Advanced
Traditional oil palm (Elaeis guineensis jacq.) and its medicinal uses: A review
Traditional oil palm (Elaeis guineensis jacq.) and its medicinal uses: A review
TANG [HUMANITAS MEDICINE]. 2014. Aug, 4(3): 16-16
Copyright © 2014, Association of Humanitas Medicine
This is an open access article under the CC BY-NC license. (http://creativecommons.org/licenses/by-nc/3.0/)
  • Received : January 11, 2014
  • Accepted : May 20, 2014
  • Published : August 31, 2014
Download
PDF
e-PUB
PubReader
PPT
Export by style
Share
Article
Author
Metrics
Cited by
TagCloud
About the Authors
Bamidele Victor Owoyele
Department of Physiology,University of Ilorin, P.M.B. 1515, Ilorin, Nigeria
deleyele@yahoo.com
Gbenga Opeyemi Owolabi
Department of Physiology, Ladoke Akintola University of Technology, Ogbomoso, Nigeria

Abstract
The oil palm ( Elaeis guineensis Jacq.) has been reported to originate along the gulf of the guinea in West Africa. The various parts of the tree have been used locally and traditionally for various medicinal purposes. Some of these uses have been proved by scientific experiments. Palm oil is extracted from the mesocarp of the fruit and is used traditionally for the treatment of headaches, pains, rheumatism, cardiovascular diseases, arterial thrombosis and an atherosclerosis due to its rich phytonutrients. The leaves are also used for the treatment of cancer, cardiovascular diseases, kidney diseases and wound healing. The sap also has been found to be rich in phytonutrients that can be used to treat various diseases. This review therefore seeks to explore many of the uses of the oil palm using the various parts of the oil palm.
Keywords
INTRODUCTION
It is generally agreed that the oil palm ( Elaeis guineensis Jacq.) originated from the equatorial tropical rain forest region of Africa, precisely along the gulf of guinea ( Naher et al., 2013 ). It exists in the wild type and cultivated state. It was first introduced to Brazil and other tropical countries in the 15 th century by the Portuguese ( Corley, 1976 ). The oil palm fruit is a drupe. The American oil palm, Elaeis oleifera is native to tropical Central America and South America.
This review intends to provide information on the documented medicinal uses of oil palm including laboratory studies on the plant. Earlier review by Obahiagbon (2012) was limited to an aspect of the plant. This present review covers both the traditional as well as the scientific uses of the oil. The review however does not extend to the core botanical aspect of the plant. The literatures used for this review were obtained from Medline and Google Scholar search carried out from September, 2013 to April, 2014.
The traditional theory about the uses of oil palm in many parts of Nigeria is that products from oil palm are antidotes that can be used in the treatment of many ailments especially gastrointestinal disorders and poisons.
- Oil palm
The African oil palm ( Elaeis guineensis Jacquin) produces two different kinds of oil namely, palm oil and palm kernel oil ( Ekwenye and Ijeomah, 2005 ). The pericarp consists of three layers: the exocarp (skin), mesocarp (outer pulp containing palm oil), and the endocarp (a hard shell enclosing the kernel or endosperm, which contains oil known as kernel oil) ( Naher et al., 2013 ). Palm oil is extracted from fleshy mesocarp of the fruit either by milling mechanically or by the traditional method ( Hartley, 1977 ; Edem and Akpanabiatu, 2006 ), which contains 45 - 55% oil, but varies from light yellow to orange-red in color, and melts at 25℃ ( Duke, 1983 ). The oil colour is determined by the carotenoids ( Cottrell, 1991 ). The major carotenoids found in palm oil are the beta-carotene ( Obahiagbon, 2012 ). Palm kernel oil is obtained from the kernels enclosed in the endocarp ( Ekwenye and Ijeomah, 2005 ). Palm oil contains saturated palmitic acid, oleic and linoleic acid, giving it a higher unsaturated acid content than palm kernel or coconut oils ( Duke, 1983 ; Edem, 2002 ). Along with coconut oil, palm oil is one of the few highly saturated vegetable fats. It is semi-solid at room temperature and contains several saturated and unsaturated fats in the forms of glyceryl laurate (0.1%, saturated), myristate (1%, saturated), palmitate (44%, satur ated), stearate (5%, saturated), oleate (39%, monounsaturated), linoleate (10%, polyunsaturated), and alpha-linolenate (0.3%, polyunsaturated) ( Cottrell, 1991 ). Palm oil also has minor constituents including phospholipids (Goh et al., 1983). Currently, palm oil is the world largest edible oil ( Naher et al., 2013 ) and is the main source of domestic or edible oil in Africa ( Obahiagbon, 2012 ; Oluba et al., 2009 ). As much as palm oil provides energy and fatty acid needs (Oguntibeju et al., 2009), much of the palm oil that is consumed as food is to some degree oxidized rather than in the fresh state, and this oxidation appears to be responsible for the health risk associated with consuming palm oil ( Edem, 2002 ).
