Tectona grandis (T. grandis) is a medicinal plant widely used in Cameroon to treat typhoid fever and several other diseases. Despite its heavy use for medical purposes, no study has yet been conducted to assess its potentially toxic effects. This study aimed at evaluating the acute and subchronic toxicological profile of Tectona grandis leaf extract in rats. The acute toxicity study revealed neither behavioral disturbances nor death in rats. The lethal dose (DL50) of this extract is greater than 5000 mg/kg body weight. The subchronic toxicity study showed no significant change in weight gain in rats at test doses throughout the treatment period. However, there was a significant decrease in alanine transaminase activity and serum protein levels at all doses. Alkaline phosphatase activity decreased at doses of 30, 90, and 270 mg/kg and increased at the dose of 810 mg/kg body weight. Serum and urinary urea levels increased simultaneously at doses of 270 and 810 mg/kg body weight. Repeated administration of the extract also increased total cholesterol, high-density lipoprotein levels in both sexes were compared to respective controls, and the ratio of high- to low-density lipoprotein was found to be greater than 1 in all animals. However, at the dose of 810 mg/kg, necrosis was observed on the kidney sections and vascular congestion on the liver sections of animals. Aqueous extract of T. grandis did not lead to any adverse effects in rats after acute and subchronic treatment at 30 and 90 mg/kg doses. This extract can, therefore, be used for the formulation of typhoid fever phytomedicine at the therapeutic dose of 30 mg/kg, but before this, chronic and mutagenic toxicity evaluations must be carried out.

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.

Infectious diseases such as typhoid fever lead to the formation of free radicals which can have a detrimental effect on the body. Typhoid fever is caused by poor sanitation, lack of clean water and resistance of germs to antibiotics and reactive oxygen species (ROS). Hence an urgent needs to find alternative treatments with little or no toxicity for the treatment of this disease. Objective: This work aims to evaluate the in vivo antisalmonellal and antioxidant activity of the 95% hydroethanolic extract of the leaves of Bauhinia rufescens (Fabaceae) in rats experimentally infected with Salmonella Typhi ATCC6539, as an alternative therapy. Methods: The rats were randomly divided into twelve groups (six per sex) of animals. Thus 3 control groups: (T0) uninfected and untreated; (T-) infected and untreated; (T+) infected and treated with ciprofloxacin (14 mg/kg) and 3 test groups: T1, T2 and T3 infected and treated with different doses of the extract (40, 80 and 117.71 mg/kg respectively). The evolution of the infection and the effectiveness of the treatment were monitored by blood culture, food consumption and weight growth were assessed during the trial; at the end of which the animals were sacrificed and the different parameters were evaluated. Results: Infected animals treated with different doses of the extract showed zero bacterial loads from the twelfth day post infection in both sexes. Regardless of sex, animals treated with the extract at the dose of 117.71mg/Kg were cured by the seventh day after the start of treatment while those treated with the doses of 40 mg/Kg and 80 mg/kg were cured by the ninth day after the start of treatment. Infection induced a significant (p < 0.05) decrease in food consumption and weight growth, while treatment induced, at all doses, an increase in food consumption and weight growth. Infection also caused a significant (p < 0.05) increase in NO and MDA levels, as well as a significant decrease in catalase and peroxidase activities in animal tissue homogenates. However, treatment resulted in a significant decrease in NO and MDA levels, and a significant (p < 0.05) increase in catalase and peroxidase activities. Conclusion: These results showed that the 95% hydroethanolic extract of Bauhinia rufescens leaves has mixed antisalmonellal and antioxidant activity in vivo and could be developed for the treatment of typhoid fever.

Salmonella infections remain one of the major health problems in both poultry farming and human medicine. In addition, resistance to Salmonella has emerged as a global health problem in both sectors. The present study aimed at evaluating the in vivo antisalmonellal and antioxidant activities of 95° ethanol extract of Khaya grandifoliola using broiler chickens as animal model. Animals were divided into the normal control group, negative control group, positive control group and three test groups treated with the extract at 10, 20 and 40 mg/kg respectively. The antioxidant status of broiler chickens was also evaluated by measuring the concentration of enzymatic antioxidants (catalase, glutathione peroxidase) and biochemical markers (malondialdehyde and nitric oxide). The results showed that infected animals treated with the Khaya grandifoliola extract at 40 mg/kg recovered on day 11 after the beginning of the treatment and on day 13 for those treated at the 10 and 20 mg/kg. The antioxidant assay showed that the infection led to the reduction of enzymatic markers in the body of infected animals, while the treatment increases such makers. The infection resulted in a significant increase in serum and pulmonary malondialdehyde. It also caused a significant decrease in cardiac and pulmonary nitric oxide whereas the treatment depending on the doses of the extract tends to normalize these biochemical markers. The overall results showed that Khaya grandifoliola extract can be successfully used in the treatment of avian salmonellosis as well as the management of the oxidative stress caused by the infection.

In Chad, enteric fever remains a major public health problem where it is still endemic due to the precariousness of life hygiene combined with the abusive and inappropriate use of antibiotics. Objective: The aim of this work was to evaluate the in vitro antisalmonella and antioxidant activity of extracts from the leaves and stem bark of B. rufescens. Methods: Phytochemical screening of these extracts was performed by standard methods to justify the observed activities. The antisalmonella activity was evaluated using the liquid microdilution method. Antioxidant activity of these extracts was determined by investigating their 1, 1-diphenyl-2 picrylhydrazyl (DPPH●) antiradical and iron reducing capacities. Results: The Minimum Inhibitory Concentrations (MICs) were varied from 256 to 1024 µg/ml. The 95% hydroethanolic extract of the leaves exhibited higher DPPH● antiradical activity than all extracts and IC50s ≤ 20 μg/ml for all extracts tested. Conclusion: These results showed that the 95% hydroethanolic extract of B. rufescens leaves possess in vitro antisalmonella and antioxidant activities and could be used for in vivo antisalmonella and antioxidant studies.