Effects of okra (Abelmoschus esculentus L) on inflammatory mediators: a systematic review of preclinical studies

Abstract

The present study aimed to systematically review the available investigations about the effects of okra on important inflammatory mediators including C-reactive protein (CRP), interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α). Electronic databases such as PubMed, Scopus, WOS, ProQuest, and the search engine Google Scholar were searched until August 2021 and search alerts were activated in order to notice papers issued after the initial search. There was no restriction in the date and/or language. No human research was found; therefore, animal and in vitro studies were considered. Also, the citations or references of these studies were assessed to gain possible research. Review papers, book chapters, and grey literature such as conference papers, dissertations, and patents were not considered. Twenty-six papers were considered in the systematic review. The concentrations of inflammatory mediators including CRP, IL-1β, IL-6, and TNF-α mainly showed a downward trend after treatment with okra. In other words, the pooled direction of impacts was consistently lower for all of the evaluated inflammatory markers in the majority of preclinical (7 of 13 in vitro and 13 of 16 animal) studies. The findings proposed the potential of okra to lower CRP, IL-1β, IL-6, and TNF-α. Okra is a promising but not yet confirmed natural ingredient to decrease systemic inflammation in patients with inflammation-predisposed diseases. Further research is needed to focus on evaluating the effects of okra on inflammatory mediators with lower variability as well as the clinical outcomes of inflammation-related diseases in order to add sufficient power to the results of this study.