Distribution of Naturally Occurring Anthraquinones, Iridoids and Flavonoids from Morinda genus: Chemistry and Biological activity

The present review covers chemistry and bioactivities of anthraquinones, iridoids, and flavonoids from the Morinda genus. The plants of Morinda species, belonging to the Rubiaceae family, have been used as traditional folk medicine with anti-bacterial, anti-fungal, anti-tumor, anti-helmin, analgesic, anti-inflammatory, and immune enhancing effects. They are rich sources of anthraquinones and iridoids. The relevant 2-methoxy-1,3,6-trihydroxyanthraquinone is one of the most potent quinone reductase enzyme inducers with no cytotoxicity with normal cells. Damnacanthol-3-O-b-D-primeveroside and lucidin-3-O-b-D-primeveroside displayed a significant reduction of the blood glucose levels in anti-diabetic tests. Additionally, iridoids, 9-epi-6a-methoxy geniposidic acid, scandoside methyl ester, asperulosidic acid, showed a more potent inhibitory effect of melanogenesis than the commercial available depigmented arbutin used in cosmetic industry.