Aim: Study aimed to evaluate the in vitro antisalmonellal and antioxidant properties of Tectona grandis, a medicinal plant commonly used in traditional Cameroonian medicine for the treatment of typhoid fever. Study Design: In vitro Antimicrobial and antioxidant analyses of plant extract using established protocols. Place and Duration of Study: Plant materiel collection at Loum (Moungo Division, Littoral region of Cameroon), identification at the National Herbarium of Cameroon, extraction of plant and all analyses at the Research Unit of Microbiology and Antimicrobial Substances, Department of Biochemistry, University of Dschang-Cameroon, between August 2018 and April 2019. Methodology: In vitro antisalmonellal activity of Tectona grandis extracts was evaluated by the liquid microdilution method as well as their antioxidant activity using by standard methods of H2O2 trapping, FRAP, DPPH radical trapping and OH radical trapping. Quantification test of total phenols and flavonoids and phytochemical screening of extract were also done. Results: The results showed that most of the Tectona grandis extracts had minimal inhibitory concentrations (MICs) ranging from 64 to 1024 μg/mL. Ethanolic extract, 70% ethanol extract and aqueous decoction are the most effective compared to aqueous extracts with activities between 64 and 128 μg/mL on the bacteria tested. Antioxidant tests showed that all extracts except macerated and aqueous infused extracts exhibited high DPPH trapping activities. The antioxidant activities of the extracts are proportionally linked in most cases to their flavonoid and total phenol contents at a concentration of 200 µg/mL. Aqueous decoction showed better H2O2 trapping activity at concentrations less than or equal to 25 µg/mL. Conclusion: These results show that the ethanolic extract and decocted aqueous of Tectona grandis leaves can be used as an alternative to treat salmonellosis.

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.

Today, Typhoid fever remains a public health problem in developing countries due to the poor quality of lifestyle associated with abusive and inappropriate use of antibiotics. Aims: Considering the ethnopharmacological relevance of Terminalia avicennioides                              (T. avicennioides) (Combretaceae), this study was designed to investigate the in vitro antisalmonella and antioxidant activities of various extracts of this plant. Methodology: The microdilution method was used to determine the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of T. avicennioides extract. These extracts were also subjected to in vitro antioxidant tests such as diphényl-2-picrylhydrazyle (DPPH) radical scavenging test, ferric reducing-antioxidant power (FRAP), hydroxyl radical (OH) nitric oxide (NO) and Hydrogen Peroxide Scavenging Capacity. Results: In vitro antisalmonella activity reveals that T. avicennioides stem bark extracts presented MIC values ranging from 64 to 512 μg / mL on tested microorganisms. This extract exhibited a good ability to trap DPPH with an IC50 of 8.30 μg / mL. The iron reducing power obtained with this extract had ODs ranging from 0.96 to 1.63. Phytochemical screening showed the presence of alkaloids, flavonoids, saponins, phenols anthocyanin and anthraquinone in all the extracts. Conclusion: The results suggest that stem extract of T. avicennioides contains antisalmonella and antioxidant substances, which could be used for the treatment of typhoid fever and another salmonellosis.

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.