Rhus coriaria L., a new candidate for controlling metabolic syndrome: a systematic review

Rhus coriaria L. (RC) is a deciduous shrub with several pharmacological activities. Evidence of the effects of RC on weight, hyperlipidaemia, hypertension and diabetes mellitus have been presented in this study. Books, thesis and internet-based resources such as PubMed, Web of Science, Scopus, EMBASE, Cochrane, Ovid and Google Scholar were searched for the English, Arabic and Persian literature from 1966 to 2020 (December). The keywords were Rhus coriaria L., Sumac, metabolic syndrome and all its medical conditions (hyperlipidaemia, hypertension, obesity and diabetes mellitus). The inclusion criteria were full-text animal and human studies conducted on RC to evaluate its efficacy on any components of metabolic syndrome (MetS). Jadad scale was used to assess the quality of evidence. Reviewing 23 relevant studies demonstrated that RC is able to decrease the level of blood glucose, glycated haemoglobin, serum insulin and insulin resistance. Studies on hyperlipidaemia and obesity have very contradicting results, and there is no definite conclusion on the effect of RC on lipid profile. However, the hypotensive and effect of RC was confirmed in the existing studies. According to the literature, RC can be considered as a promising curative candidate for MetS. However, further studies with larger sample size and higher methodological quality are needed.