Saponin content in medicinal plants in response to application of organic and inorganic fertilizers: a meta-analysis - Lv, Junyan; Liu, Shouzan; Hu, Chunli; Ding, Lan; Wang, Hongzhen; Li, Xin; Yang, Feng; Shen, Qiong; Zhang, Hongbin; Ma, Guobiao; Zhang, Shaobo; Bai, Yan (Frontiers in Plant Science, 2025)