OBJECTIVES:Ulcerative colitis, with a complex and poorly understood aetiology, is a chronic inflammatory disease of the colon. Current therapies present many side effects and lack efficiency. This study aimed to assess the healing properties of aqueous and ethanolic extracts from the roots of Dracaena arborea on ulcerative colitis induced in rats. METHODS:Acetic acid (4 %) was injected (intrarectal) to induce colitis. Prednisolone (20 mg/kg), aqueous (500 mg/kg) and ethanolic (100 mg/kg) extracts were administered orally. Clinical parameters were measured through stool consistency, relative body mass, mass-to-length ratio, macroscopic alterations of the colon, and serum and haematological parameters. Oxidative stress markers (in both serum and tissue) and anti-inflammatory parameters were evaluated. RESULTS:The results showed that both extracts significantly reduced diarrhea severity, ulcer scores, and prevented the reduction in the colon mass/length ratio. The aqueous and ethanolic extracts significantly increased red blood cell count and haematocrit percentage, as well significantly reducing white blood cell, lymphocyte, monocyte, and granulocyte counts. Regarding oxidative stress markers, in both serum and tissue, the extracts significantly reduced MDA concentrations while increasing GSH concentrations, SOD and catalase activities. The aqueous and ethanolic extracts also significantly reduced NO concentrations and MPO activity. Only the ethanolic extract significantly inhibited TNF-α, IL-6 and IL-1β production. Additionally, both extracts exhibited reparative effects on intestinal epithelium by activating tissue regeneration mechanisms. CONCLUSIONS:These findings suggest that D. arborea possessed anti-colitis effects in acetic acid-induced ulcerative colitis in rats.

Cissus quadrangularis Linn. (C. quadrangularis, Vitaceae) is a plant reported to treat injured tendons, broken bones, asthma, stomach ache, scurvy, and digestive disorders. The present study evaluated the antihyperalgesic effects of ethanolic extract of C. quadrangularis Linn. Vincristine sulfate (100 μg/kg, i.p.) was administered in rats for 10 days with 2 days break to induce painful peripheral neuropathy. Mechanical hyperalgesia and allodynia tests were performed to assess the threshold of painful neuropathy. Calcium levels in the sciatic nerve, oxidant stress markers, and levels of GABA and 5-HT were also determined in the brain and spinal cord after 15 days. Ethanolic extract of C. quadrangularis (180 and 360 mg/kg) and pregabalin (50 mg/kg) were administered for 15 consecutive days. The results revealed that the extract significantly (p < 0.001) inhibited hyperalgesia and allodynia in animals after vincristine administration. The extract decreased total calcium levels in the sciatic nerve, MDA levels while increasing GSH activity, 5-HT level, as well as GABA levels in the brain and spinal cord. The results of this study suggest that the ethanolic extract of C. quadrangularis uses antioxidant capacity, calcium inhibitory action, and neuromodulation of GABA and 5-HT to prevent the development of painful neuropathy after vincristine administration. This demonstrates that C. quadrangularis is a promising molecule for the management of peripheral neuropathic pain induced by anticancer drugs.

In traditional Cameroonian medicine, to relieve many inflammations, parts of Vernonia guineensis, are very widely used. This study considered the evaluation of acute toxicity and anti-inflammatory properties of the hydroethanolic extract of the roots of Vernonia guineensis. In an acute toxicity study, 250, 2500, and 5000 mg/kg were administered orally to mice in a single dose, and general behavior, adverse effects, and mortality were monitored. In vitro and in vivo anti-inflammatory tests were performed, and then histological, serum, hematological, and oxidative stress parameters have been evaluated. In an acute toxicity, all groups revealed neither mortality nor any significant alteration in behavior; only drowsiness, sedation, and lethargy were observed at 5000 mg/kg. For in vitro tests, the extract inhibited anti-inflammatory activity. In the formalin test, at 250 mg/kg, the extract inhibited edema with a percentage of 56.41% (4th hour) in an acute treatment and 74.44% (10th day). Joint edema was reduced by 67.24% (24th hour) in a single treatment and by 74.25% (7th day) in repeated treatment. The extract caused an increase in red blood cell, hemoglobin, and serum protein levels and reduced the white blood cells as well as the activities of alkaline phosphatase and alanine aminotransferase. The extract modulated oxidative stress parameters in the brain, spinal cord, liver, and kidneys. The extract protected the joint by reducing the bone and cartilage erosion. The present work highlights the anti-inflammatory, antioxidant, and antianemic properties of the hydroethanolic extract of the roots of Vernonia guineensis, which supports its empirical use in traditional medicine for the treatment of inflammatory pathologies.

