Crocus Sativus Tepals Water Extract in Obesity and Prediabetes (ZAFRAN)

February 3, 2026 updated by: Nina Mohorko, University of Primorska

Acute Effects of Water Extract of Crocus Sativus Tepals on Metabolic Health Parameters in Patients With Obesity and Prediabetes

The goal of this clinical trial is to determine the acute effects of ingestion of a cold aqueous extract of Crocus sativus tepals on postprandial glycemia and other indicators of metabolic health in patients with obesity and/or prediabetes. The main questions it aims to answer are:

  • Does the ingestion of Crocus sativus tepals cold aqueous extract prior to a meal improve the glycemic response to a standard meal?
  • How does the ingestion of Crocus sativus tepals aqueous extract prior to a meal impact insulin levels and other markers of metabolic health?
  • Does the ingestion of Crocus sativus tepals cold aqueous extract prior to a meal increase the resting energy expanditure?

Researchers will compare Crocus sativus tepals cold aqueous extract to cold water.

The participants will visit the Faculty twice - on one visit they will ingest Crocus sativus tepals cold aqueous extract and on the other cold water (in random order) 5 minutes prior to a standard meal of 100 g of white bread.

On each visit, anthropometric measurements will be performed upon arrival. Blood samples will be collected 3 times, preceeded by resting metabolic rate and blood pressure measurements: at baseline in fasted conditions, and 60 minutes and 120 minutes after consuming the bread.

There will be an at least 7 days wash-out period between the two visits.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

20

Phase

  • Early Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • Slovenia
      • Izola, Slovenia, 6310
        • Recruiting
        • University pf Primorska, Faculty of Health Sciences
        • Sub-Investigator:
          • Tanja Črešnovar
        • Sub-Investigator:
          • Bernarda Habe
        • Sub-Investigator:
          • Ana Petelin, PhD
        • Contact:
        • Contact:
        • Principal Investigator:
          • Nina Mohorko, PhD
        • Sub-Investigator:
          • Zala Jenko Pražnikar, PhD

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Obesity type I (ITM > 30 kg/m2) and/or
  • Prediabetes (fasting glucose levels 6,1 - 6,9 mmol/L)

Exclusion Criteria:

  • Gastrointestinal diseases
  • Diabetes mellitus of any type
  • Pregnant or lactating, without contraception
  • Serious clinical conditions such as cancer, severe infections, severe psychiatric disorders, autoimmune diseases, inflammatory diseases
  • Participation in another clinical trial 3 months prior to the study
  • ITM greater than 35 kg/m2
  • Celiac disease of gluten intolerance
  • electronic implant

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Crocus sativus
Crocus sativus tepals cold aqueous extract
Biological: Crocus sativus tepals cold aqueous extract
2 g of Crocus sativus tepals will be infused in 200 mL of water overnight at 4 °C, resulting cold aqueous extract corresponds to 40 mg GAE of polyphenols
Sham Comparator: water
cold water
Biological: cold water
200 mL of cold water, kept overnight at 4 °C

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
glucose levels
Time Frame: From enrollment to the end of second measurement at 2 weeks
Serum glucose levels will be measured from venous blood at baseline and 60 and 120 minutes after bread ingestion.
From enrollment to the end of second measurement at 2 weeks

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
insulin level
Time Frame: From enrollment to the end of second measurement at 2 weeks.
Serum insulin levels will be measured from venous blood at baseline and 60 and 120 minutes after bread ingestion.
From enrollment to the end of second measurement at 2 weeks.
Resting metabolism
Time Frame: From enrollment to the end of the second measurement, at 2 weeks

Resting metabolism will be measured with indirect calorimetry at baseline in fasted state and at 40 and 100 minutes after bread ingestion.

To determine RMR, subjects will lie relaxed on a bed in a thermoneutral room for 10 minutes to calm down, followed by a 20-minute measurement of oxygen consumption (VO2) and carbon dioxide production (VCO2). RMR and RQ will be calculated from stable values over a 15-minute period (the first 5 minutes of measurement until stabilization will not be taken into account).
From enrollment to the end of the second measurement, at 2 weeks
Blood pressure
Time Frame: baseline, 60 minutes after bread ingestion, 120 minutes after bread ingestion
baseline, 60 minutes after bread ingestion, 120 minutes after bread ingestion

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Primorska

Collaborators

Università Politecnica delle Marche

Investigators

  • Principal Investigator: Nina Mohorko, PhD, University pf Primorska, Faculty of Health Sciences

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

February 6, 2026

Primary Completion (Estimated)

June 1, 2026

Study Completion (Estimated)

December 1, 2026

Study Registration Dates

First Submitted

November 22, 2025

First Submitted That Met QC Criteria

November 22, 2025

First Posted (Actual)

December 3, 2025

Study Record Updates

Last Update Posted (Actual)

February 4, 2026

Last Update Submitted That Met QC Criteria

February 3, 2026

Last Verified

February 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • ZAFRAN-2025

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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