Isolation and synergism of in vitro anti-inflammatory and quinone reductase (QR) inducing agents from the fruits of Morinda citrifolia (noni)

Morinda citrifolia, commonly called noni, is a plant typically found in the Pacific Islands, Southeast Asia, and other tropical areas. Noni fruits have been used as folk medicine for thousands of years for the alleviation of many diseases including cancer, colds, diabetes, flu, hypertension, and pain (Wang et al., 2002). Furthermore, noni juice, which is commonly prepared as a drip/exudate from senescing fruits held in fermentation vessels, is widely consumed today as a dietary supplement or food for the purported prevention of several diseases such as diabetes, high blood pressure and arteriosclerosis. So far, over 100 compounds have been identified in noni fruits. The structures of many of these are classified as anthraquinones, coumarins, glycosyl-fatty acid esters, flavonoids, polysaccharides, sterols and sulfur-containing compounds. Coumarins and flavonoids are specific chemotypes of the broader chemical group of polyphenols, which are abundant antioxidant components of fruits and vegetables (Faller & Fialho, 2009). Biological testing of both crude extracts and several pure constituents of noni fruit has been performed, revealing anti-inflammatory (Akihisa et al., 2007; Deng et al., 2007), antioxidant (Su et al., 2005), antibacterial, and Phase II enzyme inducing (Pawlus, Su, Keller, & Kinghorn, 2005) activities. However, many of the isolated compounds remain unexamined in this regard. Published reports suggest that noni fruits have chemopreventive activity against some types of cancers (Taskin et al., 2009; Wang et al., 2009) but which compound(s) from noni are responsible has not been determined.

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