Toxicological Assessment of the Moringa Species: A Minireview

Moringa oleifera, a plant of the moringa species, is known for its nutritional and medicinal properties. It is a major constituent of several polyherbal supplements, particularly consumed in Sub-Saharan Africa. Despite its extensive application in herbal medicines, there are still concerns regarding its safety. The aim of this mini-review is to report recent toxicological findings on the genus Moringa. Several studies have reported bioactive phytochemicals in moringa species, including alkaloids, flavonoids, carotenoids, and saponins. These constituents may exert protective, therapeutic, or deleterious effects in humans, depending primarily on concentration/dose and duration of exposure. Toxicodynamic studies revealed that the extract of Moringa oleifera inhibited cell proliferation; generated free radicals such as reactive oxygen species (ROS), and induced apoptosis by activating caspase-3 in both liver cancer cells (HEPG2) and normal hepatocytes. Phytochemicals such as glucosinolates and tannins can cause hepatotoxicity, nephrotoxicity, and reproductive toxicity at high doses, due to the formation of nitriles that induce cellular oxidative stress. The toxicity of moringa has been linked to the presence of heavy metals, which can induce oxidative stress, enzyme inhibition, and neurotoxicity at high concentrations. In a case report, it was shown that Moringa oleifera caused toxicoderma in a 57-year-old woman. This was reversed by discontinuation of Moringa oleifera and the use of antihistamines. Despite these restrictions, it can be argued that the moringa species has low toxicity at lower doses, but it must be used with caution at higher doses. Further research on carcinogenicity and other drug-herb interactions is needed.

Key Words: Moringa oleifera, oxidative stress, bioactive, teratogenic, toxicodynamic, phytochemicals, safety evaluation