A systematic review of antimalarial activities of Morinda species.

• Leaf extracts of M. morindoides possess the antimalarial activity against the multi-resistant strain K1 and FcB1 of plasmodium falciparum. • The activity of M. morindoides related to terpenes, steroids, and flavonoids, whereas the active ingredients of M. lucida might be anthraquinones. • Anthraquinones extract from the stem bark present a higher effect than other extracts. • M. citrifolia, M. elliptica and M. pubescens were reported in very limited literature. Morinda , which includes many members in its genus, is a traditional medicine against malaria in Africa. We aim to systematically review the antimalarial activities of Morinda species. We conducted a systematic search in nine databases. A manual search of the reference list was also used to identify relevant articles. We included all original researches investigating the antimalarial activities and cytotoxicity of Morinda species. The protocol was registered in PROSPERO with CRD42018102856. We finalized 33 studies for quality synthesis. Our study showed that leaf extracts of M. morindoides possessed antimalarial activity against the multi-resistant strain K1 and FcB1 of Plasmodium falciparum. Its extracts including the ethanol extracts, ethyl acetate fraction and ethanol fraction from water extract, chloroform fraction from ethanol and methanol extract, presented significant antimalarial activity. Quercetin and four phenylpropanoids conjugated iridoid extracted from methanol extract might be active ingredients. Dichloromethane leaf extract of the plants was more effective than others to suppress parasite growth in vivo models. M. lucinda with its stem bark extract, ethanol, and dichloromethane leaf extracts had a noticeable antimalarial activity. The effect of the plant could relate to the synthetic action between active compounds. Anthraquinones were supposed as constituents causing its main effect. Other Morinda species only reported in limited literature. Our findings provided the chemical constituents, which may become a promising treatment in malaria. The mechanism of their actions should be elucidated in further studies. [ABSTRACT FROM AUTHOR]