Design, synthesis, molecular modeling and anti-hyperglycemic evaluation of novel quinoxaline derivatives as potential PPARγ and SUR agonists.

In our effort to develop potent anti-hyperglycemic agents with potential agonistic activities toward PPARγ and SUR, three novel series of quinoxaline derivatives bearing sulfonylurea or sulfonylthiourea moieties with different linkers were designed and synthesized. Some of the newly synthesized compounds were evaluated in vivo for their anti-hyperglycemic activities in STZ-induced hyperglycemic rats. Compounds 15a, 15e, 19b and 24a exhibited the highest anti-hyperglycemic activities with % reduction in blood glucose level of (50.58, 43.84, 45.10 and 49.62, respectively). Additionally, eight compounds revealed potent anti-hyperglycemic activities were further evaluated in vitro for their PPARγ binding affinity and insulin-secreting ability as potential mechanisms for anti-hyperglycemic activity. Four compounds (15a, 15b, 15d and 15e) significantly bound to PPARγ with IC50 values of 0.482, 0.491, 0.350 and 0.369µM, respectively. Moreover, Compounds 15a and 15b have demonstrated induction of insulin-secretion with EC50 values of 0.92 and 0.98µM, respectively. Furthermore, molecular docking and pharmacophore generation techniques were carried out to investigate binding patterns and fit values of the designed compounds with PPARγ and SUR, respectively.

Design, synthesis, molecular modeling and anti-proliferative evaluation of novel quinoxaline derivatives as potential DNA intercalators and topoisomerase II inhibitors.

New series of [1,2,4]triazolo [4,3-a]quinoxaline and bis([1,2,4]triazolo)[4,3-a:3',4'-c]quinoxaline derivatives have been designed, synthesized and biologically evaluated for their cytotoxic activities against three tumor cell lines (HePG-2, Hep-2 and Caco-2). Compounds 16e, 21, 25a and 25b exhibited the highest activities against the examined cell lines with IC50 values ranging from 0.29 to 0.90 µM comparable to that of doxorubicin (IC50 ranging from 0.51 to 0.73 µM). The most active members were further evaluated for their topoisomerase II (Topo II) inhibitory activities and DNA intercalating affinities as potential mechanisms for their anti-proliferative activities. Interestingly, the results of Topo II inhibition and DNA binding assays were consistent with that of the cytotoxicity data, where the most potent anti-proliferative derivatives exhibited good Topo II inhibitory activities and DNA binding affinities, comparable to that of doxorubicin. Moreover, the most active compound 25a caused cell cycle arrest at G2/M phase and induced apoptosis in Caco-2 cells. In addition, Furthermore, molecular docking studies were performed for the novel compounds against DNA-Topo II complex to investigate their binding patterns. Based on these studies, it was concluded that DNA binding and/or Topo II inhibition may contribute to the observed cytotoxicity of the synthesized compounds.

Immunologic studies of poisonous Anacardiaceae: oral desensitization to poison ivy and oak urushiols in guinea pigs.

Poison ivy and oak urushiols or their components were compared with the respective esterified derivatives for efficacy in oral desensitization of Hartley guinea pigs sensitized to urushiols. The esterified derivatives produced a significantly greater degree of hyposensitization than did free urushiol counterparts. Suppression produced by esterified urushiols was of longer duration than that produced by free urushiols. Groups of sensitized guinea pigs were given high (100 mg/kg) or low (10 mg/kg) doses of a mixture of acetylated, saturated urushiol congeners over a 1-, 2-, or 3-week period. High doses produced a greater degree of hyposensitization regardless of the dosage schedule used. Low doses did not produce significant hyposensitization unless given over a shorter (1 week) schedule. Large single booster doses (33 mg/kg/week) of the acetate derivatives produced a rebound in responsiveness when given, 2 weeks following the last dose of the initial series, to animals hyposensitized with 10 mg/kg. No such rebound in sensitivity occurred in animals given a series of high initial doses.

Immunologic studies of poisonous Anacardiaceae: I. Production of tolerance and desensitization to poison Ivy and oak urushiols using esterified urushiol derivatives in guinea pigs.

