Showing papers in "Farmaco in 2001"

Anti-inflammatory properties of plant flavonoids. Effects of rutin, quercetin and hesperidin on adjuvant arthritis in rat.

Abstract: The anti-inflammatory activities of three flavonoids were investigated in rats using the Mizushima et al. model of acute and chronic inflammation. Intraperitoneal administration of rutin, quercetin (flavonols) and hesperidin (flavanone), given at daily doses equivalent to 80 mg/kg, inhibited both acute and chronic phases of this experimental model of inflammation. Rutin was the most active in the chronic phase.

Antioxidant activity of different fractions of Spirulina platensis protean extract.

Abstract: Spirulina platensis, planktonic blue-green algae, is gaining increasing attention because of its nutritional and medicinal properties. This microalgae contains phycobiliproteins (phycocyanin and allophycocyanin). Previous reports from our laboratory have shown that a protean extract of S. platensis is a potent free-radical scavenger (hydroxyl and peroxyl radicals) and inhibits microsomal lipid peroxidation. The aim of this study was to purify and characterize phycocyanin of S. platensis. Besides, we tried to demonstrate that one of the main components responsible for this antioxidant activity is a biliprotein phycocyanin. For this purpose, we studied the antioxidant activity of different fractions obtained during the phycocyanin purification process, through the scavenger activity of hydroxyl radical. We also observed that an increase in phycocyanin content was related to an increase in the antioxidant activity in different fractions, and therefore phycobiliprotein phycocyanin is the component mainly responsible for the antioxidant activity.

Local anaesthetic activity of β-caryophyllene ☆

Abstract: In this work we studied the local anaesthetic activity of β-caryophyllene, one of the main components of clove oil obtained from the dried flower-buds of Syzygium aromaticum (Myrtaceae family). We compared its activity to a chemically related compound, caryophyllene oxide. Anaesthetic activity was evaluated in vivo in the rabbit conjunctival reflex test and in vitro in a rat phrenic nerve-hemidiaphragm preparation. β-Caryophyllene (10 −4 –1 μg/ml), but not caryophyllene oxide, was able to reduce drastically, in a dose-dependent manner, the electrically evoked contractions of the rat phrenic hemidiaphragm. In the rabbit, conjunctival reflex test treatment with a solution of β-caryophyllene (10–1000 μg/ml) allowed a dose-dependent increase in the number of stimuli necessary to provoke the reflex. As in the in vitro results, caryophyllene oxide was ineffective also in the in vivo test. In conclusion, these data evidence the local anaesthetic activity of β-caryophyllene, which appears to be strictly dependent on its chemical structure.

Synthesis and analgesic activity of some 1-benzyl-2-substituted-4,5-diphenyl-1H-imidazole derivatives.

Abstract: In this study, derivatives of 1-benzyl-2-substituted-4,5-diphenyl-1H-imidazole were synthesized and their analgesic activity assayed in two tests. 1,2,4,5-Tetrasubstituted imidazole compounds were obtained by the treatment of purified imidazole compounds with benzyl chloride in the presence of sodium hydride. The structure elucidation of the compounds was performed by IR, 1H-NMR and mass spectroscopic data and elemental analysis results. Generally the prepared compound exhibited only moderate analgesic activity in mice at the dose of 100 mg/kg i.p.; however, a few of them exhibited good activity, almost equivalent to that of morphine at 1 mg/kg i.p. was observed. At the above dosage, no toxicity was observed for all compounds.

Influence of the replacement of the oxo function with the thioxo group on the antimycobacterial activity of 3-aryl-6,8-dichloro-2H-1,3-benzoxazine-2,4(3H)-diones and 3-arylquinazoline-2,4(1H,3H)-diones

Abstract: Series of 3-phenyl-6,8-dichloro-2H-1,3-benzoxazine-2,4(3H)-dithiones, 3-arylquinazoline-2,4(1H,3H)-diones and 3-arylquinazoline-2,4(1H,3H)-dithiones were synthesized, and the antimycobacterial activities of the derivatives evaluated in vitro. The compounds were active against Mycobacterium tuberculosis and conditionally pathogenic mycobacteria (Mycobacterium kansasii and Mycobacterium avium). The replacement of oxygen by sulfur in 3-phenyl-6,8-dichloro-2H-1,3-benzoxazine-2,4(3H)-diones and 3-arylquinazoline-2,4(1H,3H)-diones gave rise to an increase of antimycobacterial activity. The most active compound was 3-(3-chlorophenyl)-6,8-dichloro-2H-1,3-benzoxazine-2,4(3H)-dithione.

