Catalpol regulates cholinergic nerve system function through effect on choline acetyl-transferase not M receptor affinity

Neuroprotective Iridoids and Lignans from Valeriana amurensis

Valeriana amurensis (V. amurensis) is widely distributed in Northeast China. In addition to medicines, it has also been used to prepare food, wine, tobacco, cosmetics, perfume, and functional foods. Other studies have investigated the neuroprotective effects of V. amurensis extract. As the therapeutic basis, the active constituents should be further evaluated. In this paper, six new compounds (1-6) were isolated, including five iridoids (Xiecaoiridoidside A-E) and one bisepoxylignan (Xiecaolignanside A), as well as six known compounds (7-12). The neuroprotective effects of 1-12 were also investigated with amyloid β protein 1-42 (Aβ1-42)-induced injury to rat pheochromocytoma (PC12) cells. As a result, iridoids 1 and 2 and lignans 6, 8, and 9 could markedly maintain the cells' viability by 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide (MTT) and lactate dehydrogenase (LDH) release assay.

Effects of Catalpol on Alzheimer's Disease and Its Mechanisms

Alzheimer's disease (AD) is a degenerative disease of the central nervous system characterized by memory loss and cognitive dysfunction. With the increasing aging of the population, the incidence of AD and the number of patients are also increasing year by year, causing more and more heavy burdens to the family and society. Catalpol, an iridoid glycoside compound, is one of the main active components of Rehmannia glutinosa. At present, a large number of experimental studies in vivo and in vitro have confirmed that catalpol has antioxidant, anti-inflammatory, antiapoptotic, and other neuroprotective effects, and it plays a significant role in the prevention and treatment of AD, with very small side effects and high safety. Therefore, it may be an ideal drug for the treatment of AD. Based on this, the role and mechanism of catalpol in AD will be comprehensively reviewed in the following.

Critical Review of the Alzheimer's Disease Non-Transgenic Models: Can They Contribute to Disease Treatment?

Alzheimer's disease (AD) is a growing neurodegenerative disease without effective treatments or therapies. Despite the use of different approaches and an extensive variety of genetic amyloid based models, therapeutic strategies remain elusive. AD is characterized by three main pathological hallmarks that include amyloid-β plaques, neurofibrillary tangles, and neuroinflammatory processes; however, many other pathological mechanisms have been described in the literature. Nonetheless, the study of the disease and the screening of potential therapies is heavily weighted toward the study of amyloid-β transgenic models. Non-transgenic models may aid in the study of complex pathological states and provide a suitable complementary alternative to evaluating therapeutic biomedical and intervention strategies. In this review, we evaluate the literature on non-transgenic alternatives, focusing on the use of these models for testing therapeutic strategies, and assess their contribution to understanding AD. This review aims to underscore the need for a shift in preclinical research on intervention strategies for AD from amyloid-based to alternative, complementary non-amyloid approaches.

Determination of behavior of catalpol hexapropionate in simulated gastric conditions by UPLC-ESI-HRMS

Catalpol hexapropionate (CP-6) was designed and synthesized as anti-aging drug. In order to investigate the behavior of CP-6 in simulated gastric juice, ultra-high performance liquid chromatography-electrospray ionization-high resolution mass spectrometry was used to determinate the components produced in simulated gastric conditions. Six metabolites were identified with the possible metabolic processes proposed. Hydrolysis may be the main metabolic pathways. The relative contents of CP-6 and its metabolites were determined using their extractive ion chromatograms. The results show that the relative content of CP-6 is rapidly decreased about 15% during the first 0.5 h and generally stable after 0.5 h. The mainly produced metabolites are catalpol penta-propionate (CP-5), catalpol and a spot of catalpol tetra-propionate (CP-4), catalpol tri-propionate (CP-3), catalpol dipropionate (CP-2) and catalpol propionate (CP-1). The metabolitic process of CP-6 may be an hydrolysis under acid conditions. The research results can provide useful information for development and utilization of CP-6 as a pharmaceutical preparation.

