Dichloromethane and/or ethanol extracts of 30 plants used as traditional medicines in Bukoba district, northwestern Tanzania were evaluated for brine shrimp toxicity. Among the 50 extracts tested, 32 extracts (64%) showed very low toxicity with LC50 values above 100 microg/ml. Among these 12 (24%) which had LC50 >500 microg/ml can be categorized as being practically non-toxic. Among the remaining extracts 19 (38%) which showed LC50 > 100 < 500 microg/ml are also considered to be non-toxic. Extracts that showed LC50 results between 30-100 microg/ml have been categorized as mildly toxic; these include ethanol extracts of Lantana trifolia (LC50 32.3 microg/ml), Vernonia bradycalyx (LC50 33.9 microg/ml), Antiaris toxicaria (LC50 38.2 microg/ml) and Rubus rigidus (LC50 41.7 microg/ml) and the dichloromethane extracts of Gynura scandens (LC50 36.5 microg/ml) and Bridelia micrantha (LC50 32.0 microg/ml). The dichloromethane extracts of Picralima nitida (LC50 18.3 microg/ml) and Rubus rigidus (LC50 19.8 microg/ml), were only moderately toxic. Picralima nitida and Rubus rigidus extracts are only 1.1 and 1.2 less toxic than the standard drug, cyclophosphamide (LC50 16.3 microg/ml). In conclusion, the results indicate that among the 30 plants used as traditional medicines, 28 are safe for short term use. Picralima nitida and Rubus rigidus extracts are mildly toxic, but by comparison have a remote possibility to yield active anticancer compounds.

/pdf/brine-shrimp-toxicity-of-some-plants-used-as-traditional-2bdrb385qk.pdf

Brine shrimp toxicity of some plants used as traditional medicines in Kagera Region, north western Tanzania.

Recognition and development of traditional medicine in Tanzania.

Extracts of seven medicinal plant species used for treatment of malaria in traditional/cultural health systems of the Ameru people in Kenya were tested in vitro and in vivo against Plasmodium falciparum (D6 and W2 strains) and P. berghei, respectively. Of the plants tested, 28.57% were highly active (IC50 70%) in vivo (in mice). The plants with high in vitro anti-plasmodial (low IC50 values) and high anti-malarial activity (high chemo-suppression) in vivo are potential sources of novel anti-malarial drugs.

In vitro anti-plasmodial and in vivo anti-malarial activity of some plants traditionally used for the treatment of malaria by the Meru community in Kenya

Three lethality bioassays, using the salt-water crustacean Artemia salina Leach, Artemiidae, (conventional 96 microwell plate test and the Artoxkit M microbiotest) and the freshwater crustacean Thamnocephalus platyurus Packard, Thamnocephalidae, (Thamnotoxkit F microbiotest), were compared using extracts of ten Guatemalan plant species. It was previously observed that five of them have anti-Artemia activity. These were: Solanum americanum Mill., Solanaceae, Gliricidia sepium (Jacq.) Kunth ex Walp., Fabaceae, Neurolaena lobata (L.) Cass., Asteraceae, Petiveria alliacea L., Phytolaccaceae, and Ocimum campechianum Mill., Lamiaceae. The five others: Curatella americana L., Dilleniaceae, Prunus barbata Koehne, Rosaceae, Quercus crispifolia Trel., Fagaceae, Rhizophora mangle L., Rhizophoraceae, and Smilax domingensis Willd., Smilacaceae, do not. All plants without anti-Artemia activity had no lethal effects in both assays with A. salina. For the plants with anti-Artemia activity the Artoxkit M was not sensitive to G. sepium and the conventional Artemia test was not sensitive to S. americanum, G. sepium and N. lobata. All the plant extracts, except for that of C. americana, had lethal effects on T. platyurus and the lethal median concentration (LC50) levels for this organism were in all cases substantially lower than those of the salt-water test species. This study revealed that T. platyurus is a promising test species worth further in depth investigation for toxicity screening of plant extracts with potential medicinal properties.

/pdf/comparison-of-bioassays-using-the-anostracan-crustaceans-24lvgez050.pdf

Comparison of bioassays using the anostracan crustaceans Artemia salina and Thamnocephalus platyurus for plant extract toxicity screening

Croton macrostachyus is widely used as herbal medicine by the indigenous people of tropical Africa. The potential of C. macrostachyus as herbal medicine, the phytochemistry, and pharmacological properties of its parts used as herbal medicines are reviewed. The extensive literature survey revealed that C. macrostachyus is traditionally used to treat or manage at least 81 human and animal diseases and ailments. The species is used as herbal medicine for diseases and ailments such as abdominal pains, cancer, gastrointestinal disorders, malaria, pneumonia, sexually transmitted infections, skin infections, typhoid, and wounds and as ethnoveterinary medicine. Multiple classes of phytochemicals such as alkaloids, amino acids, anthraquinones, carbohydrates, cardiac glycosides, coumarins, essential oil, fatty acids, flavonoids, phenolic compounds, phlobatannins, polyphenols, phytosteroides, saponins, sterols, tannins, terpenoids, unsaturated sterol, vitamin C, and withanoides have been isolated from the species. Pharmacological studies on C. macrostachyus indicate that it has a wide range of pharmacological activities such as anthelmintic, antibacterial, antimycobacterial, antidiarrhoeal, antifungal, anticonvulsant and sedative, antidiabetic, anti-inflammatory, antileishmanial, antioxidant, antiplasmodial, and larvicidal effects. Croton macrostachyus has potential as a possible source of a wide range of pharmaceutical products for the treatment of a wide range of both human and animal diseases and ailments.

/pdf/ethnopharmacological-uses-phytochemistry-and-pharmacological-550abuwhwq.pdf

Ethnopharmacological Uses, Phytochemistry, and Pharmacological Properties of Croton macrostachyus Hochst. Ex Delile: A Comprehensive Review

Extracts of 34 plants that are traditionally used for the treatment of different diseases exhibited various degrees of toxicity on brine shrimp. The concentration killing 50% (LC50) of the shrimps was below 50 μg/ml for 14 (41.2%), 50–100 μ g/ml for 10 (29.4%), and greater than 100 μg/ml for 10 (29.4%) of the plants, respectively. Dalbergia nitidula (LC50 0.87 μg/ml), Ozoroa insignis (LC50 2.21 μg/ml), Markhamia obtusifolia (LC50 8.94 μg/ml), Ximenia caffra (LC50 11.25 μg/ml),Croton macrostachys (LC50 13.40 μg/ml), and Mormodica calantha (LC50 19.38 μg/ml) were the most toxic. The results indicate the possibility that some of the plant extracts may be toxic or contain useful cytotoxic compounds, which was not reported by the traditional healers.

https://www.tandfonline.com/doi/pdf/10.3109/13880200490897920

Joseph C. Cosam

Papers

Testing beyond ethnomedical claims: Brine shrimp lethality of some Tanzanian plants

Testing Beyond Ethnomedical Claims: Brine Shrimp Lethality of Some Tanzanian Plants