The distribution of minerals and flavonoids in the tea plant (Camellia sinensis).

Abstract: Camellia sinensis is a plant growing in India, Sri Lanka, Java, Japan and its properties were known 4000 years ago. Since then, traditional Chinese medicine has recommended this plant for headaches, body aches and pains, digestion, depression, detoxification, as an energiser and, in general, to prolong life. Tea contains volatile oils, vitamins, minerals, purines, polyphenols, particularly carechins. We have analysed ten commercial teas from various countries to determine their mineral composition and we have analysed a green tea, an Oolong tea and a White tea to determine their polyphenols and flavonoids content. Our study shows that the variation of mineral composition, polyphenols and flavonoids are linked to different origins of the plant. For the determination of phenols compounds and flavonoids we used an HPLC apparatus and for mineral analysis an atomic absorption apparatus.

Synthesis and antimicrobial activities of novel naphtho[2,1-b]pyran, pyrano[2,3-d]pyrimidine and pyrano[3,2-e][1,2,4]triazolo[2,3-c]-pyrimidine derivatives.

Abstract: The synthesis of new naphtho[1′,2′:5,6]pyrano[2,3-d]pyrimidines and related heterocycles has been reported. The key intermediate 3-amino-8-bromo-1-(p-methoxyphenyl)-1H-naphtho[2,1-b] pyran-2-carbonitrile (3c) was obtained in one pot synthesis by treating α-cyanocinnamonitrile (1c) with 6-bromo-2-naphthol (2). Antimicrobial activity was shown for some of the synthesized compounds.

Studies on nitrophenylfuran derivatives part Xii. synthesis, characterization, antibacterial and antiviral activities of some nitrophenylfurfurylidene-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazines.

Abstract: Synthesis of four 1-aryl-3-[5-(p-nitrophenyl)-2-furyl]-2-propen-1-ones starting from substituted acetophenones and p-nitrophenylfurfuraldehyde is described. These propenones were then converted into corresponding dibromo derivatives which on dehydrobromination afforded α-bromopropenones rather than acetylenic ketones. Condensation of these dibromopropanones with 4-amino-5-mercapto-1,2,4-triazoles yielded a new class of nitrophenylfurfurylidene-1,2,4-triazolothiadiazines. The structures of nitrophenylfurfurylidene-1,2,4-triazolothiadiazines were established on the basis of analytical, IR, NMR and mass spectral studies. The formation of 1,2,4-triazolo[3,4-b]-1,3,4-thiadiazines rather than 1,2,4-triazolo[3,4-b]-1,3,4-thiadiazepines in the above condensation was unambiguously confirmed by X-ray crystallographic analysis of one of them. A possible mechanism is proposed to account for the formation of nitrophenylfurfurylidene-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazines. Some of the newly synthesized triazolothiadiazines were screened for their antibacterial and antiviral properties.

New metal complexes of 4-methyl-7-hydroxycoumarin sodium salt and their pharmacological activity

Abstract: Complexes of copper (II), zinc (II), nickel (II), cobalt (II) and iron (III) with 4-methyl-7-hydroxycoumarin sodium salt (Mendiaxon, Hymecromone) were synthesized by mixing of equimolar amounts of the respective metal nitrates and 4-methyl-7-hydroxycoumarin sodium salt in water. The complexes were characterized and identified by elemental analysis, conductivities, IR, 1 H NMR spectroscopy and mass spectral data. DTA and TGA have been applied to study the compositions of the compounds. Thermal analysis of the complexes indicate the formation of compounds which correspond to the compositions Met(HL) 2 · n H 2 O, where Met=Cu, Zn, Ni, Co; n =2, 3 or 4 and Fe(HL) 3 ·5H 2 O. The newly synthesized compounds were assayed for acute intraperitoneal and per oral toxicity, influence on blood clotting time and the most active complex was investigated for spasmolytic activity.

Synthesis and antimicrobial activity of some 1,2,4-triazole-3-mercaptoacetic acid derivatives.