OBJECTIVES:In this study, we determined the gastroprotective and ulcer-healing effects of extracts (aqueous and methanolic) of Nauclea pobeguinii stem-back.METHODS:Gastroprotective and healing activity were evaluated following a HCl/ethanol and an indomethacin-induced acute ulcers models; acetic acid, pylorus-ligature, pylorus ligature/histamine and pylorus ligature/acetylcholine-induced chronic ulcers models.RESULTS:It emerges from this study that, at 100, 200 and 400 mg/kg, the extracts significantly reduced the various ulceration parameters. Compared to negative control male rats, the aqueous (100 mg/kg) and methanolic (400 mg/kg) extracts of Nauclea pobeguinii inhibited the ulcers induced by HCl/ethanol by 80.76 % and 100 % respectively, as well as ulcers induced by indomethacin by 88.28 % and 93.47 % respectively. Animals that received 200 mg/kg of both extracts showed a significant reduction in the levels of monocytes, lymphocytes, nitric oxide, MDA and a significant increase in the activities of SOD and catalase. Histological analysis showed repaired mucous epithelium at all doses of both extracts. Aqueous and methanol extracts inhibited ulceration indices by 89.33 % and 88.53 % for pylorus ligature, 83.81 % and 61.07 % for pylorus ligature/acetylcholine and 87.29 % and 99.63 % for pylorus ligature/histamine respectively. Both extracts protected the stomach lining with percentages inhibition of 79.49 % and 81.73 %, respectively in the ethanol test. The extracts induced a significant increase in mucus mass (p<0.001).CONCLUSIONS:The aqueous and methanol extracts of Nauclea pobeguinii healed ulcers thanks to their anti-inflammatory, anti-oxidant, anti-secretory and cytoprotective properties.

Nauclea pobeguinii (N. pobeguinii) is a plant used in African medicine to treat many gastroduodenal diseases. In this study, we determined the gastro-protective mechanisms and anti-Helicobacter pylori (H. pylori) properties of N. pobeguinii extracts. Wound healing activity (acetic acid test), anti-secretory properties (pyloric ligation, pyloric ligation/acetylcholine and pyloric ligation/histamine tests) and cytoprotective effects (ethanol test) were assessed in female rat, the anti-Helicobacter pylori (agar well diffusion method) was also evaluated. At doses of 100, 200 and 400 mg/kg, the extracts reduce (p < 0.001) the various ulceration parameters. In the acetic acid test, the extracts (200 mg/kg) reduced ulcerated areas by 99.23% (aqueous) and by 98.47% (methanol), levels of monocytes, lymphocytes, nitrogen, malondialdehyde and increased (p < 0.001) superoxide dismutase and catalase activities. Histological analysis showed repair of the mucosal epithelium at all doses of both extracts. Aqueous and methanol extracts inhibited ulceration indices by 99.68 and 99.33% (pyloric ligation), 83.81% and 61.07% (pyloric ligation/acetylcholine), 97.49% and 98.50% (pylorus ligation/histamine); they increased (p < 0.001) the mucus mass and uterine mass. In vitro, the different H. pylori isolates were sensitive to both extracts; the aqueous extract showed strong anti-urease activity, a large diameter of the inhibitory zone and a better minimum inhibitory concentration. Aqueous and methanolic extracts of N. pobeguinii healed ulcers through their estrogen-modulating anti-inflammatory, antioxidant, anti-secretory and cytoprotective properties. The aqueous extract of N. pobeguinii could be a good solution for the treatment of this infection.