Ekwenye and Ijeomah (2005) reported that traditionally, palm oil has been used in the South Eastern Nigeria for the treatment of various diseases and skin infections. This was confirmed by their experiment carried out at the Michael Okpara University of Agriculture, Umudike, Abia State, Nigeria using five microorganisms namely; Staphylococcus aureus, Escherichia coli, Pseudomonas areuginosa, Candida albicans , and Aspergillus niger known to cause some infections treatable with palm oil and palm kernel oil. In this experiment, 0.04 ml of 100% concentration palm oil and palm kernel oil extracts was impregnated into the sterilized discs according to the method of Ekpa and Ebana (1996) . The anti-microbial test was done using the disc diffusion method of Brauer et al. (1996) was adapted using nutrient agar, sabouraud dextrose agar, and the impregnated discs. Palm oil has also been reported to be anodyne, anti-dotal, aphrodisiac and a diuretic ( Irvin, 1985 ; Sasidharan et al., 2012 ). It is folk remedy for headaches, pains, rheumatism, cardiovascular diseases, arterial thrombosis and an atherosclerosis ( Ekwenye and Ijeomah, 2005 ; Honstra, 1986 ; Irvin, 1985 ; Sasidharan et al., 2012 ). The palm oil is known to be effective against many forms of intestinal disorders, especially diarrhoea and dysentery in infants ( Ekpa and Ebana, 1996 .). The fruit mesocarp oil and palm kernel oil are administered as poison anti-dote and used externally with several other herbs as lotion for skin diseases. Palm kernel oil is applied to convulsing children to regulate their body temperature. Folk remedies of oil palm also include treatment for cancer and liniment ( Irvin, 1985 ; Sasidharan et al., 2012 ).
- Anti-oxidant activity
Palm oil provides a rich source of beta-carotene and vitamin E, namely tocopherols and tocotrienols which are recognized nutritional anti-oxidants that act as scavengers of the oxygen atom or free radicals ( Chong and Ng, 1991 ; Ekwenye and Ijeomah, 2005 ; Goh et al., 1985 ). The oxygen atom or free radicals can arise during the body’s normal oxidative metabolism or from the action of toxic pollutants that contaminate our food and have been implicated in ageing, heart disease and cancer ( Ekwenye and Ijeomah, 2005 ). E. guineensis is also used as a wound healing agent among the natives of Africans and as therapeutic agent in other parts of the World ( Sasidharan et al., 2010 ; Sasidharan and Vijayarathna, 2012 ). The palm oil is also used for biofuels and some manufactured products ( Naher et al., 2013 ). Carotenoids are potent anti-oxidants. Packer et al. (1992) showed that alpha-carotene is a more potent anti-oxidant than beta-carotene. Red palm oil is rich in natural phytonutrients that are important for health. These phytonutrients (i.e. tocotrienols and carotenes) are also powerful anti-oxidants that help maintain the stability of the oil during cooking process and may extend the shelf life of food prepared with red palm oil
Research has shown that consumption of red palm oil significantly enhanced vitamin A levels in humans, and it is beneficial in preventing vitamin A deficiency ( Manorama and Rukmini, 1991 ; Roo, 2000; Solomons, 1998 ) and it is used for combating vitamin A deficiency in developing countries ( Rukmini, 1994 ). Additionally, some workers have advised that nursing mothers should take red palm oil as supplement with their food in order to prevent vitamin A deficiency ( Lietz et al., 2000 ). Vitamin A deficiency may lead to blindness, skin disease and weakened immune function. The vitamin A content of the red palm oil plays important roles in growth, development and in visual process ( Edem, 2009 ). The human body is able to convert provitamin-A carotenoids (alpha- and beta-carotene) when there is a deficiency, hence it is safer to supplement with carotenes than consuming vitamin A (retinoids) directly. Excessive consumption of retinoids may lead to toxicity with symptoms ranging from mild, such as headache, nausea and dry, itchy skin to severe, such as liver damage ( Solomons, 1998 ).
Tocotrienols are members of the vitamin E family. In the body, vitamin E acts as an anti-oxidant that protects lipid from peroxidation and help quench free radicals. However, there is a difference in anti-oxidant potency between tocotrienol and its sibling tocopherol. Tocotrienol has been shown to be 40 to 60 times more potent than tocopherol as an anti-oxidant. Palm oil is the only vegetable oil available on the world market that naturally contains tocotrienols ( Cottrell, 1991 ; Ebong et al., 1999 ; Elson, 1992 ; Van Rooyen et al., 2008 ) and is the richest natural source of beta - carotene (500 - 700 mg/l) which is responsible for the characteristic colour of the oil. Similar to the tocopherols, tocotrienols consist of 4 members: alpha, beta, gamma, and delta isomers ( Serbinova, 1991 ). Alpha toco pherols and gamma tocotrienols have anti-oxidative effects on lipid peroxidation, in the presence of a xenobiotic metabolizing enzyme that induces lipid peroxidation ( Zuzana et al., 2005 ). The vitamin E, particularly the tocotrienol present in palm oil can suppress the synthesis of cholesterol in the liver ( Mcintosh et al., 1991 ; Qureshi et al., 1991 ; Qureshi et al., 1980 ). Some scientists in South Africa have been able to establish that oxidative stress plays a role in inflammatory and chronic disease such as HIV/AIDS and TB and contribute significantly to depletion of immune factors, micronutrients and progression of disease and that red palm oil could potentially retard the process because of rich anti-oxidants (Oguntibeju et al., 2009).
