In vitro and in vivo immunomodulatory and anti-ulcerogenic activities of Teucrium ramosissimum extracts

Abstract

Teucrium ramosissimum (Lamiaceae), a native and endemic plant from South Tunisia, has traditionally been used as a treatment for inflammation and for ulcers. Though the plant and its products are widely used, very few studies have analyzed the pharmacological/toxicological properties of this plant. Thus, the aim of these studies was to evaluate the anti-inflammatory/anti-ulcerogenic activities of various extracts (i.e., methanolic, aqueous, and total oligomer flavonoid [TOF]-enriched) from leaves of T. ramosissimum. In vitro, the effects from each extract on lysosomal enzyme activity and proliferation of, respectively, freshly isolated peritoneal macrophages and splenic lymphocytes were assessed. The extracts alone clearly affected macrophage function, as evidenced by a significant modulation of cell lysosomal enzyme activity and ability to form and/or release nitric oxide. These extracts were also found to be able to significantly modify the proliferation of splenocytes, even when lipopolysaccharide or lectin mitogens were absent. With respect to the anti-ulcerogenic activity of the extracts, these studies found that the leaf extracts were able to exert significant protective effects against ethanol-induced ulcers in a rat model; at some doses, the extract effects were even greater than that obtained using a cytoprotective histamine H2-antagonist, cimetidine. Based on these studies, we conclude that the extracts from T. ramosissimum appear to be potentially potent modulators of innate immunity and that their efficacy against ulcer formation may be due, in part, to a cytoprotective effect. Further, these results fortify the ethnopharmacological importance of the use of T. ramosissimum products as anti-inflammatory and anti-ulcer agents. Nevertheless, ongoing/further studies are needed to clarify more precisely mechanisms underlying effects against ulcers and on lymphocyte and macrophage functionality, as well as the causative agents.