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Objectives: The aim of this study was to investigate the ameliorative effect of platycodin D (PD) on cognitive dysfunction in type 2 diabetes mellitus (T2DM) and its potential molecular mechanisms of action in vivo and in vitro. Materials and methods: An animal model of cognitive impairment in T2DM was established using a single intraperitoneal injection of streptozotocin (100 mg/kg) after 8 weeks of feeding a high-fat diet to C57BL/6 mice. In vitro, immunofluorescence staining and Western blot were employed to analyze the effects of PD on glucose-induced neurotoxicity in mouse hippocampal neuronal cells (HT22). Results: PD (2.5 mg/kg) treatment for 4 weeks significantly suppressed the rise in fasting blood glucose in T2DM mice, improved insulin secretion deficiency, and reversed abnormalities in serum triglyceride, cholesterol, low-density lipoprotein, and high-density lipoprotein levels. Meanwhile, PD ameliorated choline dysfunction in T2DM mice and inhibited the production of oxidative stress and apoptosis-related proteins of the caspase family. Notably, PD dose-dependently prevents the loss of mitochondrial membrane potential, promotes phosphorylation of phosphatidylinositol 3 kinase and protein kinase B (Akt) in vitro, activates glycogen synthase kinase 3β (GSK3β) expression at the Ser9 site, and inhibits Tau protein hyperphosphorylation. Conclusions: These findings clearly indicated that PD could alleviate the neurological damage caused by T2DM, and the phosphorylation of Akt at Ser473 may be the key to its effect.

Ethnopharmacological Relevance: Alzheimer's disease (AD) was considered to be a neurodegenerative disease that caused cognitive impairment. Reactive Oxidative stress (ROS) was considered to be one of a major cause of the onset and progression of AD. Platycodin D (PD), a representative saponin from Platycodon grandiflorum, has conspicuous antioxidant activity. However, whether PD could protect nerve cell against oxidative injury remains unknown., Aim of Study: This study investigated the regulatory effects of PD on neurodegeneration caused by ROS. To determine whether PD could play its own antioxidant role in neuronal protection., Materials and Methods: First, PD(2.5, 5 mg/kg) ameliorated the memory impairment induced by AlCl 3 (100 mg/kg) combined with D-galactose (D-Gal) (200 mg/kg) in mice, using the radial arm maze (RAM) test, and neuronal apoptosis in the hippocampus was evaluated by hematoxylin and eosin staining (HE). Next, the effects of PD (0.5, 1, and 2 μM) on okadaic-acid (OA) (40 nM) -induced apoptosis and inflammation of HT22 cells were investigated. Mitochondrial ROS production was measured by fluorescence staining. The potential signaling pathways were identified through Gene Ontology enrichment analysis. The role of PD in regulating AMP-activated protein kinase (AMPK) was assessed using siRNA silencing of genes and an ROS inhibitor., Results: In vivo, PD improved memory in mice, and recovered the morphological changes of brain tissue and nissl bodies. In vitro experiment, PD increased cell viability (p < 0.01; p < 0.05;p < 0.001), decreased apoptosis (p < 0.01), reduced excessive ROS and MDA, rised SOD and CAT content(p < 0.01; p < 0.05). Morover, it can block the inflammatory response caused by ROS. Be important, PD strengthen antioxidant ability by elevating AMPK activation both in vivo and in vitro. Furthermore, molecular docking suggested a good likelihood of PD-AMPK binding., Conclusion: AMPK activity is vital for the neuroprotective effect of PD, suggesting that PD may be a potential pharmaceutical agent to treat ROS-induced neurodegeneration., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Previous reports have confirmed that crude saponins (ginsenosides) in Panax ginseng have a preventive effect on chemotherapy-induced intestinal injury. However, the protective effects and possible mechanisms of ginsenoside Re (G-Re, a maker saponin in ginseng) against chemotherapy-induced intestinal damage have not been thoroughly studied. In this work, a series of experiments in vivo and in vitro on the intestinal toxicity caused by cisplatin have been designed to verify the improvement effect of G-Re, focusing on the levels of Wnt3a and [Formula: see text]-catenin. Mice were intragastric with G-Re for 10 days, and intestinal injury was induced by intraperitoneal administration of cisplatin at a dose of 20 mg/kg. Histopathology, gastrointestinal digestive enzyme activities, inflammatory cytokines, and oxidative status were evaluated to investigate the protective effect. Furthermore, in IEC-6 cells, G-Re statistically reverses cisplatin-induced oxidative damage and cytotoxicity. The TUNEL and Hoechst 33258 staining demonstrated that G-Re possesses protective effects in cisplatin-induced apoptosis. Additionally, pretreatment with G-Re significantly alleviated the apoptosis via inhibition of over-expressions of B-associated X (Bax), as well as the caspase family members, such as caspase 3 and 9, respectively, in vivo and in vitro . Notably, western blotting results showed that G-Re treatment decreased Wnt3a, Glycogen synthase kinase [Formula: see text] (GSK-[Formula: see text]), and [Formula: see text]-catenin expression, suggesting that nuclear accumulation of [Formula: see text]-catenin was attenuated, thereby inhibiting the activation of GSK-[Formula: see text]-dependent Wnt/[Formula: see text]-catenin signaling, which was consistent with our expected results. Therefore, the above evidence suggested that G-Re may be a candidate drug for the treatment of intestinal injury.

