Using Porcine Jejunum Ex Vivo to Study Absorption and Biotransformation of Natural Products in Plant Extracts: Pueraria lobata as a Case Study

Bei Mu Gua Lou San facilitates mucus expectoration by increasing surface area and hydration levels of airway mucus in an air-liquid-interface cell culture model of the respiratory epithelium

BACKGROUND

Bei Mu Gua Lou San (BMGLS) is an ancient formulation known for its moisturizing and expectorant properties, but the underlying mechanisms remain unknown. We investigated concentration-dependent effects of BMGLS on its rehydrating and mucus-modulating properties using an air-liquid-interface (ALI) cell culture model of the Calu-3 human bronchial epithelial cell line and primary normal human bronchial epithelial cells (NHBE), and specifically focused on quantity and composition of the two major mucosal proteins MUC5AC and MUC5B.

METHODS

ALI cultures were treated with BMGLS at different concentrations over three weeks and evaluated by means of histology, immunostaining and electron microscopy. MUC5AC and MUC5B mRNA levels were assessed and quantified on protein level using an automated image-based approach. Additionally, expression levels of the major mucus-stimulating enzyme 15-lipoxygenase (ALOX15) were evaluated.

RESULTS

BMGLS induced concentration-dependent morphological changes in NHBE but not Calu-3 ALI cultures that resulted in increased surface area via the formation of herein termed intra-epithelial structures (IES). While cellular rates of proliferation, apoptosis or degeneration remained unaffected, BMGLS caused swelling of mucosal granules, increased the area of secreted mucus, decreased muco-glycoprotein density, and dispensed MUC5AC. Additionally, BMGLS reduced expression levels of MUC5AC, MUC5B and the mucus-stimulating enzyme 15-lipoxygenase (ALOX15).

CONCLUSIONS

Our studies suggest that BMGLS rehydrates airway mucus while stimulating mucus secretion by increasing surface areas and regulating goblet cell differentiation through modulating major mucus-stimulating pathways.

Puerarin: a potential natural neuroprotective agent for neurological disorders

Puerarin is an isoflavone compound derived from Pueraria lobata in traditional Chinese medicine. Accumulating evidence has indicated that puerarin demonstrates multiple pharmacological effects and exhibits treatment potential for various neurological disorders. Based on the latest research progress on puerarin as a neuroprotective agent, its pharmacological activity, molecular mechanism, and therapeutic application were systematically reviewed with emphasis on pre-clinical studies. The related information was extracted and compiled from major scientific databases, including PubMed, ScienceDirect, SpringerLink, and Chinese National Knowledge Infrastructure, using 'Puerarin', 'Neuroprotection', 'Apoptosis', 'Autophagy', 'Antioxidant', 'Mitochondria', 'Anti-inflammation' as keywords. This review complied with The Preferred Reporting Items for Systematic Reviews criteria. Forty-three articles met established inclusion and exclusion criteria. Puerarin has shown neuroprotective effects against a variety of neurological disorders, including ischemic cerebrovascular disease, subarachnoid hemorrhage, epilepsy, cognitive disorders, traumatic brain injury, Parkinson's disease, Alzheimer's disease, anxiety, depression, diabetic neuropathy, and neuroblastoma/glioblastoma. Puerarin demonstrates anti-apoptosis, proinflammatory mediator inhibitory, autophagy regulatory, anti-oxidative stress, mitochondria protection, Ca²⁺ influx inhibitory, and anti-neurodegenerative activities. Puerarin exerts noticeable neuroprotective effects on various models of neurological disorders in vivo (animal). This review will contribute to the development of puerarin as a novel clinical drug candidate for the treatment of neurological disorders. However, well-designed, high-quality, large-scale, multicenter randomized clinical studies are needed to determine the safety and clinical utility of puerarin in patients with neurological disorders.

Future Directions for the Discovery of Natural Product-Derived Immunomodulating Drugs

Drug discovery from natural sources is going through a renaissance, having spent many decades in the shadow of synthetic molecule drug discovery, despite the fact that natural product-derived compounds occupy a much greater chemical space than those created through synthetic chemistry methods. With this new era comes new possibilities, not least the novel targets that have emerged in recent times and the development of state-of-the-art technologies that can be applied to drug discovery from natural sources. Although progress has been made with some immunomodulating drugs, there remains a pressing need for new agents that can be used to treat the wide variety of conditions that arise from disruption, or over-activation, of the immune system; natural products may therefore be key in filling this gap. Recognising that, at present, there is no authoritative article that details the current state-of-the-art of the immunomodulatory activity of natural products, this in-depth review has arisen from a joint effort between the International Union of Basic and Clinical Pharmacology (IUPHAR) Natural Products and Immunopharmacology, with contributions from a Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation number of world-leading researchers in the field of natural product drug discovery, to provide a "position statement" on what natural products has to offer in the search for new immunomodulatory argents. To this end, we provide a historical look at previous discoveries of naturally occurring immunomodulators, present a picture of the current status of the field and provide insight into the future opportunities and challenges for the discovery of new drugs to treat immune-related diseases.