Beneficial Effects of Opuntia humifusa (Korean Cheonnyuncho) on Human Health Based on Antioxidant Properties: Systematic Review and Meta-Analysis

In this study, a systematic review and meta-analysis are conducted to evaluate the medical applications of Opuntia humifusa (OH). A total of 171 articles are peer-reviewed; however, only 15 individual studies were included after the manual screening to eliminate unnecessary studies. A comparative standardized means difference (SMD) between the OH and control groups is used as a parameter to demonstrate the beneficial effects of OH for skin aging, cancer, and diabetes treatments based on its antioxidant activities. The OH treatment exhibits positive results in improving collagen synthesis and demonstrates that it is nontoxic to normal human cells without analytical heterogeneity (SMD = 1.18 [0.11, 2.26] and I(2) = 0%). Moreover, the results confirm the effectiveness of OH treatment on downregulatory cancers in terms of decreased cancer cell proliferation and tumor weight and increased numbers of cancer cells in the apoptosis phase (pooled SMD = −1.17 [−1.72, −0.62]). However, this comparison does not yield a statistically significant result (I(2) = 69%). Additionally, the OH treatment is found to reduce the symptoms of diabetes in diabetic rats, particularly by lowering glucose and triglyceride levels and increasing high-density lipoprotein cholesterol levels. This study suggests that OH extracts are helpful for the prevention of human diseases and might be potential candidates for future medicines.