Liver Protective Effects of Morinda citrifolia (Noni)
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This study evaluated the protective effects of Noni fruit juice on acute liver injury induced by carbon tetrachloride (CCl4) in female Sprague-Dawley (SD) rats. Liver damage (micro-centrilobular necrosis) was observed in animals pretreated with 20% placebo (drinking water) + CCl4. However, pretreatment with 20% Noni juice in drinking water + CCl4 resulted in markedly decreased hepatotoxic lesions. Furthermore, serum alanine aminotransferase and aspartate aminotransferase levels were significantly lower in the Noni group than the placebo group. In a correlative time-dependent study, one dose of CCl4 (0.25 mL/kg in corn oil, p.o.) in female SD rats, pretreated with 10% placebo for 12 days, caused sequential progressive hepatotoxic lesions over a 24 h period, while a protective effect from 10% Noni juice pretreatment was observed. These results suggest that Noni juice is effective in protecting the liver from extrinsic toxin exposure.
KeywordsMorinda citrifolia Noni Liver protection Carbon tetrachloride
- H & E
hematoxylin and eosin
superoxide anion radical
Tahitian Noni® Juice
Carbon tetrachloride (CCl4) is a common environmental pollutant and liver carcinogen. Due to its detoxifying function in protecting the body, the liver is a target for CCl4 toxicity . Antioxidants and anti-inflammatory agents play a critical role in liver protection by scavenging superoxide anion radicals (SAR) and neutralizing lipid peroxides (LPO). They also suppress the inflammatory response [2, 3, 4]. Therefore, there is need for a natural product that protects the liver, but is also cost-effective and safe, without long-term side effects. This study evaluated the liver protective potential of the fruit juice of Morinda citrifolia (Noni), from Tahiti, a strong antioxidant and anti-inflammatory nutritional supplement.
We have previously reported that Noni juice is an effective antioxidant, demonstrating a dose-dependent effect against SAR and LPO in vitro . Based on the data from our laboratory and others, we suggested that Noni juice may be effective in protecting the liver against acute CCl4 toxicity. To test our hypothesis, a classic CCl4-induced liver injury model was chosen to study the liver protective effect in female SD rats. Morphological change is the most direct sign of liver injury. Histopathological changes were evaluated for morphological evidence of the liver protective properties of Noni juice. Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) assays that measure liver function were performed on the Noni group (Noni + CCl4) and compared to those of the positive control group (placebo + CCl4).
Materials and Methods
Carbon tetrachloride was purchased from Sigma Chemical Co., St. Louis, MO, USA. Noni juice was made by Morinda Holdings Inc. (Provo, UT, USA) from Noni fruit originating in Tahiti. The placebo was prepared using the same procedures and ingredients for making Tahitian Noni® Juice (TNJ), but without the Noni component.
Six-week-old female SD rats were purchased from Charles River Inc. (Wilmington, MA, USA). The animals were housed in a room maintained at 25 °C with a 12 h photoperiod. They were fed a laboratory chow diet and water ad libitum. The experimental design for these tests was approved by the Institutional Ethics Review Committee for animal experiments at the National Cancer Center.
Sixteen female SD rats were divided into two groups of eight each. Both groups were provided drinking water for 7 days. Twenty percent placebo was added to the drinking water in one group and 20% Noni juice in the other. On day 8, four animals from each group were fed 0.5 mL/kg CCl4 in corn oil. All animals were sacrificed at 6 h post-CCl4 administration. The liver was removed and fixed in 10% neutral formalin for histological examination. Blood was collected from each animal for serum AST and ALT activity to examine liver function.
Liver samples were preserved in 10% neutral buffered formalin and dehydrated in a graded alcohol series. Following xylene treatment, the specimens were embedded in paraffin blocks and cut into 5 μm thick sections. Consecutive sections were stained with hematoxylin and eosin (H & E) and examined under an Olympus BH2 light microscope. The number of foci/mm2 was counted to assess the degree of necrosis . Digital images were recorded with the Pixera Visual Communication Suite.
