Evaluation of the preventive potential of graded dietary inclusion of Hyphaene thebaica (Linn) fruit in rat model of colon carcinogenesis.

The preventive effect of Hyphaene thebaica fruit in colon carcinogenesis was evaluated in Wistar rats at 0, 2.5, 5 and 10% inclusion rates for twelve weeks with concomitant 72-h intra-rectal N-methyl-N-nitrosourea (MNU) instillations. Indices of antioxidant status and carcinogenesis were analyzed using spectrophotometric, ELISA, histological and immunohistochemical techniques. The fruit protected against lipid peroxidation and level of early biomarkers of colon carcinogenesis, accompanied by decrease in some endogenous antioxidant enzymes functionality. It also prevented colon tissues against MNU-induced severe inflammations and damage to the mutL-homolog 1 (MLH1) gene. There was significant negative correlation between endogenous antioxidant enzyme activities and carcinoembryonic antigen (CEA) as well as lipid peroxidation, but relationship between total polyphenols and percentage expression of MLH1 proteins as well as endogenous antioxidant enzyme activities was positive. These results validate the folkloric use of H. thebaica fruit in the management of colorectal disorders. PRACTICAL APPLICATIONS: Hyphaene thebaica fruit which is widely consumed in northern Nigeria and other countries of sub-Saharan Africa is rich in fiber and antioxidant polyphenols. These two classes of compounds have demonstrated capacity to prevent colorectal cancer and cancer of other sites. Therefore, the validated protective Hyphaene thebaica fruit suggests that it can be processed for inclusion in beverages/diets as functional foods for prevention and management of colorectal disorders.

Crassocephalum rubens (Juss Ex Jacq) leaf diets ameliorate systemic oxidative stress and tissue damage in a Wistar rat model.

The capacity of Crassocephalum rubens (Juss Ex Jacq) leaf to protect against systemic oxidative stress was evaluated in N-methyl-N-nitrosourea (MNU) - intoxicated rats fed at various inclusion rates for a period of twelve (12) weeks. Major organs and tissues were then assessed for indices of lipid peroxidation and oxidative stress. Crassocephalum rubens leaf significantly (p < .05) sustained the activities of superoxide dismutase and catalase with significant decrease in lipid peroxidation in MNU-intoxicated animals, particularly at 5% and 10% inlusion rates. The dietary inclusion also prevented significant changes in hematological parameters such as neutrophil and lymphocyte counts. It also reduced the severity of histologic damages such as necrosis, epithelial degeneration, inflammatory cell infiltration and other pathological changes to major organs. These results indicate that regular consumption of C. rubens leaf, prevents the deleterious biologic effects of the damaging reactive oxidative species (ROS). PRACTICAL APPLICATIONS: Crassocephalum rubens leaf has potential for development into a nutraceutical or functional food for chemoprevention and management of neurodegenerative diseases and other diseases associated with systemic oxidative stress, This is because its inclusion in the diet has attenuated lipid peroxidation, sustained the activity of antioxidant enzymes and mitigated deleterious changes in blood composition and tissue architecture resulting from exposure to a chemical carcinogen.

