Effects of Carissa opaca fruits extracts on oxidative pulmonary damages and fibrosis in rats

Carissa opaca is a Pakistani fruit, traditionally used in the treatment of various human ailments including asthma and pulmonary damage. The present study investigated the protective effects of Carissa opaca against CCl₄-induced oxidative stress in rat lungs.

To assess the protective effects of Carissa opaca, 42 Sprague–Dawley male rats (170–180 g) were randomly divided into 7 groups. Group I was untreated and group II received olive oil intraperitoneally (i.p.) and dimethyl sulfoxide orally. Groups III, IV, V, VI and VII were administered CCl₄, 3 ml/kg bodyweight (30% in olive oil i.p.). Group IV was administered 50 mg/kg bodyweight silymarin whereas groups V, VI and VII were treated with 200 mg/kg of various fractions of Carissa opaca after 48 h of CCl₄ treatment for eight weeks. Antioxidant profiles in lungs were evaluated by estimating the activities of antioxidant enzymes: catalase, peroxidase, superoxide dismutase, glutathione-S-transferase, glutathione reductase, glutathione peroxidase, quinone reductase and reduced glutathione. CCl₄-induced lipid peroxidation was determined by measuring the level of thiobarbituric acid reactive substances (TBARS) with conjugation of DNA damage and histopathology.

Administration of CCl₄ for 8 weeks significantly reduced (p < 0.05) the activities of antioxidant enzymes and GSH concentration while increasing TBARS content and DNA damage. Co-treatment of various fractions of Carissa opaca and silymarin restored the activities of antioxidant enzymes and glutathione content. Changes in TBARS concentration and DNA fragmentation was significantly decreased (p < 0.05) following Carissa opaca and silymarin treatment in lung.

Histopathological changes in rat lungs induced by CCl₄ were significantly restored by co-treatment with Carissa opaca and silymarin.