- Anti-diabetic action
Studies have indicated that the potential mechanism of action for the improvement in glucose metabolism with E. guineensis involves inhibition of the enzyme dipeptidyl peptidase-4 (DPP-4; Abdullah, 2009 ) the effect of which is to prevent degradation of gastric inhibitory polypeptide, which itself stimulates insulin secretion, suppresses glucagon secretion and slows gastric emptying. E. guineensis is rich in catechins and polyphenols ( Jaffri, 2011 ). Prior studies in streptozotocin-induced hyper glycemic rats showed that E. guineensis improved proteinuria and reduced oxidative stress levels ( Rosalina Tan, 2011 ; Yamabe, 2006 ). This suggests a potential benefit for the pre-diabetic and diabetic states. Administration of tocopherol, Vitamin E or tocotrienol-rich fractions of palm oil, have been shown to recover glycemic status, inhibit oxidative damage; prevent DNA damage in animal studies and prevent glycosylation of end-products in serum and decrease in diabetic rats ( Budin et al., 2006 ; Nazaimoon and Khalid, 2002 ; Obahiagbon, 2012 )
- Cardiovascular activities
Peer review journals have documented palm tocotrienol complex’s promising hypocholesterolemic properties ( Qureshi et al., 1991 , 1995 ). Also, the daily consumption of tocotrienols-enriched fraction of palm oil (200 mg palmvitee capsule) can result in a significant reduction of serum cholesterol, Low Density Lipoprotein cholesterol, APOB, thromboxane, platelet factor 4 and glucose of hyper cholesterolemic subjects within four weeks of administration ( Qureshi et al., 1991 ; Packer, 1992 ; Song and DeBose-Boyd, 2006 ). A number of human feeding studies reported that palm oil diets showed a reduction of blood cholesterol values ranging from 7 to 38% ( Mattson and Grundy, 1985 ; Bonanome and Grundy, 1988 ). A comparative study in young Australian adults showed that the total blood cholesterol, triglycerides and High Density Lipoprotein (HDL) - cholesterol levels of those fed on palm oil (palm olein) and olive oil were lower than those fed on the usual Australian diet ( Choudhury et al., 1995 ). A number of studies have also shown that palm oil increased HDL cholesterol and Apo A-1 levels ( Sundram et al., 1992 ; Truswell et al., 1992 ). Other studies have also shown the beneficial effects of palm oil on the cholesterol level of the body ( Marzuki et al., 1991 ; Ng et al., 1992 , 1991 ; Zhang et al., 1997 ). The position of the saturated and unsaturated fatty acid chains in a triglyceride backbone of palm oil molecule determines whether the fat will elevate cholesterol level in the blood ( Kritchevsky, 1988 , 1996 ). High blood pressure or hypertension is one of the major risk factors of cardiovascular diseases and strokes. In a human clinical trial, patients supplemented with palm tocotrienol complex for two months resulted in significant reduction in aortic systolic blood pressure ( Rasool et al., 2006 ). In an earlier review by Obahiagbon (2012) , he pointed out that Tocotrienol-rich Fraction (TRF) of palm oil exhibited cardio-protective ability in animal trials ( Das et al., 2008 ). The cardio-protective effects produced by the isomers of tocotrienol were of the order of: γ > α >δ. The inhibition of normal cellular gene, C-Src activation and proteosome stabilization were found to be reasons behind the cardio-protective properties of TRF ( Das et al., 2008 ). Feeding experiments using various animal models have highlighted that red palm oil is beneficial to health by reducing oxidative stress ( Ebong et al., 1999 ). Many studies have demonstrated the protective effects of red palm oil in an ischemia/reperfusion model of oxidative stress ( Bester et al., 2006 ; Engelbrecht et al., 2006 ; Esterhuyse et al., 2005 )
Palm oil has been shown to possess anti-clotting effect and it prevents the formation of thrombus in the blood vessels ( Oguntibeju et al, 2010 ). A human study ( Kooyenga et al., 1997 ) showed that tocotrienol (from palm oil) supplementation can reduce stenosis of patients with carotid atherosclerosis. Vitamin E in palm oil has been linked with inhibition of platelets from sticking to each other. Other reports showed that palm oil diets increases the production of prostacyclin or thromboxane ( Ng et al., 1992 ; Sundram et al., 1990 ). Thus scientific evidence indicates that the palm oil diet is anti-thrombotic. Studies in animals confirmed that palm oil do not promote the formation of plaques in the arteries. A study was conducted on rabbits to test the effect of palm oil on atherosclerosis. After feeding the rabbits for one and a half years, palm oil and sunflower oil diets caused the lowest degree of atherosclerosis in comparison with fish oil, linseed oil and olive oil. Similarly, the effects of palm oil was also compared with other types of plants derived oils and at the end of the 14-month feeding period, coconut oil fed rabbits had the most atherosclerosis lesions, while in palm oil-fed rabbits; the number of lesions was no different from that with the other oils ( Oguntibeju et al., 2010 ).
- Anti-bacterial
The anti-bacterial activity of this plant extract against different micro-organisms and anti-oxidant activity have already been reported (a; Sasidharan et al., 2009 ). Moreover, Chong together with Sasidharan and some others ( Chong et al., 2008 ) described the potential of E. guineensis leaf methanol extract as an infected wound healing agents. They observed that the bacterial count in the E. guineensis extract treated rats was significantly reduced to 102 CFU/g tissues on day 16. In a further study, Sasidharan tested wound healing activity without infection and the expression of matrix metalloproteinases ( Sasidharan et al., 2012 ).
- Toxicity
Several studies have been conducted to confirm the nontoxicity of different parts of E.guineensis at normal doses ( Rajoo et al., 2010 ; Syahmi et al., 2010 ). Syahmi et al. (2010) evaluated the acute oral toxicity of methanol extract of the leaves using a dose of 5g and found no toxicity. They also use the brine shrimp bioassay and also reported no toxicity. Also, Anyanji et al. (2013) showed that the ethanol extract of the palm leaves do not cause any toxicity at 2 g/kg but it appears toxic at 5 g/kg based on a single administration after seven days. However, the indices of toxicity were partially reversed after 14 days of administration.
- Conservation and preservation
Several literature have reported the use of palm oil in preservation purposes from various parasites including cowpea weevil, Callosobruchus maculatus ( Law-Ogbomo and Egharevba, 2006 ), Sitophilus zeamais and Callosobruchus maculates ( Abulude et al., 2007 ).
