Abderrahman Bouraoui - Academia.edu (original) (raw)
Papers by Abderrahman Bouraoui
Pharmacognosy Magazine, 2016
Dictyopteris membranacea, a species of Mediterranean brown algae, is believed to have potential p... more Dictyopteris membranacea, a species of Mediterranean brown algae, is believed to have potential pharmacological and nutritional applications. However, such potentials only make sense when devoid of any adverse health consequences. The present study should be seen in this context. It aimed at evaluating the genotoxicity and cytoxicity of its organic extract (F0) and semi purified fractions (F4, F5, and F6). Extracts were tested using the bacterial Vitotox(®) test and micronucleus assay in different concentrations (from 1.25 μg/mL up to 100 μg/mL, depending on the test and the extract). Applied concentrations were based on a preliminary dose-finding test with the neutral red uptake assay. The results show that all extracts were not genotoxic in the presence or absence of a rat metabolic enzyme fraction (S9). This is encouraging and justifies further investigations on the therapeutic and other values of this algae. Dictyopteris membranacea extracts and some of their semi purified fractions have important antibacterial properties.The organic extract (F0) and semi purified fractions (F4, F5, and F6) were not genotoxic according to the bacterial Vitotox test.They were also not genotoxic according to the micronucleus test in human C3A cells.Applied concentrations were based on the in-vitro neutral red uptake (NRU) test.
Revue Des Regions Arides, 2007
Three fatty acids respectively with C 14 , C 16 and C 18 linear sequence (1), the □-tocopherol (2... more Three fatty acids respectively with C 14 , C 16 and C 18 linear sequence (1), the □-tocopherol (2), the (3□)-stigmast-5-en-3-ol (3), a cis-polyprenol (4), a new biflavonoid (5) an isobiflavonoid (6), two flavonoids (7) and (8) and shikimic acid (9) have been isolated from the ...
International Journal of Pharmacy and Pharmaceutical Sciences
ABSTRACT Export Date: 18 October 2014
DARU Journal of Pharmaceutical Sciences, 2015
Background: Seaweed polysaccharides are highly active natural substances having valuable applicat... more Background: Seaweed polysaccharides are highly active natural substances having valuable applications. The present study was conducted to characterize the physico-chemical properties of sulphated polysaccharides from three Mediterranean brown seaweeds (Cystoseira sedoides, Cystoseira compressa and Cystoseira crinita) and to evaluate their anti-radical, anti-inflammatory and gastroprotective activities.
DARU Journal of Pharmaceutical Sciences, 2014
Background: Gorgonians of the genus Eunicella are known for possessing a wide range of pharmacolo... more Background: Gorgonians of the genus Eunicella are known for possessing a wide range of pharmacological activities such as antiproliferative and antibacterial effect. The aim of this study was to evaluate the anti-inflammatory and gastroprotective effect of the organic extract and its semi-purified fractions from the white gorgonian Eunicella singularis and the isolation and identification of pure compound(s) from the more effective fraction.
Medicinal Chemistry Research
We report the synthesis of new anti-inflammatory 1,7-dihydropyrazolo[3',4':4,5]pyrimido[1... more We report the synthesis of new anti-inflammatory 1,7-dihydropyrazolo[3',4':4,5]pyrimido[1,6-a]pyrimidine 5 from aminocyanopyrazole. All compounds were characterized by physical, chemical and spectral studies. Preliminary pharmacological evaluation of the resulting products showed that compounds 5a, b, f (50-100 mg/kg, i.p) are active anti-inflammatory agents in carrageenan-induced rat paw oedema assay, and their effects are comparable to that of acetylsalicylic-lysine (300 mg/kg, i.p.), used as a reference drug. The nature of substituent (Y, R3) had a pronounced effect on the anti-inflammatory activity. Studies of structure-activity relationships have led to selection of compound ethyl-3,5-dimethyl-7-imino-N (1)-phenyl-1,7-dihydropyrazolo[3',4':4,5]pyrimido[1,6-a]pyrimidine-6-carboxylate, 5f which exhibited the most potent anti-inflammatory activity. In addition, the compounds 5a, b, f showed a significant gastroprotective effect against HCl/EtOH-induced gastric ulcer.