The development of contact sensitivity to poison ivy urushiol in Hartley guinea pigs was inhibited by i.v. injection of the diacetate esters of poison ivy and oak urushiols into guinea pigs 2 weeks prior to attempted sensitization with homologous antigen. Immune tolerance to urushiols of poison ivy and oak developed in 80% or more of the treated animals and persisted for the duration of the study, 8 weeks. The tolerance was immunologically specific for urushiols since the tolerant animals were sensitizable to the unrelated sensitizer 2, 4-dinitrochlorobenzene. Guinea pigs already sensitive to urushiol were also desensitized or hyposensitizied by i.v. injection of urushiol acetates in successively increasing doses. After receiving the equivalent of 16 mg of poison ivy and oak urushiols in the acetate form over a period of 12 weeks, 54% of a group of guinea pigs were desensitized to poison ivy. all of the remaining 46% of the guinea pigs still sensitive to poison ivy were substantially hyposensitized (no longer responded to 1.5 or 0.80 microgram test doses of PDC). A control group of guinea pigs was not hyposensitized by injection of vehicle, and remained highly sensitive throughout the 15 week study. The majority of treated animals (less than 80%) were also hyposensitized to poison sumac and cashew nut shell liquid allergens.

Analogues of poison ivy urushiol. Synthesis and biological activity of disubstituted n-alkylbenzenes.

The total synthesis of different isomers and analogues of poison ivy urushiol is described. These include the positional isomers 1-5 and the nitrogen-containing analogues 6 and 8 and their mesylamino derivatives 7 and 9. 3,4-Dimethoxybenzaldehyde, m-dimethoxybenzene, resorcinol, and p-dimethoxybenzene were used as starting materials for compounds 1, 2, 3, and 4, respectively. Compound 5 is prepared by catalytic hydrogenation of bilobol isolated from Ginkgo biloba. Compounds 6 and 7 were prepared from anacardic acid as the starting material while compounds 8 and 9 were prepared from phenol as the starting material. Compounds 1-9 were tested for their ability to cross-react with poison ivy urushiol in sensitized guinea pigs. Compounds 6 and 8 were reactive at the 10-microgram dose level when applied topically, while compound 1 was a skin irritant at that dose. On the other hand, compounds 2-5, 7, and 9 showed no cross-reactivity up to the 30-micrograms dose level. Structural requirements for cross allergenicity are discussed.

Comparison of the subjective effects of Delta(9)-tetrahydrocannabinol and marijuana in humans.

RATIONALE: There has been controversy about whether the subjective, behavioral or therapeutic effects of whole plant marijuana differ from the effects of its primary active ingredient, Delta(9)-tetrahydrocannabinol (THC). However, few studies have directly compared the effects of marijuana and THC using matched doses administered either by the smoked or the oral form. OBJECTIVE: Two studies were conducted to compare the subjective effects of pure THC to whole-plant marijuana containing an equivalent amount of THC in normal healthy volunteers. In one study the drugs were administered orally and in the other they were administered by smoking. METHODS: In each study, marijuana users (oral study: n=12, smoking study: n=13) participated in a double-blind, crossover design with five experimental conditions: a low and a high dose of THC-only, a low and a high dose of whole-plant marijuana, and placebo. In the oral study, the drugs were administered in brownies, in the smoking study the drugs were smoked. Dependent measures included the Addiction Research Center Inventory, the Profile of Mood States, visual analog items, vital signs, and plasma levels of THC and 11-nor-9-carboxy-THC. RESULTS: In both studies, the active drug conditions resulted in dose-dependent increases in plasma THC levels, and the levels of THC were similar in THC-only and marijuana conditions (except that at the higher oral dose THC-only produced slightly higher levels than marijuana). In both the oral study and the smoking study, THC-only and whole plant marijuana produced similar subjective effects, with only minor differences. CONCLUSION: These results support the idea that the psychoactive effects of marijuana in healthy volunteers are due primarily to THC.

Biological activity of cannabichromene, its homologs and isomers.

Cannabichromene (CBC) is one of four major cannabinoids in Cannabis sativa L. and is the second most abundant cannabinoid in drug-type cannabis. Cannabichromene and some of its homologs, analogs, and isomers were evaluated for antiinflammatory, antibacterial, and antifungal activity. Antiinflammatory activity was evaluated by the carrageenan-induced rat paw edema and the erythrocyte membrane stabilization method. In both tests, CBC was superior to phenylbutazone. Antibacterial activity of CBC and its isomers and homologs was evaluated using gram-positive, gram-negative, and acid-fast bacteria. Antifungal activity was evaluated using yeast-like and filamentous fungi and a dermatophyte. Antibacterial activity was strong, and the antifungal activity was mild to moderate.

Cannabinoids in glaucoma: a primary screening procedure.

A procedure was developed for screening of cannabinoids for their ability to reduce intraocular pressure (IOP) using normal rabbits. Eight animals per group were used for statistical significance of data. A negative control group was used for every screen as well as a positive control with 1.5 mg/kg delta 9-THC given intravenously (I.V.). All compounds were tested by I.V. injection and IOP measurements were taken periodically for 5 hours. Data were analyzed by a computer program which takes into account the change in IOP of the control group. Following this procedure we found that delta 8-THC, delta 9-THC, cannabinol, and nabilone were active while cannabidiol was inactive.

