Study on Antioxidant and Anti diabetes Activities of Ethanol Extracts from Cortex Moutan
Diabetes is a chronic metabolic disease characterized by high blood sugar. With the improvement of modern living standards and the change of lifestyle, diabetes has become the third major factor affecting human health, second only to cardiovascular diseases and tumors. By 2021, there will be 140 million diabetes patients in China, and the total number of diabetes patients in the world will reach 537 million, accounting for 10.5% of the global population. The harm of diabetes to human health is not only in itself, but also causes a variety of complications, such as arterial atherosclerosis, diabetes foot disease, visual loss and even blindness caused by optic nerve injury. Studies have shown that the abnormal increase of oxidative stress will promote the occurrence of diabetes and its complications. At the same time, the high concentration of blood sugar in diabetes patients will make the glucose absorbed by cells far exceed their normal needs, leading to excessive accumulation of glucose in cells, significantly increasing the mitochondrial membrane potential difference in cells, prompting coenzyme Q to accelerate the reduction of oxygen molecules, thereby generating a large number of reactive oxygen species in cells, destroying the normal function of islet B cells and mitochondria, promoting the formation of advanced glycation end products (AGEs), increasing the state of oxidative stress, accelerating the process of diabetes and the occurrence of complications. Antioxidants can alleviate oxidative stress by clearing excessive free radicals or activating endogenous antioxidant defense system, thus alleviating the progress of diabetes and its related complications. Therefore, alleviating oxidative stress is of great significance for the prevention and control of diabetes and its complications.
Moutan Cortex (MC), the dried root bark of peony in the Ranunculaceae family, has a bitter and slightly pungent taste. It is a traditional Chinese medicinal herb with the effects of clearing heat and promoting blood circulation, and has been in use for thousands of years. The study found that the extract of paeonia has a variety of pharmacological activities, such as anti-tumor, antibacterial, antioxidant, anti diabetes and other characteristics, among which paeonol, phytosterols, sugars and flavonoids are the main active ingredients. Zhang et al. found that paeonol has significant in vitro antioxidant capacity and can induce oxidative stress by activating the nuclear factor E2 related factor 2 (Nrf2)/Kelch like ECH associated protein 1 (Keap1) – antioxidant response element (ARE) signaling pathway (Nrf2/Keap1-ARE). Lian et al found that the active polysaccharide component in cortex moutan can improve the nephropathy of diabetes complications. Wu et al. pointed out that the active ingredients of Danpi have a significant hypoglycemic effect, and its mechanism is related to inhibiting gluconeogenesis, promoting glycogen synthesis, and antioxidant activity. However, there is no report on the antioxidant and hypoglycemic activities of different polar solvent extracts from cortex moutan in vitro and in vivo, as well as the protective effect on nerves in the complications of diabetes.
This article uses 40%, 70%, and 95% ethanol for ultrasonic extraction of Danpi, compares the total phenol and total flavonoid content in ethanol extracts of Danpi at different concentrations, determines the antioxidant capacity of the samples through DPPH free radical and ABTS free radical scavenging ability experiments, examines the anti glycosylation ability of the extracts using fluorescence spectroscopy, evaluates the α – glucosidase production ability of the samples by comparing with acarbose, and finally evaluates the hypoglycemic ability of the samples in animals and their protective effect on peripheral motor nerves using a hyperglycemic animal model. It is expected to provide a theoretical basis for the comprehensive application of paeonia extract in anti diabetes and anti-oxidation.

According to relevant reports, the number of diabetes patients in China is large and young, which seriously endangers the life and health of our citizens. Nowadays, most of the drugs for diabetes on the market are chemical synthesis, which has certain side effects, while extracts from plants have the characteristics of natural, efficient and low side effects. In this paper, the anti diabetes and antioxidant activities of ultrasonic extracts from different concentrations of ethanol solution of Cortex Moutan were compared, and the application potential of Cortex Moutan in anti diabetes was analyzed. Research has shown that when 70% ethanol is used as the solvent, the yield is 4.98%. The Danpi extract has the highest total phenolic and flavonoid content, with 59.17mg GAE/g and 82.59mg QUE/g, respectively. It has good in vitro antioxidant and hypoglycemic activity. The IC50 values for DPPH free radical, ABTS free radical scavenging ability, and α – glucosidase inhibition ability are 16.30, 34.20, and 2.10 μ g/mL, respectively, and the glycosylation inhibition rate is 81.44%. Through experiments on a hyperglycemic animal model, it has been further demonstrated that MC70 has the effect of reducing blood glucose levels; When the concentration of Danpi extract is 2mg/mL, the auxiliary hypoglycemic effect is 52%, and MC70 has a peripheral motor neuroprotective effect of 56% at this concentration. The extract of cortex moutan extracted by ultrasound with 70% ethanol solution has good antioxidant, anti diabetes ability, and auxiliary hypoglycemic effect. It has research potential and application value in anti diabetes.