The study was designed to investigate the effects of administration of Aloe vera gel extract on liver enzmes on Albino rats. Twenty four male Albino rats weighing 180-200 were divided into four groups of six rats per group were used in the study. Group I which served as the control received rat food and water while those in groups II, III and IV received Aloe vera gel (100, 200 and 300mg/kg), respectively, for three weeks. The animalswere sacrificed, and serum enzymes were measured using standard methods.Serum ALT concentration was nonsignificantly reduced (P>0.05) in group 2 (47.80±7.33 IU/L), compared with group 1 (54.50±3.89 IU/L), while in group 3 (63.50±3.78 IU/L) and 4 (71.17±2.40 IU/L) it was significantly increased (P<0.05) when compared with group 1. Serum ALT concentration was significantly higher (P<0.05) in group 3 compared with group 2. It was also significantly higher in group 4 compared with group 3.Serum AST concentration was nonsignificantly lower (P<0.05) in group 2 (54.17±4.40 IU/L) when compared with control (56.67±3.08 IU/L). Serum AST concentration was significantly higher (P<0.05) in group 3 (67.67±3.20 IU/L) and 4 (75.50±2.35 IU/L) when compared with control (Group 1). It was also significantly (P<0.05) higher in group 3 compared with group 1, and group 4 compared with group 3.Serum ALP concentration was nonsignificantly lower (P>0.05) in group 2, 3 and 4 (77.17±4.02 IU/L, 75.17±5.71 IU/L and 73.67±4.63 IU/L respectively) when compared with control (81.67±4.84 IU/L). Serum ALP concentration was nonsignificantly lower (P>0.05) in group 3 when compared with group 2, and in group 4 when compared with group 3. In conclusion, Alovera gel has hepatoprotective and hepatotoxic effect.
1.1 BACKGROUND OF STUDY
Liver is one of the largest and vital organs of human body and is vulnerable for tissue insult continuously. Liver regulates various important metabolic functions, the distortion of which causes hepatic damage (Wolf, 2016). Liver disease is still a worldwide health problem. Drug-induced hepatotoxicity is one of the major concerns which limit the therapy and drug use. About 2% of all causes of jaundice in hospitalized patients are drug induced. Approximately quarters of cases of fulminant hepatic failure are thought to be drug related. More than 900 drugs have been implicated in causing liver injury and it is the most common reason for a drug to be withdrawn from the market(Friedman et al., 2013).
Conventional or synthetic drugs used in the treatment of liver diseases are inadequate and sometimes can have serious side effects. This is one of the reasons for many people in the world including those in developed countries, turning to complementary and alternative medicine. Many traditional remedies employ herbal drugs for the treatment of liver ailments (Dhuley &Naik, 2007; Venkateswaran et al., 2011; Lathaet al., 2009 and Mitra & Seshadri, 2000).
Aloe vera has been used for many centuries for its curative and therapeutic properties. The use of Aloe vera gel has been promoted for the management of many disorders. Aloe vera is a succulentperennial plant belonging to family Liliaceae, having over 350 species (Rodriguez et al., 2010). Aloe vera gel which is visible on slicing the Aloe leaf has been reported to be beneficial in T1DM (Nna et al., 2014; and Nna et al., 2013), atherosclerosis (Akpan et al., 2014) and wound healing (Davis, 2009). Aloe vera latex which is obtained from the inner part of the skin of the leaves has been reported to contain anthraquinones and possess laxative effect.
