Morphologic and Morphometric Study on Anti-ulcerogenic Effects of Selected African Nightshades (Solanum Nigrum L.) Geno-types in the Rat

Abstract

Gastric ulcers are a common cause of morbidity and mortality. A gastric ulcer is defined as a peptic ulcer restricted to the gastric mucosa, induced by exposure to excessive hydrochloric acid as well as excessive pepsin activity. It leads to impaired gastric function and pain. Conventional drugs used to manage this condition have toxicity as a common side effect leading to various undesirable effects, which appear to limit the use of these drugs thereby activating research for alternative drugs. African nightshades (Solanum nigrum L.) has been used traditionally as a herbal cure for gastric ulcers in different parts of the world. The objective of this study was to analyze, through morphologic and morphometric means, the anti-ulcerogenic activity of three S. nigrum genotypes namely, S. scabrum, S. sarrachoides and S. villosum genotypes found in Kenya on the rat stomach. Aqueous extracts of the three S. nigrum genotypes were obtained at the vegetative stage and subjected to phytochemical screening. The crude extracts were then administered to three groups of Wistar rats 30 minutes before administration of 1ml ethanol to induce ulceration. A negative control group was given distilled water orally, while a positive control group was given 1ml ethanol orally. Tissues were harvested from the stomach antrum and examined grossly, then processed for examination under light microscopy using Hematoxylin and Eosin, Periodic Acid Schiff and Masson’s Trichrome staining methods. The phytochemical testing revealed the presence of: terpenoids, tannins, saponins, flavonoids as well as glycosides. The three S. nigrum genotypes exhibited antiulcerogenic effects. S. scabrum showed the highest ulcer inhibition score of 76.4%, followed by S. sarrachoides with 72.5% and xv S. villosum with 63.3%. S. nigrum pretreated rats showed less gastric mucosal surface erosion, congestion, edema and hemorrhage. Penetrating ulcers in S. nigrum pretreated rats affected only the gastric pit region of the stomach mucosa, except for those of the S. villosum pretreated rats, which penetrated to affect the gastric glands. S. nigrum pretreatment resulted in more intense staining, (compared with rats that were not treated before ulcer induction) of the mucus regions of gastric glands with PAS and of inter-glandular connective tissue with Masson’s trichrome denoting less gastric damage in these animals. Microscopic ulcer index scores decreased 5.1, 3.6 and 2.4- fold in S. scabrum, S. sacharroides and S. villosum pretreated rats respectively. Results of this work show that extracts of the three S. nigrum genotypes are antiulcerogenic in varying degrees with S. scabrum being the most effective. The observed differences in ulcer inhibition capacities of the three S. nigrum genotypes may be attributed to genetic factors, which reportedly influence the nature and composition of bioactive ingredients synthesized in medicinal plants. Further studies to isolate and quantify phytochemicals responsible for this activity at different stages of plant maturity are recommended.