Journal of Pharmacy and Pharmacology, 2012
Objectives Clopidogrel, a thienopyridine antiplatelet agent, is a poor aqueous soluble compound a... more Objectives Clopidogrel, a thienopyridine antiplatelet agent, is a poor aqueous soluble compound and a P-glycoprotein (P-gp) efflux pump substrate. These two factors are responsible for its incomplete intestinal absorption. In this study, we have attempted to enhance the absorption of clopidogrel by improving its solubility and by inhibiting intestinal P-gp activity. Methods Solubility enhancement was achieved by preparing solid dispersions. Quinidine and naringin were selected as P-gp inhibitors, whilst tartaric acid was selected as the intestinal absorption enhancer. Absorption studies were performed using the everted gut sac model prepared from rat jejunum. The determination of clopidogrel was performed by high performance liquid chromatography. Key findings We noticed an enhancement of clopidogrel absorption by improving its solubility or by inhibiting the P-gp activity. The greatest results were obtained for solid dispersions in the presence of P-gp inhibitors at their highest concentrations, with an absorption improvement of 3.41-and 3.91-fold for naringin (15 mg/kg) and quinidine (200 mm), respectively. However, no clopidogrel absorption enhancement occurred in the presence of tartaric acid. Conclusions Naringin, a natural compound which has no undesirable side effects as compared with quinidine, could be used as a pharmaceutical excipient in the presence of clopidogrel solid dispersions to increase clopidogrel intestinal absorption and therefore its oral bioavailability.
The present study was conducted to evaluate the antiproliferative and antioxidant activities of o... more The present study was conducted to evaluate the antiproliferative and antioxidant activities of organic extract and its polar fractions from Eunicella singularis (Esper 1794). Organic extract and two fractions of E. singularis (F2 and F3) were screened for the presence of phenolic compounds, terpenoids and glycosides. The antiproliferative activity of E. singularis organic extract and its polar fractions was evaluated on human cancer cell lines (A549, lung cell carcinoma; HCT15, colon cell carcinoma and MCF7, breast adenocarcinoma), using the MTT colorimetric method and clonogenic assay, as well as the antioxidant activity, using the stable radical 1,1-diphenyl-2-picrylhydrazyl (DPPH), and the FRAP assays. The fractions F2 and F3 showed significant total phenolic content (40 and 35.72mg gallic-acid equivalent/g dried sample), respectively, and important antiproliferative properties against the cancer cell lines. The IC50 values, ranged from 36 to 274μg/ml for A549; 93 to 426μg/ml for HCT15; and 52 to 225μg/ml for MCF7 and in the clonogenic inhibition assay from 18 to 134μg/ml for A549; 43 to 357μg/ml for HCT15; and 17 to 160μg/ml for MCF7. Using the DPPH method, the fraction F2 exhibited the strongest radical scavenging activity, with IC50 0.08mg/ml, which approaches the activity of the powerful antioxidant standard, ascorbic acid (IC50=0.064mg/ml). The reducing power of the samples was in the following order: F2>organic extract>F3. These results suggest that E. singularis fractions might be used as a potential source of natural antioxidant and antitumor agents. The purification and determination of the chemical structures of compounds in these active fractions are under investigation. The results could provide a compound(s) with a promising role in future medicines.
Cancer Cell International, 2012
Background: Without doubt, natural products have been, and still are, the cornerstone of the heal... more Background: Without doubt, natural products have been, and still are, the cornerstone of the health care armamentarium. Of all natural sources, the marine environment is clearly the last great frontier for pharmaceutical and medical research.
