Toxicity and local anesthetic activity of diterpenoid alkaloids

The toxicity and local anesthetic activity of 74 diterpenoid alkaloids differing in the nature and position of functional groups in lycoctonine, heteratisine, napelline, hetisane, atisane, and denudatine skeletons and their synthetic derivatives were investigated. Compounds with local anesthetic activity and duration of action surpassing that of cocaine for surface anesthesia and that of novocaine and lidocaine for infiltration and trunk administration were identified. Structural factors affecting the toxicity and local anesthetic activity of the studied compounds were discussed. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 477–484, September–October, 2007.     

Computer-aided prediction and cytotoxicity evaluation of dithiocarbamates of 9,10-anthracenedione as new anticancer agents

Anticancer activity as an associated action for a series of dithiocarbamates of 9,10-anthracenedione was predicted using the PASS computer program and analysed with PharmaExpert software. The predicted cytotoxic activity of the dithiocarbamate derivatives of 9,10-anthracenedione was evaluated in vitro on cancer cells of the human lung (A549), prostate (PC3), colon (HT29) and human breast (MCF7) using the sulforhodamine B (SRB) cell viability assay. Among these compounds, 9,10-dioxo-9,10-dihydroanthracen-1-yl pyrrolidin-1-carbodithioate and 9,10-dioxo-9,10-dihydroanthracen-2-yl pyrrolidin-1-carbodithioate were identified as the most potent anticancer agents with cytotoxic activity against the MCF-7 human breast cell line with GI₅₀ values of 1.40 μM and 1.52 μM, whereas the GI₅₀ value for the reference anticancer drug mitoxantrone was 3.93 μM. Thus, anticancer activity predicted by PASS with a probability Pa > 30% was confirmed by the experiment. Relatively small Pa values estimated by PASS indicated the novelty of the considered derivatives comparing to the compounds from the PASS training set.     

Fabrication of Alginate-Based O/W Nanoemulsions for Transdermal Drug Delivery of Lidocaine: Influence of the Oil Phase and Surfactant

Transdermal drug delivery of lidocaine is a good choice for local anesthetic delivery. Microemulsions have shown great effectiveness for the transdermal transport of lidocaine. Oil-in-water nanoemulsions are particularly suitable for encapsulation of lipophilic molecules because of their ability to form stable and transparent delivery systems with good skin permeation. However, fabrication of nanoemulsions containing lidocaine to provide an extended local anesthetic effect is challenging. Hence, the aim of this study was to address this issue by employing alginate-based o/w nanocarriers using nanoemulsion template that is prepared by combined approaches of ultrasound and phase inversion temperature (PIT). In this study, the influence of system composition such as oil type, oil and surfactant concentration on the particle size, in vitro release and skin permeation of lidocaine nanoemulsions was investigated. Structural characterization of lidocaine nanoemulsions as a function of water dilution was done using DSC. Nanoemulsions with small droplet diameters (d < 150 nm) were obtained as demonstrated by dynamic light scattering (DLS) and cryo-TEM. These nanoemulsions were also able to release 90% of their content within 24-h through PDMS and pig skin and able to the drug release over a 48-h. This extended-release profile is highly favorable in transdermal drug delivery and shows the great potential of this nanoemulsion as delivery system.     

Synthesis, spectroscopic, and X-ray structural characterization of pharmacologically active substituted pyrazolyl-acetanilides

Five new pyrazole acetanilides were synthesized by N-alkylation of pyrazole and its derivatives with 4′-propionyl-2-iodoacetanilide. Compounds 1–5 were characterized by ¹H NMR, ¹³C NMR, IR, UV–Vis, MS, and elemental analysis. X-ray structures of representative compounds 1, 3, and 5 established their conformations and solid-state hydrogen bonding preferences. Acute toxicity, local anesthetic, and antiarrhythmic activities were assessed for compounds 1–5 using established protocols. Lower potencies and lower acute toxicities were recorded relative to lidocaine. Enhanced anesthetic activity of compound 3 was attributed to the presence of the propionyl group in the molecule. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Novel uracil derivatives: newly synthesized centrally acting agents.