- Anti-cancer action
Studies have shown that tocotrienols fractions of palm oil were able to induce an inhibitory action on the human breast cancer cells, whereas the alpha-tocopherols were not able ( Nesaretnam et al., 2004 , 2008; McIntyre et al., 2000 ). Palm oil has been reported to be with wide range of protective properties against disease, aging as well as being modulators for cellular processes / functions where photo oxidative processes predominate by acting as scavengers of oxygen and peroxyl radicals ( Van Rooyen et al., 2008 ). It has been shown that fresh palm oil has no adverse effect on body weight and morphology of body tissues, lowers the level of serum lipids and inhibits tumour growth ( Kritchevsky, 2000 ), enhances intestinal uptake of protein and the metabolism of sulphur-amino acids and promotes reproductive capacity ( Ebong et al., 1999 ). Several researches have been conducted on cancer with the view to finding a lasting solution to the disease. Sundram and his colleagues (1989) were able to conduct an experiment to show that RPO significantly reduce tumor incidence in some experimental rats compared with the control groups. RPO, when compared with saturated fats and oils, may help fight cancer, especially breast cancer ( Nesaretnam, et al., 1992 ). This may be due to tocotrienols ( Nesaretnam, 1998 : Elson, 1992 ) or other phytonutrients ( Guthrie et al., 1997 ) present in palm oil. Indeed, Professors K. K. Carroll of the Centre for Human Nutrition at the University of Western Ontario and David Kritchevsky of the Wistar Institute recently concluded that evidence from animal and in vitro studies indicate that tocotrienols of palm oil are effective anti-cancer agents and provide adequate justification for clinical trials in human cancer patients ( Nesaretnam, 1998 ). This oil has equally been shown to reduce the incidence of azoxymethane-induced aberrant crypt foci in rats and may therefore have a beneficial effect in reducing the incidence of colon cancer ( Boateng et al., 2006 ).
- Anti-inflammatory effects
The TRF of palm oil has been shown by Wu et al. (2008) to possess anti-inflammatory activities in a study involving the injection of lipopolysaccharide-induced inflammatory response. The mediators of cellular inflammation such as nitric oxide (NO), prostaglandin E2, and transcription of pro inflammatory cytokines were significantly reduced. The following were equally blocked; inducible NO, cyclooxygenase 2 expression and NF-kappa B expression.
- Leaves of palm oil
A review of the health benefits of the leaf extracts of oil palm has been provided extensively by Mohammed (2014) , however, the present review is to provide additional information.
- Anti-cancer activities
Methanolic oil palm ( Elaeis guineensis ) leaf extract is rich in polyphenols ( Runnie et al., 2003 ; Jaffri, 2011 ).The methanolic leaf extract of E. guineensis has also been shown to possess anti-cancer activities ( Sasidharan and Vijayarathna, 2012 ). Studies have observed the presence of a large number of bioactive compounds in the methanolic extracts of this plant including tannins, alkaloids, steroids, saponins, terpenoids, and flavonoids which exhibit various biological activities ( Sasidharan et al., 2010 ; Gulecha and Sivakuma, 2011 ; Kumar et al., 2011 ). These compounds are present in a number of food items and hold great potential as drug candidates due to their safety, low toxicity and wide acceptance amongst the public.
- Wound healing
Sasidharan et al. (2012) reported in their article that in traditional medicine, the leaf of E. guineensis is squeezed and the juice that is obtained is placed on wounds to promote healing ( Irvin, 1985 ). They tried to establish this in an experimental research conducted in Malaysia which showed that E. guineensis leaf extract had potent wound healing capacity as evident from the better wound closure ( p < 0.05), improved tissue regeneration at the wound site, and supporting histopathological parameters pertaining to wound healing ( Sasidharan et al., 2012 ). The wounds were treated topically with 10% formulated crude extract (5 g of the extract in 50 g of yellow soft paraffin), while the control rats were treated only with yellow soft paraffin for 16 days. The decrease in wound diameters during the healing process was measured with an analytical perimeter. The wounded animals were kept for 25 days for further observations ( Sasidharan et al., 2012 ). Although the leaf of the oil palm is a waste product, the alcohol extract of the leaf contains large amounts of phenolic compounds ( Sasidharan et al., 2009 ; Soundararajan and Sreenivasan, 2012 ) that reportedly promote vascular relaxation and anti-oxidant activity in vitro. A pooled methanolic extract was dried under vacuum using a rotary evaporator and the resultant waxy residue collected, freeze dried, flushed with nitrogen and stored at −20℃. For vascular function studies, a stock solution (100 mg/ml) was prepared using a 1:1 v/v mixture of methanol: saline and serially diluted. Aliquots (25 – 50 μL) were added directly in a cumulative fashion to the bath (aortic rings) or injected intraluminally (mesenteric vascular bed ( Abeywardena et al., 2002 ). In a recent study of streptozotocin (STZ)-induced hyperglycemic rats, E. guineensis leaf extract reduced glycemia and lipid oxidation in a dosedependent manner, possibly by inhibiting dipeptidyl peptidase-4 (DPP-4) secretion ( Tan et al., 2011 ).
- Cardiovascualar activities
The polyphenol-rich leaf extract of E.guineensis showed vasodilative properties on noradrenaline-preconstricted rat aorta and mesenteric arterial bed, mainly via endothelium-dependent mechanisms ( Abeywardena et al., 2002 ). It also effectively inhibited low-density lipoprotein oxidation better than other edible plant extracts ( Salleh et al., 2002 ). Also, in a 12-week study conducted by Jaffri et al. (2011) on rats, the leaf extract showed good anti-hypertensive and anti-oxidant effects under NO deficiency, it was not hypotensive to normal rats and produced no chronic cardiovascular toxicity in any of the rats throughout the study.
- Hepatoprotective effects
Sasidharan et al. (2009) demonstrated the hepatoprotective effects of E. guineensis against paracetamol induced liver damage by looking at the histopathology of mice liver. This was subsequently followed up by a serum analysis in which the same authors ( Sasidharan et al., 2012 ), reported that the methanol extract of the leaves of the plant also offer hepatoprotection against paracetamol induced-liver damage in mice by reducing serum markers of liver injury such aspartate aminotransferase, alanine aminotransferase, and billirubin.
