Evaluation of the antidiabetic effects of water and methanolic extracts of avocado (persea americana) seed on alloxan induced diabetic rats

Thesis Abstract

The high prevalence, complications and cost of conventional drugs in the management diabetes necessitated the search for alternative treatment. As a result, this study seeks to evaluate the composition, anti-diabetic potential toxicity and tissue-protective effects of both the water and methanolic extracts of Persea americana (avocado pear) seed on alloxan-induced diabetic albino rats were investigated. This study was conceived and designed based on information on the local use of the seed in diabetes treatment. Proximate and anti-nutritional constituents of the seed were determined and 100g of the sample was extracted with 1000ml of both water and methanol using the maceration method. The extracts were evaporated to dryness using a rotary evaporator and stored at 4oC until use. The effects of different doses (200mg/kg.b.wt., 300/kg.b.wt.) of both water and methanolic extracts of P. americana seed on alloxan-induced diabetic albino rats were compared with those of a reference drug, insulin. The glucose level and weight of the rats were measured weekly for 21 days. The liver function tests and the histopathologies of the liver, and kidneys, were investigated. Results of the proximate investigation shows that the seed is rich in carbohydrate (49.03± 0.02 g/100g), lipid (17.90± 0.14 g/100g), protein (15.55± 0.36 g/100g) moisture (15.10± 0.14 g/100g) and ash (2.26±0.23 g/100g). Anti nutritional components such as total oxalate (14.98±0.03 mg/100g), tannin (6.98±0.04 mg/100g) and phytic acid (3.18±0.16 mg/1 00g). Results also showed that both the water and methanolic extracts exhibited significant anti-diabetic effects on the experimental rats. However, the methanolic extracts showed a better anti diabetic effect than the water extracts. The extracts showed no significant effects on the liver function parameters (bilirubin, conjugate bilirubin, AST, ALP and ALT) compared with the normal control but rather reversed the histopathological damage that occurred in alloxan-induced albino diabetic rats. In conclusion, the present study provides a pharmacological basis for the traditional use of P. americana seeds extracts in the management of Diabetes mellitus. It seems P. americana seed contains substantial amount of nutrients that could warrant its utilization in animal feed or food. However, further studies are required to indentify the active ingredient responsible for the anti-diabetic properties of the seed extract.