A series of 1-amino-5-substituted uracils and their 4-thio or 2,4-dithio substituted analogues were synthesized and assayed for anti-conflict activity in rats and anesthetic activity in mice. 1-Amino-5-halogenouracils 3b-e, 1-amino-4-thiouracil (9a), and 1-amino-5-halogeno-4-thiouracils 9c, d showed both anti-conflict and anesthetic activities. The most active compound was 1-amino-5-chloro-4-thiouracil (9d) which showed anxiolytic activity at 2 mg/kg of oral administration (p.o.) on a modified Geller-Seifter conflict schedule. Its minimum effective dose (MED) was lower than that of diazepam. The 50 percent effective dose (ED50) for anesthetic activity in mice of the compound (9d) was 32.9 mg/kg, p.o.     

Prediction of biological activity spectra via the Internet

The majority of biologically active compounds have both pharmacotherapeutic and side/toxic actions. To estimate general efficacy and safety of the molecules under study, their biological potential should be thoroughly evaluated. In an early stage of study, only information about structural formulae was available and was used as an input for computational prediction. Based on a structural formulae of compounds presented as SDF or MOL-files, computer program PASS predicts 900 pharmacological effects, mechanism of action, and specific toxicity. An average accuracy of prediction in leave-one-out cross-validation is about 85%. For evaluating new compounds, scientific community may use PASS via the Internet for free at URL: http://www.ibmh.msk.su/PASS. In the first 18 months of PASS Inet's use, approximately 1000 researchers from 60 countries have obtained predicted biological activity spectra for about 23,000 different chemical compounds. More than 64 million PASS predictions for almost 250,000 compounds from Open NCI database are available on the web site http://cactus.nci.nih.gov/ncidb2/. These predictions are used for selecting compounds with desirable and without unwanted types of biological activities among the NCI samples available for screening.     

Computer aided prediction of biological activity spectra: evaluating versus known and predicting of new activities for thiazole derivatives

Computer aided prediction of biological activity spectra by the computer program PASS was applied to a set of 89 new thiazole derivatives. Experimentally tested activities (NSAID, local anaesthetic and antioxidant) coincide with the experiment in 70.8% cases, that exceeds significantly the random guess-work (approximately 0.1%). Therefore, computer aided prediction using the Prediction of Activity Spectra for Substances (PASS) system (http://www.ibmh.msk.su/PASS) provides a reliable basis for planning of synthesis and experimental study for new compounds. New psychotropic activities are predicted for some compounds from the series under study. In particular, 7, 44 and 55 compounds likely have anxiolytic, anticonvulsant and cognition enhancer effects, respectively. Most of these compounds have the estimated values of probability to be active (Pa) less than 60%. Therefore, if their activity will be confirmed by the experiment, they might occur to be New Chemical Entities.     

Synthesis and Neurotropic Activity of New Heterocyclic Systems: Pyridofuro[3,2-d]pyrrolo[1,2-a]pyrimidines,Pyridofuro[3,2-d]pyrido[1,2-a]pyrimidines and Pyridofuro[3′,2′:4,5]pyrimido[1,2-a]azepines

Background: Neurotic disturbances, anxiety, neurosis-like disorders, and stress situations are widespread. Benzodiazepine tranquillizers have been found to be among the most effective antianxiety drugs. The pharmacological action of benzodiazepines is due to their interaction with the supra-molecular membrane GABA-a-benzodiazepine receptor complex, linked to the Cl-ionophore. Benzodiazepines enhance GABA-ergic transmission and this has led to a study of the role of GABA in anxiety. The search for anxiolytics and anticonvulsive agents has involved glutamate-ergic, 5HT-ergic substances and neuropeptides. However, each of these well-known anxiolytics, anticonvulsants and cognition enhancers (nootropics) has repeatedly been reported to have many adverse side effects, therefore there is an urgent need to search for new drugs able to restore damaged cognitive functions without causing significant adverse reactions. Objective: Considering the relevance of epilepsy diffusion in the world, we have addressed our attention to the discovery of new drugs in this field Thus our aim is the synthesis and study of new compounds with antiepileptic (anticonvulsant) and not only, activity. Methods: For the synthesis of compounds classical organic methods were used and developed. For the evaluation of biological activity some anticonvulsant and psychotropic methods were used. Results: As a result of multistep reactions 26 new, five-membered heterocyclic systems were obtained. PASS prediction of anticonvulsant activity was performed for the whole set of the designed molecules and probability to be active Pa values were ranging from 0.275 to 0.43. The studied compounds exhibit protection against pentylenetetrazole (PTZ) seizures, anti-thiosemicarbazides effect as well as some psychotropic effect. The biological assays evidenced that some of the studied compounds showed a high anticonvulsant activity by antagonism with pentylenetetrazole. The toxicity of compounds is low and they do not induce muscle relaxation in the studied doses. According to the study of psychotropic activity it was found that the selected compounds have an activating behavior and anxiolytic effects on the models of “open field” and “elevated plus maze” (EPM). The data obtained indicate the anxiolytic (anti-anxiety) activity of the derivatives of pyrimidines, especially pronounced in compounds 6n, 6b, and 7c. The studied compounds increase the latent time of first immobilization on the model of “forced swimming” (FST) and exhibit some antidepressant effect similarly to diazepam. Docking studies revealed that compound 6k bound tightly in the active site of GABA_A receptor with a value of the scoring function that estimates free energy of binding (ΔG) at −7.95 kcal/mol, while compound 6n showed the best docking score and seems to be dual inhibitor of SERT transporter as well as 5-HT_1A receptor. Conclusions: Тhe selected compounds have an anticonvulsant, activating behavior and anxiolytic effects, at the same time exhibit some antidepressant effect.     

