Protective effects of guarana (Paullinia cupana) against methotrexate‐induced intestinal damage in mice

This study aimed to examine the effects of guarana (Paullinia cupana) on intestinal damage induced by MTX in mice. Mice were classified into four groups: control, MTX, guarana (Paullinia cupana), and guarana (Paullinia cupana) together with MTX. Total antioxidant capacity together with glutathione, superoxide dismutase, MDA, ALT, AST, myeloperoxidase, total protein and IL‐1β were detected in the serum. Bax and Bcl2 expressions were detected in intestine together with histopathological examination and immunohistochemical examination of caspase‐9. Intoxication with MTX inhibited antioxidant and promoted myeloperoxidase activity in experimental mouse models but pre‐administration of guarana ameliorated this effect by inhibiting IL‐1β. Real‐time quantitative PCR (qRT‐PCR) analysis found that MTX intoxication upregulated BAX expression, causing apoptosis, and downregulated Bcl2 expression. These were also brought under control following guarana pre‐administration. Histological examination of intestine indicated hyperplasia and desquamation of superficial epithelium of villi in the MTX‐administered group, as well as round cell infiltration in the lamina propria. Pre‐administration of guarana protected against these effects. The MTX group showed that caspase‐9 expression was upregulated, increasing immune‐reactivity in comparison to the guarana experimental groups. These combined effects lead to the conclusion that guarana has a preventative or protective effect against MTX‐induced oxidative stress in the intestinal tissue.