Anti-Diabetic Potential of Corn (Zea mays L.) Silk: A Systematic Review and Meta-Analysis of Preclinical Studies

This systematic review and meta-analysis aimed to quantitatively evaluate the effect of corn silk on metabolic and oxidative stress parameters in preclinical diabetic models. After a comprehensive search across PubMed, Scopus, MDPI, and GARUDA databases, eight studies were included in this review and analysis. A random-effects model was employed to assess the pooled effect of corn silk intervention on the fasting blood glucose, insulin, superoxide dismutase (SOD), and malondialdehyde (MDA) levels compared to those of the pharmacological controls. The findings revealed that the administration of corn silk was not more effective than the control drugs in reducing the fasting blood glucose [standardized mean difference (SMD)=0.99, P<0.001, heterogeneity (I²)=76%] and MDA (SMD=0.86, P<0.001, I²=85%) levels or in increasing SOD activity (SMD=-0.93, P<0.001, I²=68%). However, the intervention proved significantly more effective at increasing the insulin levels (SMD=1.61, P<0.001). Subgroup analysis indicated that efficacy varied depending on factors such as dose, duration of intervention, and extraction method. In conclusion, while corn silk demonstrates a notable effect on increasing the insulin levels, this change was not accompanied by a corresponding improvement in glycemic control. Furthermore, its overall anti-diabetic effectiveness on blood glucose and oxidative stress markers remains inconsistent in animal models. The high level of heterogeneity observed across studies (I²>68%) substantially limits the generalizability of these results and highlights the crucial need for future research with more standardized protocols to substantiate its therapeutic potential.