Abstract: Ethyl 5-(2-furyl)-4-ethyl-1,2,4-triazole-3-mercaptoacetate (2), 5-(2-furyl)-4-ethyl-1,2,4-triazole-3-mercaptoacetic acid hydrazide (3) and a series of new N-alkylidene/arylidene-5-(2-furyl)-4-ethyl-1,2,4-triazole-3-mercaptoacetic acid hydrazides (4a-f) were synthesized and evaluated for in vitro antibacterial activity against Staphylococcus aureus ATCC 6538. Staphylococcus epidermidis ATCC 12228, Klebsiella pneumoniae ATCC 4352, Pseudomonas aeruginosa ATCC 1539, Escherichia coli ATCC 8739, Shigella flexneri, Salmonella typhi, Proteus mirabilis and antifungal activity against Candida albicans ATCC 10231 using the disk diffusion and microdilution methods. Compound 4f showed antibacterial activity against some bacteria. The in vitro antimycobacterial activity of the new compounds against Mycobacterium tuberculosis H37Rv was evaluated employing the BACTEC 460 radiometric system. The highest inhibition observed was 61% at > 6.25 microg/ml.

Synthesis and antimycobacterial activity of [5-(pyridin-2-yl)-1,3,4-thiadiazol-2-ylthio]acetic acid arylidene-hydrazide derivatives.

Abstract: [5-(Pyridin-2-yl)-1,3,4-thiadiazol-2-ylthio]acetic acid arylidene-hydrazide derivatives were synthesized and tested for their in vitro antimycobacterial activity. Some compounds showed a feable activity against a strain of Mycobacterium tuberculosis and a strain of Mycobacterium avium.

Efficacy of Hypericum and Calendula oils in the epithelial reconstruction of surgical wounds in childbirth with caesarean section

Abstract: Following studies on the properties of spontaneous plants in Sardinia we have evaluated the tissue regenerating action of a mixture of oily extracts of Hypericum perforatum and Calendula arvensis on surgical wounds from childbirth with caesarean section.

Microbial fermentation-derived inhibitors of efflux-pump-mediated drug resistance.

Abstract: A library of 85000 microbial fermentation extracts was screened for inhibitors of multidrug resistance efflux pumps in Pseudomonas aeruginosa and Candida albicans. New compounds EA-371alpha and EA-371delta were isolated and demonstrated to be potent and specific inhibitors of the MexAB-OprM pump in P. aeruginosa. Two series of fungal metabolites, enniatins and beauvericins, were found to be ubiquitous and potent inhibitors of ABC transporters. Milbemycins were rediscovered as potent inhibitors of the CDRI pump in C. albicans, and demonstrated to potentiate effectively the antifungal activity of fluconazole and SCH-56592 against a wide variety of Candida clinical isolates.

Synthesis and structure elucidation of some new thioether derivatives of 1,2,4-triazoline-3-thiones and their antimicrobial activities

Abstract: 5-(4-Pyridinyl)-4-substituted-2,4-dihydro-3H-1,2,4-triazole-3-thiones and 5-(4-pyridinyl)-4-substituted-3-(benzoylmethyl)thio-4H-1,2,4-triazoles were synthesized. The structures of original nine compounds were confirmed by IR, 1H NMR, mass spectral methods and elemental analysis. The antibacterial, antifungal and antimycobacterial activities, together with those of known intermediate 1,4-disubstituted thiosemicarbazides, were reported.

Synthesis, in vitro antiproliferative activity and DNA-interaction of benzimidazoquinazoline derivatives as potential anti-tumor agents.

Abstract: The synthesis of benzimidazoquinazoline derivatives bearing different alkylamino side chains is reported. All new compounds tested by means of an in vitro assay exhibit antiproliferative activity toward human tumor cell lines. The cytotoxic effect depends on the type of side chain inserted in the planar nucleus and in some cases it is comparable to that of the well-known drug ellipticine. In order to understand the mechanism of action of these compounds, the interaction with DNA has been investigated. Linear flow dichroism measurements allowed us to verify the formation of a molecular complex with DNA and the corresponding geometry of interaction. Intrinsic binding constants have also been evaluated by performing fluorimetric titrations.

Antimicrobial activity of Epilobium spp. extracts.

Abstract: The antimicrobial activity of the Epilobium angustifolium, E. hirsutum, E. palustre, E. tetragonum and E. rosmarinifolium ethanolic extracts was studied in vitro on Gram-positive and Gram-negative bacteria, yeasts and fungi. The cytotoxicity of the extracts was also evaluated using the Artemia salina test. All the extracts showed antimicrobial activity in a range of concentrations between 10 and 650 microgml of dry extract. E. angustifolium and E. rosmarinifolium had the most broad spectrum of action inhibiting bacteria, yeasts and fungi. The extracts were devoid of toxicity on Artemia salina within the range of antimicrobial concentrations, suggesting that the action is selective on microorganisms.