Aloe vera is a stemless or very short stemmed succulent plant growing to 60- 100 cm (24-39) in tall, spreading by offsets. The leaves are thick and fleshy, green to grey with some varieties showing white flecks on their upper and lower stem surface the margin of the leaf is serrated and has small white teeth (Yate, 2002). Aloe barbadensis miller (1, 8-Dihydroxy-3- hydroxymethyl-10-(6-hydroxymethyl-3, 4, 5-trihydroxy-2-pyranyl anthrone) commonly called Aloe vera. The plant is one of the most widely used healing plants in the history of mankind. Two distinct preparations of Aloe plants are most used medicinally. The leaf exudates (Aloe) is used as a laxative and the mucilaginous gel (A. vera) extracted from the leaf parenchyma is used as a remedy against a variety of skin disorders (Wasagu et al., 2015). It is used on facial tissues where it is promoted as a moisturiser, anti –irritant to reduce chafing of the nose however, cosmetic companies commonly add sap or other derivatives from Aloe vera to product such as makeup, soaps, sunscreens, shaving cream or shampoos and as ingredient yogurts (Reynold, 2014).
Aloe vera has also been reportedly used in the treatment of many disorders such as arthritis, gout, dermatitis, peptic ulcer as well as treatment of burns (Grindlay and Reynolds, 1986). The fresh gel, juice and formulated products have long been used for medical and cosmetic purposes and general health (Chithra et al., 1998; Reynolds and Dweck, 1999). The beneficial properties of Aloe vera may be attributed to the polysaccharides present in the inner gel of the leaf, especially acemannan (acetylated mannans), which has also been shown to be an immune-modulator (Djeraba and Quere, 2000; Liu et al., 2006).
Aloe extracts have equally been demonstrated to have antioxidant abilities in humans and animals (Rajasekaran, 2005; Kardosova and Machova, 2006; Loots et al., 2007), whilst also protecting the liver, (the major detoxification organ) against injury (Can et al., 2004; Chandan et al., 2007) and improve liver enzyme functions that are associated with carcinogen metabolism (Singh et al., 2003). The antioxidant and anti-inflammatory (Yagi et al., 2002; Speranza et al., 2005; Yagi and Takeo, 2003), anti-cancer (Lee et al., 2000; Heggie et al., 2002; Chen et al., 2004; Su et al., 2004), anti-diabetic (Ayse et al., 2004) and wound healing properties (Choi et al., 2001) of Aloe vera have also been widely reported.
Increased serum ALT and AST values have been indicated for hepatic damage. ALT is a known hepato-specific enzyme that is principally found in the cytoplasm of hepatocytes (Benjamin, 1978; Ringler and Dabich, 1979). Similarly, AST, an enzyme that is present in high quantities in the cytoplasm and mitochondria of liver cells, is also present in the heart, skeletal muscle, kidney and brain (Benjamin, 1978). It has been shown that increase in the enzymatic activity of ALT and AST in the serum directly reflects a major permeability or cell rupture (Wittwer and Bohmwald, 1986).
Many people preferred medicinal plants because orthodox treatments are not readily available, expensive and often associated with serious side effects. Several herbal extracts are available in markets of most developing countries like Nigeria, where medicinal plant extracts are dispensed indiscriminately by personnel who lack toxicological knowledge of such extracts and their side effects. However, the effectiveness of the extracts for different therapeutic purposes including cancer, oxidative and purgative
diseases, anti-diabetic, topically emollient, anti-inflammatory, antimicrobial properties and precursors for the synthesis of metabolites are due to their bioactive constituents.
Despite its wide use in folk medicine for the treatment of various diseases for decades, chronic administration of this wonder plant on markers of liver damage, have not been investigated. We hypothesized that chronic administration of Aloe vera gel extract might cause hepatotoxicity or hepatoprotective effect on liver using plasma aminotransferases and alkaline phosphatase as yardsticks for assessment of hepatic function. The effect of the Aloe vera on the liver parameters was assessed. The present study was therefore carried out to evaluate whether Aloe vera leaf gel extracts have any protective or harmful effect on the liver after prolonged administration of different dosage in rats.
To evaluate the effect of Aloe vera gel on liver enzymes in albino rats.
1.4 SPECIFIC OBJECTIVES
- To determine the effect of aloe vera gel on alanine amino transaminase in albino rats.
- To determine the effect of aloe vera gel on aspartate amino transaminase in albino rats.
- To dettermine the effect of aloe vera gel on alkaline phosphatase in albino rats.