Cancer Cell International, 2012
This study progresses in the direction of identifying component(s) from the Mediterranean sponge,... more This study progresses in the direction of identifying component(s) from the Mediterranean sponge, Spongia officinalis with anticonvulsant and analgesic activities. We investigated the efficacy of crude extract and its semi-purified fractions (F1-F3) of the defensive secretion from Spongia officinalis for their in vivo anticonvulsant activity using the pentylenetetrazole (PTZ) seizure model and analgesic activity using the writhing test in mice. Among the series the crude extract exhibited interesting analgesic activity in a dose dependent manner. Similarly the fraction F2 showed a partial protection of mice from PTZ-induced seizure and interesting analgesic activity in a dose dependent manner. The purification and the determination of chemical structure(s) of compound(s) of this active fraction are under investigation.
Journal of Advances in Chemistry, Jul 2, 2014
Journal of Ethnopharmacology, Mar 2, 2010
Ethnopharmacological relevance: Inflammations and immune-related diseases such as rheumatoid arth... more Ethnopharmacological relevance: Inflammations and immune-related diseases such as rheumatoid arthritis are growing global concerns. Most of the drugs from plants which have become important in modern medicine had a folklore origin and are traditional in systems of medicine. Citrullus colocynthis Schrad. (cucurbitaceae), endemic in Southern Tunisia, is used in folk medicine to treat many inflammation diseases. Aim of study: To evaluate the acute toxicity of different parts of Citrullus colocynthis and then to screen the analgesic and anti-inflammatory activities of aqueous extracts from roots and stems of the plant and from fruits and seeds at different maturation stages. Materials and methods: After identification and acute toxicity assay Citrullus colocynthis Schrad. aqueous extracts were screened for analgesic and anti-inflammatory activities using, respectively, the acetic acid writhing test in mice and the carrageenan-induced paw edema assay in rats. Results: All extracts displayed analgesic and anti-inflammatory activities at different doses without inducing acute toxicity. Topic results were obtained with immature fruits followed by seeds. The stem and root extracts were shown to possess the less significant inhibitory activity against analgesic and antiinflammatory models.
Bioorganic Medicinal Chemistry Letters, Oct 1, 2010
We report the parallel synthesis of two natural cyclopeptides, isolated from the seeds of Annona ... more We report the parallel synthesis of two natural cyclopeptides, isolated from the seeds of Annona squamosa, cyclosquamosin D (A1), and Met-cherimolacyclopeptide B (B) and their analogs. All of the compounds were screened for anti-inflammatory activity by evaluating their inhibitory effects on the production of pro-inflammatory cytokines using the lipopolysaccharide stimulated macrophage J774A.1 cell line. Compounds having significant anti-inflammatory activity in suppressing the secretion of IL-6 and TNF-α have been identified, some of which exhibit activity superior to that observed with the natural products.
Phytomedecine, 2009
A sesquiterpenoid Bakkenolide (1), and two steroids, (3b, 22E)-Stigmasta-5, 22-diène-3-ol (Stigma... more A sesquiterpenoid Bakkenolide (1), and two steroids, (3b, 22E)-Stigmasta-5, 22-diène-3-ol (Stigmasterol) (2) and stigmasterol 3b-glucoside (3), isolated from the Hertia cheirifolia (L.) chloroform extract, were evaluated respectively for their spasmolytic and anti-inflammatory activities. We note that these natural products were isolated and purified for the first time from the specie Hertia cheirifolia. Their structures have been established by spectroscopy (1 and 2D NMR experiences) and mass spectrometry. Chloroform-, ethyl acetate-and methanol-extracts were also tested for their spasmolytic and anti-inflammatory activities. Spasmolytic and anti-inflammatory screening were based respectively on the contractile response effects on rat isolated smooth muscles and on the dose-related carrageenan induced paw edema in rats. screening of the crude extracts showed spasmolytic and anti-inflammatory positive results. The antispasmodic effect of Bakkenolide was found in the same range as that of Alverine, a standard musculotropic spasmolytic agent.
