Ethnobotanical, phytochemistry, toxicological and pharmacological significance of the underutilized indigenous Aloe species of West Africa

The genus Aloe belongs to the family Xanthorrhoeaceae with over 560 species ranging from small shrub-like plants to large trees. Despite their pharmacological applications against ailments such as arthritis, cancer, type 2 diabetes mellitus, digestive disorders, cancer, microbial infections, and skin diseases, only Aloe vera, Aloe ferox, Aloe perryi, and Aloe arborecens have received superior research attention over the years with some members of the genus such as Aloe buettneri, Aloe macrocarpa, and Aloe schweinfurthii being either neglected or underutilized. Here, we reviewed the ethnobotanical, phytochemistry, toxicological and pharmacological importance of the three indigenous and underutilized West African Aloe species- A. buettneri, A. macrocarpa, and A. schweinfurthii. Scientific databases such as Google Scholar, PubMed, JSTOR, Science Direct, and Scopus were used in retrieving the data presented in this study. The information gathered revealed that, the three species are generally underutilized with some ethnopharmacological uses against dysmenorrhea, skin diseases, female infertility, chronic gonorrhea, facilitation of childbirth, hemorrhoids, and impotency in men, being documented. Majorly, their leaves and gel are rich in alkaloids, phenolics, sterols, saponins, glycosides, anthraquinones, and anthraquinoic derivatives and the species exhibited a broad spectrum of biological activities including antidiabetic, aphrodisiac, anti-ulcer, anti-inflammatory, antimicrobial, antioxidant, analgesia, antipyretic, antileishmanial, and antimalarial. Despite their numerous therapeutic applications, Aloe species generally potentiate toxicological concerns at high doses, necessitating further research to standardize and establish their optimum therapeutic doses including those of the West African species. Furthermore, while the medicinal uses of Aloe species have been well documented in Africa, there is still paucity of information on the pharmacological and phytochemistry of the West African species. Therefore, further advanced and in-depth investigations are imperative to isolate and characterize their active compounds, as well as to understand the molecular mechanism of action of the species against human ailments with the hope of developing commercially valuable products of high economic importance.