Novel functionalized pyrido[2,3-g]quinoxalinones as antibacterial, antifungal and anticancer agents

Abstract: A series of twelve novel pyrido[2,3-g]quinoxalinones (3-14), variously substituted at the C-3 position, was synthesized, structurally determined and submitted to a preliminary in vitro evaluation for antibacterial, anticandida and anticancer activities. Results of the antimicrobial screening showed that all compounds, with the exception of 6, 11 and 12, exhibited interesting activity against all strains tested; while compound 10 was found to have encouraging in vitro anticancer activity at a concentration of l0(-4) M.

Muscarinic agonists and antagonists in the treatment of Alzheimer's disease.

Abstract: Alzheimer's disease (AD) is a neurodegenerative disease characterized by cognitive impairment and personality changes. The development of drugs for the treatment of the cognitive deficits of AD has focused on agents which counteract loss in cholinergic activity. Although symptoms of AD have been successfully treated with acetylcholinesterase inhibitors (tacrine, donepezil, rivastigmine, galanthamine), limited success has been achieved with direct M1 agonists, probably due to their lack of selectivity versus other muscarinic receptor subtypes. Muscarinic M2 antagonists have been reported to increase synaptic levels of acetylcholine after oral administration to rats (e.g. BIBN-99, SCH-57790), but their selectivity versus other muscarinic receptor subtypes is modest. Exploration of a series of piperidinylpiperidines has yielded the potent and selective M2 antagonist SCH-217443. This antagonist has excellent bioavailability in rats and dogs and shows activity in a rat model of cognition.

Anti-inflammatory effect of Pimenta racemosa var. ozua and isolation of the triterpene lupeol.

Abstract: Pimenta racemosa var. ozua (Myrtaceae) is a tropical plant, used in different inflammatory processes by the folk medicine of the Caribbean region. From the methanol extract of the leaves a terpenic compound identified as lupeol has been isolated for the first time in this species. The anti-inflammatory activity of the extract has been evaluated against two experimental models of acute inflammation: paw edema in rats, using carrageenan or dextran as phlogogen agents, and ear edema in mice, inducing the inflammation with 12-o-tetradecanoylphorbol acetate (TPA). Myeloperoxidase activity (MPO) was also assayed as an indicator of leukocytary migration in the inflamed ears. In the carrageenan test, the methanol extract (125 and 250 mg kg(-1) p.o.) had a dose-dependent and significant effect at different time intervals. On the contrary, when the dextran was injected in paw, the extract did not reduce the inflammation provoked. This behavior was similar to indomethacine (25 mg kg(-1)) used as a standard drug. In the TPA-induced ear edema, the methanol extract (0.5, 1 and 3 mg ear(-1)) significantly reduced the inflammation. In the MPO assay a significant inhibition of the enzyme was observed in the inflamed tissue in all the samples assayed. These results show that the methanol extract from the leaves of Pimenta racemosa var. ozua, is effective against acute inflammation processes, by oral route and when topically applied. The anti-inflammatory behavior of the extract was similar to that exhibited by the selective cyclo-oxygenase inhibitor, indomethacin. On the other hand, the reduction of MPO activity shows that the action mechanism is clearly related with the neutrophil migration.

Analgesic properties of Epilobium angustifolium, evaluated by the hot plate test and the writhing test

Abstract: The analgesic properties of Epilobium angustifolium (Ea), a plant containing flavonoids with anti-inflammatory activity, have not been sufficiently studied so far. Thus, we decided to evaluate, by the classical hot plate test and the writhing test, the analgesic effect of a dry extract of Ea obtained by evaporating a commercially available mother tincture. In the former assay, the effect of Ea (380 mg/kg) was slightly lower than that of morphine (10 mg/kg s.c.). In the writhing test, which is more sensitive for non-steroidal analgesics, the effect of Ea was already significant (P or = 190 mg/kg, its activity was similar to that of lysine acetylsalicylate (300 mg/kg). The LD50 of this dry extract of Ea was 1.4+/-0.1 g/kg. Further studies are necessary for the identification of the active principles and the elucidation of their mechanism of action.

Synthesis and antimycobacterial activity of 5-aryl-1-isonicotinoyl-3-(pyridin-2-yl)-4,5-dihydro-1H-pyrazole derivatives ☆

Abstract: 5-Aryl-1-isonicotinoyl-3-(pyridin-2-yl)-4,5-dihydro-1H-pyrazole derivatives were synthesized and tested for their in vitro antimycobacterial activity. The compounds showed an interesting activity against a strain of Mycobacterium tuberculosis and a human strain of M. tuberculosis H4.

