Safety of combined hydro-ethanolic Moringa oleifera (Moringaceae) seed extract and metformin therapy in Wistar rats: a 91-day sub-chronic toxicity study

Abstract

Moringa oleifera (MO) is a common medicinal plant used due to its numerous medicinal properties. Metformin has been found to have better antihyperglycemic effects when used in combination with MO than metformin alone. However, there is little information about its toxicity profile when used in combination with metformin. This study evaluated the toxicological effects of repeated oral administration of Moringa oleifera (MO) seed extract in combination with Metformin (MET) in Wistar rats. A total of six groups of male and female rats were administered distilled water (1 mL/kg), MET (125 mg/kg), MO extract (1000 mg/kg), and combinations of MO (250, 500, and 1000 mg/kg) with MET (125 mg/kg) respectively over a 91-day period. Mortality was observed across five groups. Results showed a progressive increase in feed intake across all groups, with no statistically significant difference (p>0.05) compared to the control. Similarly, water intake remained relatively stable throughout the study duration. Relative organ weights showed no significant differences (p>0.05), suggesting the absence of treatment-related atrophy. Only white blood cells (WBC) showed a significant (p<0.05) increase compared to the control. Urea levels ranged from 10.1±0.4 to 12.8±3.5 mmol/L in females and 6.5±0.35 to 8.6±1.00 mmol/L in males. Creatinine levels showed a significant increase (p < 0.05) in females treated with MO500+MET125 and in males treated with MET125 alone, compared to control values of 40.0±0.10 µmol/L (female) and 39.0±12.0 µmol/L (male). Electrolyte levels remained unchanged across all groups. Alanine aminotransferase (ALT) levels showed significant reduction in both male and female groups, while aspartate aminotransferase (AST) was significantly reduced only in females treated with MET (125 mg) and MO (250 mg). Alkaline phosphatase (ALP), total protein (TP), and albumin (ALB) showed no significant differences compared to the control. Histological examination of kidney tissues revealed normal glomerular and tubular structures in all groups, indicating preserved renal architecture. However, mild hepatocyte degeneration was observed in the MO1000+MET125 group, suggesting a possible dose-related hepatic effect at the highest combination dose. Thus, combination may warrant caution because of the mortality, mild hepatocellular degeneration, and selected biochemical alterations observed.