- Anti-diabetic effects
Kalman et al. (2013) reported that the ethanol-derived leaf extract of E. Guineensis provided a clinically significant, positive effect on fasting plasma glucose levels in individuals with pre-diabetes who were treated with the leaf extract in a dose dependent manner in human subjects. A 500 mg low dose of E. guineensis was shown to have had a more consistent effect on reducing glycemia than the higher 1000 mg dose over an eight week period.
- Anti-inflammatory activity
Oil palm ethanolic leaf extract (OPLE) at 150 mg/kg body weight showed significant pro-inflammatory activity with enhanced 46% late phase inflammation recovery effects. While at high dose, inflammation was significantly suppressed prior to the sixth hour compared to other groups, and did not require much inflammation suppression between the 18th and 48th hour. OPLE 150 mg/kg decreased lymphocyte counts, but was not as severely as dexamethasone treatment. This result suggests that OPLE extract possess strong in-vivo inflammatory-regulatory effects ( Anyanji et al., 2013 ).
The main problem for the use of oil palm leaf extract as food in its natural form is its high content of insoluble fibre. The OPLE effectively reduced blood glucose and lipid oxidation in Type II diabetic humans and diabetes-induced rodents. The optimum dose in animal studies is equivalent to consuming 5 cups of 1% palm leaf extract for diabetic humans, to prevent liver and kidney damage ( Mohammed, 2014 ).
- Sap of oil palm
- Multiple actions
The oil palm sap or wine can be descried as the exudates that flow when the palm is tapped ( Obahiagbon, 2012 ). The sap of this plant is also used as a laxative and the partially fermented palm wine is administered to nursing mothers to improve lactation ( Sasidharan et al., 2012 ). The sap has also been recorded to be involved in malaria, jaundice and measles treatment. Just like the sap of other palms like Raphia , researches conducted by authors like Obahiagbon and Oviasogie (2007) , and Obahiagbon et al. (2007) have shown that the sap contains numerous phytonutrients which plays significant roles in human health. Soap prepared with ash from fruit-husk is used for the preparation of a soap used for skin infections ( Sasidharan et al., 2012 ).
- Roots of oil palm
- Multiple actions
A root decoction is used in Nigeria for headaches. The pulverized roots are added to drinks for gonorrhea, menorrhagia and as a cure for bronchitis ( Sasidharan et al., 2012 ; Irvin, 1985 ). Chong et al. (2009) demonstrated the in vitro anti-microbial activity and fungitoxicity of syringic acid, caffeic acid and 4-hydroxybenzoic acid which are found in oil palm root. They also showed that of the three substances, syringic acid was the most fungitoxic against G. boninense .
CONCLUSION
Oil palm ( E. guineensis ) parts and products have been used in various parts of the world for different purposes. The traditional uses of the different parts of the plant have been well documented in this review. Virtually all the different parts of the plant have one or more therapeutic effects. The plant has been used extensively in local treatment of various ailments while the scientific uses of the plants have also been documented. The therapeutic effects of this plant have been attributed to the abundant anti-oxidants present in various parts of the plant. However investigations on the actual mechanisms by which the anti-oxidants perform their functions are still ongoing. Also, this review shows that products obtained from oil palm are safe for consumption at moderate doses in humans and rodents.
Acknowledgements
The authors are grateful to their respective institutions for the conductive environment provided for this review.CONFLICT OF INTERESTThe authors declare that there are no conflicts of interest.
View Fulltext  
Abdullah Z , Hussain K , Zhari I , Rasadah MA , Mazura P , Jamaludin F , Sahdan R 2009 Evaluation of extracts of leaf of three Ficus deltoidea varieties for antioxidant activities and secondary metabolites Phcog Res 1 216 - 223
Abeywardena M , Runny I , Nizar M , Mohamed S , Head R 2002 Polyphenol-enriched extract of oil palm fronds (Elaeis guineensis) promotes vascular relaxation via endotheliumdependent mechanisms Asia Pac J Clin Nutr 11 S467 - S472
Abulude FO , Ogunkoya MO , Ogunleye RF , Akinola AO , Adeyemi AO 2007 Effect of palm oil in protecting stored grains from Sitophilus zeamais and Callosobruchus maculatus J Entomol 4 393 - 396
Anyanji VU , Mohamed S , Zokti JA , Ado MA 2013 Anti-inflammatory properties of oil palm leaf (Elaeis guineensis Jacq.) extract in aged rats Int J Pharm Pharm Sci 5 134 - 136
Bester DJ , van Rooyen J , Du Toit EF , Esterhuyse AJ 2006 Red palm oil protects against the consequences of oxidative stress when supplemented with dislipidaemic diets Med Tech SA 21 3 - 6
