the sedative-hypnotic agents (benzodiazepines and barbiturates). Several substantial differences between the pharmacophores were found: the number of pharmacophoric features and their distribution in 3-D space were unique for selected groups of compounds that exhibit sedative-hypnotic or anxiolytic activity.

Hypnotics and Sedatives↗
PubMed1992

Release of multiple endothelium-derived relaxing factors from porcine coronary arteries.

Using a chemiluminescence method in the present study, we measured nitric oxide and one-electron oxidation products of nitric oxide (NOX) released from porcine coronary artery segments in response to bradykinin, ADP, and the calcium ionophore A23187. Total NOX was compared with the bioactivity of endothelium-derived relaxing factors (EDRF) by a biodetector ring preparation before and after inhibition of L-arginine-dependent nitric oxide synthesis and in the presence of indomethacin. Under basal conditions, arterial segments released NOX and relaxed biodetector rings. Bradykinin, ADP, and A23187 elicited vasorelaxation greater than that observed basally; A23187, but not bradykinin or ADP, caused additional release of NOX greater than that measured basally. Hemoglobin completely reversed vasorelaxation elicited by all three agonists. We compared the amount of nitric oxide released under basal conditions and after stimulation with bradykinin, ADP, and A23187 with the amount of authentic nitric oxide necessary to elicit a bioequivalent response. Authentic nitric oxide did not account for the observed bioactivity as compared with the amount of nitric oxide actually measured in arterial segment effluent. To investigate whether a second non-nitric oxide-containing compound was responsible for the increased bioactivity and the discrepancy between the bioactivity and quantity of nitric oxide measured, we exposed arterial segments to omega-nitro-L-arginine methyl ester to inhibit L-arginine-dependent synthesis of nitroso compounds. The drug completely abolished the nitric oxide signal derived from both basally released and A23187-stimulated relaxing factor and completely reversed vasorelaxation. In contrast, omega-nitro-L-arginine methyl ester only partially reversed bradykinin-stimulated vasorelaxation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Diphosphate↗
PubMed2005

Human colon microbiota transform polycyclic aromatic hydrocarbons to estrogenic metabolites.

Ingestion is an important exposure route for polycyclic aromatic hydrocarbons (PAHs) to enter the human body. Although the formation of hazardous PAH metabolites by human biotransformation enzymes is well documented, nothing is known about the PAH transformation potency of human intestinal microbiota. Using a gastrointestinal simulator, we show that human intestinal microbiota can also bioactivate PAHs, more in particular to estrogenic metabolites. PAH compounds are not estrogenic, and indeed, stomach and small intestine digestions of 62.5 nmol naphthalene, phenanthrene, pyrene, and benzo(a)pyrene showed no estrogenic effects in the human estrogen receptor bioassay. In contrast, colon digests of these PAH compounds displayed estrogenicity, equivalent to 0.31, 2.14, 2.70, and 1.48 nmol 17alpha-ethynylestradiol (EE2), respectively. Inactivating the colon microbiota eliminated these estrogenic effects. Liquid chromatography-mass spectrometry analysis confirmed the microbial PAH transformation by the detection of PAH metabolites 1-hydroxypyrene and 7-hydroxybenzo(a)pyrene in colon digests of pyrene and benzo(a)pyrene. Furthermore, we show that colon digests of a PAH-contaminated soil (simulated ingestion dose of 5 g/day) displayed estrogenic activity equivalent to 0.58 nmol EE2, whereas stomach or small intestine digests did not. Although the matrix in which PAHs are ingested may result in lower exposure concentrations in the gut, our results imply that the PAH bioactivation potency of colon microbiota is not eliminated by the presence of soil. Moreover, because PAH toxicity is also linked to estrogenicity of the compounds, the PAH bioactivation potency of colon microbiota suggests that current risk assessment may underestimate the risk from ingested PAHs.

Administration, Oral↗
PubMed2001

New polycyclic pyrimidine derivatives with antiplatelet in vitro activity: synthesis and pharmacological screening.

