Purslane Ameliorates Inflammation and Oxidative Stress in Diabetes Mellitus: A Systematic Review

Type 2 diabetes (T2D) is characterised by insulin resistance and leads to hyperglycaemia. Its prevalence and associated complications continue to rise exponentially, despite the existence of pharmaceutical drugs, and this has prompted research into exploring safer herbal remedies. Portulaca oleracea (purslane) has been investigated in animal and clinical trials to explore its effects on diabetes, yielding conflicting results. This study aimed to evaluate the effects of purslane on inflammation and oxidative stress in diabetes mellitus. We conducted a comprehensive literature search on Scopus PubMed, and through a manual bibliographical search to find relevant studies from inception to 13 September 2024. The search terms included purslane, portulaca oleracea, and type 2 diabetes mellitus. Of the 38 retrieved studies, 12 were considered relevant and underwent critical review. Evidence from rodent studies showed decreased inflammatory markers such as interleukin-6 (IL-6), tumour necrosis factor-alpha (TNF-α), nuclear factor kappa-beta (NF-κβ), and C-reactive (CRP), while interleukin-10 (IL-10) was increased after intervention with purslane. The markers of oxidative stress such as superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), glutathione peroxidase (GPx), and total antioxidant capacity (TAC) levels increased, thiobarbituric acid reactive substances (TBARS), reactive oxygen species (ROS) and malondialdehyde (MDA) decreased. Notably, the evidence from clinical trials showed a significant reduction in NF-κβ and CRP after purslane treatment; however, no effect was observed on MDA and TAC. The evidence gathered in this study suggests that purslane exerts anti-inflammatory properties by downregulating NF-κβ, thus suppressing the production of associated pro-inflammatory cytokines. Therefore, purslane may be used as an antioxidant and inflammatory agent for diabetes. However, further clinical evidence with a broader population is required to validate the therapeutic properties of purslane in diabetes.