Preventive potential of dietary inclusion of Brachystegia eurycoma (Harms) seeds on N-methyl-N-nitrosourea-induced colon carcinogenesis in Wistar rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Brachystegia eurycoma seed is used as dietary condiment and as part of recipes for treating colorectal disorders, while laboratory studies have established that it contains crude fiber and polyphenols which are important in cancer prevention. AIM OF THE STUDY: To establish the efficacy of a Nigerian diet in colon cancer prevention, a study was conducted to evaluate dietary inclusion of Brachystegia eurycoma seed in experimental colon carcinogenesis. METHODS: Rats undergoing intra-rectal instillations of N-Methyl-N-nitrosourea (MNU) were fed B. eurycoma included diets at 0%, 2.5%, 5% and 10% for a period of ten (10) weeks following which they were sacrificed; blood and tissues were monitored for biochemical, histological and immunohistochemical parameters. RESULTS: Brachystegia eurycoma significantly (P < 0.05) prevented MNU-induced elevation of malondialdehyde and carcinoembryonic antigen (CEA) as well as reduced activities of catalase and superoxide dismutase. The colon showed deep mucosal ulceration with moderate inter-glandular inflammation in the MNU control group, but only mild or no inflammation was observed in the colon of the MNU groups fed experimental diets. Similarly, colon immunohistochemistry assay showed that the dietary inclusion significantly prevented MNU-induced damage to mismatch repair gene (MutL homolog1). Positive relationship existed between fiber content of B. eurycoma seeds and MutL homolog1 protein expression while that between polyphenol/flavonoids contents of diets and CEA was negative. CONCLUSION: These data suggest that both dietary fiber and polyphenol/flavonoids contribute synergistically or additively to the potential preventive effect of B. eurycoma seeds in colon carcinogenesis, presumably through mechanisms that involve limiting the extent of oxidative stress and preventing or delaying the onset of pro-carcinogenic inflammatory processes.

Effect of methanolic extract of Tetrapleura tetraptera (Schum and Thonn) Taub leaves on hyperglycemia and indices of diabetic complications in alloxan-induced diabetic rats.

OBJECTIVE: To investigate the ameliorative role of Tetrapleura tetraptera (Schum and Thonn) Taub (T. tetraptera) leaf in hyperglycemia with associated conditions like oxidative stress, kidney damage and disorders in lipid metabolism. METHODS: Five groups of five rats each intraperitoneally received the following treatment schedules for 7 d: untreated normal control, untreated alloxan-diabetic control, diabetic treated with glibenclamide, normal rats treated with extract (50 mg/kg) and diabetic rats treated with the extract. Evaluations were made for fasting blood sugar, body weight changes, malondialdehyde, aspartate aminotransferase, alanine aminotransferase, bilirubin, superoxide dismutase, catalase, lipid profile, packed cell volume, hemoglobin, urea and creatinine in all the rats. RESULTS: Whereas the untreated diabetic rats showed a significant decrease (P<0.05) in packed cell volume, superoxide dismutase, catalase and high-density lipoprotein-cholesterol with a concomitant increase in the levels of malondialdehyde, fasting blood sugar, aspartate aminotransferase, alanine aminotransferase, bilirubin, urea and creatinine, administration of methanolic extract of T. tetraptera leaf or glibenclamide alleviated these altered parameters in the treated rats. CONCLUSIONS: Methanolic extract of T. tetraptera leaves possesses a potent capacity for treatment of diabetes and the accompanying complications, including oxidative stress and hyperlipidemia.

Content of polyphenolic compounds in the Nigerian stimulants Cola nitida ssp. alba, Cola nitida ssp. rubra A. Chev, and Cola acuminata Schott & Endl and their antioxidant capacity.

Varieties of kola nuts (Cola nitida alba, Cola nitida rubra A. Chev, and Cola acuminata Schott & Endl), a group of popular Nigerian and West African stimulants, were analyzed for their content of secondary plant metabolites. The three varieties of the kola nuts contained appreciable levels of (+)-catechin (27-37 g/kg), caffeine (18-24 g/kg), (-)-epicatechin (20-21 g/kg), procyanidin B 1 [epicatechin-(4beta-->8)-catechin] (15-19 g/kg), and procyanidin B2 [epicatechin-(4beta-->8)-epicatechin] (7-10 g/kg). Antioxidant capacity of the extracts and purified metabolites was assessed by two HPLC-based and two colorimetric in vitro assays. Extracts of all varieties exhibited antioxidant capacity with IC 50 values in the range 1.70-2.83 and 2.74-4.08 mg/mL in the hypoxanthine/xanthine oxidase and 2-deoxyguanosine HPLC-based assays, respectively. Utilization of HPLC-based assays designed to reflect in situ generation of free radicals (e.g., HO(*)), as opposed to general assays (DPPH, FRAP) in common use which do not, indicate that, of the major secondary plant metabolites present in kola nut extracts, caffeine is potentially the more effective cancer chemopreventive metabolite in terms of its antioxidant capacity.