Boateng J , Verghese M , Chawan CB , Shackelford L , Walker LT , Khatiwada J , Williams DS 2006 Red palm oil suppresses the formation of azoxymethane (AOM) induced aberrant crypt foci (ACF) in fisher 344 male rats Food Chem Toxicol 44 1667 - 1673
Bonanome A , Grundy SM 1988 Effect of dietary stearic acid and plasma cholesterol and lipoprotein levels New Eng J Med 318 1244 - 1248
Bauer AW , Kirby WM , Sherris JC , Turck M 1966 Antibiotic susceptibility testing by a standardized single disk method Am J Clin Pathol 45 493 - 496
Budin SB , Rajab NF , Osman K , Top AGM , Mohammed WNW , Bakar MA , Mohamed J 2006 Effects of palm vitamin E against oxidative damage in Streptozotocin-induced diabetic rats Malaysian J Biochem Mol Biol 13 11 - 17
Chong KP , Rossall S , Atong M 2009 In vitro antimicrobial activity and fungitoxicity of syringic acid, caffeic acid and 4-hydroxybenzoic acid against Ganoderma boninense J Agric Sci 1 15 - 20
Chong KH , Zuraini Z , Sasidharan S , Devi PVK , Latha LY , Ramanathan S 2008 Antimicrobial of Elaeis guineensis leaf Pharmacologyonline 3 379 - 386
Chong YH , Ng TK 1991 Effects of palm oil on cardiovascular risk Med J Malaysia 46 41 - 50
Choudhury N , Tan L , Truswell AS 1995 Comparison of palm olein and olive oil: Effects on plasma lipids and Vitamins E in young adults Am J Clin Nutr 61 1043 - 1051
Corley RHV , Corley RHV , Hardon JJ , Wood BJ 1976 Oil Palm Research. In the genus Elaeis Elsevier Scientific Publisher Amsterdam, Netherlands 532 -
Cottrell RC 1991 Introduction: nutritional aspects of palm oil Amer J Clin Nutr 53 989S - 1009S
Das S , Lekli I , Das M , Szabo G , Varadi J 2008 Cardioprotection with palm oil tocotrienols: Comparison of different isomers Am J Physiol Heart Circ Physiol 294 70 - 78
Duke AJ 1983 Handbook of Energy Crops https://www.hort.purdue.edu/newcrop/duke_energy/Elaeis_guineensis.html 1 - 5
Ebong PE , Owu DU , Isong EU 1999 Influence of palm oil (Elaesis guineensis) on health Plant Food Hum Nutr 53 209 - 222
Edem DO 2002 Palm oil: Biochemical, physiological, nutritional, hematological and toxicological aspects: a review Plant Foods Hum Nutr 57 319 - 341
Edem DO 2009 Vitamin A: A review Asian J Clin Nutr 1 65 - 82
Edem DO , Akpanabiatu MI 2006 Effects of palm oil-containing diets on enzyme activities of rats Pak J Nut 5 301 - 305
Ekpa OD , Ebana RUB 1996 Comparative Studies of Mmanyanga, Palm and Coconut Oils; Anti-microbial Effects of the Oils and their Metallic Soaps on Some Bacteria and Fungi Global J Pure and Appl Sci 2 155 - 163
Ekwenye UN , Ijeomah CA 2005 Antimicrobial effects of palm kernel oil and palm oil KMITL Sci J 5 502 - 505
Elson CE 1992 Tropical Oils: Nutritional and Scientific Issues Crit Rev Food Sci Nutr 31 79 - 102
Engelbrecht AM , Esterhuyse AJ , Du Toit EF , Lochner A , Van Rooyen J 2006 P38-MAPK and PKB/Akt, possible role players in red palm oil-induced protection of the isolated perfused rat heart? J Nutr Biochem 17 265 - 271
Esterhuyse AJ , Du Toit EF , Van Rooyen J 2005 Dietary red palm oil supplementation protects against the consequences of global ischemia in the isolated perfused rat heart Asia Pac J Clin Nutr 14 340 - 347
Goh SH , Khor HT , Gee PT 1982 Phospholipids of palm oil (Elaeis guineensis) J Am Oil Chem Soc 59 296 - 299
Goh SH , Choo YM , Ong SH 1985 Minor constituents of palm oil J Am Oil Chem Soc 62 237 - 240
Gulecha V , Sivakuma T 2011 Anticancer activity of Tephrosia purpurea and Ficus religiosa using MCF 7 cell lines Asian Pac J Trop Med 4 526 - 529
Guthrie N , Gapor A , Chambers AF , Carroll KK 1997 Palm oil tocotrienols and plant flavonoids act synergistically with each other and with tamoxifen in inhibiting proliferation and growth of estrogen receptor-negative MDA-MB-435 and -positive MCF-7 human breast cancer cells in culture Asia Pac J Clin Nutr 6 41 - 45
Hartley CWS 1977 The Oil Palm 1st ed Longmans London, England 618 -
Honstra G 1986 Beneficial Effects of Palm oil on Arterial Thrombosis (Rat) and Atherosclerosis (Rabbit) PORIM Kuala Lumpur, Malaysia 35 - 45
Irvin TT 1985 Wound healing Arch Emerg Med 2 3 - 10
Jaffri JM , Mohamed S , Rohimi N , Ahmad IN , Noordin MM , Manap YA 2011 Antihypertensive and cardiovascular effects of catechin-rich oil palm (Elaeis guineensis) leaf extract in nitric oxide-deficient rats J Med Food 14 775 - 783
Kalman DS , Schwartz HI , Feldman S , Krieger DR 2013 Efficacy and safety of Elaeis guineensis and Ficus deltoidea leaf extracts in adults with pre-diabetes Nutr J 12 36 -
Kooyenga DK , Gerler M , Watkins TR , Gapor A , Diakoumakis E , Bierenbaum ML 1997 Palm oil antioxidant effects in patients with hyper-lipidaemia and carotid stenosis-2 year experience Asia Pac J Clin Nutr 6 72 - 75
Krichevsky D 1988 Effects of triglyceride structure on lipid metabolism J Nutr Rev 46 177 - 181
Kritchevsky D , Tepper SA , Chen SC , Meijer GW 1996 Influence of triglyceride structure on experimental atherosclerosis in rabbits FASEB J 10 A187 - 187
