Research Article - (2012) Volume 2, Issue 3
Background: There are several beneficial effects of grapefruit (Citrus paradisi) in scientific literature, coupled with nutritional uses as an excellent source of many nutrients and photochemicals; able to contribute to a healthy diet. Studies have shown that grapefruit helps lowered cholesterol and there is evidence that the seeds have high level of antioxidant properties. Histological study of the effects of oral administration of extract of grape fruit juice on the cerebellum of adult male Wistar rats was therefore studied. Methods: The rats (n=20), weighing between 160 g-225 g were divided into four group (A, B, C and D), with each group consisting five rats. Groups A, B and C were the experimental groups and group D was the control group. The rats in the experimental groups received different doses of grape fruit juice extract orally, using a cannula for fourteen days. Group A received 0.6 ml/gBW/day of grapefruit juice, Group B received 0.8 ml/gBW/day of grapefruit juice and group C received 1.0 ml/gBW/day of grapefruit juice. Group D (control group) received equal volume of distilled water without the extract grapefruit juice added. The rats were sacrificed on day fifteen of the experiment. Cerebellum was carefully dissected out and quickly fixed in 10% formal saline for routine histological studies using H/E stain. Results: The histological findings indicated that the treated sections of the cerebellum showed a dose dependent cellular degeneration of the granular layer and atrophic changes in the Purkinje cells of the Purkinje layer. Conclusions: This research work indicates that grapefruit juice consumption at higher dose may probably has adverse effects on the Purkinje and granule cells of the cerebellum.
Grapefruit is a subtropical citrus tree grown for its bitter fruit, which was originally named the “forbidden fruit of Barbados. The fruit was first documented in 1750 by Rev. Griffith Hughes describing specimens from Barbados. Currently, the grapefruit is said to be one of the “seven wonders of Barbados” .
Grapefruit is very useful in removing or dissolving inorganic calcium which may have formed in the cartilage of the joint as in arthritis, as a result of excessive consumption of devitalized white floor products (Wainwright and Martin, 2004) . Grapefruit mercaptan, a sulfur-containing terpene, is one of the substances which have a strong influence on the taste and odour of grapefruit, compared with other citrus fruits .
A study in 2007 found a correlation between eating a quarter of grapefruit daily and a 30% increase in risk for breast cancer in postmenopausal women. The study points to the inhibition of CYP3A4 enzyme by grapefruit, which metabolizes estrogen. However, there is a study showing that grapefruit consumption may net increase breast cancer risk. Furthermore, related studies showed a significant decrease breast cancer risk with greater intake of grapefruit in women who never used hormone therapy . Grapefruit can have a number of interactions with drugs, often increasing the effective potency of compounds. Grapefruit contains naringin, bergamottin and dihydroxybergamottin, which inhibit the protein isoform CYP3A4 predominantly in the small intestine rather than liver. It is via inhibition of this enzyme that grapefruit increases the effects of a variety of drugs by increasing their bioavailability. The effect of grapefruit juice with regard to drug absorption was originally discovered in 1989. However, the effect became well-policized after being responsible for a number of deaths due to overdosing on medication [4-6].
Twenty mature male Wistar rats (160-225 g) obtained from an animal house in Ladoke Akintola University, Ogbomoso, Nigeria were acclimatized for two weeks in well ventilated animal house with a constant 12 hour light: 12 hour dark lighting schedule and comfortable temperature of 27 ± 2°C. The animals were housed in wire gauzed cage with wood chip beddings. They were fed with growers’ marsh pellet diet (obtained from Bendel Feeds Limited, Ilorin, Kwara State) and water was given ad libitunm.
Citrus paradisi was purchased from local commercial sources. Botanical identification and authentication was done at the Botany department of the University of Ilorin. The fruits were cut into two halves and a juice extractor was used to extract the juice. The extracted juice was then sieved to obtain a clear sample of the juice. The extract was evaporated to reduce the water content of the juice and obtain a desired concentrate. The pH of the extract before evaporation was 3.48 at 30.1°C and was 2.9 at 30.1°C after evaporation.
Twenty adult male Wistar rats were divided into four groups:
Group A: 0.6 ml/gBW/day orally for 14 days
Group B: 0.8 ml/gBW/day orally for 14 days
Group C: 1.0 ml/gBW/day orally for 14 days
Group D: Control- Water only
The rats were sacrificed twenty four hours after the administration of the last dose. The skulls of the rats were opened up using a bone crusher and the cerebellum was carefully dissected out and quickly fixed in 10% formal saline for routine histological study using H/E stain.
The cerebellum of the control group showed normal histological features, illustrating a well defined molecular, granular and Purkinje layers and presence of numerous closely packed small cells in the granular layer as well a large Purkinje cells in the Purkinje cell layer. The cerebellum of experimental group B and C (Figure 2 and 3) showed a dose dependent cellular degeneration and atrophy thus leading to a decrease in number of cells in the granular and Purkinje layers respectively. These changes were most pronounced in the group with the highest dose (group C which received 1 ml/gBW/day) of grapefruit juice extract, followed by the group with the medium dose (group B which received 0.8 ml/gBW/day) of the extract. The group that received the least dose of the extract (group B which received 0.6 ml/gBW/ day) showed a normal cytoarchitecture of the cerebellum with a slight increase in number of granule cells in the granular layer.
The results of the Haematoxylin and eosin staining (H & E) reactions showed (Figure 1 and 4) a dose dependent cellular degeneration of the granular layer. Atrophic changes were observed in the Purkinje cells and granule cells; these were more pronounced in those that received 1.0 ml/gBW/day of grapefruit extract. The increase in cellular degeneration of the granule and Purkinje cells in the experimental groups as reported in this study might have been as a result of cellular atrophy; its mechanism is not yet clear. The actual mechanism by which grapefruit juice extract induced cellular degeneration observed in this experiment needs further investigation.
Degenerative changes have been reported to result in cell death, which is of two types, namely apoptotic and necrotic cell death. These two types differ morphologically and biochemically . Pathological or accidental cell death is regarded as necrotic and could result from extrinsic insults to the cell such as osmotic, thermal, toxic and traumatic effects.
In this experiment grapefruit juice could have acted as toxins to the cells of the cerebellum. The process of cellular necrosis involves disruption of the structural and functional integrity which was a landmark of this experiment. In cellular necrosis, the rate of progression depends on the severity of the environmental insults. The greater the severity of insults, the more rapid the progression of cellular injury . It may be inferred from the present results that high dose of grapefruit juice extract resulted in a dose-dependent toxic effects on the cerebellum.