Pharmaceutical Biology, 2016
Red algae have been recognized as a rich natural source of compounds possessing interesting biolo... more Red algae have been recognized as a rich natural source of compounds possessing interesting biological and pharmacological activities. This work investigates anti-inflammatory, analgesic and gastroprotective activities of MeOH/CH2Cl2 crude extract and its fractions F1 (50% MeOH) and F2 (80% MeOH) from the whole alga plant Laurencia obtusa Hudson (Rhodomelaceae). Anti-inflammatory activity was evaluated in vitro using cytometric bead array (CBA) technology to follow up the secretion of tumour necrosis factor alpha (TNF-α) in lipopolysaccharide activated THP-1 monocytic cells at doses of 10-250 μg/mL and in vivo using carrageenan-induced paw oedema in Wistar rats at doses of 25, 50, 100 and 200 mg/kg. Crude extract and fractions were tested at the doses of 25, 50, 100 and 200 mg/kg for peripheral and central analgesic activity by acetic acid-induced writhing test and hot-plate method, respectively, in Swiss albino mice. Gastroprotective activity was evaluated using HCl/ethanol-induced gastric ulcer test in rats at doses of 25, 50, 100 and 200 mg/kg. Crude extract, F1 and F2 showed an interesting inhibition of TNF-α secretion with IC50 values of 25, 52 and 24 μg/mL, respectively, and a significant anti-inflammatory activity in vivo (p < 0.01), 3 h after carrageenan injection, the oedema inhibition was 55.37%, 52.18% and 62.86%, respectively, at the dose of 100 mg/kg. Furthermore, they showed a significant peripheral analgesic activity with 53.79%, 55.92% and 57.37% (p < 0.01) of writhing inhibition, respectively. However, no significant activity was found in the hot-plate test. An interesting gastroprotective effect was observed with crude extract and its fractions F1 and F2 with a gastric ulcer inhibition of 65.48%, 77.42% and 81.29%, respectively, at the dose of 50 mg/kg. These results suggest that L. obtusa might be used as a potential source of natural anti-inflammatory and analgesic agents with gastroprotective effect.
Data Revues 16310748 00050008 02014182, Mar 22, 2008
The reaction of compounds 6a-i, readily available from α-amino acids, with an excess of lithium d... more The reaction of compounds 6a-i, readily available from α-amino acids, with an excess of lithium diisopropylamide, leads to new 3-substituted-2H-1,2-naphthothiazin-4(3H)-one 1,1-dioxides 7a-i, with yields ranging between 21 and 70%. The key steps are: the naphthylsulfonyl ortho-deprotonation based on the directed ortho-metalation reaction followed by a regiospecific intramolecular cyclisation reaction. Lithiation-deuteration experiments carried out on the naphthylsulfonamides 8 and 9 using n-BuLi and LDA demonstrated the regioselectivity of the deprotonation of the H-3 over the H-1 one of the naphthalene ring.
Drug-nutrient interactions
Absorption and bioavailability of theophylline from a sustained-release gelatin capsule were inve... more Absorption and bioavailability of theophylline from a sustained-release gelatin capsule were investigated in 10 male rabbits after oral administration (20 mg/kg), with and without a ground capsicum fruit suspension. Comparison of pharmacokinetic parameters showed that the concomitant absorption of capsicum increases areas under plasma curves (from 86.06 +/- 9.78 mg H/liter to 138.32 +/- 17.27 mg H/liter, P less than 0.001), peak plasma levels (from 6.65 +/- 0.76 to 8.78 +/- 0.98 mg/liter, P less than 0.01), and mean residence times (from 14.94 +/- 2.97 to 20.98 +/- 5.75 H, P less than 0.001). A second administration of the capsicum suspension, 11 hours after dosing, produced a new rise of theophylline plasma levels in every rabbit. The variations in pharmacokinetic and bioavailability parameters are discussed in accordance with the mechanisms of action of capsaicin, an active compound present in capsicum fruit.