Objective: To evaluate the anti-arthritic effect of aqueous and methanolic extracts of Distemonanthus benthamianus. Methods: Monoarthritis was induced by an injection of 0.3 mL zymosan A (0.9% NaCl, v/v) in the right posterior knee joints of rats. Then, joint diameter and pain threshold were determined. Polyarthritis was induced by an intracaudal injection of complete Freund's adjuvant and rats were treated from day 14 post 1st complete Freund's adjuvant injection until 28 day. The clinical, hematological, biochemical and oxidative stress parameters were evaluated. In addition, histological analysis of the knee joint was perfomed in both tests. Results: The aqueous and methanolic extracts of Distemonanthus benthamianus at a dose of 500 mg/kg ameliorated zymosan A-induced monoarthritis, as evidenced by reduced joint diameter, increased pain threshold, as well as improved joint architecture. In addition, both extracts of Distemonanthus benthamianus markedly increased body weight and pain threshold, while reducing paw edema in polyarthritic rats. They also led to a marked decrease in platelets and white blood cells (P < 0.05), as well as a significant increase in red blood cells, hemoglobin and hematocrit (P < 0.05). The aqueous and methanolic extracts of Distemonanthus benthamianus significantly reduced alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase activities, while increasing serum protein levels (P < 0.05) with no significant variation in creatinine level. Moreover, both extracts increased catalase and glutathione activities (P < 0.05), and inhibited malondialdehyde and nitric oxide production (P < 0.01 and P < 0.001) in the liver and kidneys. Histological analysis of the joints showed that both extracts triggered tissue reparation. Conclusions: Distemonanthus benthamianus could be used as a potential candidate in the treatment of rheumatoid arthritis.

Cissus quadrangularis Linn. (Vitaceae) is a plant used to treat injured tendons, broken bones, asthma, stomach ache, scurvy and digestive disorders. The present study purposed to evaluate the antihyperalgesic effects ( in vivo ) and the immunomodulatory, antioxidant and anti-inflammatory properties ( in vitro ) of aqueous and ethanolic extracts of Cissus quadrangularis ( C. quadrangularis ). Immunomodulatory (chemiluminescence, cytokines and cell proliferation), anti-inflammatory (protein denaturation, 5-lipoxygenase, cyclooxygenase 1 and 2) and antioxidant (DPPH, ABTS and NO) tests were performed in vitro, while the anti- hyperalgesic (vincristine) investigations were conducted in vivo on Wistar rats. The results revealed that extracts developed immunomodulatory activity by inhibiting the production of ROS (intracellular/extracellular), of TNFα, IL-1β, IL-6 as well as inhibiting cell proliferation, and by stimulating the production of IL-10. The anti-inflammatory activity of the extracts was demonstrated by an inhibition of 5-LOX, protein denaturation and cyclooxygenases 1 and 2. In addition, extracts showed interesting scavenging effects, attesting their antioxidant potential. The extracts administered to the animals (180 and 360 mg/kg) inhibited (p < 0.001) hyperalgesia and allodynia in animals. These extracts also led to the reduction in serum and sciatic nerve levels of TNFα, IL-1β and IL-6, as well as to an increase in cell growth factors (NGF and IGF) production of treated animals. These results suggest that extracts of C. quadrangularis use immunomodulatory, anti-infammatory and antioxidant capacity to prevent and/cure painful neuropathy after vincristine administration. C. quadrangularis is therefore a promising natural substance for the management of neuropathic pain.

