Antidiarheal activity of catechol and ethyl 5, 8,11,14,17 - icosapentanoate-rich fraction of Annona senegalensis stem bark.

Background and aim: Secretory diarrhea is the most common type of diarrhea. This study aimed at exploring the possible mechanism of antisecretory action of Annona senegalensis stem bark and to identify the bioactive compounds. Experimental procedure: The ability of three crude extract; aqueous, dichloromethane and hexane stem bark extracts to inhibit castor oil-induced stooling in albino rats were assessed. Bioactivity guided fractionation of the most active extract was done using solvent-solvent partitioning (with hexane, dichloromethane, ethylacetate) and column chromatography. In vitro antioxidant activity of the most active sub-fraction was done using standard methods. The most active sub-fraction (25 mg/kg b. wt.) was administered to castor oil-induced diarrheal rats. Diarrheal rats small intestinal malondialdehyde concentration, antioxidant enzyme, cyclooxygenase II and Na+- K+ ATPase activities were determined using standard procedures. GC-MS analysis was done to identify the chemical compounds in the sub-fraction. Result and conclusion: Aqueous extract significantly decreased the number of wet stools. Sub-fraction 1 of ethylacetate fraction of aqueous stem bark extract (EFAS1) showed the highest stool inhibition. The H2O2 scavenging activity of EFAS1 was significantly greater than ascorbic acid. The sub-fraction significantly increased (p < 0.05) the activity of catalase and Na+- K+ ATPase activities but significantly decreased the concentration of malondialdehyde and cyclooxygenase II activity. GC-MS analysis revealed that EFAS1 is rich in catechol, n-hexadecanoic acid and ethyl-5,8,11,14,17-icosapentanoate. The sub-fraction exerts its antisecretory activity by its antioxidative, inhibition of prostaglandin synthesis and stimulation of Na+- K+ ATPase properties due to the presence of catechol, n-hexedecanoic acid and ethyl-5,8,11,14,17-icosapentanoate.

Sphaeranthus senegalensis DC: Evaluation of chemical constituents, oral safety, gastroprotective activity, and mechanism of action of its hydroethanolic extract.

ETHNOPHARMACOLOGICAL RELEVANCE: Sphaeranthus senegalensis DC is a seasonal herb with a spicy smell that grows wild in wet grounds of tropical Africa and Asia. The plant is used in folk medicine for the treatment of various diseases; that includes its use to treat gastric ulcers. AIM OF THE STUDY: This study aimed to investigate the chemical constituents of the hydroethanolic extract of Sphaeranthus senegalensis DC and evaluate its oral safety, gastroprotective activity, and mechanisms of action using laboratory models in rats and mice. MATERIALS AND METHODS: Hydroethanolic extract (70%) of the powdered whole dried material was prepared, and chemical constituents of the resultant extract (denoted HESs) standardized using the high-performance liquid chromatography (HPLC) method. The safety profile of HESs was assessed using 2000 mg/kg, oral (p.o.) for Hippocratic screening in mice, and 800 mg/kg, p.o. for 28 days subchronic toxicity assay in rats. The gastroprotective effect of HESs (25, 100, and 400 mg/kg, p.o.) was investigated using acidified ethanol, piroxicam, water immobilization stress, and acetic acid-induced ulcer models. The gastroprotective mechanisms of HESs were evaluated using its effect on gastric mucus protection, nitric oxide modulation, gastric juice secretory parameters, catalase and myeloperoxidase activities. Histological analysis of the stomach tissues was also carried out. RESULTS: The HPLC analysis indicated the presence of 25.94% phenolics (gallic acid, caffeic acid, and ferulic acid) and 14.53% flavonoids (rutin, morin, luteolin, quercetin, and apigenin). Hippocratic screening and the 28 days subchronic study indicated that HESs is generally safe. Result shows that oral administration of HESs (25, 100 and 400 mg/kg) alleviated the severity of the gastric ulcers induced by acidified ethanol by 35.65% (p < 0.05), 48.70% (p < 0.05) and 78.02% (p < 0.001) respectively; exhibited gastroprotective effect against the gastric lesions induced by piroxicam by 37.97% (p < 0.05), 53.27% (p < 0.05) and 76.23% (p < 0.001) respectively; and decreased the severity of the water immobilization stress-induced gastric ulcers by 32.43% (p < 0.05), 55.26% (p < 0.01) and 74.05% (p < 0.001) respectively, when compared to the vehicle control group. The mechanisms of action assays indicated that the gastroprotective activity was mediated mainly through gastroprotection, antisecretory, and antioxidant activities. Histological analysis showed it inhibited epithelial cell loss, vascular damage, and leucocyte infiltration. CONCLUSION: HESs contains useful phytochemicals, is safe, and exhibited significant gastroprotective action. The results provided justification for its claim in the treatment of gastric ulcers and its evaluation for potential application as a gastroprotective agent.

Alpha Amylase Inhibitory Potential and Mode of Inhibition of Oils from Allium sativum (Garlic) and Allium cepa (Onion).

BACKGROUND: Alpha amylase inhibitors are used in the treatment of type II diabetes mellitus. Allium sativum and Allium cepa, widely consumed as spices have several medicinal uses which include their traditional use in the management of diabetes. This study was conducted to investigate the alpha amylase inhibitory potential and mode of inhibition of A. sativum and A. cepa oils. METHOD: Oil was extracted from dried bulb of A. sativum and A. cepa by Soxhlet extraction. The α-amylase inhibitory potential of the 2 oils were evaluated. The mode of inhibition of the oils were determined from the lineweaver-burk plot and the kinetic parameters obtained from the lineweaver - burk plot. RESULT: A. sativum oil had 58.13 ± 1.09 and 69.8 ± 1.11 percent inhibition at 5.0 and 7.0% concentrations respectively while A. cepa oil had 55.45 ± 1.35, 59.73 ± 1.11 and 65.21 ± 1.11 percent inhibition at 5.0, 7.5 and 10% concentrations respectively. The IC50 values for A. sativum oil, A. cepa oil and acarbose were 3.0 ± 0.02%, 4.4 ± 0.03% and 14.1 ± 0.09% respectively. The lineweaver - burk plot showed that the Vmax of the 2 oils did not change when compared with that of the no inhibitor (no oil) but the Km increased. CONCLUSION: These findings indicate that A. sativum and A. cepa oils are competitive inhibitors of α- amylase and can both be used in the treatment of type II diabetes mellitus. A. sativum oil is a better inhibitor than A. cepa oil.