Phytochemical and Pharmacological Evaluation of Coccinia grandis Leaf Extract on Letrozole-Induced Polycystic Ovary Syndrome in Female Rats

Polycystic ovary syndrome (PCOS) is a heterogeneous endocrine disorder characterized by reproductive, hormonal, and metabolic abnormalities. Disturbances in luteinizing hormone (LH), follicle-stimulating hormone (FSH), estrogen, and testosterone may interfere with normal follicular development and ovulation. Insulin resistance, hyperandrogenism, obesity, oxidative stress, and dysregulation of the hypothalamic-pituitary-ovarian axis are important components of PCOS pathophysiology.

The metabolic consequences of PCOS may include impaired glucose tolerance, dyslipidemia, obesity, and increased long-term cardiometabolic risk. Reproductive manifestations include irregular menstrual cycles, anovulation, follicular arrest, and infertility. Conventional pharmacological management includes insulin sensitizers such as metformin, hormonal therapies, anti-androgenic agents, and ovulation-inducing drugs. Although these therapies can be effective, prolonged treatment and adverse effects may limit their use in some patients.

Medicinal plants have attracted considerable attention as potential complementary approaches because of their diverse phytochemical constituents and multiple biological activities. Coccinia grandis belongs to the family Cucurbitaceae and is traditionally used for several metabolic and inflammatory conditions. Different parts of the plant have been reported to possess hypoglycemic, antioxidant, anti-inflammatory, hypolipidemic, hepatoprotective, and other pharmacological activities.

The thesis literature review reports the presence of several phytochemical classes in Coccinia grandis, including alkaloids, flavonoids, steroids, phenolic compounds, glycosides, terpenoids, and other constituents. The plant has also been investigated for antidiabetic and antioxidant effects, providing a rationale for evaluating its possible activity against the metabolic and reproductive abnormalities associated with PCOS.

Letrozole, a non-steroidal aromatase inhibitor, is commonly employed to establish experimental PCOS because inhibition of aromatase decreases estrogen synthesis and produces a hyperandrogenic state. Chronic administration results in endocrine, metabolic, and ovarian morphological alterations resembling several important features of PCOS.

Therefore, the present investigation was undertaken to evaluate the phytochemical characteristics and pharmacological effects of ethanolic leaf extract of Coccinia grandis in a letrozole-induced PCOS model in female rats.

2. MATERIALS AND METHODS

2.1 Collection and Authentication of Plant Material

Fresh leaves of Coccinia grandis were collected from a local vendor and authenticated by a qualified botanist. The collected leaves were washed, shade-dried, powdered, and used for extraction.

2.2 Preparation of Ethanolic Extract

The powdered leaves were subjected to Soxhlet extraction using 95% ethanol as the extraction solvent. Following extraction, the solvent was evaporated using a water bath maintained at 45–50°C. The concentrated extract was subsequently air-dried at room temperature. The percentage yield was determined relative to the initial quantity of powdered plant material.

The experimental results reported a practical extract yield of 4.73 g with an overall yield of 8.5% w/w.

2.3 Preliminary Phytochemical Screening

The ethanolic extract was subjected to qualitative phytochemical screening using standard chemical tests. The extract was found to contain alkaloids, flavonoids, steroids, phenolic compounds, cardiac glycosides, and tannins.

2.4 Estimation of Total Flavonoid Content

Total flavonoid content was determined using the aluminium chloride colorimetric method, with quercetin used as the reference standard. The calibration curve showed the regression equation:

Y = 0.0057X − 0.0065

with R² = 0.9903.

The total flavonoid content of the extract was reported as 27.65 mg QE/g of extract.

2.5 Estimation of Total Phenolic Content

Total phenolic content was estimated using the Folin–Ciocalteu method with gallic acid as the reference standard. The calibration curve was represented by:

Y = 0.0077X + 0.1358

with R² = 0.9914.

The reported total phenolic content was 27.94 µg GAE/g of extract.

2.6 Experimental Animals

Female Wistar albino rats were used. Animals were maintained under controlled environmental conditions with a temperature of 22 ± 2°C, relative humidity of 50 ± 10%, and a 12-h light/dark cycle. Animals were provided food and water ad libitum and acclimatized for at least one week before experimentation.

2.7 Induction of PCOS

PCOS was induced using letrozole at a dose of 1 mg/kg body weight, dissolved in 0.5% carboxymethylcellulose (CMC) and administered for 21 days.

Letrozole inhibits aromatase-mediated conversion of androgens to estrogens, resulting in increased androgenic activity and disruption of normal ovarian function.

2.8 Experimental Design

The study was conducted over a total period of 36 days. The experimental groups consisted of five groups:

The thesis reports six animals per group for the statistical analyses.

1. 9. Evaluation Parameters

The following parameters were evaluated: Body weight, Ovarian weight, Uterine weight, Testosterone, Progesterone, Estradiol, FSH, LH, HDL, Triglycerides, Total cholesterol, Blood glucose, Reduced glutathione (GSH), Catalase (CAT).

2.12 Statistical Analysis

Values were expressed as mean ± SEM. Statistical analysis was performed using one-way analysis of variance (ANOVA) followed by Bonferroni post hoc test. Statistical significance was considered at p < 0.05. The thesis used the following notation:

• *p < 0.05
• **p < 0.01
• ***p < 0.001

Comparisons were made against the disease-control group.

3. RESULTS

3.1 Phytochemical Screening

Qualitative phytochemical screening of the ethanolic leaf extract demonstrated the presence of alkaloids, flavonoids, steroids, phenols, cardiac glycosides, and tannins.

These findings indicate that the extract contains several classes of bioactive constituents that may contribute collectively to its observed pharmacological effects.

3.2 Total Flavonoid and Phenolic Content

The total flavonoid content was 27.65 mg QE/g extract, while the total phenolic content was reported as 27.94 µg GAE/g extract. Both calibration curves demonstrated high coefficients of determination, with R² values of 0.9903 and 0.9914, respectively.

3.3 Effect on Body Weight

The normal-control group demonstrated relatively stable body weight during the experimental period. The disease-control group showed progressive weight gain, increasing from 180 ± 1.50 g at day 0 to 225 ± 0.63 g at day 36.

After treatment, body weight declined in the standard and extract-treated groups. At day 36, the reported body weights were:

The 400 mg/kg dose therefore demonstrated a marked reduction in PCOS-associated weight gain.

3.4 Effect on Ovarian and Uterine Weight

The disease-control group showed an increase in ovarian weight and reduction in uterine weight compared with normal controls.

Treatment with ECG reduced ovarian weight and increased uterine weight toward normal values. The higher dose showed greater improvement.

3.5 Effect on Reproductive Hormones

Letrozole administration produced substantial hormonal disturbances. Testosterone and LH were increased, whereas progesterone, estradiol, and FSH were reduced.

ECG treatment improved the hormonal disturbances in a dose-related manner, with the 400 mg/kg group showing greater normalization than the 200 mg/kg group.

3.6 Effect on Lipid Profile

The disease-control group showed reduced HDL and increased triglycerides and total cholesterol.

Treatment with ECG improved the lipid abnormalities induced by letrozole. The 400 mg/kg dose produced greater improvement than the 200 mg/kg dose.

*The thesis labels this parameter as mg/mL; the manuscript retains the source value but this unit should be verified against the original laboratory record before journal submission.

3.7 Effect on Blood Glucose

Blood glucose increased progressively in the disease-control group. At day 36, glucose was 97 ± 2.2 in the disease group compared with 79.00 ± 2.2 in the normal group.