An ulcer is an erosion of the gastric mucosa that occurs following an imbalance between the aggression and protective factors and/or an infection with Helicobacter pylori (H. pylori). About 90-100% of duodenal ulcers and 70-80% of gastric ulcers are caused by H. pylori. The objective of this work was to evaluate in vitro the anti-H. pylori activity and then the anti-inflammatory and antioxidant properties of aqueous and methanol extracts of Alstonia boonei. The anti-H. pylori tests (CMI and antiureasic activity) were determined using the agar well diffusion method, the microbroth dilution method, and the measurement of ammonia production by the indophenol method; the anti-inflammatory properties were evaluated by inhibition of proteinases, denaturation of albumin, production of NO by macrophages, cell viability, and hemolysis of red blood cells by heat; then, the antioxidant properties were evaluated by the FRAP method (ferric reducing antioxidant power) and the DPPH (1,1-diphenyl-2-picrylhydrazyl) test. The results show that the best trapping of the DPPH radical was obtained with the methanol extract (EC50 = 8.91 μg/mL) compared to the aqueous extract (EC50 = 19.86 μg/mL). The methanol extract also showed greater iron-reducing activity than the aqueous extract and vitamin C. Furthermore, at the concentration of 200 μg/mL, the methanol extract showed a percentage (96.34%) strains of H. pylori higher than that of the aqueous extract (88.52%). The MIC90 of the methanol extract was lower than that of the aqueous extract. The methanol extract showed a higher percentage inhibition (85%) of urease than the aqueous extract (73%). The methanol extract at a concentration of 1000 μg/mL showed the greatest ability to inhibit proteinase activity, albumin denaturation, and red blood cell hemolysis; on the other hand, maximum cell viability and greater production of nitrite oxide by macrophages were obtained with the aqueous extract. Aqueous and methanol extracts of Alstonia boonei possess anti-H. pylori which would probably be linked to their antioxidant and anti-inflammatory properties.

The greatest common and devastating complication of diabetes is painful neuropathy that can cause hyperalgesia and allodynia. It can disturb psychosocial functioning by increasing levels of anxiety and depression. This work was designed to evaluate the antihyperalgesic, antidepressant, and anxiolytic-like effects of the aqueous and methanol extracts of Nauclea pobeguinii stem-bark in diabetic neuropathy induced by streptozotocin in mice. Diabetic neuropathy was induced in mice by the intraperitoneal administration of 200 mg/kg streptozotocin (STZ) to provoke hyperglycemia. Nauclea pobeguinii aqueous and methanol extracts at the doses of 150 and 300 mg/kg were administered by oral route, and their effects were evaluated on antihyperalgesic activity (Von Frey filaments, hot plate, acetone, and formalin tests), blood glucose levels, body weight, serum, sciatic nerve proinflammatory cytokines (TNF-α, IL-1β, and IL-6) and sciatic nerve growth factor (IGF and NGF) rates, depression (open field test, forced swimming test, tail suspension test), and anxiety (elevated plus maze, light-dark box test, social interaction). Oral administration of Nauclea pobeguinii stem-bark aqueous and methanol extracts (150 and 300 mg/kg) produced antihyperalgesic, antidepressant, and anxiolytic-like effects in STZ-induced diabetic neuropathic mice. Extracts also triggered a decrease in glycaemia and increased body weight in treated animals. They also significantly ( p <0.001) reduced tumour necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1β), and IL-6 and significantly ( p <0.001) increased nerve growth factor (NGF) and insulin-like growth factor (IGF) in sciatic nerves. The results of this study confirmed that Nauclea pobeguinii aqueous and methanol extracts possess antihyperalgesic, antidepressant, and anxiolytic activities and could be beneficial therapeutic agents.

Diabetic neuropathy, which affects 7 to 9% of the world’s population and that is usually accompanied by anxiety and depression, is chronic pain that results from impaired function of the central or peripheral nervous system. This study aimed at evaluating the antihypernociceptive, antiallodynic, anxiolytic, and antidepressant effects of Dissotis thollonii extracts. Diabetic neuropathy was induced by intraperitoneal injection of streptozotocin (200 mg/kg) in mice. The aqueous and ethanol extracts (250 and 500 mg/kg) were administered orally. Hyperalgesia (thermal and chemical), allodynia (mechanical and thermal), anxiety (high plus labyrinth, light-dark box, and social interaction), and depression (open field test, suspension test tail, and forced swimming test) were evaluated, and then the levels of some cytokines and growth factors were determined. The aqueous and ethanol extracts of Dissotis thollonii demonstrated significant antihypernociceptive (inhibition of hyperalgesia and allodynia), anxiolytic, and antidepressant activities in mice made diabetic by STZ. The extracts also significantly inhibited (p<0.001) the levels of TNF- α , IL-1 β , and IL-6 in the blood as well as the levels of TNF- α , IL-1 β , IL-6, IGF, and NGF in the sciatic nerve. This study shows that the extracts of Dissotis thollonii have antihypernociceptive and neuroprotective effects which could be linked to the inhibition of proinflammatory cytokines and growth factors in the blood and the sciatic nerve.

