Noni (Morinda citrifolia L.) is being evaluated in laboratory research for its benefits as an antioxidant and immunity booster, as well as for its properties to prevent tumors and cure diabetes. The vast spread of Noni in tropical region of the globe, from America reaching to Africa and Southeast Asia, contributed in enhancing its usage and potency due to the diversity in harvest zone. Noni parts comprise fruits, seeds, leaves, and flowers are being used for individual nutritional and therapeutical values. Nevertheless, the fruit is widely characterized to contain the most valuable bioactive substances. On the other hand, diabetic retinopathy (DR) is a microvascular disorder impacting the small blood vessels in the retina, which includes microaneurysms, retinal hemorrhages, and hard exudates results from prolonged exposure to high blood glucose levels. The anti-diabetes effect of Noni extract and juice has been examined but the beneficial role of Noni and its potential mechanisms against the development of diabetic retinopathy phenotype is still ambiguous.  This review, therefore, will discusses in details the pharmacological actions of M. citrifolia fruit, along with their isolated phytochemical compounds on diabetic retinopathy markers, through describing the conducted in vitro and in vivo studies as well as clinical data.

Morinda citrifolia L. generally recognized as noni, which is belonging to the Rubiaceae family, It is a small evergreen tree or shrub, native to the tropical zones of South Asia, Hawaii, islands of French Polynesia and Australia (Deng et al., 2008). The designation as Morinda citrifolia is referring to the botanical appellation that is initially resulting from the two Latin words ‘‘morus’’ imputing to mulberry, and ‘‘indicus’’ imputing to Indian [157]. In Hawaii M. citrifolia is known as Noni, while in India M. citrifolia is known as Indian mulberry and nuna, or ach. Malaysians refer to M. citrifolia as mengkudu whereas in Southeast Asia M. citrifolia is known as nhaut, but in Caribbean, M. citrifolia is known as the cheese fruit or painkiller bush (Chan-Blanco et al., 2006). Noni fruit are distinctly recognizable. White tube-shaped flowers are formed in collections on the early fruits. The syncarpous fruit develop to be approximately 5–10 cm in length long  and roughly 3-6 cm wide-ranging in an elliptical form, fleshy having stamped form which transform from a green coloration to a glowing yellow to white coloration after complete ripping (Lachenmeier et al., 2006; 156]. The fruit exterior is enclosed with multilateral segments which surrounded post flowered nectarines that continually function throughout fruit development (Dixon et al., 1999). Over 20 century, the plant has been recognized as a curative plant by Polynesians and Tahitians and is utilized for therapy. M. citrifolia fruit is usually utilized and consumed as a  juice, even though the flower, leaves, root and bark also can be utilized in preparing traditional medicine (McClatchey, 2002; Wang et al., 2002). In recent times, the health claims associated M. citrifolia comprise of wide-ranging health benefits in individual having infections, hypertension, arthritis, cancer, pain, diabetes and asthma. M. citrifolia is described to possess wide-ranging theraputic properties (Figure.1), which comprising of anti-inflammatory, analgesic, immune enhancing, antituberculous, antioxidant, antistress, antihypertensive, antiviral, anticancer, antiprotozoal, antibacterial, antifungal, and similarly tranquillizing characteristics. Nevertheless, the underlying mechanisms of these properties are still unidentified (Kumar et al., 2010; Krishnaiah et al., 2012). The numerous therapeutic profits of Noni are as a result of the phytoconstituents of the plant.                         

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