Antioxidant and antibacterial effects of a new macrocyclic bis(bibenzyl) ether from Combretum molle (Combretaceae).

A new compound, combrebisbibenzyl (1) as well as two sterols including stigmasterol (2) and 3-O-ß-D-glucopyranoside of ß-sitosterol (3) and seven triterpenoids namely mollic acid (4), oleanolic acid (5), ursolic acid (6), arjunglucoside I (7), arjungenin (8), bellericagenin B (9) and combregenin (10) were isolated from the root of Combretum molle. Compounds 1, 7 and 9, AcOEt and MeOH extracts exhibited moderate antioxidant activity with an IC50 value of 179.32, 185.21, 195.11 197.41 and 170.21 µg/mL, respectively, for reactive oxygen species inhibition and, inhibition percent value of 57.23, 64.52, 53.55, 67.42 and 65.04, respectively, for DPPH free-radical scavenging. The E. MeOH presented a moderate antibacterial activity against Staphylococcus aureus with DIZs value of 10.1 ± 0.2 from 800 µg/mL while the others tested strains were not sensitive. However, most of the tested bacteria, (S. aureus, Escherichia coli and Salmonella typhimurium) were moderately sensitive to E. AcOEt from 800 µg/mL with DIZs value of 8.2 ± 0.1. From the E. AcOEt, five of the isolated compounds were tested against four bacteria strains using the disc-dilusion method. The results showed that compound 1 and 2 exhibited very good antibacterial activity against all the tested bacteria at the concentration of 30 µg/mL with respective DIZ value of 22.2 and 25.4 for E. coli, 20.2 and 30.2 for S. typhimurium, 22.3 and 23.1 for S. aureus and, 22.1 and 24.1 for Streptococcus faecalis. This antibacterial activity significantly depends on the concentration.

Crotoliganfuran, a new clerodane-type furano-diterpenoid from Croton oligandrus Pierre ex Hutch.

The phytochemical investigation of the methanol extract of the bark of Croton oligandrus Pierre ex Hutch yielded a new clerodane-type diterpenoid crotoliganfuran (1) along with ten other compounds including 12-epicrotocorylifuran (2), lupeol (3), syringic acid (4), aleuritolic acid acetate (5), aleuritolic acid (6), scopoletin (7), geddic acid (8), ß-sitosterol (9), vanilic acid (10) and stigmastane-3,6-dione (11). Their structures were established by spectroscopic means. The extract and all the isolates were screened for their inhibitory properties against butyrylcholinesterase and urease enzymes, respectively. The extract and compounds 1, 4 and 7 displayed the most potent urease inhibitory properties with IC50 values, 22.2, 26.7 and 28.5 µM, respectively. Compound 9 was the most active of all the tested compounds against butyrylcholinesterase enzyme with an IC50 value of 36.3 µM.[Formula: see text].

Antihypernociceptive and neuroprotective effects of Combretin A and Combretin B on streptozotocin-induced diabetic neuropathy in mice.

Painful diabetic neuropathy (PDN) is known to adversely affect psychosocial functioning by enhancing levels of anxiety and depression. This study was designed to verify the antihypernociceptive, anxiolytic, and antidepressant-like effects of Combretin A and Combretin B (two triterpenes cycloartane-type isolated from the leaves of Combretum fragrans) in streptozotocin-induced diabetic neuropathy in mice. PDN was induced in mice by the administration of streptozotocin (STZ, 200 mg/kg, i.p.). The effect of oral administration of Combretin A (25 and 50 mg/kg) and Combretin B (25 and 50 mg/kg) on nociception (mechanical allodynia, thermal hyperalgesia, cold allodynia, and chemical hyperalgesia), anxiety (elevated plus maze, light-dark box test, social interaction), and depressant (open field test, forced swimming test, tail suspension test) was evaluated. Combretin A (25 and 50 mg/kg) and Combretin B (25 and 50 mg/kg) caused antihypernociceptive, anxiolytic, and antidepressant-like effects in in STZ-induced diabetic neuropathy in mice. Both compounds also caused a decrease in blood glucose and improved body weight in treated animals. They also significantly (p < 0.001) reduced tumor necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1ß), malondialdehyde (MDA), and nitric oxide (NO) production in serum and sciatic nerves, and, significantly (p < 0.001) increased superoxide dismutase (SOD) and catalase (CAT) activity in serum, sciatic nerves, and brain. Combretin A and Combretin B also showed a great systemic effect, conserving values of evaluated parameters close to normal in treated mice. The results of this study confirm the antihypernociceptive, antianxiety, and antidepressant activities of Combretin A and Combretin B.