Computer aided prediction of biological activity spectra: Evaluating versus known and predicting of new activities for thiazole derivatives

Computer aided prediction of biological activity spectra by the computer program PASS was applied to a set of 89 new thiazole derivatives. Experimentally tested activities (NSAID, local anaesthetic and antioxidant) coincide with the experiment in 70.8% cases, that exceeds significantly the random guess-work (～0.1%). Therefore, computer aided prediction using the Prediction of Activity Spectra for Substances (PASS) system (http://www.ibmh.msk.su/PASS) provides a reliable basis for planning of synthesis and experimental study for new compounds. New psychotropic activities are predicted for some compounds from the series under study. In particular, 7, 44 and 55 compounds likely have anxiolytic, anticonvulsant and cognition enhancer effects, respectively. Most of these compounds have the estimated values of probability to be active ( P a ) less than 60%. Therefore, if their activity will be confirmed by the experiment, they might occur to be New Chemical Entities.     

PASS: identification of probable targets and mechanisms of toxicity

Toxicity of chemical compound is a complex phenomenon that may be caused by its interaction with different targets in the organism. Two distinct types of toxicity can be broadly specified: the first one is caused by the strong compound's interaction with a single target (e.g. AChE inhibition); while the second one is caused by the moderate compound's interaction with many various targets. Computer program PASS predicts about 2500 kinds of biological activities based on the structural formula of chemical compounds. Prediction is based on the robust analysis of structure-activity relationships for about 60,000 biologically active compounds. Mean accuracy exceeds 90% in leave-one-out cross-validation. In addition to some kinds of adverse effects and specific toxicity (e.g. carcinogenicity, mutagenicity, etc.), PASS predicts approximately 2000 kinds of biological activities at the molecular level, that providing an estimated profile of compound's action in biological space. Such profiles can be used to recognize the most probable targets, interaction with which might be a reason of compound's toxicity. Applications of PASS predictions for analysis of probable targets and mechanisms of toxicity are discussed.     

Robustness of biological activity spectra predicting by computer program PASS for noncongeneric sets of chemical compounds

The computer system PASS provides simultaneous prediction of several hundreds of biological activity types for any drug-like compound. The prediction is based on the analysis of structure-activity relationships of the training set including more than 30000 known biologically active compounds. In this paper we investigate the influence on the accuracy of predicting the types of activity with PASS by (a) reduction of the number of structures in the training set and (b) reduction of the number of known activities in the training set. The compounds from the MDDR database are used to create heterogeneous training and evaluation sets. We demonstrate that predictions are robust despite the exclusion of up to 60% of information.     

Synthesis and physiological activity of novel tocopheryl glycosides

Vitamin E glycosides were synthesized and enzymatic hydrolysis was examined for use as potential pro-drugs, however, the glycoside bond was found to be stable. On the other hand, among the glycosides synthesized, dl-alpha-tocopherylglucoside (6b) and dl-alpha-tocopherylmannoside (6c) showed strong inhibitory action on histamine release from mast cells. In addition, 6c also showed a suppressive action on IgE antibody formation. Thus, tocopheryl glycoside showed new properties compared to tocopherol (vitamin E). In particular, 6c was shown to be a novel lead compound with excellent manifold anti-allergic activity and anti-inflammatory activity.     