Prostaglandins & other lipid mediators
Journal of Food Agriculture and Environment
ABSTRACT
AFRICAN JOURNAL OF BIOTECHNOLOGY
ABSTRACT
Pharmacognosy Magazine, 2016
Dictyopteris membranacea, a species of Mediterranean brown algae, is believed to have potential p... more Dictyopteris membranacea, a species of Mediterranean brown algae, is believed to have potential pharmacological and nutritional applications. However, such potentials only make sense when devoid of any adverse health consequences. The present study should be seen in this context. It aimed at evaluating the genotoxicity and cytoxicity of its organic extract (F0) and semi purified fractions (F4, F5, and F6). Extracts were tested using the bacterial Vitotox(®) test and micronucleus assay in different concentrations (from 1.25 μg/mL up to 100 μg/mL, depending on the test and the extract). Applied concentrations were based on a preliminary dose-finding test with the neutral red uptake assay. The results show that all extracts were not genotoxic in the presence or absence of a rat metabolic enzyme fraction (S9). This is encouraging and justifies further investigations on the therapeutic and other values of this algae. Dictyopteris membranacea extracts and some of their semi purified fractions have important antibacterial properties.The organic extract (F0) and semi purified fractions (F4, F5, and F6) were not genotoxic according to the bacterial Vitotox test.They were also not genotoxic according to the micronucleus test in human C3A cells.Applied concentrations were based on the in-vitro neutral red uptake (NRU) test.
Revue Des Regions Arides, 2007
Three fatty acids respectively with C 14 , C 16 and C 18 linear sequence (1), the □-tocopherol (2... more Three fatty acids respectively with C 14 , C 16 and C 18 linear sequence (1), the □-tocopherol (2), the (3□)-stigmast-5-en-3-ol (3), a cis-polyprenol (4), a new biflavonoid (5) an isobiflavonoid (6), two flavonoids (7) and (8) and shikimic acid (9) have been isolated from the ...
International Journal of Pharmacy and Pharmaceutical Sciences
ABSTRACT Export Date: 18 October 2014
DARU Journal of Pharmaceutical Sciences, 2015
Background: Seaweed polysaccharides are highly active natural substances having valuable applicat... more Background: Seaweed polysaccharides are highly active natural substances having valuable applications. The present study was conducted to characterize the physico-chemical properties of sulphated polysaccharides from three Mediterranean brown seaweeds (Cystoseira sedoides, Cystoseira compressa and Cystoseira crinita) and to evaluate their anti-radical, anti-inflammatory and gastroprotective activities.
DARU Journal of Pharmaceutical Sciences, 2014
Background: Gorgonians of the genus Eunicella are known for possessing a wide range of pharmacolo... more Background: Gorgonians of the genus Eunicella are known for possessing a wide range of pharmacological activities such as antiproliferative and antibacterial effect. The aim of this study was to evaluate the anti-inflammatory and gastroprotective effect of the organic extract and its semi-purified fractions from the white gorgonian Eunicella singularis and the isolation and identification of pure compound(s) from the more effective fraction.
Medicinal Chemistry Research
We report the synthesis of new anti-inflammatory 1,7-dihydropyrazolo[3',4':4,5]pyrimido[1... more We report the synthesis of new anti-inflammatory 1,7-dihydropyrazolo[3',4':4,5]pyrimido[1,6-a]pyrimidine 5 from aminocyanopyrazole. All compounds were characterized by physical, chemical and spectral studies. Preliminary pharmacological evaluation of the resulting products showed that compounds 5a, b, f (50-100 mg/kg, i.p) are active anti-inflammatory agents in carrageenan-induced rat paw oedema assay, and their effects are comparable to that of acetylsalicylic-lysine (300 mg/kg, i.p.), used as a reference drug. The nature of substituent (Y, R3) had a pronounced effect on the anti-inflammatory activity. Studies of structure-activity relationships have led to selection of compound ethyl-3,5-dimethyl-7-imino-N (1)-phenyl-1,7-dihydropyrazolo[3',4':4,5]pyrimido[1,6-a]pyrimidine-6-carboxylate, 5f which exhibited the most potent anti-inflammatory activity. In addition, the compounds 5a, b, f showed a significant gastroprotective effect against HCl/EtOH-induced gastric ulcer.