Distemonanthus benthamianus (Caesalpiniaceae) is a plant from the Cameroon pharmacopoeia very widely used in the treatment of many pathologies among which are gastrointestinal disorders. The main purpose of this study was to assess the healing properties of gastric ulcer from the methanolic extract of Distemonanthus benthamianus and its mechanisms of action. The healing properties of gastric ulcers (chronic ulcer model induced by ethanol and indomethacin) were evaluated in vivo in adult male rats, while the mechanisms of action were evaluated in vitro by anti-inflammatory assay (protein denaturation, cyclooxygenase, and lipoxygenase assays) and immunomodulatory assay (ROS production (using technical chemiluminescence), cytokine (TNF-α, IL-1β, IL-6) production (using ELISA), proliferation of T cells (using liquid scintillation counter), and cytotoxicity (using MTT assay)). The methanolic extract of Distemonanthus benthamianus inhibited protein denaturation (75.63%) and the activities of cyclooxygenase (78.92%) and 5-lipoxygenase (81.54%). The extract also significantly (p < 0.001) inhibited intracellular and extracellular ROS production and T cell proliferation and reduced significantly (p < 0.01, p < 0.001) TNF-α, IL-1β, IL-6, and PGE2 production. At all doses (125, 250, and 500 mg/kg), the extract significantly reduces the ulceration index and the area of ulceration and significantly increases the mass of gastric mucus. In addition, the extract significantly decreases the level of MDA, significantly increases the activities of catalase and glutathione, and then improves the hematological parameters in sick animals. Histological micrographs show that in the presence of the extract, there is advanced reepithelialization with recovery of the ulcerated epithelium. Thus, the extract of Distemonanthus benthamianus has healing properties against gastric ulcers which are associated with its anti-inflammatory, immunomodulatory, and antioxidant effects.

Among the most exploited species in Cameroon, Alstonia boonei is widely used in African medicine for the relief of several pathologies including gastrointestinal disorders. This study was conducted in order to assess the effects of aqueous and methanol stem-bark extracts of Alstonia boonei on DSS- (dextran sodium sulfate-) induced intestinal colitis and to determine its antioxidant potential. The classes of secondary metabolites present in these extracts were determined by chemical screening. The production of TNF-α, IL-6, IL-1β, and PGE2 was performed by in vitro ELISA analysis. Anticolitis effects were determined using an in vivo model of ulcerative colitis induced by DSS. The colitis was induced with a double dose of DSS (3% and 1%), and the aqueous and methanol extracts were administered orally from the 6th day after commencement of induction. The phytochemical screening revealed the presence of six classes of secondary metabolites in these crude extracts: tannins, saponins, alkaloids, steroids, flavonoids, and phenols. Methanol and aqueous extracts of Alstonia boonei significantly (P < 0.001) inhibited TNF-α, IL-6, IL-1β, and PGE2 production stimulated by LPS. Both extracts at all doses significantly reduced (P < 0.01, P < 0.001) the signs of DSS-induced colitis in the Wistar rats by decreasing inflammation and chronic colon damage. In addition, the extracts significantly (P < 0.001) reduced malondialdehyde and nitric oxide levels in the colon and significantly (P < 0.01) increased superoxide dismutase and catalase and reduced glutathione (P < 0.05). Both extracts showed greater activity than the reference substance (prednisolone 4 mg/kg) used in this study. This study has demonstrated that aqueous and methanol extracts of Alstonia boonei stem bark have healing properties against colitis experimentally induced by DSS in rats.