PASS biological activity spectrum predictions in the enhanced open NCI database browser

The application of the program PASS (Prediction of Activity Spectra for Substances) to about 250 000 compounds of the NCI Open Database and the incorporation of over 64 million PASS predictions in the Enhanced NCI Database Browser are described. A total of 565 different types of activity are included, encompassing general pharmacological effects, specific mechanisms of action, known toxicities, and others. Application of this Web-based service to prediction of activities of the kinds "Angiogenesis inhibitor," "Antiviral (HIV)", and a set of activities that can be associated with antineoplastic action are reported. For this latter data set, a very substantial enrichment over random selection was found in the PASS predictions. It is shown how the user can conduct complex searches by combining ranges of PASS-predicted probabilities of compounds to be active or to be inactive, respectively, with, e.g., value ranges of physicochemical parameters, presence or absence of particular substructural fragment, and other search criteria.     

PASS: identification of probable targets and mechanisms of toxicity†

Toxicity of chemical compound is a complex phenomenon that may be caused by its interaction with different targets in the organism. Two distinct types of toxicity can be broadly specified: the first one is caused by the strong compound's interaction with a single target (e.g. AChE inhibition); while the second one is caused by the moderate compound's interaction with many various targets. Computer program PASS predicts about 2500 kinds of biological activities based on the structural formula of chemical compounds. Prediction is based on the robust analysis of structure-activity relationships for about 60,000 biologically active compounds. Mean accuracy exceeds 90% in leave-one-out cross-validation. In addition to some kinds of adverse effects and specific toxicity (e.g. carcinogenicity, mutagenicity, etc.), PASS predicts ～2000 kinds of biological activities at the molecular level, that providing an estimated profile of compound's action in biological space. Such profiles can be used to recognize the most probable targets, interaction with which might be a reason of compound's toxicity. Applications of PASS predictions for analysis of probable targets and mechanisms of toxicity are discussed.     

Synthesis and characterization of two homologous series of diastereomeric 2-alkoxyphenylcarbamates

Two homologous series of racemic diastereomeric cis- and trans-(2-dimethylaminomethylcycloheptyl)-2-alkoxyphenylcarbamates with alkyl chain lengths ranging from C? to C? were synthesized by stereoselective reactions. The chemical structures of these compounds were confirmed by 1H-NMR, 13C-NMR and IR spectroscopy and their physico-chemical properties were characterized. The two new series of diastereomeric compounds were tested for their local anesthetic activity and parabolic relationship between the local anesthetic activity and lipophilicity was found for both cis- and trans-series. Interestingly, cis-stereoisomers exhibited higher local anesthetic activity.     

Nonionic Cellulose Ethers as Potential Drug Delivery Systems for Periodontal Anesthesia

Nonionic cellulose ethers displaying a lower consolute temperature, or cloud-point, close to body temperature were investigated as potential carrier systems for the delivery of local anesthetic agents to the periodontal pocket. The interaction between the polymers, i.e., ethyl(hydroxyethyl)cellulose (EHEC) and hydrophobically modified EHEC (HM-EHEC), and ionic surfactants was determined in the absence and in the presence of the local anesthetic agents lidocaine and prilocaine. The cloud-point and rheology data indicate interactions between the polymer and both anionic and cationic surfactants. More precisely, a number of ionic surfactants were found to result in an increase in cloud-point at higher surfactant concentrations, a surfactant-concentration-dependent thickening, and a temperature-induced gelation upon heating. Upon addition of the local anesthetic agents lidocaine and prilocaine in their uncharged form to EHEC and HM-EHEC, in the absence of surfactants, only minor interaction with the polymer could be inferred. However, these substances were found to affect the polymer-surfactant interaction. In particular, the drug release rate in vitro as well as the stability and temperature-dependent viscosity were followed for an EHEC/SDS system and EHEC/myristoylcholine bromide system upon addition of lidocaine and prilocaine. The data indicate a possibility of formulating a local anesthetic drug delivery system suitable for administration into the periodontal pocket where at least small amounts of active ingredients can be incorporated into the system without severely affecting the gelation behavior. The results found for the cationic myristoylcholine bromide system are particularly interesting for the application in focus here since this surfactant is antibacterial and readily biodegradable. Copyright 2000 Academic Press.     