Journal of Pharmacy and Pharmacology, 2012
Objectives Clopidogrel, a thienopyridine antiplatelet agent, is a poor aqueous soluble compound a... more Objectives Clopidogrel, a thienopyridine antiplatelet agent, is a poor aqueous soluble compound and a P-glycoprotein (P-gp) efflux pump substrate. These two factors are responsible for its incomplete intestinal absorption. In this study, we have attempted to enhance the absorption of clopidogrel by improving its solubility and by inhibiting intestinal P-gp activity. Methods Solubility enhancement was achieved by preparing solid dispersions. Quinidine and naringin were selected as P-gp inhibitors, whilst tartaric acid was selected as the intestinal absorption enhancer. Absorption studies were performed using the everted gut sac model prepared from rat jejunum. The determination of clopidogrel was performed by high performance liquid chromatography. Key findings We noticed an enhancement of clopidogrel absorption by improving its solubility or by inhibiting the P-gp activity. The greatest results were obtained for solid dispersions in the presence of P-gp inhibitors at their highest concentrations, with an absorption improvement of 3.41-and 3.91-fold for naringin (15 mg/kg) and quinidine (200 mm), respectively. However, no clopidogrel absorption enhancement occurred in the presence of tartaric acid. Conclusions Naringin, a natural compound which has no undesirable side effects as compared with quinidine, could be used as a pharmaceutical excipient in the presence of clopidogrel solid dispersions to increase clopidogrel intestinal absorption and therefore its oral bioavailability.
The present study was conducted to evaluate the antiproliferative and antioxidant activities of o... more The present study was conducted to evaluate the antiproliferative and antioxidant activities of organic extract and its polar fractions from Eunicella singularis (Esper 1794). Organic extract and two fractions of E. singularis (F2 and F3) were screened for the presence of phenolic compounds, terpenoids and glycosides. The antiproliferative activity of E. singularis organic extract and its polar fractions was evaluated on human cancer cell lines (A549, lung cell carcinoma; HCT15, colon cell carcinoma and MCF7, breast adenocarcinoma), using the MTT colorimetric method and clonogenic assay, as well as the antioxidant activity, using the stable radical 1,1-diphenyl-2-picrylhydrazyl (DPPH), and the FRAP assays. The fractions F2 and F3 showed significant total phenolic content (40 and 35.72mg gallic-acid equivalent/g dried sample), respectively, and important antiproliferative properties against the cancer cell lines. The IC50 values, ranged from 36 to 274μg/ml for A549; 93 to 426μg/ml for HCT15; and 52 to 225μg/ml for MCF7 and in the clonogenic inhibition assay from 18 to 134μg/ml for A549; 43 to 357μg/ml for HCT15; and 17 to 160μg/ml for MCF7. Using the DPPH method, the fraction F2 exhibited the strongest radical scavenging activity, with IC50 0.08mg/ml, which approaches the activity of the powerful antioxidant standard, ascorbic acid (IC50=0.064mg/ml). The reducing power of the samples was in the following order: F2>organic extract>F3. These results suggest that E. singularis fractions might be used as a potential source of natural antioxidant and antitumor agents. The purification and determination of the chemical structures of compounds in these active fractions are under investigation. The results could provide a compound(s) with a promising role in future medicines.
Cancer Cell International, 2012
Background: Without doubt, natural products have been, and still are, the cornerstone of the heal... more Background: Without doubt, natural products have been, and still are, the cornerstone of the health care armamentarium. Of all natural sources, the marine environment is clearly the last great frontier for pharmaceutical and medical research.
