Antibacterial and antishigellosis activity of Xylopia staudtii (engl. & diels), Annonaceae.

ETHNOPHARMACOLOGICAL RELEVANCE: Xylopia staudtii is a medicinal plant which fruits are traditionally used in western Cameroon as a spice in the preparation of soups known for their abdominal cramp relieving properties. Often identified as Xylopia africana, its bark is used in the treatment of dysentery in Mont Cameroun localities. This plant could therefore contain active ingredients against intestinal pathogens, including Shigella spp, which are responsible of the deathly dysenteric diarrhoea. AIM OF THE STUDY: This study aims to assess the efficacy of the hydroethanolic extract from Xylopia staudtii bark in immunodepressed mice infected with Shigella flexneri. MATERIALS AND METHODS: Qualitative detection of compounds in the crude extract was done using UPLC-DAD-(HR) ESI-MS analysis in an attempt to link the activity to the chemical composition. The MIC and the MBC of the extract was determined using broth dilution method. Shigellosis was induced by intraperitoneal administration of Shigella flexneri to immunodepressed mice pretreated with streptomycin. These infected mice were then treated with the extract (100, 200 and 400 mg/kg), and reference substances (ciprofloxacin and saline). During the 9 days of treatment, animal morphology, fecal pathology and deaths were recorded. At the end of the treatment period, blood and organs were collected from any surviving animals for hematological, biochemical and histopathological analyses. RESULTS: The extract was found to be significantly active, with a bactericidal effect against Shigella and a bacteriostatic effect against Escherichia coli. It was able to reduce and stop the faecal pathology caused by the infection in mice, as well as the rate of deaths which was brought to zero (0) in animal treated at 400 mg/kg. The bacteria load in faeces was reduced by 100% in animal treated at 400 mg/kg. Xylopia staudtii extract elicited anti-inflammatory properties by reducing MPO activity and Lcn2 intestinal level. It also prevents damages in the intestinal tissue and the shortening of colon which characterise Shigella infection. The serum level of ASAT, ALAT, bilirubin, urea and creatinine in animals treated with the extract was similar to those of normal animal used in the study. These activities of the plant may be due at least in part to the presence of ent-kauran type diterpens such as kaurenoic acid identified in the extract. CONCLUSION: These findings support the usage of Xylopia staudtii as an antimicrobial against bacillary dysentery, making this plant a potential candidate for the formulation of an improved standardized traditional medicine.

Antibacterial Flavonoids and Other Compounds from the Aerial Parts of Vernonia guineensis Benth. (Asteraceae).

An extensive phytochemical study of the aerial parts of Vernonia guineensis Benth. (Asteraceae) led to the isolation of a new flavone, vernoguinoflavone and a naturally isolated glycerol ester, eicosanoic acid 2-hydroxy-1,3-propanediyl ester, together with eighteen known secondary metabolites including quercetin, luteolin, vernopicrin, vernomelitensin, ß-amyrin, oleanolic acid, ursolic acid, lupeol, betulinic acid, ß-carotene, a mixture of stigmasterol and ß-sitosterol, ß-sitosterol-3-O-ß-D-glucoside, 2,3-dihydroxypropyl heptacosanoate, pentacosanoic acid, docosan-1-ol, tritriacontan-1-ol, and heptatriacontan-1-ol. Eleven compounds are reported herein for the first time from this species. The structures of these compounds were elucidated on the basis of extensive spectroscopic analyses, particularly 1D and 2D NMR, and HR-ESI-MS and by comparison of their data with those reported in the literature. The crude extract, fractions and some isolated compounds were evaluated for their antibacterial activity against Gram-negative bacteria: Escherichia coli (ATCC 25922), Shigella flexineri (NR 518), Salmonella muenchen, Salmonella typhimurium and Salmonella typhi (ATCC 19430). All the tested compounds demonstrated inhibitory activities against the tested enteric bacteria with MIC values ranging from 3.12 to 100 µg/ml. Three flavonoids isolated from the most active fraction demonstrated the best bioactivities against Escherichia coli, Salmonella muenchen and Salmonella typhimurium with MIC values ranging from 3.12 to 25 µg/mL.

Evaluation of the antidiabetic and antioxidant properties of Morinda lucida stem bark extract in streptozotocin intoxicated rats.

The present research evaluated the antidiabetic and antioxidant properties of M. lucida stem bark (50 and 500mg/kg) and glibenclamide (25mg/kg, standard drug) in acute (Oral glucose tolerance test) and sub-acute (Streptozotocin 60mg/kg, i.p. diabetic model) administration. A group of healthy rats constituted the normal control. The sub-acute experiment lasted 28 days during which water, food intake and weight gain were measured and biochemical parameters analyzed in both plasma and erythrocytes at the end of the experiment. The chemical substances present in M. lucida bark extract were determined. In the Oral glucose tolerance test, the reduction of blood glucose level was statistically significant for both M. lucida extracts and glibenclamide. However, in the diabetic rats acute administration of 500mg/kg extract had better blood sugar lowering effect than glibenclamide, which was better than 50mg/kg extract. Streptozotocin diabetic animal model was characterized by a decrease in weight gain, erythrocyte SOD and CAT activities and an increase in water and food consumption, lipid peroxidation, cholesterol, triglycerides, plasma glucose, creatinine and urea concentrations, and transaminases activities. M. lucida extract and glibenclamide significantly prevented the alteration of these parameters, thus indicating a corrective effect on diabetes and its complications. This study justifies the traditional claim and provides a rationale for the use of M. lucida to treat diabetes. Its antioxidant properties may serve to curb oxidative stress and hence prevent the diabetic complications related to oxidative stress. Chemical substances, which may be accountable for the antidiabetic and antioxidant properties of M. lucida were detected in the aqueous extract of M. lucida bark.

