The effects of Cuminum cyminum on glycemic parameters: A systematic review and meta-analysis of controlled clinical trials

Ethnopharmacological relevance: Cuminum Cyminum (CC) is a traditional herbal medicine using as an antiseptic, anti-carcinogenic, anti-mutagenic, anti-cancer, anti-hypertensive, anti-inflammatory, and antioxidant. Recently hypoglycemic characteristics of CC have been indicated. Aim of the study: We intended to conduct a meta-analysis on the effect of CC supplementation on glycemic parameters in patients with different chronic diseases. Materials and methods: PubMed, Embase, Web of Science, and Scopus were searched until May 2021. Random effect model was conducted to perform the meta-analysis. Source of heterogeneity was explored using the metaregression and subgroup analyses. The Cochrane Collaboration's tool was used to assess the quality of studies. The GRADE approach was used to assess the quality of evidence. Results: Findings of eight studies showed that CC supplementation reduced FBS (SMD = -1.4 mg/dl; 95 % CI: -2.29, -0.51; P = 0.002), HbA1c (SMD = -1.71 %; 95 % CI: -3.24, -0.18; P = 0.028), and HOMA-beta (SMD = 0.46; 95 % CI: -0.62, 1.55; P = 0.404) significantly. Also, CC increased QUICKI level (SMD = 0.89; 95 % CI: 0.37, 1.4; P = 0.001. However, no significant effect of CC was observed on insulin (SMD = -0.70 mu IU/dl; 95 % CI: -1.84, 0.45; P = 0.234) and HOMA-IR (SMD = 0.46; 95 % CI: -0.62, 1.55; P = 0.404). Conclusion: CC had an improving effect on FBS, HbA1C, HOMA-B, and QUICKI. The effect of CC on amending HOMA-IR was significant after sensitivity analysis. However, the insulin level was not changed significantly.