A Systematic Review of Medicinal Plants and Their Compounds Validated as Agents for the Management of Sickle Cell Disease

Some plants used in traditional medicine to manage sickle cell disease have been validated pharmacologically to ascertain their anti-sickling properties. However, there is no global systematic review of the evidence in support of their use for sickle cell management. This research aimed to conduct a systematic review of the pharmacological evidence to highlight species, genera, and some phytochemicals which could be primed for novel anti-sickling medications. The Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines were used. Articles in English, published from 2000 to 2022 were included in the analysis. The literature search covered 411 publications of which 82 were found to be eligible. More than half (53.65%) of the articles were published from 2016 to 2022. Anti-sickling research from Africa accounted for 86.58% of the publications, with more than half coming from Nigeria, 12.20% from Asia and only 1.22% from Europe. The Fabaceae, Euphorbiaceae, and Annonaceae were the top three plant families whereas Zanthoxylum and Terminalia were the most reported genera. Carica papaya and Terminalia catappa were the most reported species. Sickling reversal ( n = 33/82) and hemoglobin polymerization studies ( n = 29/82) were the most reported assays. Benzoic acid derivatives, butyl stearate, ellagic acid derivatives, and some pentacyclic triterpenoids were the only plant derived compounds validated for anti-sickling activities. A total of 117 plant species with anti-sickling activities were documented. Studies on secondary metabolites with anti-sickling properties to serve as scaffolds for novel drug development for sickle cell management were limited.