Cancer Cell International, 2012
This study progresses in the direction of identifying component(s) from the Mediterranean sponge,... more This study progresses in the direction of identifying component(s) from the Mediterranean sponge, Spongia officinalis with anticonvulsant and analgesic activities. We investigated the efficacy of crude extract and its semi-purified fractions (F1-F3) of the defensive secretion from Spongia officinalis for their in vivo anticonvulsant activity using the pentylenetetrazole (PTZ) seizure model and analgesic activity using the writhing test in mice. Among the series the crude extract exhibited interesting analgesic activity in a dose dependent manner. Similarly the fraction F2 showed a partial protection of mice from PTZ-induced seizure and interesting analgesic activity in a dose dependent manner. The purification and the determination of chemical structure(s) of compound(s) of this active fraction are under investigation.
Journal of Advances in Chemistry, Jul 2, 2014
Journal of Ethnopharmacology, Mar 2, 2010
Ethnopharmacological relevance: Inflammations and immune-related diseases such as rheumatoid arth... more Ethnopharmacological relevance: Inflammations and immune-related diseases such as rheumatoid arthritis are growing global concerns. Most of the drugs from plants which have become important in modern medicine had a folklore origin and are traditional in systems of medicine. Citrullus colocynthis Schrad. (cucurbitaceae), endemic in Southern Tunisia, is used in folk medicine to treat many inflammation diseases. Aim of study: To evaluate the acute toxicity of different parts of Citrullus colocynthis and then to screen the analgesic and anti-inflammatory activities of aqueous extracts from roots and stems of the plant and from fruits and seeds at different maturation stages. Materials and methods: After identification and acute toxicity assay Citrullus colocynthis Schrad. aqueous extracts were screened for analgesic and anti-inflammatory activities using, respectively, the acetic acid writhing test in mice and the carrageenan-induced paw edema assay in rats. Results: All extracts displayed analgesic and anti-inflammatory activities at different doses without inducing acute toxicity. Topic results were obtained with immature fruits followed by seeds. The stem and root extracts were shown to possess the less significant inhibitory activity against analgesic and antiinflammatory models.
Bioorganic Medicinal Chemistry Letters, Oct 1, 2010
We report the parallel synthesis of two natural cyclopeptides, isolated from the seeds of Annona ... more We report the parallel synthesis of two natural cyclopeptides, isolated from the seeds of Annona squamosa, cyclosquamosin D (A1), and Met-cherimolacyclopeptide B (B) and their analogs. All of the compounds were screened for anti-inflammatory activity by evaluating their inhibitory effects on the production of pro-inflammatory cytokines using the lipopolysaccharide stimulated macrophage J774A.1 cell line. Compounds having significant anti-inflammatory activity in suppressing the secretion of IL-6 and TNF-α have been identified, some of which exhibit activity superior to that observed with the natural products.
Phytomedecine, 2009
A sesquiterpenoid Bakkenolide (1), and two steroids, (3b, 22E)-Stigmasta-5, 22-diène-3-ol (Stigma... more A sesquiterpenoid Bakkenolide (1), and two steroids, (3b, 22E)-Stigmasta-5, 22-diène-3-ol (Stigmasterol) (2) and stigmasterol 3b-glucoside (3), isolated from the Hertia cheirifolia (L.) chloroform extract, were evaluated respectively for their spasmolytic and anti-inflammatory activities. We note that these natural products were isolated and purified for the first time from the specie Hertia cheirifolia. Their structures have been established by spectroscopy (1 and 2D NMR experiences) and mass spectrometry. Chloroform-, ethyl acetate-and methanol-extracts were also tested for their spasmolytic and anti-inflammatory activities. Spasmolytic and anti-inflammatory screening were based respectively on the contractile response effects on rat isolated smooth muscles and on the dose-related carrageenan induced paw edema in rats. screening of the crude extracts showed spasmolytic and anti-inflammatory positive results. The antispasmodic effect of Bakkenolide was found in the same range as that of Alverine, a standard musculotropic spasmolytic agent.