Objective: To explore the immunomodulatory, anti-inflammatory, anti-oxidant and anti-arthritic activity of aqueous and methanolic extracts of Nauclea pobeguinii stem bark. Methods: For in vitro assays, the production of reactive oxygen species (chemiluminescence technique), the proliferation of T cells (liquid scintillation counter method), as well as the inhibition of cyclooxygenase, lipoxygenase, protein denaturation, and free radicals [DPPH, ABTS and nitric oxide (NO) inhibition methods] were evaluated. For in vivo assays, a polyarthritis model was induced by complete Freund’s adjuvant in rats. The aqueous and methanolic extracts of Nauclea pobeguinii stem bark were administered orally at 150 and 300 mg/kg. After 28 days of treatment, the total blood was taken to quantify the hematological parameters and the serum was used to evaluate the biochemical parameters (alanine aminotransferase, aspartate transaminase, phenylalnine ammonialyase, and proteins) and oxidative stress parameters (malondialdehyde, catalase, superoxide dismutase, glutathione and NO), and then the knee joint was removed for histological analysis. Results: The extracts of Nauclea pobeguinii significantly reduced the production of intra- and extracellular reactive oxygen species and decreased T cell proliferation. They had an inhibitory effect on cyclooxygenase, lipoxygenase, and protein denaturation, and both extracts had antioxidant capacity on DPPH, ABTS and NO. Both extracts alleviated joint inflammation and pain sensitivity after complete Freund’s adjuvant injection, reduced alanine aminotransferase, aspartate transaminase, alkaline phosphatase, NO and malondialdehyde levels, increased protein concentration, superoxide dismutase, catalase and glutathione activity, and restored the cytoarchitecture of the joint after complete Freund’s adjuvant injection. Conclusions: The aqueous and methanolic extracts of Nauclea pobeguinii have immunomodulatory, anti-inflammatory, anti-oxidant and anti-arthritic properties.

Nauclea diderrichii , is a common woody plant in Africa where it is traditionally used for the relief and treatment of multiple pain-related conditions. The aim was to evaluate the inflammatory and anti-arthritic properties of the aqueous extract of N. diderrichii stem bark. Carrageenan and formalin were used to induce inflammation while zymosan A was used to induce monoarthritis in rats. The extract was given orally at doses of 100, 200 and 400 mg/kg. The extract significantly reduced carrageenan-induced edema up to 6 h, with 61.94% (6th hour). The extract induces a significant inhibition of the formalin-induced edema from the 2nd to the 8th hour with 61.50% (2nd hour). In continuous treatment, the activity of the extract remains significant from the 2nd to the 10th day of treatment with 63.85% (9th day). The extract (400 mg/kg) induces a significant decrease of the organ weight while the body weight increases significantly. At 400 mg/kg, the extract significantly increases the levels of red blood cells, hemoglobin and proteins, as well as the catalase and SOD activities, then a significant decrease of the levels of white blood cells, lymphocytes, hematocrit, MDA and NO. Furthermore, the extract significantly inhibited zymosan A-induced edema from the 1st to the 5th day with 60.99% (5th day). The joints of the treated animals show a close to normal architecture compared to that of the untreated animals. These results demonstrate the anti-inflammatory and anti-arthritic properties of N. diderrichii and confirm its traditional use to relieve pain and inflammation.

Abstract Objectives In African traditional medicine, Distemonanthus benthamianus (Caesalpiniaceae) is used to treat many diseases including gastric ulcers. We evaluated in this study, the cytoprotective and antisecretory properties of the methanolic extract of the stem bark of this plant using different technics of gastric lesion induction. Methods Cytoprotective and antisecretory activity of the methanolic extract of D. benthamianus stem bark was evolved through six methods of gastric lesion induction in experimental Wistar male rats (150–200 g): (1) gastric lesions induced by HCl/ethanol, (2) gastric lesions induced by Indomethacin- HCl/ethanol, (3) gastric lesion induced by Indomethacin, (4) gastric lesions induced by Pylorus ligation, (5) gastric lesions induced by histamine-Pylorus ligation, (6) gastric lesions induced by carbachol-Pylorus ligation. Mucus and gastric mucosal ulceration were evaluated. pH, gastric volume, and acidity were quantified in all pylorus ligation induction technics. Nitric oxide (NO) level was determined in indomethacin induced gastric ulcers. Results At different doses (125, 250 and 500 mg/kg), extract reduced significantly the ulcer index. In all models used, that is 100.00% with HCl/ethanol; 100.00% with HCl/ethanol/indomethacin; 95.70% with Indomethacin; 74.79% with pylorus ligation, 95.94% histamine-Pylorus ligation, 99.54% carbachol-Pylorus ligation at the highest dose of 500 mg/kg. The lesion formation reduces in all the methods used followed by a significant increase of mucus production. The pylorus ligation technic revealed that the extract has an antisecretory activity. Conclusions The methanolic extract of D. benthamianus stem bark has both cytoprotective and antisecretory effects. This extract exerts its antisecretory effect trough cholinergic and histaminergic pathways.

