Effects of Persea americana Mill (Lauraceae) (avocado) ethanolic leaf extract (PAE) on blood glucose and kidney function in streptozotocin (STZ)-induced diabetic rats and on kidney cell lines of the proximal (LLC-PK1) and distal tubules (MDBK)

Abstract

Extracts of Persea americana Mill (Lauraceae) ("Avocado") have been traditionally used to treat hypertension and diabetes mellitus. Accordingly, we studied the hypoglycaemic and renal function effects of P. americana leaf ethanolic extracts (PAE) in STZ-induced diabetic rats. Oral glucose tolerance responses to various doses of PAE were monitored in fasted rats following a glucose load. Rats treated with deionized water or standard hypoglycaemic drugs acted as untreated and treated positive controls, respectively. Acute renal effects of PAE were investigated in anesthetized rats challenged with 0.077 M NaCl after a 3.5-h equilibration for 4 h comprising 1 h control, 1.5 h treatment and 1.5 h recovery periods. PAE was added to the infusate during the treatment period. Hepatic glycogen concentration was measured after 6 weeks of daily treatment with PAE. PAE induced dose-dependent hypoglycaemic responses in STZ-induced diabetic rats while subchronic PAE treatment additionally increased hepatic glycogen concentrations. Acute PAE infusion decreased urine flow and electrolyte excretion rates, whilst subchronic treatment reduced plasma creatinine and urea concentrations. These results indicate not only the basis of the ethnomedicinal use of P. americana leaf extract in diabetes management, but also of need for further studies to identify and evaluate the safety of PAE's bioactive compounds.

The Effects ofSyzygium aromaticum-Derived Oleanolic Acid on Glycogenic Enzymes in Streptozotocin-Induced Diabetic Rats

“…15 Briefly, the tissue samples (1-1.5 g) were homogenized in 2 mL of 30% KOH solution and digested at 100°C for 30 min and then cooled in ice-saturated sodium sulfate. The glycogen was precipitated with ethanol and then pelleted, washed, and resolubilized in deionized water.…”

Phytoconstituents, antimicrobial and antioxidant properties of the leaves of Persea americana Mill cultivated in Ghana

“…Because of the high demand for P. Americana fruit worldwide owing to its high nutritional value and reported health benefits, including anticancer activity, the food industry has grown tremendous interest in processing this crop and enhancing its value (Lu et al, 2005). P. americana leaves' extracts have been used as analgesic, anti-inflamatory, hypoglycaemic, anticonvulsant, antidiabetic and vasorelaxant among other therapeutic uses (Adeyemi et al, 2002;Antia et al, 2005;Gondwe et al, 2007;Ojewole and Amabeoku, 2006;Owolabi et al, 2005).…”

Anti-diabetic activity of extract from Persea americana Mill. leaf via the activation of protein kinase B (PKB/Akt) in streptozotocin-induced diabetic rats

“…Preliminary studies by Antia et al (2005) and Gondwe et al (2008) have shown that administration of Persea americana leaf extract may have a hypoglycaemic effect. Studies suggest that a decrease of the serum glucose level and increase glucose uptake, via the protein kinase B (PKB/Akt) pathway, could be produced by flavonoids (Cazarolli et al, 2009;Tzeng et al, 2009).…”