Potential functional foods in the traditional Maori diet

The Maori people were early New Zealand settlers of Polynesian descent. The incidence of non-infectious diseases appears to have been low in these people, perhaps in part due to the presence of protective chemical constituents within their food plant supply. Three of the tropical crops they introduced are still eaten here today: the sweet potato or kumara (Ipomoea batatas), the taro (Colocasia esculenta) and the cabbage tree or ti (Cordyline terminalis). Sporamins A and B, the major storage proteins of kumara tubers, act as proteinase inhibitors, and may have other anti-cancer properties. The tubers also contain the anti-coagulant coumarins, scopoletin, aesculetin, and umbelliferone. The corms of taro contain the anthocyanins, cyanidin 3-glucoside, pelargonidin 3-glucoside and cyanidin 3-rhamnoside, reported to have antioxidant and anti-inflammatory properties. Anthocyanins are also major components of a so-called "Maori potato", a variety officially known as Ureniki, which has a purple skin and flesh and was widely eaten in the early 1900s. Anthocyanins are also present in ripe berries of the ramarama (Lophomyrtus bullata) and rohutu (Neomyrtus pedunculata). Both the leaves and seeds of the introduced cabbage tree (Cordyline terminalis) and the native Cordyline spp., C. australis, C. indivisa, and C. pumilo, were eaten. The seeds of C. australis, of some Astelia spp., and of hinau (Elaeocarpus dentatus) are good sources of various essential fatty acids, generally regarded as protective against cardiovascular disease. Shoots and leaves from a wide range of native species were traditionally eaten as greens, especially "sow thistle" or puha (Sonchus spp.), reportedly high in Vitamin C and various phenolics. "New Zealand spinach" (Tetragonia tetragonioides or T. expansa) has anti-ulcerogenic activity that has been traced to two cerebrosides and anti-inflammatory activity that has been traced to novel water-soluble polysaccharides, as well as antioxidant phenylpropanoids including caffeic acid. Leaves of the "hen and chickens" fern (Asplenium bulbiferum) contain antioxidant flavonoids such as kaempferol glucosides. Native seaweeds also have useful nutritive properties.