Flavonoids and triterpenes from Combretum fragrans with anti-inflammatory, antioxidant and antidiabetic potential.

Despite the well-documented benefits of Combretum fragrans in Cameroon, only few scientific works have been done on it. In this study we isolated eight compounds from the leaves extract of C. fragrans: velutin (1), belamcanidin (2), cirsilineol (3), cirsimaritin (4), 3ß-acetoxy-20,24-epoxy-11,25-hydroxy-dammarane (5), combretin A (6), combretin B (7) and a mixture of arjunolic acid (8a) and asiatic acid (8b). Compounds 6 and 7 presented potent anti-inflammatory, antioxidant and antidiabetic activities. Compounds 1, 3, 5 and the mixture of 8a and 8b were significantly active, and compounds 2 and 4 presented moderate activity for reactive oxygen species inhibitory and free-radical scavenging. All compounds were isolated using chromatographic techniques; their structures were elucidated by spectroscopic techniques and their spectroscopic data compared with those of the literature. Anti-inflammatory activity was evaluated via the oxidative burst assay using a luminol-amplified chemiluminescence technique, antioxidant activity by free-radical scavenging activity (DPPH) and antidiabetic activity via α-glucosidase inhibition. All of the isolated compounds (1-8) were reported to exhibit significant antioxidant activity. Compounds 1, 3, and 5-8 exhibited potent chemiluminescence inhibition effect, and only compounds 6 and 7 inhibited α-glucosidase. Thus, C. fragrans can be used as an effective natural source of anti-inflammatory, antioxidant and antidiabetic compounds.

Bioactive chemical constituents of Duboscia macrocarpa Bocq., and X-ray diffraction study of 11ß, 12ß-epoxyfriedours-14-en-3α-ol.

A new γ-lactone triterpenoid, Evodoulolide (1) and a new triterpenoid Duboscic acid B (2), along with five known compounds, maslinic acid (3), arboreic acid (4), (E)-3-(4-hydroxyphenyl)-N-[2-(4-hydroxyphenyl) ethyl] prop-2-enamide (5), (E)-heptacos-19-enoic acid (6) and 11ß,12ß-epoxyfriedours-14-en-3α-ol (7) were isolated from the trunk wood of Duboscia macrocarpa. Their structures were elucidated from extensive 1D- and 2D-NMR and MS and by comparison of their spectra with published data. Compounds 1, 3, 5 and 6 exhibited significant α-glucosidase inhibitory activity. Compound 5 was found to be a potent inhibitor (IC50=5.1±0.1µM) of α-glucosidase as compared to acarbose (IC50=625.0±1µM) used as standard drug. These compounds did not show anti-glycation activity using the BSA-MG glycation model or inhibition against the α-chymotrypsin enzyme. The chemotaxonomic connotation of the isolated secondary metabolites is also herein described. The single-crystal X-ray and absolute configuration diffraction analysis of 11α, 12α-epoxyfriedours-14-en-3-ol (7) is also described here for the first time.

Analgesic, anti-inflammatory and anticancer activities of Combretin A and Combretin B isolated from Combretum fragrans F. HOFFM (Combretaceae) leaves.

