Bioactivity and toxicity of Bridelia micrantha, Chenopodium ambrosoides and Ocimum americanum plant extracts

Abstract

Background: Bridelia micrantha, Chenopodium ambrosoides and Ocimum americanum plant species are commonly used in traditional medicine for a number of ailments. The extracts of these plants have been shown to have anti-schistosomal activity suggesting that they could be used for the development of new chemical entities (NCEs) for the treatment of schistosomiasis. However there is limited knowledge on their toxicological profile and their use in traditional medicine may not be a satisfactory safety indication.Methods: In this study the extracts were first screened for bioactivity using brine shrimp lethality test for the determination of LC50 followed by rodent acute toxicity and 28 day subchronic studies.Results: B. micrantha water extract with a LC50 of 77µg/ml was deemed toxic while C. ambrosoides methanol and water extracts were moderately toxic with LC50 of 104.63µg/ml and 696.44µg/ml respectively. O. americanum hexane and water extracts toxicity varied from moderate to slightly toxic with LC50 of 887.59µg/ml and 2254.60µg/ml respectively. C. ambrosoides and O. americanum water extracts which were preferentially selected for subsequent studies were found to have mild to no irritation to rodent eyes and skin. Moreover, the aminotransferases AST and ALT which were used to detect liver injury suggested negligible effect.Conclusions: This therefore confirms that C. ambrosoides and O. americanum water extracts are safe for clinical use with O. americanum water extract having a slight edge.

Ethnopharmacology and Therapeutic Value of Bridelia micrantha (Hochst.) Baill. in Tropical Africa: A Comprehensive Review

“…Future research should identify the bioactive compounds, details of their molecular modes or mechanisms of action, pharmacokinetics and physiological pathways for specific bioactives of B. micrantha. B. micrantha has been categorized as poisonous by Verdcourt and Trump [ 101 ], toxicity and cytotoxicity studies conducted by Steenkamp [ 96 ], Moshi et al [ 97 ], Omosa et al [ 98 ] and Osebe et al [ 99 ] appear to suggest that the species is toxic and may cause damage to genetic material and therefore, has potential to cause long-term damage in patients when administered as herbal medicines. There is need for rigorous toxicological and clinical studies aimed at identification of poisonous compounds, associated pharmacological activities and the side effects that are likely to be caused when B. micrantha is used as herbal medicine.…”

“…The following activities have been reported from B. micrantha : anthelmintic [ 79 ], antibacterial [ 19 , 32 , 36 , 74 , 80 , 81 , 82 , 83 ], anticonvulsant and sedative [ 84 ], antidiabetic [ 85 ], antidiarrhoeal [ 25 ], antifungial [ 36 , 83 ], anti- Helicobacter pylori [ 70 , 81 , 82 ], antimycobacterial [ 78 , 86 ], antinociceptive [ 87 ], antioxidant [ 77 , 85 , 87 , 88 , 89 ], antiplasmodial [ 59 , 90 , 91 ], antischistosomal [ 92 ], antiviral [ 39 , 40 ], hepatoprotective [ 88 ], insecticidal [ 93 ], β-lactamase inhibitory [ 94 ], toxicity and cytotoxicity [ 87 , 95 , 96 , 97 , 98 , 99 ].…”

“…Oral administration of the B. micrantha extract was well tolerated at the dose of 2000 mg/kg and no death and clinical signs of toxicity were observed [ 87 ]. Similarly, Osebe et al [ 99 ] evaluated toxicity of water stem bark extract of B. micrantha using brine shrimp lethality test for the determination of LC 50 and the water extract with LC 50 of 77 μg/mL was deemed toxic.…”

A Review of the Toxicity and Phytochemistry of Medicinal Plant Species Used by Herbalists in Treating People Living With HIV/AIDS in Uganda

“…contained a toxic compound, 4-Methoxypyridoxine that is a vitamin B6 antagonist (Botha and Penrith, 2008). (Byamukama et al, 2015;Osebe et al, 2016) conducted a phytochemical evaluation of the ethyl acetate extract of A. coriaria extracts and identified and characterized lupeol, lupenone, betulinic acid, acacic acid lactone, (+)-Catechin and Benzyl alcohol. Anywar et al documented prolonged boiling of A. coriaria decoctions for up to 6 h and administering it in small amounts by herbalists in Uganda (Anywar et al, 2020a).…”

“…Likewise, (Omosa et al, 2016) found the dichloromethane and methanol extracts of the leaves and stem bark of B. micrantha to be cytotoxic to CCRF-CEM leukaemia cells with IC 50 values of 9.43 μg/ml and 23.5 μg/ml respectively. Using the brine shrimp lethality assay, (Osebe et al, 2016) showed the water stem bark extract of B. micrantha to have a 50% lethal concentration (LC 50 ) of 77 μg/ml, and was considered toxic. Using the same assay, (Moshi et al, 2010) showed the ethanol root extract of B. micrantha to be mildly toxic, LC 50 30 μg/ml.…”