In-vitro Anti-cercarial activity of extracts and steroidal alkaloids from the stem bark of Holarrhena floribunda (G. Don) Dur. & Schinz

Context: Schistosomiasis continues to be the leading cause of morbidity and mortality among the neglected tropical diseases. Apart from the high cost of chemotherapy, concerns over drug resistance and tolerance have been raised in the past decade. Objective: The aim of the study was to evaluate the anticercarial activity of extracts and compounds from the stem bark of Holarrhena floribunda on cercaria of Schistosoma haematobium. Methods: Hydroethanolic and alkaloidal extracts from the stem bark of H. floribunda were tested on cercaria at concentrations between 500.00 and 15.625 μg/mL for 180 minutes and assessing the percentage viability at time intervals of 0, 15, 30, 60, 120 and 180 minutes. Praziquantel, used as reference drug, and the isolated compounds were tested at similar concentrations. The cercaria mortalities and IC50 of extracts and compounds were estimated after 30 minutes of incubation. Results: The 70 %v/v ethanol extract showed the highest activity (IC50=20.09±1.11 μg/mL) with praziquantel giving IC50 of 695.50±1.12. The alkaloids holonamine, holadienine and conessine, isolated from the stem bark, showed considerable cercaricidal activity with the latter recording an IC50 of 33.28±1.04. Conclusion: The study gives first-hand knowledge of the anti-cercarial activity of H. floribunda and its steroidal alkaloids. This gives credence to the traditional uses of the plant as an anti-parasitic agent

Indigenous Medicinal Plants as Biofilm Inhibitors for the Mitigation of Antimicrobial Resistance

The majority of indigenes in the rural areas of Ghana use herbal medicines for their primary health care. In this study, an ethnobotanical survey was undertaken to document medicinal plants used by traditional healers in the Ejisu-Juaben district in the Ashanti region of Ghana to treat infections and to further investigate the antibiofilm formation properties of selected plants in resisting pathogenic bacteria. Seventy medicinal plants used by traditional practitioners for the treatment of skin infections and wounds were documented from the ethnobotanical survey. Forty out of the seventy plants were collected and their methanol extracts evaluated for antimicrobial activity by the agar diffusion assay. Extracts that showed antibacterial activity were tested for biofilm inhibitory activity, and the most active plant was subsequently purified to obtain the active constituents. Biofilm formation was significantly mitigated by petroleum ether, ethyl acetate, and methanol extracts of Holarrhena floribunda stem bark. Bioassay-guided fractionation of an alkaloidal extract prepared from the methanol fraction led to the isolation of three steroidal alkaloids, namely, holonamine, holadienine, and conessine. The isolated compounds demonstrated varying degrees of biofilm formation inhibitory properties. The current study reveals that screening of indigenous medicinal plants could unravel potential leads to salvage the declining efficacy of conventional antibiotics. Holarrhena floribunda stem bark extract has strong biofilm formation inhibition properties, which could be attributed to the presence of steroidal alkaloids