Previous pharmacological and phytochemical studies showed that, Combretum fragrans F. HOFFM (Combretaceae) is a Cameroonian medicinal plant possessing numerous therapeutic virtues and rich in various active secondary metabolites. In this study, we investigate in vivo anti-nociceptive and anti-inflammatory activity and, in vitro anticancer, anti-TNFα, ROS and NO-inhibitory activities of Combretum A and Combretin B, two triterpenes cycloartane-type isolated from the leaves of Combretum fragrans. The effect on ROS, TNF-α and NO production, anticancer activity and cytotoxicity assay were done using chemiluminescence technique, ELISA kit, colorimetric method, MCF-7 cells and MTT assay, respectively. Antinociceptive and anti-inflammatory activities were estimated using a model of acetic acid, formalin and carrageenan. Combretin A and Combretin B significantly (p < 0.001) inhibited extracellular ROS production. These compounds also significantly (p < 0.001) reduced TNF-α and NO production. Moreover, these compounds decreased cell viability of MCF-7 cell lines. For acetic acid- or formalin-induced pain, as well as carrageenan-induced acute inflammation, Combretin A and Combretin B exhibited significant (p < 0.001) anti-nociceptive and anti-inflammatory activities. Anti-nociceptive, anti-inflammatory and anticancer potential associated with inhibitory effects on ROS, TNFα and NO production in this study show that, Combretin A and Combretin B could be considered as the promising chemotherapeutic agents in breast cancer treatment and inflammatory disease.

Antinociceptive Activities of the Methanolic Extract of the Stem Bark of Boswellia dalzielii Hutch. (Burseraceae) in Rats Are NO/cGMP/ATP-Sensitive-K+ Channel Activation Dependent.

Boswellia dalzielii (B. dalzielii) is traditionally used in the treatment of rheumatism, pain, and inflammation. The present investigation evaluates the property and possible mechanism of action of the methanolic extract of B. dalzielii (BDME) on inflammatory and neuropathic pain models. Effects of BDME (250 and 500 mg/kg), orally administered, were verified in mechanical hypernociception induced by LPS or PGE2. Mechanical hyperalgesia, cold allodynia, and heat hyperalgesia were used in vincristine-induced neuropathic pain. NW-nitro-L-arginine methyl ester (inhibitor of nitric oxide synthase), glibenclamide (ATP-sensitive potassium channel blocker), methylene blue (cGMP blocker), or naloxone (opioid antagonist receptor) has been used to evaluate the therapeutic effects of BDME on PGE2-induced hyperalgesia. Chemical profile of BDME was determined by using HPLC-XESI-PDA/MS. BDME showed significant antinociceptive effects in inflammatory pain caused by LPS and PGE2. The extract also significantly inhibited neuropathic pain induced by vincristine. The antinociceptive property of BDME in PGE2 model was significantly blocked by L-NAME, glibenclamide, methylene blue, or naloxone. The present work reveals the antinociceptive activities of BDME both in inflammatory and in neuropathic models of pain. This plant extract may be acting firstly by binding to opioid receptors and secondly by activating the NO/cGMP/ATP-sensitive-K+ channel pathway.

Termiglaucescin, a new polyhydroxy triterpene glucoside from Terminalia glaucescens with antioxidant and anti-inflammatory potential.

Termiglaucescin (1), a new triterpene glucoside, has been isolated from the ethyl acetate extract of the root bark of Terminalia glaucescens Planch. ex Benth, together with 11 known compounds, ß-D-glucopyranosyl 2α,3ß,6ß-trihydroxy-23-galloylolean-12-en-28-oate (2), arjunglucoside I (3), sericoside (4), arjungenin (5), sericic acid (6), arjunetin (7), chebuloside II (8), 3,3',4-tri-O-methylelagic acid (9), 3,3'-di-O-methylelagic acid (10), ß-sitosterol (11) and stigmasterol (12). Compounds 2, 3, 7, 8 and 9 are reported from the plant for the first time. The structures of the isolated compounds were characterized by spectroscopic data interpretations, especially 1D and 2D NMR. The triterpenic isolates showed potent antioxidant and anti-inflammatory activities.

Piptadenin, a Novel 3,4-Secooleanane Triterpene and Piptadenamide, a New Ceramide from the Stem Bark of Piptadeniastrum africanum (Hook.f.) Brenan.

