Bioactive compounds from Prosthechea karwinskii decrease obesity, insulin resistance, pro-inflammatory status, and cardiovascular risk in Wistar rats with metabolic syndrome

Ethnopharmacological relevance: The orchid Prosthechea karwinskii is a species endemic to Mexico, which is used in traditional medicine to lower glucose levels in patients with diabetes, and to treat inflammation-related problems. Recent studies have shown that this orchids can reduce glucose, cholesterol, and triglyceride levels in Wistar rats, which were previously induced to have metabolic syndrome (MS). Aim of the study: To evaluate the effect of P. karwinskii leaves extract on the components of metabolic syndrome: obesity, insulin resistance, pro-inflammatory status, and cardiovascular risk in a Wistar rat model, and to identify the bioactive compounds in the extract. Materials and methods: UPLC-ESI-qTOF-MS/MS was used to identify the compounds present in the extract. MS was induced in Wistar rats through administration of a 40% sucrose diet for 20 weeks. The rats were divided into five groups that received different treatments for 4 weeks: one group without any treatment, one group receiving metformin (200 mg/kg p.o.), and three groups receiving different doses of P. karwinskii leaves extract (100, 200, and 300 mg/kg p.o.). The animals’ body weights were recorded weekly, and at the end of the experiment, they were sacrificed after fasting for 18 h to determine the levels of glucose, insulin, insulin resistance index, total cholesterol, triglycerides, and adiponectin in the serum, as well as levels of TNF-α and HS-CRP in the serum and liver homogenates. The abdominal and pericardial fat weights were also recorded. Results: The main bioactive compounds of the extract were quinic acid, neochlorogenic acid, chlorogenic acid, rutin, kaempferol-3-o-β-rutinoside, and embelin, known to exhibit MS-related bioactivity. Oral administration of P. karwinskii leaves extract at a dose of 300 mg/kg decreased weight gain, abdominal and pericardial fat deposits, and insulin resistance. At the end of the treatment, levels of triglycerides, TNF-α, HS-CRP, and adiponectin returned to levels similar to normal. Conclusion: P. karwinskii extract (300 mg/kg) had an anti-obesity effect, decreased insulin resistance, pro-inflammatory status, and cardiovascular risk in rats with induced MS by increasing adiponectin levels and decreasing TNF-α and HS-CRP levels. The compounds identified in the extract could be responsible for these effects, acting alone or in synergy, as several compounds in the extract are known to have MS-related bioactivity. The foliar extract of P. karwinskii has potential as an effective alternative to a cocktail of drugs used to treat problems associated with MS.