Antidiabetic and antioxidant effects of catalpol extracted from Rehmannia glutinosa (Di Huang) on rat diabetes induced by streptozotocin and high-fat, high-sugar feed

Abstract

BackgroundDiabetes, associated with hyperlipidemia and oxidative stress, would lead to an increased production of reactive oxygen species. Rehmannia glutinosa (Di Huang) is widely used to nourish yin, invigorate the kidney (shen), and treat xiao ke (a diabetes-like syndrome in Chinese medicine). This study aims to investigate the antidiabetic and antioxidant effects of catalpol from R. glutinosa on rat diabetes induced by streptozotocin (STZ) and high-fat, high-sugar feed.MethodsRats (eight rats in each group at least) were induced diabetes by an initial high-fat high-sugar feed for 3 weeks, followed by an intraperitoneal injection of STZ (30 mg/kg) for 3 days, and rats were fasted overnight before treatments. Catalpol at a dose of 0, 5, 10, 20 or 50 mg/kg was administrated through bolus intravenous injection to the experimental rats to find the most effective anti-hyperglycemic dose of catalpol to further study body weight loss, water intake, and food intake. The most effective catalpol dose was given to the diabetic model rats with hyperlipidemia, and the levels of blood sugar, plasma total cholesterol (TC), triglyceride (TG), and high-density lipoprotein cholesterol (HDL-C) were measured after catalpol administration once a day for 2 weeks. An oral glucose challenge test (OGCT) was performed after above experiments in which the most effective dose of catalpol has been determined. Levels of glutathione peroxidase (GSH-PX), catalase (CAT), superoxide dismutase (SOD), and malondialdehyde (MDA) were measured by corresponding reagent kits and morphological changes of the pancreas were observed with histopathological examination using H&E stain.ResultsCatalpol at a dose of 50 mg/kg ameliorated body weight loss and increased water and food intake. Catalpol also attenuated the increase of plasma TC (P = 0.0067) and TG (P = 0.0084) and increased HDL-C (P = 0.0336). The OGCT revealed that catalpol reduced the increase of plasma glucose. The activities of antioxidative enzymes (SOD, P = 0.0037; GSH-PX, P = 0.0066; CAT, P = 0.005) were enhanced and MDA was reduced (P = 0.003). Furthermore, catalpol reduced the morphological impairment of the pancreas.ConclusionCatalpol protected against STZ-induced diabetes with high-fat and high-sugar feed with ameliorated structural impairment of the pancreas and restored balance between oxidative enzymes and antioxidative enzymes.

Catalpol protects against 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin‐induced cytotoxicity in osteoblastic MC3T3‐E1 cells

“…For example, recent studies by our research group have shown that various flavonoids, including actein (Choi et al, 2017), 27-deoxyactein (Suh, Choi, Jung, et al, 2018) and xanthohumol (Suh, Choi, Kim, et al, 2018), inhibit TCDD-induced toxicity in MC3T3-E1 osteoblastic cells. The beneficial effects of catalpol are primarily associated with their antioxidant activities, including the scavenging of free radicals (Zhu et al, 2016). However, to the best of our knowledge, there is no study of catalpol on TCDD toxicity in cultured osteoblastic cells.…”

Camel milk improvement of antioxidant and lipid profile in hypercholesterolemic rabbits

“…It is well-defined between hyperlipidemia and the development of oxidative stress, and the introduction of medicinal plants with higher antioxidant content proved effective (Tunsophon and Chootip, 2016). Previous studies indicated that a variety of plants extracts (Natal et al, 2016;Vivarelli et al, 2016;Sripradha et al, 2016), natural product (Zhu et al, 2016) and whey protein isolates (Betik et al, 2016) were used to ameliorate hyperlipidemia's laboratory animal models.…”

Catalpol attenuates oxidative stress and promotes autophagy in TNF-α-exposed HAECs by up-regulating AMPK

“…Decreased AMPK activity promotes smooth muscle cell proliferation, monocyte-to-macrophage differentiation, 37 accelerates endothelium inammation 14,38 and so on. As catalpol has been reported to play a relieving role in diabetes through regulating glucose and lipid metabolism, 39 and AMPK is a critical enzyme in energy metabolism, we posited that the protective effect of catalpol on TNF-a-treated HAECs was depending on activating AMPK. Previous studies indicated that activated AMPK could promote the accumulation of NAD + , thereby affecting SIRT1 deacetylase activity and performing variety of effects.…”

“…46,47 It was also reported that AMPK was involved in modulating endothelial cell injury in diabetes induced by NADPH oxidase overexpression. 39,48,49 By using AMPK inhibitor compound C and AMPK siRNA, we proved that catalpol enhanced AMPK activity to reduce NOX4 expression and ROS production. These ndings revealed that catalpol attenuated TNF-a induced oxidative stress partially via enhancing AMPK activity.…”