Piptadenin (1), a new triterpene along with piptadenamide (10), a new ceramide, have been isolated from the AcOEt-soluble fraction of the MeOH extract of the stem bark of Piptadeniastrum africanum along with nine known compounds, 1-O-[(3ß,22ß)-3,22-dihydroxy-28-oxoolean-12-en-28-yl]-ß-d-glucopyranose (2), 22ß-hydroxyoleanic acid (3), oleanic acid (4), lupeol (5), betulinic acid (6), 5α-stigmasta-7,22-dien-3ß-ol (7), 5α-stigmasta-7,22-dien-3-one (8), (3ß)-stigmast-5-en-3-yl ß-d-glucopyranoside (9) and 2,3-dihydroxypropyl hexacosanoate (11). Except for compound 11, all the isolated compounds are reported for the first time from this plant. The structures of the isolated compounds were elucidated by spectroscopic data including 1D and 2D NMR. The pure compounds 1 - 11 were subjected to the pharmacological screening and compounds 2, 5 - 7 and 9 exhibited potent urease inhibitory activity with IC50 value of 25.8, 28.9, 30.1, 31.8 and 32.7 µm, respectively, whereas compound 1 showed moderate activity (IC50 = 98.7 µm). The potent urease inhibitory activity supplemented the previous literature reports and medicinal uses of this plant.

Extracts of Feretia apodanthera Del. demonstrated anticonvulsant activities against seizures induced by chemicals and maximal electroshock.

Extracts of Feretia apodanthera Del. (Rubiaceae) have been extensively used in traditional Cameroonian medicine to treat a variety of diseases, including some neurological disorders. The present study was aimed to tests the anticonvulsant properties of the aqueous extract and the alkaloid fraction of the stem barks of Feretia apodanthera. The anticonvulsant investigation was carried out against bicuculline-, picrotoxin-, pentylenetetrazol-, Methyl-ß-carboline-3-carboxylate-, N-Methyl-D-aspartate-, 4-aminopyridine-, and maximal electroshock-induced seizures or turning behavior in mice. The aqueous extract protected mice against bicuculline-, picrotoxin-, pentylenetetrazol-, Methyl-ß-carboline-3-carboxylate-, N-methyl-D-aspartate -, 4-aminopyridine- and maximal electroshock-induced seizures or turning behavior. Also, N-Methyl-D-aspartate-, 4-aminopyridine- and maximal electroshock- induced seizures or turning behavior, were significantly antagonized by the alkaloid fraction (80mg/kg) from Feretia apodanthera. The total protection of mice provided by the aqueous extract against convulsions induced by pentylenetetrazol or picrotoxin was anagonized by flumazenil, a specific antagonist of the benzodiazepine site in the GABAA receptor complex. The aqueous extract of Feretia apodanthera (but not the alkaloid fraction) increased the brain GABA content and inhibited the GABA transaminase activity. In conclusion, Feretia apodanthera was revealed possessing anticonvulsant effects in mice, likely via the GABAergic neurotransmission.

Nauclea latifolia Smith (Rubiaceae) exerts antinociceptive effects in neuropathic pain induced by chronic constriction injury of the sciatic nerve.

ETHNOPHARMACOLOGICAL RELEVANCE: The roots of Nauclea latifolia Smith (Rubiaceae) popularly known as "koumkouma" is used in traditional Cameroonian medicine as neuropathic pain remedy and for the treatment of headache, inflammatory pain and convulsion. This study was conducted to evaluate the antinociceptive effects of the alkaloid fraction isolated from Nauclea latifolia in neuropathic pain induced by chronic constriction injury (CCI) of the sciatic nerve in rat. MATERIALS AND METHODS: Bioactive-guided fractionation of the root extracts of Nauclea latifolia using the Von Frey in a rat model of neuropathic pain (Benett model), afforded a potent anti-hyperalgesic fraction IV. Further fractionation of this fraction was performed by high-performance liquid chromatography (HPLC), yielded eight sub-fractions (F1-F8) which were tested for antinociceptive effects. The alkaloid fraction (F3) collected by HPLC, exhibited potent antinociceptive effects, and the anti-allodynic and anti-hyperalgesic effects of this fraction (8, 16, 40 and 80 mg/kg) were determined using the von Frey and acetone tests respectively in a rat model of neuropathic pain. Rota-rod performance and catalepsy tests were used for the assessment of motor coordination. RESULTS: The alkaloid fraction (80 mg/kg) administered intraperitoneally induced a completely decreased hyperalgesia 90 min post-dosing. In the acetone test, the Nauclea latifolia fraction at 80mg/kg showed its maximal anti-allodynic effects 120 min post-injection. The areas under the curve (AUC) of the anti-allodynic or anti-hyperalgesic effects produced by the alkaloid fraction at 80 mg/kg were significantly (p<0.001) greater than the AUC of effects produced by vehicle in CCI rats. The alkaloid fraction did not exhibit any significant effects on the spontaneous locomotor activity of the mice in rota-rod performance and no sign of catalepsy was observed. CONCLUSION: The analysis of the effects, expressed as the time course of AUC, supports the traditional use of Nauclea latifolia in neuropathic pain therapy. The pharmacological and chemical studies are continuing in order to characterize the mechanism(s) responsible for this anti-hyperalgesic and anti-allodynic action and also to identify the active substances present in the roots extracts of Nauclea latifolia.