Saponins from the roots of Platycodon grandiflorum , an edible medicinal plant, have shown a wide range of beneficial effects on various biological processes. In this study, an animal model was established by a single intraperitoneal injection of cisplatin (20[Formula: see text]mg/kg) for evaluating the protective effects of saponins from the roots of P. grandiflorum (PGS, 15[Formula: see text]mg/kg and 30[Formula: see text]mg/kg) in mice. The results indicated that PGS treatment for 10 days restored the destroyed intestinal mucosal oxidative system, and the loosened junctions of small intestinal villi was significantly improved. In addition, a significant mitigation of apoptotic effects deteriorated by cisplatin exposure in small intestinal villi was observed by immunohischemical staining. Also, western blot showed that PGS could effectively prevent endoplasmic reticulum (ER) stress-induced apoptosis caused by cisplatin in mice by restoring the activity of PERK (an ER kinase)-eIF2[Formula: see text]-ATF4 signal transduction pathway. Furthermore, molecular docking results of main saponins in PGS suggested a better binding ability with target proteins. In summary, the present work revealed the underlying protective mechanisms of PGS on intestinal injury induced by cisplatin in mice.

Background: Cisplatin is one of the most common chemotherapeutic drugs. Cisplatin-induced toxicity gives rise to gastrointestinal cell damage, subsequent diarrhea and vomiting, leading to the discontinuation of its clinical application in long-term cancer chemotherapy. Panax quinquefolium L., also known as American ginseng, has many pharmacological activities such as improving immunity, anti-tumor, anti-radiation and blood sugar lowering., Purpose: Previously, our laboratory reported that American ginseng berry extract could alleviate chemotherapeutic agents-induced renal damage caused by cisplatin. Hence, this study further explored the protective effect of P. quinquefolium saponins (PQS) on cisplatin-induced intestinal injury in mice and the possible molecular mechanisms., Methods: Biochemical markers, levels of inflammatory factors, histopathological staining and western blotting were used to analyze intestinal injury based on various molecular mechanisms., Results: We demonstrated the destruction of the intestinal barrier caused by cisplatin exposure by detecting the activity of diamine oxidase (DAO) and the expression of tight junction proteins zonula occludens-1 (ZO-1) and occludin. Meanwhile, cisplatin exposure changed SOD and MDA levels in the small intestine, causing oxidative damage to the intestinal mucosa. The inflammation associated-intestinal damage was further explored by the measurement of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and analysis of nuclear factor-kappa B (NF-κB) inflammatory pathway protein expression. Moreover, apoptotic cells labeled with TUNEL staining-positive cells and activated caspase family proteins suggest that cisplatin induces intestinal apoptosis. Interestingly, PQS pretreatment significantly reversed these situations., Conclusion: These evidences clearly suggest that PQS can alleviate cisplatin-induced intestinal damage by inhibiting oxidative stress, reducing the occurrence of inflammation and apoptosis, and improving intestinal barrier function., (Copyright © 2020. Published by Elsevier GmbH.)

Cisplatin, a proven effective chemotherapeutic agent, has been used clinically to treat malignant solid tumors, whereas its clinical use is limited by serious side effect including nephrotoxicity. Platycodin D (PD), the major and marked saponin isolated from Platycodon grandiflorum, possesses many pharmacological effects. In this study, we evaluated its protective effect against cisplatin-induced human embryonic kidney 293 (HEK-293) cells injury and elucidated the related mechanisms. Our results showed that PD (0.25, 0.5, and 1 μM) can dose-dependently alleviate oxidative stress by decreasing malondialdehyde and reactive oxygen species, while increasing the levels of glutathione, superoxide dismutase, and catalase. Moreover, the elevation of apoptosis including Bax, Bad, cleaved caspase-3,-9, and decreased protein levels of Bcl-2, Bcl-XL induced by cisplatin were reversed after PD treatment. Importantly, PD pretreatment can also regulate PI3K/Akt and ERK/JNK/p38 signaling pathways. Furthermore, PD was found to reduce NF-κB-mediated inflammatory relative proteins. Our finding indicated that PD exerted significant effects on cisplatin induced oxidative stress, apoptosis and inflammatory, which will provide evidence for the development of PD to attenuate cisplatin-induced nephrotoxicity., (© 2020 Wiley Periodicals LLC.)

Acute liver injury (ALI) induced by acetaminophen (APAP) overdose is the most common cause of drug-induced liver injury. Saponins from Platycodon grandiflorum (PGSs) ameliorate alcohol-induced hepatotoxicity and enhance human lung carcinoma cell death via AMPK signaling pathway. However, whether PGS could protect from APAP-induced ALI through AMPK activation and its downstream signals is still poorly elucidated. This work investigated the protective effect and the underlying mechanisms of PGS against APAP-induced liver toxicity in mouse. PGS was administered at 15 or 30 mg/kg i.g./day for 1 week before a single injection of APAP (250 mg/kg, i.p.) 1 hr after last treatment of PGS. Serum alanine/aspartate aminotransferases, liver tumor necrosis factor-α and interleukin-1β levels, liver malondialdehyde formation, liver glutathione depletion, cytochrome P450 E1, and 4-hydroxynonenal levels were measured to demonstrate the protective efficacy of PGS against APAP-induced ALI. Liver histological observation provided further evidence on PGS's protective effects. PGS treatment altered the phosphorylation of AMPK and PI3K/Akt, as well as the downstream signals including Bcl-2 family, caspase, and NF-κB in a dose-dependent manner. In conclusion, we demonstrate that PGS exhibits a significant liver protection against APAP-induced ALI, mainly through NF-κB and AMPK/PI3K/Akt signaling pathways., (© 2018 John Wiley & Sons, Ltd.)