Browsing by Author "Rwegoshora, Frank"

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    Epifriedelanol is the key Compound to antibacterial Effects of extracts of synadenium glaucescens (pax) against Medically important bacteria
    (Frontiers, 2023) Msengwa, Zaituni; Rwegoshora, Frank; David, Credo; Mwesongo, James; Mafuru, Magesa; Mabiki, Faith P; Mwang’onde, Beda J; Mtambo, Madundo M; Kusiluka, Lughano J. M; Mdegela, Robinson H; Olsen, John E
    Introduction: Synadenium glaucescens has been used for the treatment of bacterial infections in many parts of the world. We investigated the antibacterial and cytotoxicity activities of secondary metabolites of this plant. Methods: Hexane, dichloromethane, methanol, and water were used as extraction solvents. The extract of the root bark was fractionated with ethyl acetate and methanol. The isolation of compounds from root barks, leaves and stem wood extracts were carried out using column chromatography. Antibacterial activities were characterized based on growth curves, killing curves and MIC determinations. Haemolytic effect towards sheep red blood cells (RBCs) was analysed with spectrophotometer at the wavelength of 540nm. Results and Discussion: Extracts from whole root and root bark showed strong activity against Staphylococcus aureus, and Streptococci and Enterococci species, and moderate to weak activity against Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella species, Shigella sonnei and Yersinia enterocolitica. Staphylococcus aureus was the most susceptible, and E. coli and Klebsiella pneumonia were the least susceptible ones. Likewise, extracts, fractions, sub-fractions and epifriedelanol demonstrated bacteriostatic activity against S. aureus. The haemolytic activity of the extracts, fractions, sub-fractions and epifriedelanol was significantly low compared to the positive control, hydrogen peroxide. But extract from leaves showed high haemolytic effects at the concentrations of 500 mg/mL and 1000 mg/mL. Thus, extracts of S. glaucescens have antibacterial activity against several Gram-positive bacteria including Methicillin Resistant S. aureus with low haemolytic activity. At high concentrations, the extracts from leaves have toxicity risk. More studies for the active compounds are required for biological testing.
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    Isolation and toxicity evaluation of feruloyl ester and other triterpenoids from synadenium glaucescens pax
    (The Journal of Phytopharmacology, 2022) Rwegoshora, Frank
    The use of plants as sources of drug agents is attributed by factors among which are the easy accessibility to plants, less toxicity and little or no drug resistance. An improvement in both traditional medicine and drug discovery field necessitates investigation of pure compounds in any plant with medicinal value. Synadenium glaucescens Pax of the family Euphorbiaceae is among the medicinal plant in Tanzania which are proven to contain bioactive compounds against microbial infections. Analysis of ethanolic and methanolic extracts of root and stem barks respectively aided to isolated six pure compounds (SG1- 6). These compounds were analyzed by both 1D, 2D NMR and GC-MS while their spectral processing was achieved in the Bruker TopSpin 3.6.2. Among these compounds, one was a phenolic (hemicosanyl ferulate-SG1), three triterpenoids, (lupeol- SG2, epifriedelanol- SG4 and euphol- SG5), one steroid (β-sitosterol- SG6) and a long chain alkene (1-nonacosene- SG2). Cytotoxicity evaluation by Brine shrimp lethality test (BLST) indicated the compounds under report were practically non-toxic.