ALT and AST Assay
Serum was separated from clotted blood by centrifugation at 1,600 rpm for 10 min at 4 °C. Serum ALT and AST activities were measured using an automatic biochemical analyzer calibrated with quality control standards (E.I. du Pont de Nemours) in a clinical laboratory (Family Medicine Laboratory, UIC College of Medicine at Rockford).
Thirty-six female SD rats were divided into two groups of 18 each. While dose range-finding experiments revealed that maximum protection occurred with 20% Noni juice in drinking water, optimum protection (per amount ingested) occurred with 10%. Therefore, each group was supplied 10% placebo or 10% Noni juice in drinking water for 12 days. On day 13, 15 animals from each group were fed 0.25 mL/kg CCl4 in corn oil. Three animals from each group were sacrificed at 1, 3, 6, 16, and 24 h post-CCl4 administration. The remaining three animals in each group were fed 1 mL/kg corn oil and sacrificed 1 h later, to serve as vehicle placebo and Noni controls. Multiple liver-tissue samples were removed from each rat to be fixed for LM examination.
Liver samples for experiment 2 were prepared and observed for light microscopy as described in experiment 1.
Statistical analysis was done by a Student two-tail T test . Differences were considered as significant at P < 0.05 and highly significant at P < 0.01. Results were expressed as mean ± SD.
Results and Discussion
Noni Juice Suppresses ALT and AST Activities
Effect of Noni juice on acute CC14-induced hepatitis in SD rats
67 ± 31**
222 ± 121**
67 ± 26**
222 ± 99**
Noni juice (20%)
65 ± 59**
184 ± 31**
Placebo (20%) + CCl4 0.5 mL/kga
136 ± 41
1135 ± 466
Noni juice (20%) + CCl4 0.5 mL/kg
68 ± 12**
358 ± 69*
The present study supports the protective effects of Noni juice on acute CCl4-induced hepatotoxicity. Necrosis of hepatocytes was minimized in livers of animals pretreated with Noni juice in both experiments. Noni juice prevented free-radical-induced oxidative-pathological events.
Damaged hepatocytes release ALT and AST enzymes following acute exogenous toxin exposure. Therefore these elevated serum enzyme levels are good chemical indicators of liver damage. Noni juice is able to normalize liver function after acute exposure to CCl4. Serum ALT and AST activity, a measure of defense enzyme levels, was significantly suppressed after CCl4 exposure in the Noni juice pretreated animals, compared with the elevated enzyme levels in the placebo pretreated animals. Therefore, pretreatment with Noni juice indeed protected hepatocytes from acute CCl4 exposure.
A few reports have suggested the involvement of Noni juice in the development of chemically induced hepatitis in a limited number of cases in Europe. However, no causal role has been established in any of these instances. Further, an official European investigation of these cases determined that no relationship between Noni juice and hepatitis was evident and that consumption of Noni juice is unlikely to induce adverse human liver effects . Animal and human studies have revealed that Noni juice is not hepatotoxic, even at very high doses [9, 10].
Our investigation suggests that Noni juice exerts effective protection against acute extrinsic chemical induced hepatic injury by inhibiting inflammatory response and suppressing elevated liver enzyme activities; thus preventing consequent cell membrane damage. Histopathological observations revealed morphological evidence, and bioassays revealed functional evidence, that Noni confers resistance to acute CCl4-induced hepatotoxicity. High dosages of Noni and placebo pretreatments did not induce liver damage. Noni may thus be an efficacious natural hepatoprotective nutritional supplement against chemically induced hepatotoxicity. Future studies should focus on how Noni juice influences the inflammatory and cytotoxic cytokines involved in liver injury.
This study was financially supported by Morinda Holding Inc. We thank Drs. Richard Novak, University of Illinois, and Leland White, Morinda Holdings, Inc., Provo, UT, USA for the editing and preparation of the manuscript. We thank technicians in the clinical laboratory of Family Health Center of UIC College of Medicine for their technical help in the liver function tests. A special thanks to Mr. John Javaherian for his effort on animal care.
This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.
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