Disruption of microbial cell morphology by Buxus macowanii.

BACKGROUND: Microbial infections are one of the major causes of death globally. This is attributed to the rising costs of primary healthcare and its inaccessibility especially in developing countries. Moreover, there has been an increase in microbial strains that have reduced susceptibility to antimicrobial drugs. Research on the antimicrobial properties of medicinal plants, which could address these problems, has become more important as they present fewer side effects when compared to the antibiotics currently in use. This study evaluated the antimicrobial properties of a methanolic extract from Buxus macowanii in order to assess its potential in the development of novel antimicrobial drugs. METHODS: Antimicrobial activity of the extract was evaluated using the broth microdilution method. The effects of B. macowanii on the morphology of B. cereus were observed using Scanning and Transmission electron microscopy. Chemical profiling of the plant extract was performed using the GCMS. RESULTS: The extract showed antimicrobial activity against all the microbial species used. Microscopic examination of the cells of B. cereus cells treated with Buxus macowanii showed some changes in morphology such as damage of the cell wall, swelling of the cells and incomplete cell division that eventually resulted in cell death. Neophytadiene, an antimicrobial compound was detected in the extract using GCMS. CONCLUSION: The morphological disruptions of the cell wall of Bacillus cereus explain the antimicrobial properties of B. macowanii and indicate its possible application in the development of natural antimicrobial drugs.

Cytotoxicity and cell cycle analysis of Asparagus laricinus Burch. and Senecio asperulus DC. on breast and prostate cancer cell lines.

AIMS: Medicinal plants play an important role in our African communities for treatment and prevention of various diseases including cancer. This study was aimed on evaluating the cytotoxicity activities of Asparagus laricinus Burch. and Senecio asperulus DC. MAIN METHODS: In vitro cytotoxicity screening was carried out using fluorescent cellular stains on human prostate cancer (PC3), human breast cancer (MCF-7) and the non-cancerous African green monkey kidney (Vero) cell lines. The cells were imaged with the ImageXpress Micro XLS Widefield fluorescent Microscope, and the acquired images were analysed using the MetaXpress software and the Multi-Wavelength cell scoring application module. Melphalan was used as a positive control in all experiments. KEY FINDINGS: Asparagus laricinus methanol and Senecio asperulus DC. dichloromethane extracts exhibited cytotoxicity activity against breast cancer cells with IC50 values of 97.6 µg/mL and 69.15 µg/mL, respectively. Cell cycle analysis suggested that Asparagus laricinus methanol extract induced cell death selectively through apoptosis observed from Annexin V-FITC and PI stain. Cell cycle analysis also showed that Senecio asperulus DC. dichloromethane extracts induced breast cancer cells death through cell arrest at the synthesis phase and G2 phase. Senecio asperulus DC. dichloromethane extracts further showed cytotoxicity activity against prostate cancer cells with IC50 values of 69.25 µg/mL due to cell arrest at the G2 and early mitotic (G2/M) phase. SIGNIFICANCE: We, therefore, propose that the methanol extract of Asparagus laricinus is a suitable aspirant for future breast cancer chemotherapeutic drug, due to its selective cytotoxicity on cancer cells and not on non-cancerous cells.