Effect of α-asarone on angiogenesis and matrix metalloproteinase

Alpha-Asarone modulates kynurenine disposal in muscle and mediates resilience to stress-induced depression via PGC-1α induction

INTRODUCTION

Kynurenine (KYN) accumulation in periphery induces brain injury, responsible for depression. α-Asarone is a simple phenylpropanoids that exerts beneficial effects on central nervous system. However, the effect of α-asarone on periphery is unexplored.

AIMS

Here, we investigated its protective role against depression from the aspect of KYN metabolism in skeletal muscle.

METHODS

The antidepressant effects of α-asarone were evaluated in chronic mild stress (CMS) and muscle-specific PGC-1α-deficient mice. The effects of KYN metabolism were determined in mice and C2C12 myoblasts.

RESULTS

α-Asarone exerted antidepressant effects in CMS and KYN-challenged mice via modulating KYN metabolism. In myoblasts, α-asarone regulated PGC-1α induction via cAMP/CREB signaling and upregulated KYN aminotransferases (KATs) to increase KYN clearance in a manner dependent on PGC-1α. KAT function is coupled with malate-aspartate shuttle (MAS), while α-asarone combated oxidative stress to protect MAS and mitochondrial integrity by raising the NAD⁺ /NADH ratio, ensuring effective KYN disposal. In support, the antidepressant effect of α-asarone was diminished by muscle-specific PGC-1α deficient mice subjected to KYN challenge.

CONCLUSION

KATs coupled with MAS to clear KYN in muscle. α-Asarone increased PGC-1α induction and promoted KYN disposal in muscle, suggesting that protection of mitochondria is a way for pharmacological intervention to depression.

Acorus calamus: a bio-reserve of medicinal values

Many plants are found to possess reliable pharmacological properties and have started to attract the attention of researchers. One such holistic plant is Acorus calamus, commonly known as sweet flag, belonging to the rhizomatous family Acoraceae. The different parts of this plant, such as the leaves and rhizomes, are used traditionally in different medicinal preparations for the treatment of various ailments including arthritis, neuralgia, diarrhoea, dyspepsia, kidney and liver troubles, eczema, sinusitis, asthma, fevers, bronchitis, hair loss, and other disorders. Many reports have also appeared in mainstream scientific journals confirming its nutritional and medicinal properties. Biochemical analysis of the plant has revealed a large number of secondary metabolites that may be responsible for its rich medicinal properties. Basic scientific research has uncovered the mechanisms by which itexerts its therapeutic effects. Medicinal herbs such as A. calamus are quite promising in the recent therapeutic scenario, with a large number of people favouring remedies and health approaches that are free from the side effects often associated with synthetic chemicals. In this review, we try to summarise the ethno-medicinal uses, botanical descriptions, phytochemical constituents, and biological activity of the plant parts, as well as the molecular targets of A. calamus, which we hope will serve as a good base for further work on this plant.

Oral Administration of α-Asarone Promotes Functional Recovery in Rats With Spinal Cord Injury

α-asarone, a bioactive compound found in Acorus plant species, has been shown to exhibit neuroprotective, anti-oxidative, anti-inflammatory, and cognitive-enhancing effects. However, the effects of α-asarone on spinal cord injury (SCI) have not yet been elucidated. The present study investigated the effects of α-asarone on the mRNA of pro-inflammatory cytokines, macrophage polarization toward an anti-inflammatory M2 phenotype, and angiogenesis in rats with compressive SCI. α-Asarone was orally administered (10 mg/kg) once per day for 14 days following moderate static compression SCI. Compared to controls, α-asarone treatment significantly improved locomotor score, prevented neuroinflammation, and facilitated angiogenesis in the spinal cord at 14 days after SCI. Furthermore, α-asarone significantly reduced the TNF-α, IL-1β, IL-6, monocyte chemoattractant protein 1 (MCP-1), macrophage inflammatory protein 2 (MIP-2), and inducible nitric oxide synthase (iNOS) levels but increased the IL-4, IL-10, and arginase 1 levels at 24 h after SCI. At 7 and 14 days after SCI, immunohistochemistry showed reduced reactive gliosis and neuroinflammation and an increased expression of M2 macrophage markers and angiogenesis. The results suggest that the inhibition of pro-inflammatory cytokines, macrophage polarization toward an anti-inflammatory M2 phenotype, and angiogenesis by α-asarone may be some of the mechanisms underlying the α-asarone-mediated neuroprotective effects on an injured spinal cord.

Pharmacology and toxicology of α- and β-Asarone: A review of preclinical evidence

BACKGROUND

Asarone is one of the most researched phytochemicals and is mainly present in the Acorus species and Guatteria gaumeri Greenman. In preclinical studies, both α- and β-asarone have been reported to have numerous pharmacological activities and at the same time, many studies have also revealed the toxicity of α- and β-asarone.

PURPOSE

The purpose of this comprehensive review is to compile and analyze the information related to the pharmacokinetic, pharmacological, and toxicological studies reported on α- and β-asarone using preclinical in vitro and in vivo models. Besides, the molecular targets and mechanism(s) involved in the biological activities of α- and β-asarone were discussed.

METHODS

Databases including PubMed, ScienceDirect and Google scholar were searched and the literature from the year 1960 to January 2017 was retrieved using keywords such as α-asarone, β-asarone, pharmacokinetics, toxicology, pharmacological activities (e.g. depression, anxiety).

RESULTS

Based on the data obtained from the literature search, the pharmacokinetic studies of α- and β-asarone revealed that their oral bioavailability in rodents is poor with a short plasma half-life. Moreover, the metabolism of α- and β-asarone occurs mainly through cytochrome-P450 pathways. Besides, both α- and/or β-asarone possess a wide range of pharmacological activities such as antidepressant, antianxiety, anti-Alzheimer's, anti-Parkinson's, antiepileptic, anticancer, antihyperlipidemic, antithrombotic, anticholestatic and radioprotective activities through its interaction with multiple molecular targets. Importantly, the toxicological studies revealed that both α- and β-asarone can cause hepatomas and might possess mutagenicity, genotoxicity, and teratogenicity.

CONCLUSIONS

Taken together, further preclinical studies are required to confirm the pharmacological properties of α-asarone against depression, anxiety, Parkinson's disease, psychosis, drug dependence, pain, inflammation, cholestasis and thrombosis. Besides, the anticancer effect of β-asarone should be further studied in different types of cancers using in vivo models. Moreover, further dose-dependent in vivo studies are required to confirm the toxicity of α- and β-asarone. Overall, this extensive review provides a detailed information on the preclinical pharmacological and toxicological activities of α-and β-asarone and this could be very useful for researchers who wish to conduct further preclinical studies using α- and β-asarone.