Quantitative Phytochemical Profile and In Vitro Antioxidant Properties of Ethyl Acetate Extracts of Xerophyta spekei (Baker) and Grewia tembensis (Fresen).

Overproduction of free radicals in excess of antioxidants leads to oxidative stress which can cause harm to the body. Conventional antioxidants have drawbacks and are believed to be carcinogenic. The present study seeked to confirm folklore use and validate the antioxidant potentials of Grewia tembensis and Xerophyta spekei which have been widely used in the Mbeere community as medicinal plants. Antioxidant properties were determined through scavenging effects of diphenyl-1-picrylhydrazyl (DPPH) and hydrogen peroxide radicals as well as iron chelating effects. The data obtained was assayed in comparison to the standards (Ascorbic acid and EDTA). Ascorbic acid had a significantly greater DPPH radical scavenging property with an inhibitory concentration (IC50) value of 20.54 ± 2.24 µg/mL in comparison to the plant extracts, which had IC50 values of 33.00 ± 1.47 µg/mL, 69.66 ± 1.01 µg/mL and 86.88 ± 2.64 µg/mL for X. spekei, G. tembensis leaf and G. tembensis stem bark extracts, respectively. EDTA demonstrated a significantly greater iron chelating effect having a significantly lesser IC50 value of 25.05 ± 0.79 µg/mL as opposed to 43.56 ± 0.46 µg/mL, 89.78 ± 0.55 µg/mL, and 120.70 ± 0.71 µg/mL for X. spekei, G. tembensis leaf, and G. tembensis stem bark extracts respectively. Additionally, ascorbic acid also exhibited stronger hydrogen peroxide radical scavenging effect than the studied extracts. Generally, X. spekei extract had higher antioxidant activities as compared to both the leaf and stem bark extracts of G. tembensis. The phytochemical screening demonstrated the presence of secondary metabolites associated with antioxidant properties. The present study therefore, recommends ethno medicinal and therapeutic use of G. tembensis and X. spekei in the treatment and management of oxidative stress related infections.

Antibacterial properties and GC-MS analysis of ethyl acetate extracts of Xerophyta spekei (Baker) and Grewia tembensis (Fresen).

Conventional antibiotics are associated with various side-effects. Therefore, there is need of using plant-derived antibiotics with fewer side-effects. Grewia tembensis and Xerophyta spekei, which have been extensively utilized in the Mbeere community, were studied to support their folkloric use and demonstrate their antibacterial capabilities. Salmonella Typhi ATCC 1408, Bacillus subtilis ATCC 21332, Staphylococcus aureus ATCC 25923, and Escherichia coli ATCC 25922 were all used in this study. As a standard reference, Ciprofloxacin (100 µg/ml) was employed, and 5% DMSO was used as a negative reference. Tests for antibacterial activities included disc diffusion, minimum inhibitory concentrations, and bactericidal concentrations. G. tembensis exhibited effects on S. aureus only with Mean Zone Inhibition (MZI) of 07.07 ± 0.07 to 12.33 ± 0.33 mm and 08.33 ± 0.33 to 11.67 ± 0.33 mm for stem bark and leaf extracts respectively. While X. spekei extract had effects on S. aureus with MZI of 07.67 ± 0.33 to 14.67 ± 0.33 mm and B. subtilis with MZI of 09.67 ± 0.33 to 14.33 ± 0.33 mm. Ciprofloxacin demonstrated significantly higher activities as compared to the plant extracts in all the concentrations (p < 0.05), while 5% DMSO had no activity. GC-MS analysis demonstrated the availability of compounds with known antibacterial effects. Therefore, the current study recommends ethnomedicinal and therapeutic use of G. tembensis and X. spekei as antibacterial agents.

GC-MS Analysis, Antibacterial and Antioxidant Potential of Ethyl Acetate Leaf Extract of Senna singueana (Delile) Grown in Kenya.

Bacterial diseases are a leading cause of mortality and morbidity globally. During bacterial diseases, an elevation of host immune response occurs, which involves the production of free radicals in response to the bacterial infection. The overproduction of free radicals in excess of the antioxidants leads to oxidative stress. Conventional antibiotics are linked to side effects such as hypersensitivity reactions in addition to bacterial pathogens developing resistance against them. Artificial antioxidants are said to be carcinogenic. This study sought to confirm folklore use and validate the antibacterial and antioxidant potential of Senna singueana which has been widely used in the Mbeere community. The in vitro antibacterial potentials of the plant extract were investigated on Bacillus subtilis ATCC 21332, Escherichia coli ATCC 25922, Salmonella typhi ATCC 1408, and Staphylococcus aureus ATCC 25923. Ciprofloxacin (100 µg/ml) drug was used as a standard reference, whereas 5% DMSO was used as a negative reference. The antibacterial tests included disc diffusion and minimum inhibitory and bactericidal concentrations. S. singueana ethyl acetate extract showed broad-spectrum potential against tested bacterial microbes producing mean zones of inhibition (MZI) from 07.67 ± 0.33 to 17.67 ± 0.33 mm. The extract demonstrated a greater effect on Gram-positive than Gram-negative bacterial pathogens. Antibacterial properties of ciprofloxacin were significantly greater in comparison to plant extract in all the dilutions (p < 0.05), while 5% DMSO was inactive against all the tested bacteria. MBC values were greater than MIC values. Antioxidant properties of the extract were determined through scavenging effects of DPPH and hydroxyl radicals (•OH) as well as ferric reducing antioxidant potential (FRAP) assay. S. singueana demonstrated effects against all radicals formed. Additionally, the extract exhibited ferric reducing abilities. The extract also contained various phytocompounds with known antibacterial and antioxidant properties. This study recommends the therapeutic use of S. singueana as an antibacterial as well as an antioxidant agent.