Figure 1

Flow diagram showing the identification of relevant studies in the meta-analysis. A total of 500 articles (203 from Pubmed and 297 from EMBASE) were identified from the electronic database searching. Besides, 43 more records were identified through consulting the citations of the relevant reviews and articles. A total of 165 records were detailed evaluated and19 full-text were assessed for eligibility after removing 146 reviews, case reports and overlapped articles. Subsequently 3 articles in which tea extract was studied and 7 ones in which the data not in usable format were excluding from the inclusion and in final, a total of 9 articles were included for the quantitative synthesis.