The solvents used for the study (petroleum ether and ethanol) were obtained from SD Fine Chemicals India Ltd. and were of laboratory grade. Gemfibrozil was purchased from Medindia, dexamethasone and all other chemicals used in the present study were purchased from Merck, India and of analytical grade.

T.stans plant flowers were collected in the month of August 2019 from Namakkal, Tamilnadu, India. The plant was then taxonomically identified and authenticated by the botanist in the botanical surveyor of India, Coimbatore.

Male Wister rats (150-180 g) of approximately the same age, obtained from Elite labs, Hyderabad, India, were used for the study. They were kept in polypropylene animal cages and fed with normal rodent pellet diet (Hindustan Lever Limited, Hyderabad) and water ad libitum. All the animals were exposed to an alternate cycle of 12 h of darkness and 12 h of light. Before each test, the animals were withdrawn from food for at least 12 h. All the experiments were carried out in the morning as per the current guidelines for care of laboratory animals and the ethical guidelines for investigations of experimental pain in conscious animals. The standard oral gastric cannula and syringe were used for drug administration in experimental animals. [21]

The plant flowers were dried in shade, after confirmation of the moisture content limits, the dried flowers were coarsely powdered using a mechanical grinder. Then, the powder was passed through sieve No. 40 and stored in an airtight container for the extraction.

The powder of the dried flowers of T.stans was extracted with petroleum ether at temperature 60-80°C up to 48 h. After completion of extraction, the solvent was filtered, and the powder was separated. The crude extract was subjected to distillation and solvent was removed. Dark green-colored residue was obtained, and it was stored in desiccators.

The marc left after petroleum ether extraction was dried and then extracted with 95% ethanol at 75-78°C up to 48 h. After completion of extraction, the solvent was distilled off from the crude extract. Dark brown-colored residue was obtained. The residue was concentrated and then stored in desiccators.

The marc left after ethanol extraction was dried and then macerated with distilled water, up to 48 h. After completion of extraction, it was filtered and the solvent was removed by evaporation to dryness on a water bath. Brown color residue was obtained, and it was stored in desiccators.

Glucocorticoid hormonal level elevation induces the plasma lipid concentration but varies from species to species. Few synthesis of triacylglycerol in the liver is stimulated by the injection of glucocorticoid in rats and consequently may lead to the accumulation of fatty liver. The stimulation of the TG production could lead to increased secretion of VLDL. Increasing VLDL secretion has been reported when dexamethasone is injected for several days in rats. The increase in TG level induces imbalance in lipid metabolism leads to hyperlipidemia. Similarly, dexamethasone treatment in newborn rats for 4 days showed widespread increase in serum lipids. [23-26]

Hyperlipidemia will be induced using dexamethasone; a glucocorticoid is known to evoke plasma lipid elevation. Dexamethasone (10 mg/kg/day, subcutaneous) was administered to rats for 8 days to induce hyperlipidemia. The animals were divided into five groups each group contains six rats details were shown in Table 3.

All the animals in Groups II, III, IV, and V were subjected to subcutaneous injection of dexamethasone (10 mg/kg/day, S.C) for 8 days to induced hyperlipidemia. The animals in normal and hyperlipidemic control groups were received normal saline, whereas Group III animals received gemfibrozil (10 mg/kg/day I.P, suspended in gum acacia in water) and Groups IV and V animals received extract by oral route in doses of 200 mg/kg/day and 400 mg/kg/day, respectively, throughout the 8 days experiment. After the experimental period, the overnight fasted experimental rats were sacrificed by decapitation under light ether anesthesia and blood was collected. Serum was separated, and lipid profiles (biochemical parameters) were analyzed. The lipid profiles of dexamethasone-induced hyperlipidemia model and the results of the antihyperlipidemic effect of extract treated groups of dexamethasone-treated groups were shown in Table 1.

All the values were expressed as mean ± standard error of mean. The data were statistically analyzed by one-way ANOVA followed by Dennett’s t-test, and value P < 0.05 was considered to be significant.

Total cholesterol levels in the hyperlipidemia-induced group have significantly increased compared to normal rats. The values have risen to 116.83 ± 1.686 mg/dl compared to Group I (normal rat group), in which values lie in the range 64 ± 1.351 mg/dl. This indicates hypercholesterolemia. In the treatment group treated with EETS (200 mg/kg) and EETS (400 mg/kg), the values are reduced to 82 ± 2.306 (P < 0.001) and 78.0 ± 2.386 mg/dl (P < 0.01), respectively. There is a significant reduction in total cholesterol values in EETS treatment group. On the other hand, gemfibrozil also has significantly reduced serum total cholesterol levels to 70.50 ± 1.351 mg/dl (P < 0.001) [Table 1].

The TG levels have reached as 150.83 ± 1.666 mg/dl in dexamethasone-induced group compared to normal rats where the values are 62.83 ± 1.776 mg/dl. This indicates triglyceridemia. In the group treated with EETS (200 mg/kg) and EETS (400 mg/kg), the values are significantly reduced to 77.16 ± 1.686 mg/dl (P < 0.01) and 73.16 ± 1.686 mg/dl (P < 0.01), respectively. In the gemfibrozil treated group, the values are reduced to 66.33 ± 0.763 mg/dl (P < 0.001) [Table 1].

Phospholipids are amphipathic lipid constituents of a membrane. They play an essential role in the synthesis of plasma lipoproteins. They function in transduction of messages from cell-surface receptors to certain messengers that control cellular processes and as surfactants.[19] Phospholipid levels in the dexamethasone-induced group have significantly increased compared to normal rats. The values have risen to 131.1 ± 2.982 mg/dl compared to normal rat group, in which values lie in the range 91.73 ± 1.165 mg/dl. In the treatment group treated with EETS (200 mg/kg) and EETS (400 mg/kg), the values are reduced to 103.65 ± 1.776 mg/dl (P < 0.01) and 98.32 ± 1.720 mg/dl (P < 0.01), respectively. There is a significant reduction in phospholipid values in EETS treatment group. On the other hand, gemfibrozil also has significantly reduced serum phospholipid levels to 94.37 ± 1.514 mg/dl (P < 0.001) [Table 1].

Free fatty acid levels in dexamethasone-induced group have significantly increased compared to normal rats. The values have risen to 34.1 ± 0.151 mg/dl compared to normal rat group, in values lie in the range 19.37 ± 0.395 mg/dl. In the treatment group treated with EETS (200 mg/kg) and EETS (400 mg/kg), the values are reduced to 26.73 ± 0.306 (P < 0.001) and 25.37 ± 0.257 mg/dl (P < 0.001), respectively. There is a significant reduction in free fatty acid values in EETS treatment group. On the other hand, gemfibrozil also has significantly reduced serum free fatty acid levels to 21.62 ± 0.222 mg/dl (P < 0.001) [Table 1].

HDL-cholesterol in dexamethasone-induced group has significantly decreased compared to normal rats. The values have reduced to 26.16 ± 0.307 mg/dl compared to normal rat group, 37.66 ± 1.686 mg/dl. In the group treated with EETS (200 mg/kg) and EETS (400 mg/kg), the values were 23.33 ± 0.2 (P < 0.01) and 27.33 ± 0.332 mg/dl (P < 0.01), respectively. In gemfibrozil treated group, the values were 33.33 ± 0.420 mg/dl (P < 0.001) [Table 1].

Table 1: Effect of EETS against dexamethasone induced hyperlipidemia in rats