Kritchevsky D 2000 Impact of red palm oil on human nutrition and health Food Nutr Bull 21 182 - 188
Kumar RS , Rajkapoor B , Perumal P 2011 In vitro and in vivo anticancer activity of Indigofera cassioides Rottl. Ex. DC Asian Pac J Trop Med 4 379 - 385
Law-Ogbomo KE , Egharevba RKA 2006 The use of vegetable oils in the control of Callosobruchus maculatus (F) (Coleoptera: Bruchidae) in three cowpea varieties Asian J Plant Sci 5 547 - 552
Lietz G , Henry CJK , Mulokozi G , Mugyabuso J , Ballart A 2000 Use of red palm oil for the promotion of maternal vitamin A status Food Nutr Bull 21 215 - 218
Manorama R , Rukmini C 1991 Nutritional evaluation of crude palm oil in rats Am J Clin Nutr 53 1031 - 1033
Marzuki A , Arshad F , Razak TA , Jaarin K 1991 Influence of dietary fat on plasma lipid profiles of Malaysian adolescents Am J Clin Nutr 53 1010 - 1014
Mattson FH , Grundy SM 1985 Comparison of effects of dietary saturated, monounsaturated and polyunsaturated fatty acids on plasma lipids and lipoproteins in man J Lipid Res 26 194 - 202
Mclntosch GH , Whyte J , McAthur R. , Nestle P. J. 1991 Barley and wheat foods; Influence on plasma cholesterol cocntrations in hypercholesterolemic men Am J Clin Nutr 53 1205 - 1209
McIntyre BS , Briski KP , Gapor A , Sylvester PW 2000 Antiproliferative and apoptotic effects of tecopherols and tocotrienols on preneoplastic and neoplastic mouse mammary epithelial cells Proc Soc Exp Biol Med 224 292 - 301
Mohamed S 2014 Oil Palm Leaf: A New Functional Food Ingredient for Health and Disease Prevention J Food Process Technol 5 300 -
Naher L , Yusuf UK , Ismail A , Tan SG , Mondal MMA 2013 Ecological status of Ganoderma and basal stem rot disease of oil palms (Elaeis guineensis Jacq.) AJCS 7 1723 - 1727
Nazaimoon WMW , Khalid BA 2002 Tocotrienols-rich diet decreases advanced glycosylation end products in non-diabetic rats and improves glycemic control in Streptozotocin-induced diabetic rats Malays J Pathol 24 77 - 82
Nesaretnam K 1998 Tocotrienols inhibit the growth of human breast cancer cells irrespective of estrogen receptor status Lipids 33 461 - 469
Nesaretnam K , Khor HT , Ganeson J , Chong K , Gapor A 1992 The effect of vitamin E tocotrienols from palm oil on chemically-induced mammary carcinogenesis in female rats Nutr Res 12 879 - 892
Nesaretnam K , Ambra R , Selvaduray KR , Radhakrishnan A , Reimann K , Razak G , Virgili F 2004 Tocotrienol-rich fraction from palm oil affects gene expression in tumors resulting from MCF-7 cell inoculation in athymic mice Lipids 39 459 - 467
Ng TKW , Hayes KC , De Witt GF , Jegathesan M , Satgunasingham N , Ong ASH , Tan DTS 1992 Dietary palmitic and oleic acids exert similar effects on serum cholesterol and lipoprotein profiles in normocholesterolemic men and women J Am Coll Nutr 11 383 - 390
Ng TKW , Hassan K , Lim JB , Lye MS , Ishak R 1991 Nonhypercholestrolemic effects of a palm oil diet in Malasysian volunteers Am J Clin Nutr 53 1015S - 1020S
Obahiagbon FI 2012 A Review: Aspects of the African Oil Palm (Elaeis guineesis jacq.) and the Implications of its Bioactives in Human Health Amer J Biochem Mol Biol 2 106 - 119
Obahiagbon FI , Oviasogie PO , Ukhun ME , Oviawe PN 2007 Comparative studies of the thiamine and riboflavin contents in the sap of Raphia hookeri palm by the application of fluorimetric method and arrhenius equation Tren Appl Sci Res 2 260 - 263
Obahiagbon FI , Oviasogie PO 2007 Changes in the physicochemical characteristics of processed and stored Raphia hookeri palm sap (shelf-life studies) Am J Food Technol 2 323 - 326
Oguntibeju OO , Esterhuyse AJ , Truter EJ 2010 Possible role of red palm oil supplementation in reducing oxidative stress in HIV/AIDS and TB patients: A review J Med Pl Res 4 188 - 196
Oluba OM , Onyeneke CE , Ojieh GC , Eidangbe GO , Orole RT 2009 Effects of Palm Oil Supplementation on Lipid Peroxidation and Glutathione Peroxidase Activity in Cholesterol - Fed Rats The Internet J Cardio Res 6 1 -
Packer L 1992 Interactions among antioxidants in health and disease: Vitamin E and its redox cycle Exp Biol Med 200 271 - 276
Packer L , Serbinova E , Choo M 1992 Distribution and antioxidant activity of a palm oil carotene in rats Biochem Inter 28 881 - 886
Qureshi AA , Qureshi N , Wright JJ , Shen Z , Kramer G 1991 Lowering of serum cholesterol in hypercholesterolemic humans by tocotrienols (palmvitee) Am J Clin Nutr 53 1021 - 1026
Qureshi A , Burger WC , Prentice N , Bird HR , Sunde ML 1980 Regulation of Lipid metabolism in chicken liver by dietary cereals J Nutr 110 388 - 393
Qureshi AA , Pearce BC , Parker RA , Deason ME 1995 Response of hypercholesterolemic subjects to administration of tocotrienols Lipids 30 1171 - 1177
Rajoo A , Ramanathan S , Sasidharan S , Mansor SM 2010 Standardization of Elaeis guineensis with respect to authenticity, assay and chemical constituent analysis Afr J Biotechnol 9 7544 - 7549
