Antidiabetic, Cardio protective and ROS scavenging effects of Avocado

Rao , U.S. Mahadeva (2012) Antidiabetic, Cardio protective and ROS scavenging effects of Avocado. Discussion Paper. LAP Lambert Academic Publishing, Germany.

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Abstract

1. Remnant beta cell stimulative and Free radical scavenging property: Insulin-stimulative and anti-oxidative effects of Alligator pear (Persea americana Mill.) or avocado fruit extract were evaluated using streptozotocin (STZ). Ethanol extract of P.americana in the concentration of 300 mg/kg body weight/rat /day was orally administered to rats introduced into STZ-induced hyperglycemic state for a period of 30 days. After the treatment with avocado fruit extract, the elevated levels of blood glucose, glycosylated hemoglobin, blood urea and serum creatinine seen in the hyperglycemic rats, reverted back to near normal. Similarly, significantly decreased plasma insulin and hemoglobin levels went back to near normal after the treatment, suggesting the insulin-stimulative effect of P.americana fruit. Determination of thiobarbituric acid reactive substances (TBARS), hydroperoxides and both enzymatic and non-enzymatic antioxidants, confirmed the anti-oxidative potential of avocado fruit extract which, in turn, might be responsible for its hypoglycaemic potential. Changes in activities of enzymes such as serum aspartate transaminase (AST), serum alanine transaminase (ALT), and serum alkaline phosphatase (ALP) seen in the control and experimental rats, revealed the tissueprotective nature of Persea americana fruits, while all of the analysed biochemical parameters were comparable to those obtained with gliclazide as a standard reference drug. 2. Diabetic dyslipidemia ameliorative property: In Diabetes mellitus, the insulin defect reflects in elevated gluconeogenic metabolite accumulation, which leads to excess acetyl Co-A storage, and, in turn, the acetyl Co-A acts as a precursor of lipids directly, and lipoprotein indirectly, synthesis. Thus, hyperlipidemia is an associated complication of diabetes mellitus. Previously, we have reported that ethanolic extract of Persea americana lowered the blood glucose and oxidative stress in diabetic rats. In this present study, the hypolipidemic effect of Persea americana fruit was investigated in streptozotocin-induced diabetic rats. Oral administration of fruit extract (300 mg/kg b.w.) for 30 days resulted in significant reduction in serum and tissue cholesterol, triglycerides, phospholipids and free fatty acids in STZ-diabetic rats. In addition to that, significant decrease in high density lipoprotein while significant increase in low density lipoprotein and very low density lipoprotein, were observed in diabetic rats, which were brought to near normal after 30 days of herbal extract treatment. The results obtained are comparable with glyclazide, a standard drug. Results of the present study indicate that the fruits of Avocado showed antihyperlipidemic effect in addition to its antidiabetic and free radical scavenging activity properties in type 2 diabetic rats. 3. Antihyperlipidemic property: Alligator pear has been used for a long time as a daily food in Ethiopia because of its nourishing components. In our earlier work, we reported that, extracts from avocado are known to ameliorate not only hyperglycemia in diabetic rats induced by STZ. However, its hypolipidemic activity has not yet been clearly studied. Hypolipidemic activity of the extracts from leaf by dichloromethane (PAL-I) and methanol (PAL-II), and from fruit by dichloromethane (PAF-I) and methanol (PAF-II), was studied and compared to that of simvastatin. Hyperlipidemia in rats was induced by single intra-peritoneal injection of 300 mg of tyloxapol / kg b.w.. Mentioned herbal extracts were orally administered at dose equivalent to 300mg of dry extract/kg b.w. immediately after tyloxapol injection. Cholesterol levels decreased 59.74%, 58.01%, 44.82%, 43.09% and 61.11%, respectively in groups orally administered PAL-I, PAL-II, PAF-I, PAF-II and simvastatin, as compared to the tyloxapol injected group. Triglyceride levels in treated groups had no significant difference as compared to simvastatin group except the PAF-II treated group. Avocado could lower cholesterol and triglyceride levels in hyperlipidemic rat. 4. Biochemical evaluation of anti-diabetic phytomolecule: This study was to evaluate the most effective fraction and subfraction having hypoglycemic activity from the hydro-methanolic (2:3) extract of the fruit of Persea americana Mil. through bioactivity guided investigation in streptozotocin induced diabetic rats. Out of different solvent fractions and subfractions, the effective fraction and subfraction of Persea americana Mill. were subjected to antidiabetic study in streptozotocin induced diabetic rat. Serum insulin, glycosylated hemoglobin, transaminases, carbohydrate metabolic enzymes in liver, kidney, cardiac and skeletal muscle, were also assessed after 8 weeks of treatment and compared to the vehicle control. A significant recovery was noted in the level of serum insulin, glycosylated hemoglobin, activities of carbohydrate metabolic enzymes and serum transaminases after n-hexane fraction treatment in respect with other treated groups. Two sub fractions A and B were obtained using petroleum ether sub fractionation of which sub fraction B was more bioactive considering the above biosensors and was comparable with glibenclamide. HPTLC study focused four and two components (P1 and P2) in sub fraction A and B respectively where P1 is major, confirmed by HPLC study. The dose of sub fraction B was 1/4th of the n-hexane fractions dose. It has been concluded that sub fraction B (P1 and P2) which was obtained from nhexane fraction had the antidiabetic activities in the streptozotocin - induced diabetic model.

Item Type: Monograph (Discussion Paper)
Subjects: R Medicine > RC Internal medicine > RC1200 Sports Medicine
R Medicine > RM Therapeutics. Pharmacology
Faculty / Institute: Faculty of Medicine
Depositing User: Dr U.S.Mahadeva Rao
Date Deposited: 19 May 2014 02:40
Last Modified: 28 Apr 2015 06:26
URI: http://erep.unisza.edu.my/id/eprint/774

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