Piperidine renin inhibitors: from leads to drug candidates.

Abstract: Non-peptidomimetic renin inhibitors of the piperidine type represent a novel structural class of compounds potentially free of the drawbacks seen with peptidomimetic compounds so far. Synthetic optimization in two structural series focusing on improvement of potency, as well as on physicochemical properties and metabolic stability, has led to the identification of two candidate compounds 14 and 23. Both display potent and long-lasting blood pressure lowering effects in conscious sodium-depleted marmoset monkeys and double transgenic rats harboring both the human angiotensinogen and the human renin genes. In addition, 14 normalizes albuminuria and kidney tissue damage in these rats when given over a period of 4 weeks. These data suggest that treatment of chronic renal failure patients with a renin inhibitor might result in a significant improvement of the disease status.

Synthesis of some halogen-containing 1,2,4-triazolo-1,3,4-thiadiazines and their antibacterial and anticancer screening studies--part I.

Abstract: A series of 7-arylidene-6-(2,4-dichloro-5-fluorophenyl)-3-substituted-1,2,4-triazolo[3,4-b]-1,3,4-thiadiazines (3) were prepared by the condensation of 4-amino-5-mercapto-3-substituted-1,2,4-triazoles (1) and 3-aryl-1-(2,4-dichloro-5-fluorophenyl)-2-bromo-2-propen-1-one (2). An alternative route for the synthesis of the title compound 3 has been described. The newly synthesised compounds were characterised on the basis of N-analyses, IR, 1H NMR and mass spectral data. Some of the newly synthesised compounds were tested for their antibacterial activities against Gram +ve and Gram −ve bacteria. Among the tested compounds 3n showed the highest degree of antibacterial activity against S. aureus and evaluation of the LD50 value of this compound was carried out. Some of the newly synthesised compounds were also screened for their anticancer activities. Among these, compounds 3b, 3g, 3n and 3p are found to be active against NCI-H460 (lung), MCF7 (breast), SF 268 (CNS) in the preliminary anticancer screening studies. Further, 60-cell-line anticancer studies of these compounds were carried out. The results of such studies are discussed in this paper.

Stability studies of new cosmetic formulations with vegetable extracts as functional agents

Abstract: A formulation study, using increasing amounts of Sepigel 305 as an emulsifier, has been carried out to find new O/W emulsions and value their stability also in presence of vegetable extracts. Stability results have been compared with those obtained from formulations described in the National Formulary of Italian Pharmacopoeia X and functionalised by us with the same vegetable extracts. By using centrifugation and accelerated ageing tests capable of bringing out the gelling and thermostability properties of Sepigel 305, the study emphasised that the new gel emulsions have a greater stability compared to the other formulations.

The 4-anilinoquinazoline class of inhibitors of the erbB family of receptor tyrosine kinases.

Abstract: The erbB family of receptor tyrosine kinase enzymes, and particularly EGFR and HER2/neu, have become important targets for potential anticancer drugs. The substrate protein binding site theoretically is the more attractive intracellular target on these enzymes, possessing lower homology than the ATP site between different receptor kinases. However, a major breakthrough in this field was the discovery that 4-anilinoquinazolines are potent and selective inhibitors, despite binding at the ATP site. The very tight structure-activity relationships shown by these compounds suggested a clearly-defined binding mode, where the quinazoline ring binds in the adenine pocket and the anilino ring binds in an adjacent, unique lipophilic pocket. A unique cysteine (Cys-773) adjacent to the quinazoline binding site has prompted the development of irreversible inhibitors that target this residue. Three 4-anilinoquinazoline analogues (two reversible and one irreversible inhibitor) have been evaluated clinically as anticancer drugs. Data from the most advanced, the reversible inhibitor Iressa, suggest that this class of compounds may be of value in cancer chemotherapy.

Effects of Calotropis procera on oestrous cycle and on oestrogenic functionality in rats.

Abstract: Effects of ethanolic and aqueous extracts of Calotropis procera (Ait.) R.Br. roots, have been studied on oestrous cycle and on some parameters of oestrogenic functionality in rats. Both extracts have been shown to interrupt the normal oestrous cycle in 60 and 80%, respectively, of rats treated. The rats exhibited prolonged dioestrous stage of the oestrous cycle with consequent temporary inhibition of ovulation. The contemporary administration of commercial oestro-progestinic preparation exhibited the same effects in 100% of rats treated. However, the extracts have not demonstrated to possess oestrogenic activity when tested in immature female bilaterally ovariectomized rats.