Antipsychotic and sedative effects of the leaf extract of Crassocephalum bauchiense (Hutch.) Milne-Redh (Asteraceae) in rodents.

ETHNOPHARMACOLOGICAL RELEVANCE: Crassocephalum bauchiense (Hutch.) Milne-Redh (Asteraceae) has been used as a medicine for the treatment of epilepsy, insomnia, dementia and psychotic disorders in Cameroonian traditional medicine. AIM OF THE STUDY: This study was designed to examine whether the aqueous extract and the alkaloid fraction prepared from the leaves of Crassocephalum bauchiense possess antipsychotic and sedative properties in rodents. MATERIALS AND METHODS: The rectal temperature of mice was recorded with a probe thermometer at a constant depth. Novelty-induced rearing behavior is used to evaluate a central excitatory locomotor behavior in mice. The antipsychotic effects of the extracts were assessed using the apomorphine animal model of psychosis. The catalepsy test was tested based on the ability of the leaves extracts of Crassocephalum bauchiense to alter the duration of akinesia by placing the naive mice with both forelegs over a horizontal bar. The extracts of Crassocephalum bauchiense effects were evaluated on sodium pentobarbital-induced sleeping time. In addition, gamma-aminobutyric acid concentrations in the brain treated mice were also estimated. RESULTS: The aqueous extract and the alkaloid fraction from Crassocephalum bauchiense caused dose-dependent inhibition of novelty-induced rearing behavior, decreased the apomorphine-induced stereotypy and fighting, and had significant fall of the body temperature. The aqueous extract prolonged the sodium pentobarbital sleeping time. This prolongation was not reversed by bicuculline, a light-sensitive competitive antagonist of GABA(A) receptors complex. However, the effect of the aqueous extract on sodium pentobarbital-induced sleeping time was blocked by N-methyl-ß-carboline-3-carboxamide, a partial inverse agonist of the benzodiazepine site in the GABA(A) receptor complex and flumazenil, a specific antagonist of the benzodiazepine site in the GABAA receptor complex. In biochemical experiments, the concentration of the inhibitory amino acid, gamma-aminobutyric acid, was significantly increased in the brain of animals treated with the aqueous extract of Crassocephalum bauchiense and sodium valproate. CONCLUSIONS: The results show that the antipsychotic and sedative properties of Crassocephalum bauchiense are possibly mediated via the blockade of dopamine D-2 receptors and GABAergic activation, respectively. However, pharmacological and chemical studies are continuing in order to characterize the mechanism(s) responsible for these neuropharmacological actions and also to identify the active substances present in the extracts of Crassocephalum bauchiense.

Evaluation of antinociceptive effects of Crassocephalum bauchiense Hutch (Asteraceae) leaf extract in rodents.