Catalpol in Diabetes and its Complications: A Review of Pharmacology, Pharmacokinetics, and Safety

This review aimed to provide a general view of catalpol in protection against diabetes and diabetic complications, as well as its pharmacokinetics and safety concerns. The following databases were consulted with the retrieval of more than 100 publications through June 2019: PubMed, Chinese National Knowledge Infrastructure, WanFang Data, and web of science. Catalpol exerts an anti-diabetic effect in different animal models with an oral dosage ranging from 2.5 to 200 mg/kg in rats and 10 to 200 mg/kg in mice. Besides, catalpol may prevent the development of diabetic complications in kidney, heart, central nervous system, and bone. The underlying mechanism may be associated with an inhibition of inflammation, oxidative stress, and apoptosis through modulation of various cellular signaling, such as AMPK/PI3K/Akt, PPAR/ACC, JNK/NF-κB, and AGE/RAGE/NOX4 signaling pathways, as well as PKCγ and Cav-1 expression. The pharmacokinetic profile reveals that catalpol could pass the blood-brain barrier and has a potential to be orally administrated. Taken together, catalpol is a well-tolerated natural compound with promising pharmacological actions in protection against diabetes and diabetic complications via multi-targets, offering a novel scaffold for the development of anti-diabetic drug candidate. Further prospective and well-designed clinical trials will shed light on the potential of clinical usage of catalpol.

Iridoids and Other Monoterpenes in the Alzheimer's Brain: Recent Development and Future Prospects

Iridoids are a class of monoterpenoid compounds constructed from 10-carbon skeleton of isoprene building units. These compounds in their aglycones and glycosylated forms exist in nature to contribute to mechanisms related to plant defenses and diverse plant-animal interactions. Recent studies have also shown that iridoids and other structurally related monoterpenes display a vast array of pharmacological effects that make them potential modulators of the Alzheimer’s disease (AD). This review critically evaluates the therapeutic potential of these natural products by assessing key in vitro and in vivo data published in the scientific literature. Mechanistic approach of scrutiny addressing their effects in the Alzheimer’s brain including the τ-protein phosphorylation signaling, amyloid beta (Aβ) formation, aggregation, toxicity and clearance along with various effects from antioxidant to antiinflammatory mechanisms are discussed. The drug likeness of these compounds and future prospects to consider in their development as potential leads are addressed.

Catalpol protects synaptic proteins from beta-amyloid induced neuron injury and improves cognitive functions in aged rats

Synapse loss is one of the common factors contributing to cognitive disorders, such as Alzheimer’s disease (AD), which is manifested by the impairment of basic cognitive functions including memory processing, perception, problem solving, and language. The current therapies for patients with cognitive disorders are mainly palliative; thus, regimens preventing and/or delaying dementia progression are urgently needed. In this study, we evaluated the effects of catalpol, isolated from traditional Chinese medicine Rehmannia glutinosa, on synaptic plasticity in aged rat models. We found that catalpol markedly improved the cognitive function of aged male Sprague-Dawley rats and simultaneously increased the expression of synaptic proteins (dynamin 1, PSD-95, and synaptophysin) in the cerebral cortex and hippocampus, respectively. In beta-amyloid (Aβ) injured primary rat’s cortical neuron, catalpol did not increase the viability of neuron but extended the length of microtubule-associated protein 2 (MAP-2) positive neurites and reversed the suppressive effects on expression of synaptic proteins induced by Aβ. Additionally, the effects of catalpol on stimulating the growth of MAP-2 positive neurites and the expression of synaptic proteins were diminished by a PKC inhibitor, bisindolylmaleimide I, suggesting that PKC may be implicated in catalpol’s function of preventing the neurodegeneration induced by Aβ. Altogether, our study indicates that catalpol could be a potential disease-modifying drug for cognitive disorders such as AD.