Synthesis and Anticancer Activity of 1,3,4-Thiadiazoles with 3-Methoxyphenyl Substituent

Based on the results of previous work, we designed and synthesized 1,3,4-thiadiazole derivatives. The cytotoxic activity of the obtained compounds was then determined in biological studies using MCF-7 and MDA-MB-231 breast cancer cells and a normal cell line (fibroblasts). The results showed that all compounds displayed weak anticancer activity towards two breast cancer lines: an estrogen-dependent cell line (MCF-7) and an estrogen-independent cell line (MDA-MB-231). The compound most active towards MCF-7 breast cancer cells was SCT-4, which decreased DNA biosynthesis to 70% ± 3 at 100 µM. The mechanism of the anticancer action of 1,3,4-thiadiazole was also investigated. We choose a set of the most investigated proteins, which are attractive anticancer targets. In silico studies demonstrated a possible multitarget mode of action for the synthesized compounds but the most likely mechanism of action for the new compounds is connected with the activity of caspase 8.     

Synthesis and biological evaluation of amide derivatives of (6-Chloro-2,3-dihydro-1H-inden-1-yl)acetic acid as potential anti-inflammatory agents with lower gastrointestinal toxicity

A variety of amide derivatives of (6-chloro-2,3-dihydro-1H-inden-1-yl)acetic acid were synthesized and screened for their anti-inflammatory and related biological activities. These compounds were found to be longer acting and showed residual activity exceeding that of standard indomethacin. The studies with SKF-525A, a standard hepatic microsomal enzyme inhibitor showed that probably the test compound per se is the active species. The compound 6y showed best activity profile with ED30 of 6.45 mg/kg however this compound was found to be toxic at 100 mg/kg p.o. Though these compounds exhibited appreciable analgesic and antipyretic activities but they failed to prevent the development of secondary inflammation in adjuvant induced arthritis assay. The compound 6x showed 94% inhibition of acetic acid induced writhing. Studies showed that antagonism of TNF-alpha is not possibly involved in the mechanism of action of these compounds. However these compounds were found to have only mild ulcerogenic potential at the tested dose level of 100 mg/kg p.o. in comparison to indomethacin.     

4-Hydroxy-2-quinolones 173*. 1-R-3-(2-diethylamino- ethyl)-1H-quinazoline- 2,4-dione hydrochlorides as potential local anesthetic agents

Different variants of the preparation and procedures in the synthesis of a series of 1-R-3-(2-dialkyl-aminoethyl)-1H-quinazoline-2,4-dione hydrochlorides having a structural similarity to the 4-hydroxy-2-quinolinone anesthetic chinoxicaine are discussed. A comparative analysis of the biological properties of the synthesized compounds and the known local anesthetics chinoxicaine and lidocaine is reported.     

Discovery of 5-Methylthiazole-Thiazolidinone Conjugates as Potential Anti-Inflammatory Agents: Molecular Target Identification and In Silico Studies

A series of previously synthesized 5-benzyliden-2-(5-methylthiazole-2-ylimino)thiazoli- din-4-one were evaluated for their anti-inflammatory activity on the basis of PASS predictive outcomes. The predictive compounds were found to demonstrate moderate to good anti-inflammatory activity, and some of them displayed better activity than indomethacin used as the reference drug. Structure–activity relationships revealed that the activity of compounds depends not only on the nature of the substituent but also on its position in the benzene ring. The most active compounds were selected to investigate their possible mechanism of action. COX and LOX activity were determined and found that the title compounds were active only to COX-1 enzymes with an inhibitory effect superior to the reference drug naproxen. As for LOX inhibitory activity, the derivatives failed to show remarkable LOX inhibition. Therefore, COX-1 has been identified as the main molecular target for the anti-inflammatory activity of our compounds. The docking study against COX-1 active site revealed that the residue Arg 120 was found to be responsible for activity. In summary, the 5-thiazol-based thiazolidinone derivatives have been identified as a novel class of selective COX-1 inhibitors.