2.1. Plant material and preparation of extract
Thymus kotschyanus was gathered from mountains nearby Ardabil city in Iran. The plant was identified in the Department of Pharmacognosy at the School of Pharmacy (Mashhad, Iran) under the voucher number: 13580. The leaves (500g) were cleaned and shade dried, turned into powder using an electrical blender, and then homogenized in ethanol (70%; 750 ml). The mixture was left in a conical flask at room temperature for 2 days and then the plant was extracted by percolation method. The extract was concentrated using a rotary evaporator (Heidolph, Germany) and Thymus kotschyanus extraction mixed with microcrystalline cellulose and formulated by the wet granulation method. Then each 500 mg capsule was filled with a mixture of the extraction and microcrystalline cellulose. Each treatment capsule contained 0.167 mg of pure Thymus kotschyanus extraction powder. The placebo 500mg capsule consisted of microcrystalline cellulose powder, but no known active agents, and placebo were identical in taste and appearance to the extract capsule.
2.2. Inclusion and exclusion criteria
Inclusion criteria were: (1) ulcerative colitis out-patients (2) age between 13 to 65 years (3) the Simple Clinical Colitis Activity Index (SCCAI) between 5 and 13 (4) taking mesalazine with fixed-dose since one month ago and not exceed more than 4500 mg mesalazine in a day (5) if taking topical, mesalazine it should be used at least for 2 weeks with a fixed-dose and not exceed more than 4000 mg in a day (6) hemoglobin higher than 10. Exclusion criteria were: (1) incidence of any adverse reaction of Thymus kotschyanus extraction (2) diagnosing concurrent diseases such as diabetes, cardiovascular disease, kidney disease, liver disease, thyroid disease, and bile disease (3) having leukopenia, thrombocytopenia, or other blood coagulation disorders (4) concurrent sepsis or any active infection (5) administering another anti-inflammatory or immunomodulatory or anticoagulant medicine (6) having epilepsy and convulsion (7) pregnancy and lactation, and (8) being reluctant to continue this trial.
2.3. Study design
This study was conducted as a randomized double-blind placebo-controlled trial which both patients and trial investigator were blinded. Trial was carried out at the Imam Reza hospital (Mashhad, Iran) and the School of Pharmacy (Mashhad, Iran) in 2019-2021. Out-patients who met the inclusion criteria were qualified to participate in this clinical trial and the diagnosis of ulcerative colitis was confirmed by a relative physician, based on the medical history of patients. Patients were registered based on the mentioned criteria by a trial pharmacist at the school of pharmacy (Mashhad, Iran). Randomization was performed using a computer-generated, randomization formula with A and B sequence, to receive treatment or placebo, which A used for the intervention group and B used for the control group and divided patients into each group. Finally, a research assistant handed over the capsules to the two groups and was not interfere in the other stages of the trial. The intervention group consisted of 15 patients who were randomized by computer took one extraction capsule three times a day by the effective daily dose of 500 mg of T. kotschyanus. These patients were administered the Thymus kotschyanus extraction capsule for 3 months by a total dose of 45 grams of this capsule in the whole time of the trial. 15 patients who were randomized by computer, took one placebo capsule three times a day for 3 months were assigned to the control group. The Ethics Committee of Mashhad University of Medical Sciences (Mashhad, Iran) approved the study protocol. Patients gave written informed consent and were informed about the possible adverse reaction of the treatment prior to the participation. The study protocol has been registered in the Iranian Registry of Clinical Trials (IRCT.ir) under the identification code: IRCT20200406046965N2.
2.4. Efficacy measures
Qualified patients were interviewed and informed of the details of the trial and patients were asked about the symptoms and SCCAI score was recorded at the starting point of the trial (week 0). Patients completed the Short Inflammatory Bowel Disease Questionnaire (SIBDQ) for the quality of life. At the same visit, blood count, routine biochemistry including serum albumin concentration, C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR), and stool calprotectin were measured and SEO index was recorded. Patients were instructed to continue the main therapy (mesalazine) with a steady dose and take the trial capsule as complementary medicine. In addition, they were guided to contact the trial pharmacist for any unexpected adverse effects. Afterward, patients were followed up by the trial pharmacist at weeks 4 and 8, and any change of the symptoms and occurrence of any adverse effect were asked. Finally, patients were reviewed to calculate the SCCAI and to record compliance with the study medication at week 12. Blood count and stool calprotectin and routine trial biochemistry were checked and SIBDQ and SEO index were recorded.
2.5. Outcome measures
The primary outcome was reduction in calprotectin as the specific bowel inflammation marker after 12 weeks, a rational time scale for evaluation of mucosal healing (25) .
The secondary outcomes are included as reduction in SCCAI index score, remission and improvement changes in SIBDQ scores and SEO index which consist of changes in laboratory measures of hemoglobin, ESR, CRP, and albumin. Possible adverse effects of the trial medications were also recorded.
2.6. Statistical analysis
We estimated that a sample size of 15 patients per group was required to calculate difference of calprotectin and SCCAI with 80% power and 0.05 significance level.
Statistical calculations were evaluated using computer software programs (Microsoft Excel and SPSS version 16.0). The Levene`s test and t-test were used to compare the groups at week 0 and week 12 according to hemoglobin, ESR, CRP, albumin, calprotectin, WBC, platelet, and SEO index. Man-Whitney U test and Wilcoxon W test showed the comparison between SIDBQ and SCCAI at week 0 and week 12. A two-sided p-value of <0.05 was considered statistically significant in all comparisons.