Principal component analysis of flavonoids from different varieties of Epimedium and their protective effects on rats with kidney yang deficiency
Epimedium is a plant of the Berberidaceae family, including Epimedium wushanense T.S.Ying and Epimedium sagittatum (Sieb. et Zucc.) Maxim The dried leaves of Epimedium pubescens Maxim. or Epimedium koreanum Nakai from Korea, four species, are included in the 2015 edition of the Pharmacopoeia of the People’s Republic of China. This medicine was first recorded in the “Shennong Bencao Jing” and is classified as a top-grade medicine with many aliases. It is referred to as “Gangqian” in the “Ben Jing”, “Xianling Pi” in the “Lei Gong Pao Zhi Lun”, and “Rihuazi Bencao” as “Fang Tiao Cao”, “Fei Tiao Cao”, “Qian Liang Jin”, “Gan Ji Jin”, and “Huang Lianzu”. The book “Bielu”, “Treatise on Medicinal Properties”, “Shu Bencao”, and “Dian Nan Bencao” all record that its nature is pungent, sweet, and warm, and it belongs to the liver and kidney meridians. It has the effects of tonifying kidney yang, strengthening tendons and bones, and dispelling wind and dampness. Modern pharmacological research has shown that Epimedium can stimulate sexual function, enhance human immunity, regulate the balance of blood and oxygen supply to the heart, improve heart and brain ischemia and hypoxia, promote hematopoietic function, prevent and treat osteoporosis, as well as have anti-aging, antiviral, anti-tumor, antidepressant, anti-inflammatory and other effects. The chemical components of Epimedium include flavonoids, lignans, phenolic glycosides, alkaloids, polysaccharides, volatile oils, trace elements, chromogens, phenanthrene, anthraquinone, tannins, sesquiterpenes, sterols, etc. Among them, flavonoids such as icariin, Asahuoding A, Asahuoding B, and Asahuoding C are its main active ingredients. Principal component analysis is one of the commonly used methods for comprehensive evaluation of sample information. Its application in the field of traditional Chinese medicine has compensated for the uncertainty of the weights of various indicators and the inconvenience caused by the correlation between certain indicators in the quality evaluation of traditional Chinese medicine, further improving the quality evaluation method of traditional Chinese medicine. According to literature review, Epimedium mainly focuses on the research of immune regulation, anti-inflammatory, anti-aging, anti-tumor and other activities. There is little research on the kidney tonifying and yang nourishing effects of Epimedium, so we conducted preliminary exploration on its kidney tonifying and yang nourishing effects. Provide scientific theoretical basis and medical foundation for the clinical application of Epimedium.

HPLC was used to determine the content of four effective components, namely icariin, icariin A, icariin B, and icariin C, in different varieties of Epimedium (Table 1). Principal component analysis was used to analyze and evaluate the quality of different varieties of Epimedium, and the protective effect of Epimedium on kidney yang deficiency in rats was investigated. The experimental animals were randomly divided into a Yang deficiency model control group (model group), a Jin Kui Shen Qi Wan intervention group (positive group), and low (125 mg/kg, YYH-LG), medium (250 mg/kg, YYH-MG), and high (500 mg/kg, YYH-HG) dose groups of Epimedium. Four weeks later, uric acid (UA), creatinine (CRE), and urea nitrogen (BUN) were measured in the serum of kidney yang.

The results of principal component analysis in this study showed that two principal components were extracted from the four components, the first principal component being icariin and chaohuoding C, and the second principal component being chaohuoding B. By using the contribution rate to weight average the principal components and comparing the scores of 12 batches of Epimedium herb, it was found that 5 batches of samples had lower scores, indicating differences in the quality of the 12 batches of samples. This study selected Epimedium pilosum with high scores for the next research on the protective effect of kidney yang deficiency.
In clinical practice, when renal function is impaired, the levels of UA, CRE, and BUN will change. In this study, rat kidney yang deficiency induced by hydrocortisone was used as the experimental object, and UA, CRE, and BUN were used as detection indicators. The results showed that YYH-LG group, YYH-MG group, and YYH-HG group could all reduce the levels of UA, CRE, and BUN. Overall, the YYH-LG group showed good improvement in various indicators and kidney damage. Therefore, Epimedium is of great significance as a medicine in the treatment of kidney yang deficiency.