Antiulcerogenic activity of Lippia alba (Mill.) N. E. Brown (Verbenaceae).

Abstract: Lippia alba (Mill.) N. E. Brown Verbenaceae, known popularly as 'Juanilama' or 'Salvia Sija', is prized widely in folk medicine in Guatemala. Its leaves are employed as an infusion and decoction as a remedy for stomach problems, dysentery, colds and cough, febrifuge, as well as a sedative and in spasmolitic remedies. The present study reports the effects of the infusion of L. alba on the rat gastric mucosa. The following behavioural parameters were evaluated: (a) gastric irritancy test in Wistar rats; (b) antiulcer activity, short term and long term; (c) acid secretion; (d) measurement of total proteins; (e) estimation of total protein bound and nonprotein sulfhydryl groups. Ranitidine (100 mg/kg, p.o.) was used as the reference antiulcer drug. Oral treatment with the infusion (12.5 g dry plant/kg) did not cause gastric irritancy in the rats treated during five consecutive days. In addition, the oral administration of L. alba was found to be effective at preventing gastric ulceration induced by indomethacin (50 mg/kg, p.o.) in rats in the short term (1 day) and long term (5 days).

Spectrophotometric method for the determination of amlodipine besylate with ninhydrin in drug formulations.

Abstract: A spectrophotometric method has been developed for the determination of amlodipine besylate in pure form and in pharmaceutical preparations. The method is based on the reaction of the primary amino group of the drug with ninhydrin in N,N'-dimethylformamide (DMF) medium producing a coloured complex which absorbs maximally at 595 nm. Beer's law is obeyed in the concentration range of 10-60 microg ml(-1) with RSD of 0.66% and molar absorptivity of 6.52 x 10(3) l mol(-1) cm(-1). All variables were studied in order to optimize the reaction conditions. The proposed method has been applied successfully to the analysis of the bulk drug and its dosage forms. No interference was observed from common pharmaceutical adjuvants. Statistical comparison of the results with the reference method shows excellent agreement and indicates no significant difference in accuracy and precision.

Anti-proliferative effect on a prostatic epithelial cell line (PZ-HPV-7) by Epilobium angustifolium L.

Abstract: Symptomatic benign prostatic hyperplasia (BPH) is a common condition in elderly men and has a significant impact on their daily lives. The drugs prescribed for treatment include alpha1-blockers, 5-alpha-reductase inhibitors and plant preparations. Epilobium angustifolium L. is deemed to be helpful in BPH therapy, although there is less information regarding the mechanism of its biological activity. The present study evaluated the effect of E. angustifolium extract on human prostatic epithelial cells (PZ-HPV-7). The exposure to E. angustifolium extract induced a marked inhibition of cell growth in all tested conditions. The anti-proliferative effect observed in in vitro systems clearly indicates a biologically relevant effect of compounds present in the extract. Considering these results, the use in traditional medicine of E. angustifolium extract against BPH seems to be justified. However, further experimental studies are needed to determine the biochemical mechanism of the action and the clinical value of the E. angustifolium extract.

Antituberculosis agents II. Evaluation of in vitro antituberculosis activity and cytotoxicity of some 2-(1-methyl-5-nitro-2-imidazolyl)-1,3,4-thiadiazole derivatives.

Abstract: Using the radiometric BACTEC 460-TB methodology, the minimum inhibitory concentration (MIC) of a series of 2-(1-methyl-5-nitro-2-imidazolyl-1,3,4-thiadiazole-5-alkylsulfides, alkylsulfoxides and alkylsulfones which had been reported previously as antifungal agents, were determined. Active compounds were also screened by serial dilution to assess toxicity to a VERO cell line. The results indicate that compounds bearing a primary alkylthio substitution displayed good antituberculosis activity (MIC = 3.13-6.25 microg/ml). Oxidation to sulfone abolished the antituberculosis activity in methyl and propyl derivatives while the ethylsulfonyl analogue was active (MIC = 1.56 microg/ml). The cytotoxic effects indicate that 2-(1-methyl-5-nitro-2-imidazolyl)-5-methylthio-1,3,4-thiadiazole was the least toxic compound (IC50 > 10 microg/ml). Generally, all compounds showed a low selectivity index.