The effect of Zataria multiflora on respiratory symptoms, pulmonary functions, and oxidative stress parameters: a systematic review and meta-analysis.

Abstract

Background: Zataria multiflora (Z. multiflora), also known as Shirazi thyme, is recognized for its medicinal properties, including antioxidant, anti-inflammatory, and immunomodulatory effects. Its longstanding use in traditional medicine for respiratory ailments underscores its significance. Given the widespread prevalence of respiratory disorders and inconclusive outcomes from previous trials, this research aims to conduct a systematic review and meta-analysis to evaluate Z. multiflora's impact on respiratory symptoms, pulmonary function, and oxidative stress markers using available randomized controlled trials (RCTs).

Methods: In this systematic review and meta-analysis, a comprehensive search of published literature was conducted up to January 2024, encompassing databases such as PubMed, Scopus, Web of Science, and the Cochrane Central for Randomized Clinical Trials. The assessment of the quality of each eligible study was conducted using the Cochrane risk-of-bias tool. The random-effects model was used in the meta-analysis to determine the weighted mean difference (WMD) with 95% confidence intervals (CIs). All statistical analyses were conducted using STATA (version 15).

Results: A total of 9 studies involving 394 participants were included. The administration of Z. multiflora showed significant effects on cough (WMD: -0.99; 95% CI: -1.66, -0.33; P = 0.003), day wheezing (WMD: -1.18; 95% CI: -1.44, -0.92; P < 0.001), night wheezing (WMD: -0.74; 95% CI: -1.09, -0.37; P < 0.001), chest wheezing (WMD: -1.15; 95% CI: -1.65, -0.64; P < 0.001), forced expiratory volume (WMD: 11.38; 95% CI: 7.40, 15.35; P < 0.001), forced vital capacity (WMD: 16.01; 95% CI: 12.26, 19.75; P < 0.001), and peak expiratory flow (WMD: 8.78; 95% CI: 4.13, 13.43; P < 0.001) compared to the control group. Additionally, Z. multiflora significantly reduced malondialdehyde levels (SMD: -1.54; 95% CI: -2.17, -0.90; P < 0.001) and increased catalase levels (SMD: 0.97; 95% CI: 0.46, 1.46; P < 0.001).

Conclusion: Z. multiflora shows potential as a complementary treatment for respiratory diseases by improving symptoms, pulmonary functions, and reducing oxidative stress. However, due to the limited number of trials, findings should be interpreted cautiously, and further research is needed.