A Guidance Manual for the Toxicity Assessment of Traditional Herbal Medicines.

Herbal remedies have been used for thousands of years in worldwide traditional medicines for their potential health benefits. Although they are generally presumed safe unless a significant risk has been identified in humans, increasing number of case reports notify acute or chronic intoxications resulting from their use. This study aims to produce a scientific guide for the evaluation of traditional herbal medicines (THMs) in terms of their toxicity risks based on the published regulatory documents. For this purpose recommended in vitro and in vivo toxicity tests on medicinal products for human use issued by the international regulatory bodies are overviewed and they are then adopted to be used for the toxicity assessment of THMs. Accordingly, based on compilation of these issued regulations, the following tests are recommended for the toxicity assessment of THMs; in vitrocytotoxicity, genotoxicity, acute and repeated dose toxicity, carcinogenicity, reproductive and developmental toxicity, local tolerance tests, toxicokinetic studies, and additional toxicity tests including safety pharmacology, immunotoxicity and antigenicity, endocrine system toxicity, gastro-intestinal toxicity, renal and hepatotoxicity, and drug interaction studies. This study describes and discusses the applicability of these tests for the risk assessment in THMs.

Synthesis and characterization of celecoxib derivatives as possible anti-inflammatory, analgesic, antioxidant, anticancer and anti-HCV agents.

A series of novel N-(3-substituted aryl/alkyl-4-oxo-1,3-thiazolidin-2-ylidene)-4-[5-(4-methylphenyl)-3-(trifluoromethyl)-1H-pyrazol-1-yl]benzenesulfonamides 2a-e were synthesized by the addition of ethyl a-bromoacetate and anhydrous sodium acetate in dry ethanol to N-(substituted aryl/alkylcarbamothioyl)-4-[5-(4-methylphenyl)-3-(trifluoro-methyl)-1H-pyrazol-1-yl]benzene sulfonamides 1a-e, which were synthesized by the reaction of alkyl/aryl isothiocyanates with celecoxib. The structures of the isolated products were determined by spectral methods and their anti-inflammatory, analgesic, antioxidant, anticancer and anti-HCV NS5B RNA-dependent RNA polymerase (RdRp) activities evaluated. The compounds were also tested for gastric toxicity and selected compound 1a was screened for its anticancer activity against 60 human tumor cell lines. These investigations revealed that compound 1a exhibited anti-inflammatory and analgesic activities and further did not cause tissue damage in liver, kidney, colon and brain compared to untreated controls or celecoxib. Compounds 1c and 1d displayed modest inhibition of HCV NS5B RdRp activity. In conclusion, N-(ethylcarbamothioyl)-4-[5-(4-methylphenyl)-3-(trifluoromethyl)-1H-pyrazol-1-yl]benzenesulfonamide (1a) may have the potential to be developed into a therapeutic agent.

Novel 3,6-disubstituted 7H-1,2,4-triazolo[3,4-b][1,3,4]thiadiazines: synthesis, characterization, and evaluation of analgesic/anti-inflammatory, antioxidant activities.

In this study, the synthesis of a new series of 3,6-disubstituted-7H-1,2,4-triazolo[3,4-b][1,3,4]thiadiazine 1a-4c compounds derived from 4-amino-3-substituted-1,2,4-triazole-5-thiones 1-4 is described. All of the synthesized compounds were screened for their possible analgesic / anti-inflammatory, antioxidant activities and gastric toxicity. The compound 2c was found to have both significant analgesic and consistent anti-inflammatory activity without inducing any gastric lesions along with minimal lipid peroxidation. A deep insight into the structures of the active compounds revealed that the compounds carrying an electron withdrawing group (a chloride or fluoride) on the phenyl ring at 6-position of the condensed heterocyclic derivatives exhibited noticeable higher activity.

Synthesis and characterization of some new 2(3H)-benzoxazolones with analgesic and antiinflammatory activities.

The synthesis, characterization and pharmacological activities of a new series of (6-difluorobenzoyl)-5-methyl-3-benzoylmethyl-2(3H)-benzoxazolone and 5-methyl-3-(2-hydroxyl-2-phenylethyl)-2(3H)-benzoxazolone are described. Antiinflammatory activity was investigated by the carrageenin-induced paw oedema test and analgesic activity by acetic acid writhing and hot plate tests in mice. Among the synthesized compounds, compound 3e 6-(2,5-difluorobenzoyl)-3-(4-bromobenzoylmethyl-2(3H)-benzoxazolone was found to be the most promising compound for analgesic activity. Reduced compounds (4a-4d) displayed considerable anti-inflammatory activity compared to the other derivatives.

Evaluation of hepatoprotective effect of Gentiana olivieri herbs on subacute administration and isolation of active principle.

Hepatoprotective effect of Gentiana olivieri Griseb. (Gentianaceae) flowering herbs on subacute administration were studied using in vivo models in rats. For the activity assessment on carbon tetrachloride-induced hepatic damage following biochemical parameters were evaluated; plasma and hepatic tissue malondialdehyde formation, and liver tissue glutathione level, as well as plasma transaminase enzyme levels (aspartate transferase and alanine transferase). Results of biochemical tests were also confirmed by histopathological examination. Through bioassay-guided fractionation procedures isoorientin, a known C-glycosylflavone, was isolated from the ethyl acetate fraction as the active antihepatotoxic constituent by silica gel column chromatography. Isoorientin exhibited significant hepatoprotective effect at 15 mg/kg b.w. dose.

Synthesis of some 1,2,4-triazolo[3,2-b]-1,3-thiazine-7-ones with potential analgesic and antiinflammatory activities.

Starting from 3-substituted-1,2,4-triazole-5-thiones (la-h), eight new 5-carbomethoxy-2-substituted-7H-1,2,4-triazolo[3,2-b]-1,3-thiazine-7-ones (2a-h) were synthesized and characterized by spectral and elementary analysis. The obtained compounds were submitted to preliminary pharmacological assay to evaluate their antiinflammatory and analgesic activities as well as gastrointestinal irritation liability and acute toxicity. Among the compounds studied, compounds 2c, 2d, 2e and 2h showed most remarkable antiinflammatory activity in the carrageenan and serotonin induced edema and in the inhibition of castor oil-induced diarrhea tests. The analgesic activity of these active compounds correlated with their antiinflammatory activities in the inhibition of acetic acid-induced writhing test. In gastric ulceration studies, the compounds were found safety at low dose levels (10 and 20 mg/kg).