Markhamia lutea leaves aqueous and ethanolic extract with curative anti-inflammatory activity attenuates paclitaxel toxicity in rat's intestine.

OBJECTIVES: Markhamia lutea (M. lutea, Bignoniaceae) is mainly found in tropical/neotropical regions of America, Africa and Asia. The plant's leaves, stems or roots are used to treat anaemia, bloody diarrhoea, parasitic and microbial infections. This study evaluates anti-inflammatory properties (in vitro) of Markhamia lutea and their curative effects on paclitaxel-induced intestinal toxicity (in vivo). METHODS: The anti-inflammatory potential of Markhamia lutea was tested over cytokines (TNF-alpha, IL-6, IL-1ß, IL-10), reactive oxygen species (ROS) and enzymes (cyclooxygenase and 5-lipoxygenase). While in vivo, intestinal toxicity was induced for 10 days by oral administration of paclitaxel (3 mg/kg, 0.05 mL). Animals in each group were further treated with aqueous (300 mg/kg) and ethanolic (300 mg/kg) leaves extracts of Markhamia lutea during 7 days and clinical symptoms were recorded, hematological, biochemical and histological analysis were subsequently performed. RESULTS: In vitro, aqueous (250 µg/mL) and ethanolic (250 µg/mL) extracts of Markhamia lutea inhibited the activities of cyclooxygenase 1 (56.67 % and 69.38 %), cyclooxygenase 2 (50.67 % and 62.81 %) and 5-lipoxygenase (77.33 % and 86.00 %). These extracts inhibited the production of intracellular ROS, extracellular ROS and cell proliferation with maximum IC50 of 30.83 µg/mL, 38.67 µg/mL and 19.05 µg/mL respectively for the aqueous extract, then 25.46 µg/mL, 27.64 µg/mL and 7.34 µg/mL respectively for the ethanolic extract. The extracts also inhibited the production of proinflammatory cytokines (TNFα, IL-1ß and IL-6) and stimulated the production of anti-inflammatory cytokines (IL-10). In vivo, after administration of paclitaxel, the aqueous and ethanolic extracts of Markhamia lutea significantly reduced the weight loss, the diarrheal stools and the mass/length intestines ratio of the treated animals compared to the animals of the negative control group. Biochemically, the extracts lead to a significant drop in serum creatinine and alanine aminotransferase levels, followed by a significant increase in alkaline phosphatase. In addition to bringing the haematological parameters back to normal values after disturbance by paclitaxel, the extracts caused tissue regeneration in the treated animals. CONCLUSIONS: In vitro, aqueous and ethanolic extracts of Markhamia lutea showed anti-inflammatory properties (inhibition of COX1, COX2, 5-LOX activities, inhibition of ROS production and cell proliferation); in vivo, the same extracts showed curative properties against intestinal toxicity caused by paclitaxel.

Gastroprotective and ulcer healing effects of Nauclea pobeguinii (Rubiaceae) on experimentally induced gastric ulcers in male Wistar rats.

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.

Antihypernociceptive and Neuroprotective Effects of the Aqueous and Methanol Stem-Bark Extracts of Nauclea pobeguinii (Rubiaceae) on STZ-Induced Diabetic Neuropathic Pain.

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-1ß, 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-1ß), 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.

Effects of Aqueous and Methanolic Extracts of Stem Bark of Alstonia boonei De Wild. (Apocynaceae) on Dextran Sodium Sulfate-Induced Ulcerative Colitis in Wistar Rats.

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-1ß, 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-1ß, 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.

In Vitro Anti-Inflammatory and In Vivo Antiarthritic Activities of Aqueous and Ethanolic Extracts of Dissotis thollonii Cogn. (Melastomataceae) in Rats.

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.