Antioxidant activity and lipid-lowering effects of Tulsi (Ocimum sanctum L.) leaf powder on high-fat diet-induced hyperlipidemic rats
摘要
Tulsi (Ocimum sanctum L.) is an aromatic medicinal herb abundant in nutrients and bioactive constituents. This study aimed to assess the nutritional, phytochemical, antioxidant, and therapeutic attributes of Tulsi leaf powder (TLP), focusing on its capacity to regulate hyperlipidemia, liver function, and oxidative stress. Proximate analysis demonstrated elevated levels of crude fiber (18.76%), protein (19.37%), and ash (16.23%), alongside a low-fat content (9.20%), suggesting its appropriateness for metabolic health. The mineral profile indicated reasonable concentrations of calcium, iron, potassium, and zinc, essential minerals for cardiovascular and enzymatic processes. Phytochemical analysis revealed markedly higher total phenolic (36.9 mg GAE/g) and flavonoid (35.11 mg QE/g) concentrations in methanolic extracts than in aqueous extracts, indicating robust antioxidant activity. This was also corroborated by DPPH, FRAP, and ABTS tests. GC-MS profiling revealed 19 bioactive compounds, including eugenol (17.24%), germacrene D (10.25%), and caryophyllene (10.22%), which are recognized for their anti-inflammatory, hepatoprotective, and lipid-lowering effects. To evaluate the effectiveness of therapy, 60 Sprague-Dawley rats were divided into two primary groups: Group I (n = 10), the negative control, received a conventional diet, whereas Group II (n = 50) received a high-fat diet to induce hyperlipidemia. After two weeks, Group II was divided into five subgroups, receiving either no treatment (positive control), Tulsi leaf powder at 100, 150, or 200 mg/kg/day, and atorvastatin at 10 mg/kg/day for six weeks via oral gavage. The results indicated that Tulsi leaf powder, particularly at 200 mg/kg/day, significantly (p < 0.001) decreased body weight (21.05 ± 0.23 g), total cholesterol (170.12 ± 8.99 mg/dl), triglycerides (127.88 ± 1.01 mg/dl), and LDL (45.10 ± 3.67 mg/dl), while elevating HDL (52.65 ± 3.35 mg/dl) levels. Liver function indicators (ALT (38.13 ± 2.07 U/L), AST (73.96 ± 6.92 U/L), ALP (118.90 ± 2.22 U/L) showed significant improvement. Antioxidant defense indicators: serum MDA (31.28 ± 0.23 mmol/dL), CAT (77.63 ± 1.02 U/mL), and SOD (36.01 ± 0.08 U/dL) demonstrated decreased oxidative stress. Histological examinations of hepatic and cardiac tissues showed tissue preservation and reduced lipid infiltration at high Tulsi leaf powder doses. These findings support Tulsi’s role in lipid metabolism, hepatic and cardiac organ protection, and antioxidant defense. For metabolic disorders and cardiovascular risk management, more clinical trials are needed to determine their long-term efficacy.