Subacute safety and Antihyperglycemic Effects of Freeze-Dried Beetroot (Beta vulgaris) Powder in Normoglycemic Male and Female Wistar Rats
Description
Beetroot (Beta vulgaris L.) is rich in phytochemicals with potential health benefits. This study investigated the subacute safety, hypoglycemic, hepatoprotective, and nephroprotective effects of freeze-dried beetroot powder (BR) in male and female Wistar rats. Methods: Fifty rats (25/sex) were divided into ten groups (n=5/group/sex). Groups received distilled water (control), glibenclamide (5 mg/kg), or BR at 100, 500, and 1000 mg/kg body weight orally for 28 days. Body weight was monitored, and an oral glucose tolerance test (OGTT) was performed on day 7. Upon termination, haematological, biochemical, and histological analyses of the liver and kidney were conducted. Results: BR administration did not adversely affect normal growth or cause overt signs of toxicity. In the OGTT, BR (100 and 500 mg/kg) significantly (p<0.005) reduced postprandial blood glucose levels in both sexes. Haematological and most biochemical parameters remained within normal ranges. Notably, BR treatment significantly reduced serum bilirubin and alanine aminotransferase (ALT) levels, indicating hepatoprotective activity. Furthermore, histopathological examination of the liver and kidney revealed normal tissue architecture across all BR-treated groups, corroborating its organ-protective effects. The highest dose (1000 mg/kg) showed some significant alterations in relative organ weights, but without corresponding histological damage
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Materials and Methods Fresh, mature beetroots (Beta vulgaris L.) free from visible damage were purchased from Bantama vegetable market, Kumasi, Ghana. The roots were washed under running water, air-dried, and cut into uniform cubes (~2 cm). The samples were freeze-dried in a laboratory freeze-dryer (Model HRFDXL, Harvest Right®, USA) at −66 °C under high vacuum until constant weight was achieved. The dried material was pulverized using a laboratory blender (USHA MG 2853), sieved for uniformity, and stored in airtight, light-resistant bags at ambient temperature until use. Qualitative phytochemical screening of the freeze-dried beetroot powder was performed using standard methods described by Harborne and Sofowora to detect saponins, flavonoids, terpenoids, phenols, tannins, cardiac glycosides, and steroids. Fifty (50) healthy Wistar rats (25 males and 25 females; 108–191 g) were acclimatized for two weeks under standard laboratory conditions (12 h light/dark cycle, 25 ± 2 °C) with free access to food and water. Animals were randomly assigned into ten groups (n = 5/sex/group): normal control (distilled water), positive control (glibenclamide, 5 mg/kg), and beetroot powder at doses of 100, 500, and 1000 mg/kg. Treatments were administered orally by gavage once daily for 28 days at 10 mL/kg body weight. Animals were monitored daily for signs of toxicity, and body weights were recorded every four days. An oral glucose tolerance test (OGTT) was conducted on day 8 following a 12-hour fast. Baseline blood glucose was measured from the tail vein, treatments were administered, and a glucose load (2 g/kg) was given orally 30 minutes later. Blood glucose levels were measured at 2, 4, 6, 8, and 24 hours post-glucose administration using a glucometer. On day 28, animals were fasted overnight and sacrificed by cervical dislocation. Blood was collected via cardiac puncture for haematological and biochemical analyses. Complete blood count was determined using an automated Sysmex Haematology Analyser. Serum liver, renal, and lipid parameters were analyzed using a Flexor Chemistry Analyser with commercial kits. Major organs were excised, weighed to determine relative organ weights, and liver and kidney tissues were fixed in 10% neutral buffered formalin, processed, sectioned, and stained with haematoxylin and eosin for histopathological evaluation.