Madecassic Acid Reduces Fast Transient Potassium Channels and Promotes Neurite Elongation in Hippocampal CA1 Neurons

Self-Nanoemulsifying Drug Delivery System for Enhanced Bioavailability of Madecassic Acid: In vitro and in vivo Evaluation

Purpose

Madecassic acid (MCA) is a natural triterpenoid isolated from centellae herba that has diverse biological effects, such as anti-inflammatory, antioxidant, and anticancer activities. However, the efficacy of MCA is limited by low oral bioavailability caused by its extremely poor aqueous solubility. This study aimed to develop a self-nanoemulsifying drug delivery system (SNEDDS) for MCA to improve its oral absorption.

Methods

The utilized oil phases, surfactants, and co-surfactants for SNEDDS were selected based on the solubility of MCA and emulsification efficiency. The optimized formulation was characterized for pharmaceutical properties and its pharmacokinetic behavior was examined in rats. Besides, the intestinal absorption property of MCA was investigated using in situ single-pass intestinal perfusion and intestinal lymphatic transport.

Results

The optimized nanoemulsion formula consists of Capryol 90:Labrasol:Kolliphor ELP:Transcutol HP in a weight ratio of 1:2.7:2.7:3.6 (w/w/w/w). MCA-loaded SNEDDS presented a small droplet size (21.52 ± 0.23 nm), with a zeta potential value of -3.05 ± 0.3 mV. Compared with pure MCA, SNEDDS had a higher effective permeability coefficient and showed 8.47-fold and 4.01-fold of maximum plasma concentration (C_max) and area under the plasma concentration-time curve (AUC), respectively. Cycloheximide was pretreated before the experiment to evaluate the degree of lymphatic uptake. The results showed that cycloheximide greatly influenced the absorption of SNEDDS, resulting in 82.26% and 76.98% reduction in C_max and AUC, respectively.

Conclusion

This study reports the MCA-loaded SNEDDS with distinctly enhanced in vitro and in vivo performance compared with pure MCA and concludes that the SNEDDS formulation could be a viable and effective strategy for improving the dissolution rate and bioavailability of poor aqueous-soluble ingredients.

Madecassic Acid Ameliorates the Progression of Osteoarthritis: An in vitro and in vivo Study

PURPOSE

Osteoarthritis (OA) places a significant burden on society and finance, and there is presently no effective treatment besides late replacement surgery and symptomatic relief. The therapy of OA requires additional research. Madecassic acid (MA) is the first native triterpenoid compound extracted from Centella asiatica, which has a variety of anti-inflammatory effects. However, the role of MA in OA therapy has not been reported. This study aimed to explore whether MA could suppress the inflammatory response, preserve and restore chondrocyte functions, and ameliorate the progression of OA in vitro and in vivo.

METHODS

Rat primary chondrocytes were treated with IL-1β to simulate inflammatory environmental conditions and OA in vitro. We examined the effects of MA at concentrations ranging from 0 to 200 µM on the viability of rat chondrocytes and selected 10 µM for further study. Using qRT-PCR, immunofluorescent, immunocytochemistry, and Western blotting techniques, we identified the potential molecular mechanisms and signaling pathways that are responsible for these effects. We established an OA rat model by anterior cruciate ligament transection (ACLT). The animals were then periodically injected with MA into the knee articular cavity.

RESULTS

We found that MA could down-regulate the IL-1β-induced up-regulation of COX-2, iNOS and IL-6 and restore the cytoskeletal integrity of chondrocytes treated with IL-1β. Moreover, MA protects chondrocytes from IL-1β-induced ECM degradation by upregulating ECM synthesis related protein expression, including collagen-II and ACAN, and further down-regulating ECM catabolic related protein expression, including MMP-3 and MMP-13. Furthermore, we found that NF-κB/IκBα and PI3K/AKT signaling pathways were involved in the regulatory effects of MA on the inflammation inhibition and promotion of ECM anabolism on IL-1β-induced chondrocytes.

CONCLUSION

These findings suggest that MA appears to be a potentially small molecular drug for rat OA.

Centella asiatica (L.) Urb. attenuates cardiac hypertrophy and improves heart function through multi-level mechanisms revealed by systems pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

Cardiac hypertrophy (CH) is an incurable heart disease, contributing to an increased risk of heart failure due to the lack of safe and effective strategies. Therefore, searching for new approaches to treat CH is urgent. Centella asiatica (L.) Urb. (CA), a traditional food and medicinal natural plant, has been turned out to be effective in the treatment of cardiovascular disease, but its efficacy and potential mechanisms in alleviating CH have not yet been investigated.

