Sub-Acute Toxicity of Ethanol Leaf Extract of Heliotropium indicum in Male Wistar Rats: A Dose-Response Study

Oyenike, Musiliu Adewale¹, Akintunde, Olalekan Wasiu², Alamu, Olufemi Akinyinka², Alade, Oluwagbenga Tosin³, Jimoh, Abdullah Abiodun⁴, Balogun, Musbau Olusesan⁵, Olawuyi, Abdulahi Olaleye⁶, Lawal, Abdulrasheed Adeleke² 

1. Department of Histopathology, Faculty of Medical Laboratory Science, Mercy Medical University, Iwara, Iwo, Osun State, Nigeria. 
2. Department of Anatomy, Faculty of Basic Medical Sciences, Ladoke Akintola University of Technology, Ogbomoso, Oyo State, Nigeria 
3. Pathology Department, State Specialist Hospital, Ilare-Ekiti, Nigeria 
4. Department of Medical Laboratory Science, College of Health Sciences, LAUTECH, Ogbomoso, Nigeria 
5. Department of Pathology and Morbid Anatomy, University of Ilorin Teaching Hospital, Ilorin, Nigeria 
6. Department of Medical Laboratory Science, Federal University of Health Sciences, Ila-Orangun, Nigeria 

  ABSTRACT

This study investigated the phytochemical profile and sub-acute toxicity of the ethanolic leaf extract of Heliotropium
indicum in male rats following 28-day oral administration to evaluate its safety for traditional medicinal use. Phytochemical screening revealed high levels of alkaloids (6.3%), flavonoids (8.8%), phenolics (15.0%), and tannins (9.0%), with pyrrolizidine alkaloids likely contributing to observed toxic effects. Acute toxicity testing (OECD 423) classified the extract under GHS Category 5 (LD₅₀ > 3000 mg/kg), indicating low acute risk; however, 5000 mg/kg caused over 50% mortality within 48 hours. In the sub-acute toxicity test, doses ≥3200 mg/kg significantly suppressed body weight gain and induced haematological alterations, including reduced RBCs, haemoglobin, and platelets, alongside elevated WBCs and neutrophilia; indicating systemic inflammation. Serum biomarkers showed dose-dependent increases in ALT, AST, urea, and creatinine, showing significant hepatorenal impairment. Morphometric analysis using Image J confirmed organ damage, with increased hepatocyte, glomerular,and cardiomyocyte dimensions; while histopathology revealed steatosis, tubular necrosis, myocardial disarray, and pulmonary oedema at high doses. Although LH, testosterone, and oestrogen remained stable, FSH reduction suggests possible reproductive toxicity. The NOAEL was established at 1600 mg/kg, with LOAEL at 3200 mg/kg. These findings significantly contribute to the understanding of H. indicum s toxicity threshold, highlighting its multi-organ risk at high doses despite moderate safety at lower levels. 

KEYWORDS: Lethal Dose -50, Sub acute toxicity, hepatorenal-dysfunction, pyrrolizidine-alkaloids