ETHNOPHARMACOLOGICAL RELEVANCE: The leaves of Crassocephalum bauchiense have long been used in traditional Cameroonian medicine for the treatment of epilepsy, pain, inflammatory disorders, arthritis and intestinal pain. AIM OF THE STUDY: In this study, we attempted to identify the possible antinociceptive action of the aqueous extract and the alkaloid fraction prepared from the leaves of Crassocephalum baucheiense. MATERIALS AND METHODS: Using acetic acid induced abdominal constrictions, formalin-, capsaisin- and glutamate-induced nociception, and hot plate assay procedures, the antinociceptive effects of the aqueous extract and the alkaloid fraction was assessed after oral administration in mice. Morphine sulfate was used as reference analgesic agent. Mice were submitted to the rota-rod task and open-field test in order to assess any non-specific muscle-relaxant or sedative effects of the extracts of Crassocephalum bauchiense. Male and female Swiss mice were used to assess acute toxicity of these extracts. RESULTS: The aqueous extract and the alkaloid fraction of Crassocephalum bauchiense produced a significant antinociceptive effects in the acetic acid, formalin, glutamate, capsaicin and hot plate tests. These antinociceptive effects of Crassocephalum bauchiense were significantly attenuated by pretreatment with naloxone. The extracts of Crassocephalum bauchiense did not alter the locomotion of animals in the open-field or rotarod tests, which suggest a lack of a central depressant effect. The animals did not exhibit any acute toxicity to the aqueous extract and the alkaloid fraction, so it was not possible to calculate the LD(50). CONCLUSION: The results confirm the popular use of Crassocephalum bauchiense as an antinociceptive, and contribute to the pharmacological knowledge of this species because it was shown that the aqueous extract and the alkaloid fraction of Crassocephalum bauchiense produced dose related antinociception in models of chemical and thermal nociception through mechanisms that involve an interaction with opioidergic pathway.

Antipyretic and antinociceptive effects of Nauclea latifolia root decoction and possible mechanisms of action.

CONTEXT: Nauclea latifolia Smith (Rubiaceae) is a small tree found in tropical areas in Africa. It is used in traditional medicine to treat malaria, epilepsy, anxiety, pain, fever, etc. OBJECTIVE: The aim of this study was to investigate the effects of Nauclea latifolia roots decoction on the peripheral and central nervous systems and its possible mechanisms of action. MATERIALS AND METHODS: The analgesic investigation was carried out against acetic acid-induced writhing, formalin-induced pain, hot-plate and tail immersion tests. The antipyretic activity was studied in Brewer's yeast-induced pyrexia in mice. Rota-rod test and bicuculline-induced hyperactivity were used for the assessment of locomotor activity. RESULTS: Nauclea latifolia induced hypothermia and had antipyretic effects in mice. The plant decoction produced significant antinociceptive activity in all analgesia animal models used. The antinociceptive effect exhibited by the decoction in the formalin test was reversed by the systemic administration of naloxone, N(ω)-L-nitro-arginine methyl ester or glibenclamide. In contrast, theophylline did not reverse this effect. Nauclea latifolia (antinociceptive doses) did not exhibit a significant effect on motor coordination of the mice in Rota-rod performance. Nauclea latifolia protected mice against bicuculline-induced behavioral excitation. DISCUSSION AND CONCLUSION: Overall, these results demonstrate that the central and peripheral effects of Nauclea latifolia root decoction might partially or wholly be due to the stimulation of peripheric opioid receptors through the action of the nitric oxide/cyclic monophosphate guanosin/triphosphate adenosine (NO/cGMP/ATP)-sensitive- K(+) channel pathway and/or facilitation of the GABAergic transmission.

In vitro hepatoprotective and antioxidant activities of crude extract and isolated compounds from Ficus gnaphalocarpa.

The in vitro hepatoprotective effect of the methanolic extract from Ficus gnaphalocarpa (Miq.) Steud. ex A. Rich (Moraceae) on the CCl4-induced liver cell damage as well as the possible antioxidant mechanisms involved in this protective effect, were investigated. The phytochemical investigation of this methanolic extract led to the isolation of six compounds identified as: betulinic acid (1); 3-methoxyquercetin (2); catechin (3); epicatechin (4); quercetin (5); and quercitrin (6). The hepatoprotective activity of these compounds was tested in vitro against CCl4-induced damage in rat hepatoma cells. In addition, radical-scavenging activity, ß-carotene-linoleic acid model system, ferric-reducing antioxidant parameter and microsomal lipid peroxidation assays were used to measure antioxidant activity of crude extract and isolated compounds. Silymarin and trolox were used as standard references and, respectively, exhibited significant hepatoprotective and antioxidant activities. (5), (6) and (2) showed significant antioxidant and hepatoprotective activities as indicated by their ability to prevent liver cell death and lactate dehydrogenase leakage during CCl4 intoxication. These results suggest that the protective effects of crude extract of F. gnaphalocarpa against the CCl4-induced hepatotoxicity possibly involve the antioxidant effect of these compounds.