Orchid Extract Reduces Weight in Rats by Modifying Appetite-Regulating Peptides Including Ghrelin, NPY, and CCK | Research

The takeaway

Salep orchid extract caused significant weight loss in rats by reducing appetite-stimulating peptides (ghrelin, NPY, orexin-A) while increasing satiety peptides (CCK, obestatin, leptin) and improving lipid profiles.

12+ appetite peptides modified
Salep extract simultaneously shifted the balance of over a dozen appetite and metabolic hormones — decreasing hunger signals like ghrelin and NPY while boosting satiety signals like CCK and leptin — causing significant weight loss in rats.

What the researchers found

Salep extract at 160 and 320 mg/kg caused significant weight loss in rats over 29 days. The extract shifted the balance of appetite-regulating peptides in favor of satiety:

Increased: leptin, adiponectin, AgRP, obestatin, CCK, chemerin, and total antioxidants.

Decreased: ghrelin, omentin, resistin, NPY, amylin, orexin-A, epinephrine, and MDA (oxidative stress marker).

Lipid profiles also improved. The simultaneous reduction of multiple appetite-stimulating peptides (ghrelin, NPY, orexin-A) combined with elevation of satiety signals (CCK, obestatin, leptin) suggests a broad anti-obesity mechanism affecting both central and peripheral appetite regulation.

Why it matters

The obesity epidemic affects hundreds of millions of people, and current drug options are limited, expensive, or have significant side effects. Understanding how natural compounds affect the body's intricate network of appetite-regulating peptides could lead to new anti-obesity approaches. The breadth of peptide changes observed — affecting ghrelin, NPY, CCK, and many others simultaneously — is unusual and suggests a multi-target mechanism that could be more effective than single-target drugs.

How the study worked

Forty male Wistar rats were divided into five groups: control, sham, and three Salep extract dose groups (80, 160, and 320 mg/kg). The hydro-alcoholic extract was administered by oral gavage daily for 29 days. On day 29, blood and tissue samples were collected. ELISA kits measured 12 appetite and metabolic hormones/peptides (adiponectin, obestatin, resistin, orexin-A, insulin, epinephrine, AgRP, omentin, chemerin, amylin, NPY, ghrelin) plus leptin, CCK, antioxidants, and lipid profile factors.

What this study cannot tell us

This is an animal study in healthy male rats, not obese rats or humans. The 29-day treatment period is relatively short. The mechanism by which Salep extract simultaneously modifies over a dozen different peptide hormones is unclear and may reflect indirect metabolic effects rather than specific peptide-targeting activity. The AgRP increase is paradoxical (AgRP normally stimulates appetite) and is not explained. No dose-response analysis for individual peptides is described. Human bioavailability and safety of Salep extract are unknown.

How to read the evidence

This is a preclinical rat study with a controlled design (5 groups, 40 animals) and comprehensive hormone panel. While the breadth of measurements is impressive, the study is in normal (non-obese) male rats, the short duration and lack of mechanistic explanation for how a plant extract affects so many peptide systems limit the evidence quality. The paradoxical AgRP finding is unexplained.

When this study was published

Published in 2024, this study represents current interest in botanical approaches to obesity that work through peptide hormone modulation. The results are preliminary and require confirmation in obesity models and human studies.

The bigger picture

Appetite regulation involves a complex interplay of peptide hormones from the gut (ghrelin, CCK, GLP-1), brain (NPY, AgRP, orexin), and fat tissue (leptin, adiponectin, resistin). Most pharmaceutical approaches target just one or two of these pathways. This study is notable for the sheer number of peptide hormones simultaneously affected by a single botanical extract, though the mechanism by which a plant extract modulates so many different peptide systems requires further investigation.

Questions still open

How does a plant extract simultaneously modify the secretion of so many different appetite-regulating peptides — is there a common upstream mechanism?
Would these effects translate to obese animals or humans, where appetite regulation is already dysregulated?
Why did AgRP (an appetite-stimulating peptide) increase despite the overall appetite-suppressing and weight-loss effects?

Common questions

How does the body's peptide system control appetite and weight?

Your body uses a network of peptide hormones to balance hunger and fullness. Ghrelin from the stomach tells your brain you're hungry. NPY and orexin-A in the brain amplify appetite. On the other side, CCK from the gut signals fullness after eating, leptin from fat cells tells the brain about energy stores, and obestatin suppresses appetite. In obesity, this system is often imbalanced. This study found that Salep extract shifted the balance toward satiety across nearly all of these peptide systems simultaneously.

Can I take Salep orchid extract to lose weight?

This study was conducted in rats, not humans, and the extract was delivered directly into the stomach by gavage — not as a dietary supplement. While the results are interesting, there is no evidence that commercially available Salep products would produce similar effects in humans. The doses, bioavailability, and safety in humans are unknown. Weight management should be discussed with a healthcare provider.

Read the original research

Investigating the Preventive Effects of Oral Consumption of Dactylorhiza Maculate (Salep) Hydro-alcoholic Extract on Appetite and Body Weight in Male Rats.

Archives of Razi Institute, 79(2), 418-425

View on PubMed ↗Publisher’s paper ↗

Citation

Haghshenas, H; Molayem, M; Shafiei Jahromi, N; Kargar Jahromi, H; Dehghani, M; Ebrahimi, B; Moazeni, R; Rezaeian, S; Shaterian, N; Daniali, S. (2024). Investigating the Preventive Effects of Oral Consumption of Dactylorhiza Maculate (Salep) Hydro-alcoholic Extract on Appetite and Body Weight in Male Rats.. Archives of Razi Institute, 79(2), 418-425. https://doi.org/10.32592/ARI.2024.79.2.418