A weakly antimalarial biflavanone from Rhus retinorrhoea.

The biflavanone (2S,2"S)-7,7"-di-O-methyltetrahydroamentoflavone and five known flavonoids, 7-O-methylnaringenin, 7,3'-O-dimethylquercetin, 7-O-methylapigenin, 7-O-methylluteolin, and eriodictyol were isolated from the leaves of Rhus retinorrhoea Steud, Ex Olive. The biflavanone exhibited moderate antimalarial activity with IC50 0.98 microg/ml against Plasmodium falciparum (W2 Clone) and weak activity against P. falciparum (D6 Clone) with IC50 2.8 microg/ml. Nevertheless, it did not display any cytotoxicity. 7-O-Methylnaringenin showed weak antimicrobial activity against Candida albicans, C. krusei, Staphylococcus aureus, Mycobacterium smegmatis, M. intracellulare, and M. xenopi with MIC approximately 100 microg/ml. Characterization of each compound was based on spectral analysis and comparison with reported data.

GC/MS analysis of m-hydroxybenzoylecgonine in urine. Forensic implication in cocaine use.

m-Hydroxybenzoylecgonine (m-OH-BE) and d3-m- hydroxybenzoylecgonine (d3-m-OH-BE) have been synthesized, and a GC/MS procedure with d3-m-OH-BE as internal standard has been developed. Among 24 human urine specimens that were positive for BE, all of them have shown detectable levels of m-OH-BE with 75% of the specimens exceeding the LoQ (5 ng/mL), compared with only 50% of the specimens containing detectable levels of EME. The presence of m-OH-BE in urine suggested that this metabolite may serve as a valuable marker of cocaine use in addition to BE and EME.

Perinatal exposure to cannabichromene and delta 9-tetrahydrocannabinol: separate and combined effects on viability of pups and on male reproductive system at maturity.

The effects of cannabichromene (CBC), delta 9-tetrahydrocannabinol (delta 9-THC) and their combination (all doses 50 mg/kg orally) were determined after being administered to female mice for 7 days beginning on the 20th day of gestation. The THC treatment reduced postnatal viability, impaired male reproductive behavior at maturity and significantly reduced seminal vesicle weights. No changes from control values occurred after CBC or CBC + THC. Thus, CBC alone at this dosage did not act like THC; moreover, it antagonized the effects of THC when the two were given in combination.

GLC analysis of poison ivy and poison oak urushiol components in vegetable oil preparations.

A procedure is described for the analysis of urushiol content of pharmaceutical preparations containing extracts of poison ivy (Toxicodendron radicans) and poison oak (T. diversilobum) in vegetable oils. The procedure involves extraction of the urushiols from the oily solutions using 90% methanol in water followed by GLC analysis of the extracts. Recoveries of both poison ivy and poison oak urushiols from solutions in corn oil, olive oil, sesame seed oil, and cottonseed oil were calculated. Correlation coefficients (r2) ranged from 0.97 to 1.00, and the coefficients of variations ranged from 3.08 to 7.90%.

Synthesis and antiallergenic properties of 3-n-pentadecyl- and 3-n-heptadecylcatechol esters.

A synthetic procedure is described for the preparation of 3-n-pentadecyl- and 3-n-heptadecylcatechols and their acetate and alaninate esters. The Wittig reagent prepared from 2,3-dimethoxybenzyltriphenylphosphonium bromide (III) was coupled with 1-tetradecanal or 1-hexadecanal to give the olefins IV and V, respectively. Catalytic reduction of IV and V followed by demethylation with boron tribromide afforded VIII and IX. The acetates were prepared using acetic anhydride and pyridine, while the alaninates were prepared using N-(tert-butoxycarbonyl)-L-alanine and dicyclohexylcarbodiimide followed by removal of the tert-butoxycarbonyl group with hydrogen chloride gas. The esters were active in guinea pigs in the production of tolerance and desensitization or hyposensitization to poison ivy-type contact dermatitis.

New GLC analysis of urushiol congeners in different plant parts of poison ivy, Toxicodendron radicans.

Methods are presented for the direct GLC analysis of the catechol C15 alkenyl side-chain congeners contained in the urushiol fraction of poison ivy (Toxicodendron radicans) and the C17 homologs of poison oak (Toxicodendron diversilobum). A number of liquid phases were investigated and demonstrated varying degrees of separation. The methods developed were applied to the analysis of the urushiol fractions obtained from different plant parts of poison ivy. The effects of extraction before and after drying demonstrated tht a larger percentage of urushiol was obtained when the fresh plant material was extracted with ethanol.

Chemical constituents of fruit of Cocculus carolinus D.C. (Menispermaceae).

