Exploring Non-anthraquinone Metabolites of the Morinda Genus: Distribution and Biological Activities

The Morinda genus, part of the Rubiaceae family, is a valuable source of diverse bioactive compounds beyond the well-known anthraquinones. This review focuses on the secondary metabolites from Morinda species that do not contain anthraquinone structures, highlighting their chemical variety and biological importance. Important groups such as iridoids, phenolic compounds, coumarins, and polysaccharides are covered in terms of their distribution and effects. Numerous biological activities have been demonstrated by these compounds, notably antioxidant, anti-inflammatory, antimicrobial, antimalarial, neuroprotective, anticancer, antiviral, and immune-enhancing properties contributing to the therapeutic potential of Morinda. By reviewing recent advances in phytochemical research and pharmacological evaluation, this article identifies promising non-anthraquinone molecules for further development in medicine and biotechnology. This work aims to stimulate further exploration of Morinda’s unique natural products for their effective use in modern and traditional healthcare, including preliminary structure–activity relationship (SAR) insights.