The preparation and the pharmacological screening of novel anti-aggregatory/antiphlogistic polycyclic pyrimidine derivatives are described. The compounds were developed starting from bioactive 2-aminobenzopyranopyrimidine derivatives in order to assess the importance of the benzopyrano[4,3-d]pyrimidine structure and the role of an amino basic moiety in position 2. Antiplatelet activity was assessed in vitro against ADP and arachidonic acid-induced aggregation in guinea-pig plasma. Anti-inflammatory/analgesic/antipyretic activities were studied in rat paw oedema, mouse writhing test and E. coli-induced rat fever. Ulcerogenic and gastroprotective effects were also investigated in vivo on rat gastric mucosa. Among the tested compounds, the 5-substituted benzopyranopyrimidine derivatives 3d and 4d proved to be the most active antiplatelet agents as potent as acetylsalicylic acid against arachidonic acid-stimulated aggregation. Furthermore the 2-methylthio derivative 4d was endowed with greater efficacy against ADP aggregation suggesting that additional non-TXA2 dependent mechanisms are involved in its biological activity. Orally administered at 100 mg kg(-1) in rats this latter compound displayed antiphlogistic acitivity comparable to indomethacin (10 mg kg(-1)) coupled with an unusual gastroprotective effect on ethanol-induced ulcers. In conclusion, these findings indicate that the 5-pyrrolidino-2-methylthiobenzopyrano[4,3-d]pyrimidine 4d fulfils the chemical requirements to exhibit antiplatelet activity associated with gastroprotective effect.

Analgesics↗
PubMed2006

2-amino and 2'-aminocombretastatin derivatives as potent antimitotic agents.

A novel series of 2-amino and 2'-aminocombretastatin derivatives were synthesized and evaluated for antitumor activity. Several compounds had excellent antiproliferative activity as inhibitors of tubulin polymerization. Compounds 11, 20, and 21 with IC(50) values of 1.6, 1.7, and 1.8 microM, respectively, exhibited more potent inhibition of tubulin polymerization than colchicine and approximately as active as combretastatin A-4. They also displayed antiproliferative activity with an IC(50) values ranging from 11 to 44 nM in a variety of human cell lines from different organs. Structure activity relationship information suggests that the NH(2) substituent at the 2-position of either ring A or ring B in combretastatin molecular skeleton may play an important role in the bioactivity of this series of compounds.

Antineoplastic Agents↗
PubMed1992

Thom Award Lecture. Trends in the search for bioactive microbial metabolites.

Bioactive microbial metabolites are attracting increasing attention as useful agents for medicine, veterinary medicine, agriculture, and as unique biochemical tools. A review of the current trends in the discovery of new metabolites shows that the number of active compounds with non-antibiotic type of activity has increased, resulting in an expansion of the variety of bioactivity of microbial metabolites. Factors that contribute to the increased rate of discovery include: development of new methods for activity measurement, exploitation of novel groups of microorganisms as sources of active compounds, new directions for chemical modification, and incorporation of newer knowledge of biotechnology into screening systems. To exemplify this, typical screening methods, and chemical and biological properties of several bioactive compounds obtained by these methods are discussed.

Amino Acid Sequence↗
PubMed1999

Rational design, conformational studies and bioactivity of highly potent conformationally constrained calcitonin analogues.

Calcitonin is known for its hypocalcaemic effect and the inhibition of bone resorption, and is used therapeutically for the treatment of osteoporosis and Paget's disease. Our studies on the conformational features of human calcitonin (hCt) bioactivity have led to the conformationally constrained hCt analogue cyclo17,21-[Asp17, Lys21]hCt (1), which had a 5-10 times higher in vivo hypocalcaemic potency than hCt [Kapurniotu, A. & Taylor, J.W. (1995) J. Med. Chem. 38, 836-847]. We hypothesized that a stabilized, possibly type I beta turn/beta sheet conformation between residues 17 and 21 could play a crucial role in hCt bioactivity. Here, we designed, synthesized and studied the conformation and bioactivity of 19-member to 17-member ring-size analogues of 1 with the structure cyclo17,21-[Asp17,XX21]hCt with XX = Orn (2), Dab (3) and Dap (4), of the control peptide [Asp17,Orn21]hCt (5), and of the 19-member cyclo17,21-[Glu17,Dab21]hCt (6). Analyses of the far-UV CD spectra indicated increased type I beta turn and antiparallel beta sheet content in the bicyclic analogues compared with hCt. In the in vivo hypocalcaemic assay, cyclo17,21-[Asp17,Orn21]hCt (2) was found to have a 400-fold higher potency than hCt and was fourfold more potent than salmon calcitonin (sCt), which has been the most potent known Ct. Analogue 3 had a 30-fold higher potency than hCt, whereas the highly constrained analogue 4 was as potent as hCt. Bioactivity was not enhanced for the nonbridged compound [Asp17, Orn21]hCt (5), whereas cyclo17,21-[Glu17,Dab21]hCt (6) showed the same bioactivity as 1. This study identifies 2 as exhibiting the highest in vivo potency among currently known Cts, while it differs in only one amino acid residue from hCt, strongly suggesting that the introduced constraint may have served in 'freezing' hCt in a bioactive conformation. Our findings provide evidence for the first time that a beta turn/beta sheet conformation in region 17-21 of hCt and the topological features of the side chain of Asn17 are strongly associated with in vivo bioactivity, and offer a novel lead structure for a hCt-based drug for the treatment of osteoporosis and other bone-disorder-related diseases.