Pharmaceutical Biology, 2016
Red algae have been recognized as a rich natural source of compounds possessing interesting biolo... more Red algae have been recognized as a rich natural source of compounds possessing interesting biological and pharmacological activities. This work investigates anti-inflammatory, analgesic and gastroprotective activities of MeOH/CH2Cl2 crude extract and its fractions F1 (50% MeOH) and F2 (80% MeOH) from the whole alga plant Laurencia obtusa Hudson (Rhodomelaceae). Anti-inflammatory activity was evaluated in vitro using cytometric bead array (CBA) technology to follow up the secretion of tumour necrosis factor alpha (TNF-α) in lipopolysaccharide activated THP-1 monocytic cells at doses of 10-250 μg/mL and in vivo using carrageenan-induced paw oedema in Wistar rats at doses of 25, 50, 100 and 200 mg/kg. Crude extract and fractions were tested at the doses of 25, 50, 100 and 200 mg/kg for peripheral and central analgesic activity by acetic acid-induced writhing test and hot-plate method, respectively, in Swiss albino mice. Gastroprotective activity was evaluated using HCl/ethanol-induced gastric ulcer test in rats at doses of 25, 50, 100 and 200 mg/kg. Crude extract, F1 and F2 showed an interesting inhibition of TNF-α secretion with IC50 values of 25, 52 and 24 μg/mL, respectively, and a significant anti-inflammatory activity in vivo (p < 0.01), 3 h after carrageenan injection, the oedema inhibition was 55.37%, 52.18% and 62.86%, respectively, at the dose of 100 mg/kg. Furthermore, they showed a significant peripheral analgesic activity with 53.79%, 55.92% and 57.37% (p < 0.01) of writhing inhibition, respectively. However, no significant activity was found in the hot-plate test. An interesting gastroprotective effect was observed with crude extract and its fractions F1 and F2 with a gastric ulcer inhibition of 65.48%, 77.42% and 81.29%, respectively, at the dose of 50 mg/kg. These results suggest that L. obtusa might be used as a potential source of natural anti-inflammatory and analgesic agents with gastroprotective effect.
Data Revues 16310748 00050008 02014182, Mar 22, 2008
The reaction of compounds 6a-i, readily available from α-amino acids, with an excess of lithium d... more The reaction of compounds 6a-i, readily available from α-amino acids, with an excess of lithium diisopropylamide, leads to new 3-substituted-2H-1,2-naphthothiazin-4(3H)-one 1,1-dioxides 7a-i, with yields ranging between 21 and 70%. The key steps are: the naphthylsulfonyl ortho-deprotonation based on the directed ortho-metalation reaction followed by a regiospecific intramolecular cyclisation reaction. Lithiation-deuteration experiments carried out on the naphthylsulfonamides 8 and 9 using n-BuLi and LDA demonstrated the regioselectivity of the deprotonation of the H-3 over the H-1 one of the naphthalene ring.
Drug-nutrient interactions
Absorption and bioavailability of theophylline from a sustained-release gelatin capsule were inve... more Absorption and bioavailability of theophylline from a sustained-release gelatin capsule were investigated in 10 male rabbits after oral administration (20 mg/kg), with and without a ground capsicum fruit suspension. Comparison of pharmacokinetic parameters showed that the concomitant absorption of capsicum increases areas under plasma curves (from 86.06 +/- 9.78 mg H/liter to 138.32 +/- 17.27 mg H/liter, P less than 0.001), peak plasma levels (from 6.65 +/- 0.76 to 8.78 +/- 0.98 mg/liter, P less than 0.01), and mean residence times (from 14.94 +/- 2.97 to 20.98 +/- 5.75 H, P less than 0.001). A second administration of the capsicum suspension, 11 hours after dosing, produced a new rise of theophylline plasma levels in every rabbit. The variations in pharmacokinetic and bioavailability parameters are discussed in accordance with the mechanisms of action of capsaicin, an active compound present in capsicum fruit.
Prostaglandins & other lipid mediators
Journal of Food Agriculture and Environment
ABSTRACT
AFRICAN JOURNAL OF BIOTECHNOLOGY
ABSTRACT