Maesa lanceolata: a comprehensive review of its traditional medicinal uses, phytochemistry, pharmacological potential, toxicology, and safety profile

Maesa lanceolata Forssk. (Primulaceae) is a well-known medicinal plant in Rwanda and it is used to treat conditions such as malaria, asthma, elephantiasis, wounds, backache, stomachache, menorrhagia, sexually transmitted diseases (syphilis and gonorrhea), etc. in many African countries. This study aims to combine all the available information on the botanical characteristics, distribution, phytochemistry, pharmacological activity, and toxicology of M. lanceolata. Data collection was done using multiple electronic search engines like Scopus, Science Direct, PubMed, ResearchGate, and Google Scholar. Significant medicinal properties such as antioxidant, antibacterial, cytotoxic, antiviral, antifungal, antiplasmodial, molluscicidal, and antiulcerogenic properties have been found in a variety of studies that align with its various ethnomedicinal applications. Phytochemical studies have identified nearly 70 compounds from different parts of the plant, including triterpenoid saponins, benzoquinones, steroids, terpenoids, and other components. Benzoquinones, specifically maesanin, dihydromaesanin, and isomeric mixtures, exhibited significant cytotoxicity against the HL-60 cell line. Furthermore, structurally related acylated benzoquinones with shorter alkyl substituents [(2- acetoxy-5-hydoxy-6-methyl-3-tridecyl-1,4-benzoquinone and 2-hydoxy-5-acetoxy-6-methyl-3-tridecyl-1,4- benzoquinone)] display both antioxidant and antiproliferative effects on the SK-MEL, KB, BT-549 and SK-OV-3 cancer cell lines. The compound maesasaponin II demonstrated promising antiangiogenic activity without concurrent hemolytic effect. Additionally, maesanin showed inhibitory activity against 5-lipoxygenase, suggesting potential anti-inflammatory applications. These findings indicate the potential of M. lanceolata in various biological applications and show the necessity of further studies to explore its potential therapeutic benefits in numerous public health issues. Human clinical trials and studies on the mechanisms of action are needed to determine if any compounds in the plant can be used as leads in drug development.