In vitro and in vivo Antioxidant potential of aqueous and hydroethanolic extracts leaves ofDracaena deistelianaEng. (Dracacenaceae)

Abstract

Enterobacteria such as those of the genus Salmonella express the oxyR gene that codes for several proteins that allow it to resist free radicals. This resistance of Salmonella is often at the origin of an overproduction of these free radicals that can lead to oxidative stress. To investigate the antioxidant activity in vitro (aqueous and hydroethanolic extracts in vivo (of the 55% hydroethanolic extract) of Dracaena deisteliana leaves in albino rats of Wistar strain previously infected with the Salmonella strain Typhi ATCC 6539. The in vitro antioxidant activity of these extracts was determined by studying their anti-radical power with DPPH•, then their iron-reducing power and determining their flavonoids and total phenols content. In vivo antioxidant activity was determined in plasma and tissues of albino rats of wistar strain aged between 8 and 10 weeks previously infected with Salmonella typhi ATCC 6539. These infected rats concurrently received daily doses of Dracaena deisteliana extract (10, 20 and 51.84 mg/kg) or ciprofloxacin (14 mg/kg) as positive control, for 15 days. At the end of the treatment period, the animals were sacrificed and blood, liver, kidney, heart, lung, spleen testis and ovaris were collected for evaluation of antioxidants parameters, which included malondialdehyde, nitric oxide, catalase and peroxidase, as well as biological responses. Regarding in vitro antioxidant tests, the 65% hydroethanolic extract showed an anti-radical activity with DPPH• superior to that of all hydroethanolic extracts at 100 μg/ml. However, the infused showed lower antiradical activity than all extracts at 12.5 and 200 μg/ml concentrations. The 55% hydroethanolic extract had the best IC50of (11.99 μg/ml). The iron reducing power of this extract was higher than the other extracts at 200 μg/ml. The highest levels of flavonoids and total phenols were obtained respectively with the 55% and 95% hydroethanolic extract. The hydroethanol extract of Dracaena deisteliana (10, 20 and 51.84 mg/kg) cured the infected rats between the 9th and 13th day of treatment. The extract also significantly reduced (p < 0.05) blood malondialdehyde and nitric oxide levels, and significantly increased (p >0.05) the activity of catalase and peroxidase in the infected rats. The results suggest that leaves extract of Dracaena deisteliana contains antisalmonella and antioxidant substances, which could be used for the treatment of typhoid fever and another salmonellosis. In addition, 55% hydroethanolic extract of this plant possesses antisalmonella activity and reduces the state of oxidative stress caused by S. typhi during rat's infection.