Synergistic Amelioration of Endocrine Dysregulation by Vernonia amygdalina and Tamarindus indica in Letrozole and Diet-induced Polyendocrine Metabolic Ovarian Syndrome in Rats
Ogerovor Joy Ben *
Department of Biochemistry, Faculty of Natural and Applied Sciences, Lead City, University, Nigeria.
Osasenaga MacDonald Ighodaro
Department of Biochemistry, Faculty of Natural and Applied Sciences, Lead City, University, Nigeria.
Adewoluwa Olu Akinrinmola
Department of Biochemistry, Faculty of Natural and Applied Sciences, Lead City, University, Nigeria.
Beauty Mayowa Igbekele
Department of Biochemistry, Faculty of Natural and Applied Sciences, Lead City, University, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Background: Polyendocrine metabolic ovarian syndrome (PMOS) is characterised by endocrine and reproductive disturbances involving the hypothalamic–pituitary–ovarian axis.
Aim: The present study aimed to evaluate the synergistic effects of Vernonia amygdalina water extract (VAWE) and Tamarindus indica methanol extract (TIME) on HPO axis hormonal parameters in a letrozole and high-fat high-fructose (HF-HFr) diet-induced PMOS rat model.
Study Design: This research was an experimental, randomised, controlled in vivo study.
Place and Duration of Study: Department of Biochemistry, Lead City University, Ibadan, Nigeria, between October 2024 and August 2025.
Methods: PMOS was induced via letrozole (1 mg/kg) and HF-HFr diet for 21 days. Forty-eight (48) female Wistar rats were randomly assigned to eight groups (n=6): normal control, PMOS untreated, positive control (metformin 10 mg/kg + clomiphene citrate 1 mg/kg), VAWE monotherapy (200 mg/kg), TIME monotherapy (400 mg/kg), low-dose combination (VAWE 100 mg/kg + TIME 200 mg/kg), high-dose combination (VAWE 200 mg/kg + TIME 400 mg/kg), and mid-dose combination (VAWE 200 mg/kg + TIME 200 mg/kg). All treatments were administered orally for 21 days. Serum hormones were quantified by ELISA. Estrous cyclicity was monitored by daily vaginal smear cytology.
Results: Induction of PMOS resulted in significant hormonal imbalance characterised by elevated testosterone (0.3495 ± 0.0412 vs control 0.2310 ± 0.0189), luteinising hormone (LH: 0.1118 ± 0.005 vs control 0.06275 ± 0.001), and LH/FSH ratio (0.6900 ± 0.04761 vs control 0.2025 ± 0.1025), alongside marked reductions in progesterone (0.04775 ± 0.00275 vs control 0.3688 ± 0.08625) and sex hormone-binding globulin (SHBG: 291.1 ± 72.70 vs control 3604 ± 228.6). Treatment with VAWE 200 mg/kg effectively attenuated testosterone (0.2510 ± 0.01715), suppressed LH (0.06750 ± 0.003), and restored progesterone levels (0.2880 ± 0.03291). Single administration of TIME 400 mg/kg normalised testosterone levels (0.2215 ± 0.03794), restored SHBG (4045 ± 111.2) and improved the LH/FSH ratio (0.3450 ± 0.1025). Polyherbal combinations demonstrated dose-dependent modulation, with the low-dose combination (VAWE 100 mg/kg + TIME 200 mg/kg) showing superior restoration of progesterone (0.2428 ± 0.04125) and LH/FSH balance (0.4625 ± 0.03577) while the mid-dose (200 + 200 mg/kg) combination produced the greatest reduction in serum testosterone (0.1890 ± 0.01273).
Conclusions: These findings provide pharmacological justification for the combined ethnomedicinal use of Vernonia amygdalina and Tamarindus indica in reproductive health and warrant further mechanistic and clinical investigation.
Keywords: Polyendocrine metabolic ovarian syndrome, hypothalamic-pituitary-ovarian axis, letrozole-induced PMOS, Vernonia amygdalina, Tamarindus indica