Animals↗
PubMed1998

[SAR and QSAR methods in the study of dioxin action].

Thousand chemicals are present within our environment, and for many of them, there is a little reliable information detailing their relative hazard. Added to that increasing concern over the use of animals in toxicity testing, high costs of these tests has made the search for and validation of alternative methods to predict the hazard and the relative risk of xenobiotics. QSAR (quantitative structure activity relationship) attempt to relate statistically the biological activity of compound with its physicochemical and structural properties. QSAR methods are often seen as the first step for valid toxicological prediction. Halogenated aromatic hydrocarbons typified by polychlorinated dibenzo-p-dioxins (PCDD), dibenzofurans (PCDF) and biphenyls (PCBs) have been identified as residues in almost every component of the ecosystem. Some chemicals in this class cause adverse biological effects after binding to an intracellular cytosolic protein called the Ah receptor (AhR). Because of importance of the Ah receptor in determining toxicity, there have been a number of attempts to model the relationship between receptor binding and structure of xenobiotics. QSAR have found wide use in correlating the bioactivity of dioxins and related compounds with many kinds of biological entities. This paper will briefly summarise some SAR and QSAR study for halogenated aromatics as ligand for Ah receptor and the characteristic biological and toxic responses elicit by this class of chemicals. These study strongly support the role of AhR in dioxin toxicity.

Animals↗
PubMed2000

Cytotoxic activities of mono and bis Mannich bases derived from acetophenone against Renca and Jurkat cells.

Mannich bases of acetophenones have been disclosed to have antitumour and cytotoxic activities. 1-Phenyl-3-dimethylaminopropan-1-one hydrochloride, 1, and related piperidino, 2, and morpholino, 3, derivatives, and compound 4, which is a quaternary form of 1, were synthesized as mono Mannich bases derived from acetophenone. They were converted to corresponding bis Mannich bases, 5-8, to see whether it increases the bioactivity. The biological activity of the compounds was examined by cytotoxicity against mouse renal carcinoma (Renca) and transformed human T-lymphocyte (Jurkat) cell lines. Conversion of mono Mannich bases to corresponding bis Mannich bases remarkably increased the cytotoxicity in most cases. Quaternization procedure also improved the bioactivity in mono derivatives against Jurkat cells. Bis mannich bases 5-7 were found to be more active than 5-fluorouracil (6-23 fold) and melphalan (1.25-5 fold) against Renca cells. Except 2 and 8, the compounds synthesised were found to be more active than 5-fluorouracil (1.2-33 fold) against Jurkat cells.

Acetophenones↗
PubMed1999

Acetogenins and other compounds from Rollinia emarginata and their antiprotozoal activities.

Bioactivity-directed fractionation of the MeOH extract of the stem barks of Rollinia emarginata resulted in the isolation of six compounds, four acetogenins, rolliniastatin-1, sylvaticin, squamocin, and rollidecin B, one lignan, lirioresinol B, and an oxoaporphine, liriodenin. Their structures were determined by spectroscopic analysis and their in vitro leishmanicidal and trypanocidal properties are reported.

Antiprotozoal Agents↗