No abstract

Medicinal plants have been the good source of treatment for different ailments of humans as well as animals for centuries. However, in Tanzania, few plants were investigated for their efficacy against various diseases of chickens. In the present study, four medicinal plants were investigated against Salmonella gallinarum isolated from chickens. The minimum inhibitory concentration (MIC) using the broth microdilution methods and minimum bactericidal concentration (MBCs) were used to evaluate the activities of plants against chicken salmonellosis. For the safety of chickens against the toxicity of plants, the cytotoxicity assay was determined using a brine shrimp lethality test. Aloe secundiflora leaf ethyl acetate (ALEA), Aloe rabaiensis leaf methanolic (ArM), Aloe rabaiensis leaf ethyl acetate (ArLEA), and Punica granatum leaf ethyl acetate (PGLEA) extracts exhibited the highest MIC (0.3906 mg/mL) and MBC (3.125 mg/mL), respectively. The Dolichos kilimandscharicus tuber ethyl acetate (DTEA) and Dolichos kilimandscharicus tuber pet ether (DTPE) extracts displayed MIC of 1.563 mg/mL and 12.50 mg/mL and MBC of 12.50 mg/mL and 25.50 mg/mL, respectively. The highest LC50 values exhibited in Dolichos kilimandscharicus ranged from 7.937 × 10−4 mg/mL to 7.242 × 10−2 mg/mL for pet ether and methanolic extracts, respectively, while ALEA extract exhibited LC50 of 7.645 × 10−3 mg/mL. Generally, the extracts with MIC 0.3906 mg/mL and MBC 3.125 mg/mL demonstrated the highest antibacterial activity with low toxicity efficient to manage chicken salmonellosis. Dolichos kilimandscharicus, which exhibited higher toxicity, warrants further investigation on insecticidal and anticancer agents.

Aim: This study aimed to identify Salmonella enterica serovars by polymerase chain reaction (PCR) based on virulence genes invasion A (inv A) and Salmonella plasmid virulence C (spvC). Materials and Methods: DNA extraction of eight bacteria isolates was done using the PowerSoil® DNA Isolation Kit. The amplification of invA and spvC genes was done using conventional PCR. The positive PCR products were purified using the GeneJET Purification Kit and then sequenced using ABI 3730 XL automated genetic analyzer. The sequences obtained were compared for similarities with other Salmonella serovars deposited on the NCBI GenBank using BLASTN. Results: Four out of eight samples were amplified by primers FS139/RS141 that target invA gene with products of about 284 bp, and three out of four of the same invA positive samples were also amplified by primers FSPV-1/RSPV-2 targeting spvC with a product of about 571 bp. One sample was not amplified by primers FSPV-1/RSPV-2 as it lacked virulence plasmid. Analysis of sequences indicated 100% homology with closely related serovars of S. enterica subspecies enterica serovar Typhimurium. Conclusion: Salmonella Typhimurium that contained invA and spvC genes are pathogenic and virulent strains.

This study was undertaken to evaluate preclinical acute and sub-acute toxicity of Aloe rabaiensis leaf methanolic extract (ARLME) on BALB/c mice following OECD guidelines 423 and 407, respectively. In an acute oral toxicity test, ARLME was administered to the mice by oral gavage at a single dose of 1000, 2000, 3000, 4000 and 5000 mg/Kg body weight. The mice were observed for toxic signs for 14 days. In sub-acute oral toxicity test, ARLME was administered to the mice by oral gavage at 500, 800 and 1000 mg/Kg body weight daily up to 28 th day. At the end of the test, haematological and biochemical analyses of the collected blood sample were carried out as well as gross and microscopic pathology. The control group (F) received a single oral dose of 0.5 mL of 1% DMSO in normal saline. In acute oral toxicity, no treatment-related death or toxic signs at the dosage below 4000 mg/Kg was observed. Nevertheless, at the dosage of 4000 and 5000 mg/Kg, drowsiness and sedation were observed. It was, therefore, revealed that ARLME could be tolerated up to the dose of 3000 mg/Kg body weight and may be classified as category 5. Sub-acute toxicity study at dosage 500 and 800 mg/Kg displayed no adverse changes in the haematological parameter, body weights and histopathological examination. However, at a dosage of 1000 mg/Kg, the serum biochemical aspartate transaminase and alanine transaminase increased, and in histopathological examination of liver and kidney, there was a proliferation of bile duct and leucocytes infiltration respectively. Thus, observations from this study indicate that oral administration of ARLME had no adverse toxic effects in BALB/c mice at the dosage below 1000 mg/Kg, hence supports the use of Aloe rabaiensis in drug formulations.

Background ad objective: Among the notable achievements of the twentieth century was the discovery and identification of new drugs from plants against microbial infections. However, the discovery of novel drugs since then is inadequate due to emergence of resistant microbes. In an effort to discover novel drugs, the study aimed to investigate the antimicrobial activity of crude extracts from endophytic fungi isolated from Cnidoscolas aconitifolius and Ocimum suave. Methods: Following morphological characterization and initial screening for antimicrobial activity, isolates that had higher inhibition were genotypes by Sanger sequencing. Two isolates (Candida tropicalis from O. suave and Phyllosticta capitalensis from C. aconitifolius) were tested for antimicrobial activity against Escherichia coli and Staphylococcus aureus. Results: Overall, the range of crude extract concentration was from 152 mg/mL to 1353 mg/mL, and that of a zone of inhibition was from 7 to 21 mm. The lowest minimum inhibition concentration (19>MIC>9.5) was observed in Phyllosticta spp. extract against S. aureus. Conclusions: Findings of the present study have shown that endophytes isolated from medicinal plants can generate secondary metabolites with therapeutic applications. Therefore, further investigations are warranted to decipher the content and structure of bioactive compounds that may be associated with the antimicrobial activity of crude extracts.