Antihypertensive activities of the aqueous extract of Kalanchoe pinnata (Crassulaceae) in high salt-loaded rats.

ETHNOPHARMACOLOGICAL RELEVANCE: The leaves of Kalanchoe pinnata (Crassulaceae) are used in Cameroon folk medicine to manage many diseases such as cardiovascular dysfunctions. In this work, we aimed to evaluate the activities of aqueous leaf extract of Kalanchoe pinnata on the blood pressure of normotensive rat (NTR) and salt hypertensive rats (SHR), as well as its antioxidant properties. MATERIALS AND METHODS: Hypertension was induced in rats by oral administration of 18% NaCl for 4 weeks. For the preventive study, three groups of rats received 18% NaCl solution and the plant extract at 25 mg/kg/day, 50 mg/kg/day or 100 mg/kg/day by gavage. Two positive control groups received 18% NaCl solution and either spironolactone (0.71 mg/kg/day) or eupressyl (0.86 mg/kg/day) by gavage for 4 weeks. At the end of this experimental period, systolic arterial pressure (SAP), diastolic arterial pressure (DAP) and heart rate (HR) were measured by the invasive method. Some oxidative stress biomarkers (reduced glutathione (GSH), superoxide dismutase (SOD), nitric monoxide (NO) were evaluated in heart, aorta, liver and kidney. NO level was indirectly evaluated by measuring nitrite concentration. RESULTS: Kalanchoe pinnata extract prevented significantly the increase of systolic and diastolic arterial pressures in high salt-loaded rats (SHR). In SHR, concomitant administration of Kalanchoe pinnata at 25, 50 and 100 mg/kg/day significantly prevented the increase in blood pressure by 32%, 24% and 47% (for SAP); 35%, 33% and 56% (for DAP), respectively. No significant change was recorded in heart rate of those rats. The plant extract improved antioxidant status in various organs, but more potently in aorta. Thus, antioxidant and modulatory effects of Kalanchoe pinnata at the vasculature might be of preponderant contribution to its overall antihypertensive activity. CONCLUSION: The work demonstrated that the concomitant administration of high-salt and the aqueous extract of Kalanchoe pinnata elicits prevention of salt-induced hypertension in rat. This antihypertensive activity is associated with an improvement of antioxidant status. Overall, results justify and support the use of Kalanchoe pinnata as antihypertensive medicine.

Evaluation of the antidiarrheal and antioxidant properties of Justicia hypocrateriformis.

CONTENT: Justicia hypocrateriformis Vahl (Acanthaceae) is used as an herbal remedy for diarrhea in Cameroon folk medicine. OBJECTIVE: This study evaluates the antidiarrheal and antioxidant properties of the aqueous extract of J. hypocrateriformis (JH). MATERIALS AND METHODS: Preliminary phytochemical screening and an acute toxicity testing of the extract were carried out. The antidiarrheal activity of JH extract (100, 250, and 500 mg/kg) was assessed at curative and preventive levels in castor oil-induced diarrhea in mice. The antioxidant activity was measured by ferric reducing antioxidant power (FRAP), total phenolic content, and radical scavenging activity. RESULTS: A high lethal dose (LD50) of 14.35 g/kg obtained in acute toxicity implies the extract is not toxic. Phytochemical screening revealed the presence of phenols, tannins, flavonoids, saponins, anthraquinones, and anthocyanins. JH showed a significant protection against castor oil-induced diarrhea as evidenced by a decrease in the number of defecation and wet stool. JH (100-500 mg/kg, p.o.) produced a non-significant dose-dependent decrease in castor oil-induced intestinal transit in the preventive study. In the curative and in healthy mice study, the decrease was only significant at 500 mg/kg. JH possessed a radical scavenging activity with an IC50 of 9.93 mg/ml compared to 4.90 mg/ml for catechin. JH FRAP of 2703.77 ± 0 mg/g (catechin equiv) and phenolic concentration of 14 169.99 ± 612.39 mg/g (catechin equiv) were also obtained. CONCLUSION: Justicia hypocrateriformis extract possesses antidiarrheal activity supported by its antioxidant potential and phytochemical constituents.

Analgesic and antiinflammatory activities of the ethyl acetate fraction of Bidens pilosa (Asteraceae).

Bidens pilosa is an Asteraceae widely used in traditional medicine for the treatment of various ailments including pain and inflammation. The present work was undertaken to assess the analgesic and antiinflammatory properties of the ethyl acetate fraction of methylene chloride/methanol (1:1) extract of leaves of Bidens pilosa at the gradual doses of 50, 100 and 200 mg/kg in mice and rats, respectively. The analgesic properties of Bidens pilosa were investigated using the acetic acid writhing, hot plate, capsaicin and formalin-induced pain models. This was followed by a study of the antiinflammatory properties using carrageenan, dextran, histamine and serotonin to induce acute inflammation in rat hind paw. The extract provided a significant (p < 0.01) reduction in pain induced by all four models of nociception. It also presented significant (p < 0.05) antiinflammatory activity in all four models of acute inflammation. These results show that the ethyl acetate fraction of methylene chloride/methanol (1:1) of Bidens pilosa has both analgesic and antiinflammatory properties. The qualitative analysis of the fraction by the high-performance liquid chromatography (HPLC) fingerprint revealed the presence of two flavonoids, namely quercetin and iso-okanin, known to have antiinflammatory and antinociceptive properties, which could be responsible for the analgesic and antiinflammatory effects observed.