Dissotis thollonii Cogn. (Melastomataceae) is a tropical plant widely used in traditional Cameroonian medicine to relieve and treat many pathologies. It is widespread in the western region where it is used to treat typhoid fever, gastrointestinal disorders, and inflammatory diseases. The purpose of this study is to scientifically demonstrate the anti-inflammatory and antiarthritic properties of the aqueous and ethanolic extracts of the leaves of Dissotis thollonii. The anti-inflammatory properties were evaluated in vitro by inhibition tests for cyclooxygenase, 5-lipoxygenase, protein denaturation, extracellular ROS production, and cell proliferation; while antiarthritic properties were evaluated in vivo in rats using the zymosan A-induced monoarthritis test and the CFA-induced polyarthritis model. This study shows that aqueous and ethanolic extracts at a concentration of 1000 μg/ml inhibit the activity of cyclooxygenase (47.07% and 63.36%) and 5-lipoxygenase (66.79% and 77.7%) and protein denaturation (42.51% and 44.44%). Similarly, both extracts inhibited extracellular ROS production (IC50 = 5.74 μg/ml and 2.96 μg/ml for polymorphonuclear leukocytes, 7.47 μg/ml and 3.28 μg ml for peritoneal macrophages of mouse) and cell proliferation (IC50 = 16.89 μg/ml and 3.29 μg/ml). At a dose of 500 mg/kg, aqueous and ethanolic extracts significantly reduce edema induced by zymosan A (69.30% and 81.80%) and CFA (71.85% and 79.03%). At the same dose, both extracts decreased sensitivity to mechanical hyperalgesia with 69.00% and 70.35% inhibition, respectively. Systemic and histological analyzes show that both extracts maintain the studied parameters very close to normal and greatly restored the normal architecture of the joint in animals. Dissotis thollonii would therefore be a very promising source for the treatment of inflammatory diseases.

Background Nauclea pobeguinii is a plant species found in the centre region of Cameroon. The stem bark of this plant is traditionally used to ease pain and cure inflammation. Method This study was undertaken to evaluate the effects of doses 150 and 300 mg/kg of the aqueous and methanolic stem bark extracts from Nauclea pobeguinii on acute pain, acute and chronic inflammation induced by formalin and arthritis induced by zymosan A in rats. Oxidative stress parameters such as catalase, malondialdehyde and nitric oxide were measured in rats subjected to chronic inflammation. The standard used was diclofenac at 5 mg/kg. Results Aqueous extract as well as methanolic extract of Nauclea pobeguinii led to a significant reduction in the second phase of formalin induced pain with 54.22 and 48.02% of inhibition percentage, respectively. The formalin-induced inflammatory oedema was reduced by both extracts, and this effect remains significant until the tenth day of treatment. Equally, extracts significantly increased the catalase activity and inhibited the production of malondialdehyde (MDA) in serum, brain and spinal cord and NO reduction only in serum. Both extracts significantly reduced the articular oedema induced by zymosan A for 6 h and for 5 days. Furthermore, the histological study of the articulations shows a non-altered synovial membrane and a small cartilage in all treated animals versus negative control group. Conclusions From these results, it can be concluded that pain, inflammation and arthritic healing activities of both stem bark extracts were expressed in rats and could conciliate the use of this vegetable by traditional African healers.