Abstract

Noni (Morinda citrifolia l.) is a shrub in the family Rubiaceae. It is found in tropical or subtropical areas such as Southeast Asia and the Pacific islands. In the past, noni has been used in folk medicine, dye, and food. At the present time, noni is consumed in the form of juice as a supplemental food by people around the world to gain purported health benefits such as boosting of the immune system. However, there is a lack in convincing scientific evidence on health benefits of noni so far in humans. A few medical case reports noted both beneficial and adverse effects of noni consumption.

At a dolphin facility in the Republic of Palau (North Pacific Ocean), we had some prior experience in supplementing noni to the diet of an adult female bottlenose dolphin (Tursiops truncatus). The blood tests of an eight-year old female revealed high-levels of AST and ALT (AST: 2568IU/L and ALT: 459IU/L) after administration of noni juice for a year; 120 ml twice a day for six month, 200ml twice a day for six month and 300ml twice a day for five days. Following withdrawal of noni AST and ALT levels declined; after 11 days levels became lower (AST: 552IU/L and ALT: 131IU/L), and three months later levels returned to the levels considered normal for this individual (AST: 295IU/L and ALT: 60IU/L).

To further investigate the effects of noni, a small-scale study was carried out on eight clinically normal dolphins, aged between eight and 10 years old. For two years, a group of three dolphins received noni juice following a regime of 200 ml noni juice once a day with 2 L of water (through gastric tubing under voluntary behavior). The control group consisted of five dolphins and they were given 2 L water only once a day. Blood samples from the eight dolphins were collected approximately once a month. There were some individual differences in the variations of AST and ALT levels in both study groups. Mean AST level of the control group was 248.0 ± 100.0IU/L (number of blood samples = 73) which was higher than that of the noni-group, 235.2 ± 64.2IU/L (number of blood samples = 44). Mean ALT level of the control group was 77.6 ± 37.1IU/L (number of blood samples = 76), which was also higher than that of the noni-group, 75.0 ± 34.0IU/L (number of blood samples = 46). Overall, no significant difference (P < 0.05) was found in the levels of AST and ALT between the test (noni) and control groups. Throughout the study period, all the subjects cooperated well for the tubing procedure; overall behaviour appeared normal and did not show any obvious adverse effects due to the intake of noni.

Results presented here are only preliminary findings as the number of subjects studied was small and study period was short. The effects of noni in dolphins require further clinical investigation. In the absence of comprehensive and conclusive data, supplementation should be carried out with caution. Also, monitoring should be conducted on an individual basis and should include the use of other diagnostic tools, such as ultrasonography.