A phytochemical investigation of an ethanolic extract of the fruit of Cocculus carolinus resulted in the isolation and characterization of the alkaloids, cocculolidine and cocculine. The cyccculine, magnoflorine, and palmatine, previously reported in the stems and leaves of this species, were also isolated and identified.

Anhydrocannabisativine, a new alkaloid from Cannabis sativa L.

Ethanol extracts of the leaves and roots of a Mexican variant of Cannabis sativa L. (marijuana) afforded, after partitioning and chromatography, the new spermidine alkaloid, anhydrocannabisativine. The structure was determined by spectral analysis and semisynthesis.

Immunological studies of poisonous anacardiaceae: effect of vehicle on absorption of 3-n-pentadecylcatechol and its diacetate ester derivative after oral feeding in rats.

Tritium-labeled 3-n-pentadecylcatechol and its diacetate ester were fed to Sprague-Dawley rats. Both compounds were dissolved in ethanol and in corn oil vehicles and administered by gavage. The rats were placed in metabolic cages, and the urine and feces was determined by liquid scintillation counting, and the percentage of the administered dose was utilized as a measure of absorption. While there was no difference between the absorption of either compound, absorption was affected by the vehicle. Approximately 30% of the administered radioactivity appeared in the urine when ethanol was the vehicle, but about half that amount (14%) was excreted in the urine when the compounds were dissolved in corn oil. A subsequent bile cannulation study showed that the balance of the radioactivity found in the feces was not a result of biliary excretion. The majority of the activity recovered from urine and feces was eliminated within 48 hr after dosing. These data indicate that oil is a poor vehicle for GI absorption of urushiol components.

Rectal bioavailability of delta-9-tetrahydrocannabinol from the hemisuccinate ester in monkeys.

Oral administration of delta-9-tetrahydrocannabinal (delta 9-THC) was shown to result in low and erratic bioavailability, while the drug showed no bioavailability from various suppository formulations. delta 9-THC-Hemisuccinate was formulated as a prodrug for delta 9-THC in suppositories using Witepsol H15 base. The bioavailability of delta 9-THC from this formulation was evaluated in monkeys. The plasma levels of delta 9-THC and its metabolite 11-nor-delta 9-THC-9-COOH were determined using GC/MS analysis. The calculated bioavailability of delta 9-THC from this formulation was found to be 13.5%. Non-compartmental analysis of the plasma concentration data using statistical moments showed the mean residence time (MRT) for delta 9-THC in the body to be 3 h following iv administration of delta 9-THC or its hemisuccinate ester (3.4 and 2.7 h, respectively), as compared with 5.8 h following rectal administration of the delta 9-THC hemisuccinate. The observed rectal bioavailability of delta 9-THC from suppositories containing the hemisuccinate ester as a prodrug is of significant importance in developing an alternative approach to oral administration of the drug.

Cannabinoids and appetite stimulation.

Appetite stimulation by cannabinoids is highly variable. Four within-subject design studies explored the effects of age, gender, satiety status, route of drug administration, and dose on intake. One study involved a single oral administration of active drug (15 mg males, 10 mg females) or placebo to an age and gender stratified sample of 57 healthy, adult light marijuana users. Eleven subjects received single doses by oral, sublingual, and inhaled routes in a second study. In the third study, 10 subjects ingested a single oral dose in fasted and fed states. A 2.5 mg dose was administered b.i.d. for 3 days by oral and rectal suppository routes in the fourth study. Mean daily energy intake was significantly elevated following chronic dosing by rectal suppository, but not oral capsule, relative to all acute dosing regimens except inhalation. Total daily energy intake was comparable on fed and fasted days, suggesting satiety mechanisms were not impaired by the drug. Subject age, gender, reported "high," and plasma drug level were not significantly associated with drug effects on food intake.

Bypassing the first-pass effect for the therapeutic use of cannabinoids.

An oral formulation of delta-9-tetrahydrocannabinol (THC) in sesame oil (Marinol) is at present used for the management of chemotherapy-related nausea and emesis. However, due partly to poor bioavailability, its efficacy is variable. To circumvent possible metabolism in the gut and a first-pass effect by the liver, a suppository formulation of THC hemisuccinate ester was prepared. Administration of the suppository containing 11.8 mg of the hemisuccinate ester (equivalent to 9 mg THC) to three adult females (two of whom had previously exhibited low plasma drug levels following a 10-mg dose of the oral formulation) led to a marked and sustained elevation of plasma drug levels. Areas under the curves for plasma THC were more than 30-fold higher than after oral dosing. The suppository was well tolerated. The higher and more sustained plasma drug level achieved with this new formulation should enhance its antiemetic efficacy.