AIM OF STUDY

In this study, we aimed to elucidate the multi-level mechanisms underlying the effect of CA against CH.

STUDY DESIGN AND METHODS

A systems pharmacology approach was employed to screen active ingredients, identify potential targets, construct visual networks and systematically investigate the pathways and mechanisms of CA for CH treatment. The cardiac therapeutic potential and mechanism of action of CA on CH were verified with in vivo and in vitro experiments.

RESULTS

Firstly, we demonstrated the therapeutic effect of CA on CH and then screened 13 active compounds of CA according to the pharmacokinetic properties. Then, asiatic acid (AA) was identified as the major active molecule of CA for CH treatment. Afterwards, network and functional enrichment analyses showed that CA exerted cardioprotective effects by modulating multiple pathways mainly involved in anti-apoptotic, antioxidant and anti-inflammatory processes. Finally, in vivo, the therapeutic effects of AA and its action on the YAP/PI3K/AKT axis and NF-κB signaling pathway were validated using an isoproterenol-induced CH mouse model. In vitro, AA decreased ROS levels in hydrogen peroxide-treated HL-1 cells.

CONCLUSION

Overall, the multi-level mechanisms of CA for CH treatment were demonstrated by systems pharmacology approach, which provides a paradigm for systematically deciphering the mechanisms of action of natural plants in the treatment of diseases and offers a new idea for the development of medicinal and food products.

Identification of TrkB Binders from Complex Matrices Using a Magnetic Drug Screening Nanoplatform

Brain-derived neurotrophic factor (BDNF) and its receptor tyrosine receptor kinase B (TrkB) have been shown to play an important role in numerous neurological disorders, such as Alzheimer's disease. The identification of biologically active compounds interacting with TrkB serves as a drug discovery strategy to identify drug leads for neurological disorders. Here, we report effective immobilization of functional TrkB on magnetic iron oxide nanoclusters, where TrkB receptors behave as "smart baits" to bind compounds from mixtures and magnetic nanoclusters enable rapid isolation through magnetic separation. The presence of the immobilized TrkB was confirmed by specific antibody labeling. Subsequently, the activity of the TrkB on iron oxide nanoclusters was evaluated with ATP/ADP conversion experiments using a known TrkB agonist. The immobilized TrkB receptors can effectively identify binders from mixtures containing known binders, synthetic small molecule mixtures, and Gotu Kola (Centella asiatica) plant extracts. The identified compounds were analyzed by an ultrahigh-performance liquid chromatography system coupled with a quadrupole time-of-flight mass spectrometer. Importantly, some of the identified TrkB binders from Gotu Kola plant extracts matched with compounds previously linked to neuroprotective effects observed for a Gotu Kola extract approved for use in a clinical trial. Our studies suggest that the possible therapeutic effects of the Gotu Kola plant extract in dementia treatment, at least partially, might be associated with compounds interacting with TrkB. The unique feature of this approach is its ability to fast screen potential drug leads using less explored transmembrane targets. This platform works as a drug-screening funnel at early stages of the drug discovery pipeline. Therefore, our approach will not only greatly benefit drug discovery processes using transmembrane proteins as targets but also allow for evaluation and validation of cellular pathways targeted by drug leads.

Centella asiatica L. Phytosome Improves Cognitive Performance by Promoting Bdnf Expression in Rat Prefrontal Cortex

A wide range of people in the world use natural remedies as primary approaches against illnesses. Accordingly, understanding the mechanisms of action of phytochemicals has become of great interest. In this context, Centella asiatica L. is extensively used, not only as anti-inflammatory or antioxidant agent but also as brain tonic. On this basis, the purpose of this study was to evaluate whether the chronic administration of C. asiatica L. to adult male rats was able to improve the expression of Bdnf, one of the main mediators of brain plasticity. Moreover, we assessed whether the treatment could affect the cognitive performance in the novel object recognition (NOR) test. We confirmed the presence of the main compounds in the plasma. Furthermore, C. asiatica L. administration induced an increase of Bdnf in the prefrontal cortex, and the administration of the higher dose of the extract was able to improve cognitive performance. Finally, the increase in the preference index in the NOR test was paralleled by a further increase in Bdnf expression. Overall, we highlight the ability of C. asiatica L. to affect brain functions by increasing Bdnf expression and by enhancing the cognitive performance.