Rasool AHG , Yuen KH , Yusoff K , Wong AR , Rahman AR 2006 Dose dependent elevation of plasma tocotrienol levels and its effect on arterial compliance, plasma total antioxidant status, and lipid profile in healthy humans supplemented with tocotrienol rich vitamin E J Nutr Sci Vitaminol 52 473 - 478
Rao BSN 2000 Potential use of red palm oil in combating vitamin A deficiency in India Food Nutr Bull 21 202 - 211
Rosalina Tan RT , Mohamed S , Samaneh GF , Noordin MM , Goh YM , Manap MYA 2011 Polyphenol rich oil palm leaves extract reduce hyperglycaemia and lipid oxidation in STZ-rats Int Food Res J 18 179 - 188
Rukmini C 1994 Red palm oil to combat vitamin A deficiency in developing countries Food Nutr Bull 15 126 - 129
Runnie I , Mustapha NM , Radzali M , Azizah H , Hapizah N , Abeywardena MY , Mohamed S 2003 Antioxidant and hypocholesterolemic effects of Elaeis guineensis frond extract on hypercholesterolemic rabbits Asean Food J 12 137 - 147
Salleh MN , Runnie I , Roach PD , Mohamed S , Abeywardena MY 2002 Inhibition of low-density lipoprotein oxidation and up-regulation of low-density lipoprotein receptor in HepG2 cells by tropical plant extracts J Agric Food Chem 50 3693 - 3697
Sasidharan S , Vijayarathna S 2012 Cytotoxicity of methanol extracts of Elaeis guineensis on MCF-7 and Vero cell lines Asian Pac J Trop Biomed 2 826 - 829
Sasidharan S , Nilawatyi R , Xavier R , Yoga Latha L , Amala R 2010 Wound healing potential of Elaeis guineensis Jacq leaves in an infected albino rat model Molecules 15 3186 - 3199
Sasidharan S , Selvarasoo L , Latha LY 2012 Wound Healing Activity of Elaeis guineensis Leaf Extract Ointment Int J Mol Sci 13 336 - 347
Sasidharan S , Vijayarathna S , Jothy SL , Ping KY , Latha LY 2012 Hepatoprotective potential of Elaeis guineensis leaf against paracetamol induced damage in mice: A serum analysis IPCBEE 39 231 - 234
Sasidharan S , Sharmini R , Vijayarathna S , Yoga Latha L , Vijenthi R , Amala R , Amutha S 2009 Antioxidant and hepatoprotective activity of methanolic extracts of Elaeis Guineensis Jacq leaf Pharmacologyonline 3 84 - 90
Serbinova E , Kagan V , Han D , Packer L 1991 Free Radical Recycling and Intramembrane Mobility in the Antioxidant properties of Alpha-tocopherol and Alpha-tocotrienol Free Radic Biol Med 10 263 - 275
Solomons NW 1998 Plant sources of vitamin A and human nutrition: red palm oil does the job Nutr Rev 56 309 - 311
Song BL , DeBose-Boyd RA 2006 Insig-dependent ubiquitination and degradation of 3-hydroxy-3-methylglutaryl coenzyme a reductase stimulated by δ- and γ-tocotrienols J Biol Chem 281 25054 - 25061
Soundararajan V , Sreenivasan S 2012 Antioxidant activity of Elaeis guineensis leaf extract: An alternative nutraceutical approach in impeding aging APCBEE Procedia 2 153 - 159
Sundram K , Khor HT , Ong SHA , Pathmanthan R 1989 Effect of dietary palm oils on mammary carcinogenesis in female rats induced by 7, 12-dimehtlbenz (a) anthra-cene Cancer Res 49 1447 - 1451
Sundram K , Hornstra G , Houwelingen AC 1992 Replacement of dietary fat with palm oil: Effect on human serum lipid, lipropotein and apoproteins Br J Nutr 68 677 - 692
Sundram K , Khor HT , Ong ASH 1990 Effect of dietary palm oil and its fractions on rat plasma and high density lipoprotein lipids Lipids 25 187 - 193
Syahmi ARM , Vijayarathna S , Sasidharan S , Latha LY , Kwan YP , Lau YL , Shin LN , Chen Y 2010 Acute oral toxicity and brine shrimp lethality of Elaeis guineensis jacq., (oil palm leaf) methanol extract Molecules 15 8111 - 8121
Tan RT , Mohamed S , Samaneh GF , Noordin MM , Goh YM , Manap MYA 2011 Polyphenol rich oil palm leaves extract reduce hyperglycaemia and lipid oxidation in STZ-rats Int Food Res J 18 179 - 188
Truswell AS , Choudhury N , Roberts DCK 1992 Double blind comparison of plasma lipids in healthy subjects eating potato crisps fried in palmolein or canola oil Nutr Res 12 S34 - S52
Van Rooyen J , Esterhuyse AJ , Engel brecht A , Toit EF 2008 Health benefits of natural carotenoid rich oil: a proposed mechanism of protection against ischemia reperfusion injury Asia Pac J Clin Nutr 17 316 - 319
Wu SJ , Liu PL , Ng LT 2008 Tocotrienol-rich fraction of palm oil exhibits anti-inflammatory property by suppressing the expression of inflammatory mediators in human monocytic cells Mol Nutr Food Res 52 921 - 929
Yamabe N , Yokozawa T , Oya T , Kim M 2006 Therapeutic potential of (−)-epigallocatechin 3-O-gallate on renal damage in diabetic nephropathy model rats J Pharmacol Exp Ther 319 228 - 236
Zhang J , Wang CR , Dai J , Chen XS , Ge KY 1997 Palm oil diet may benefit mildly hyper cholestrerolaemic Chinese adults Asia Pac J Clin Nutr 6 22 - 25
Zuzana M , Suhana M , Zalinah A , Gapor MT , Ngah WZW 2005 Comparative effects of α-tocopherol and γ tocotrienol on lipid peroxidation status in Hep G2 cell live transfected with CYZEI gene Eur J Sci Res 7 41 - 56