A review on the ethnobotany, phytochemistry, pharmacology and toxicology of butterbur species (Petasites L.)

ETHNOPHARMACOLOGICAL RELEVANCE

Petasites (butterbur, Asteraceae) species have been used since Ancient times in the traditional medicine of Asian and European countries to treat central nervous system (migraine), respiratory (asthma, allergic rhinitis, bronchitis, spastic cough), cardiovascular (hypertension), gastrointestinal (ulcers) and genitourinary (dysmenorrhea) disorders.

AIM OF THE REVIEW

This study summarized and discussed the traditional uses, phytochemical, pharmacological and toxicological aspects of Petasites genus.

MATERIALS AND METHODS

A systematic search of Petasites in online databases (Scopus, PubMed, ScienceDirect, Google Scholar) was performed, with the aim to find the phytochemical, toxicological and bioactivity studies. The Global Biodiversity Information Facility, Plants of the World Online, World Flora Online and The Plant List databases were used to describe the taxonomy and geographical distribution.

RESULTS

The detailed phytochemistry of the potentially active compounds of Petasites genus (e.g. sesquiterpenes, pyrrolizidine alkaloids, polyphenols and essential oils components) was presented. The bioactivity studies (cell-free, cell-based, animal, and clinical) including the traditional uses of Petasites (e.g. anti-spasmolytic, hypotensive, anti-asthmatic activities) were addressed and followed by discussion of the main pharmacokinetical and toxicological issues related to the administration of butterbur-based formulations.

CONCLUSIONS

This review provides a complete overview of the Petasites geographical distribution, traditional use, phytochemistry, bioactivity, and toxicity. More than 200 different sesquiterpenes (eremophilanes, furanoeremophilanes, bakkenolides), 50 phenolic compounds (phenolic acids, flavonoids, lignans) and volatile compounds (monoterpenes, sesquiterpenes) have been reported within the genus. Considering the phytochemical complexity and the polypharmacological potential, there is a growing research interest to extend the current therapeutical applications of Petasites preparations (anti-migraine, anti-allergic) to other human ailments, such as central nervous system, cardiovascular, malignant or microbial diseases. This research pathway is extremely important, especially in the recent context of the pandemic situation, when there is an imperious need for novel drug candidates.

Antioxidant compounds of Petasites japonicus and their preventive effects in chronic diseases: a review

Petasites japonicus (P. japonicus) is a plant of the Asteraceae family. Its roots and stems have been used for the treatment or the prophylaxis of migraine and tension headache as a traditional Chinese medicine in Japan and Korea. Sesquiterpenoids, lignans, and flavonoids are components of P. japonicus. Regarding the biological activity of P. japonicus, its anti-allergic effect has been researched extensively using IgE antigen-stimulated degranulation of RBL-2H3 cells or passive cutaneous anaphylaxis reaction in experimental animal models. The study of the antioxidant activity of P. japonicus was initiated approximately 15 years ago using in vitro assays. In addition, its in vivo effect has also been examined in animal models with induced oxidative injury. Moreover, recently, many types of antioxidant compounds have been rapidly and simultaneously identified using the liquid chromatography–mass spectrometry technique. The number of reports on the other functions of this plant, such as its neuroprotective and anti-inflammatory effects, has been increasing. In this review, I summarized the studies of functional foods derived from P. japonicus, which may provide a basis for the development of potential functional foods. Finally, I discuss the future research avenues in this field.

Kaempferol attenuates the glutamate-induced oxidative stress in mouse-derived hippocampal neuronal HT22 cells

It is thought that the neuronal cell loss caused by oxidative stress is the primary mechanism underlying the pathogenesis of several neurodegenerative disorders. Glutamate is an endogenous neurotransmitter, but at high concentrations it can act as a neurotoxicant by increasing the intracellular levels of reactive oxygen species (ROS). Therefore, the development of factors that can attenuate glutamate-induced oxidative stress in neuronal cells is a good strategy by which new drugs could be discovered that may treat or prevent neurodegenerative diseases. Here, the neuroprotective effects of kaempferol (KF) isolated from the stems of butterbur (Petasites japonicus) were examined in glutamate-treated hippocampal neuronal cells (HT22). The administration of KF (25 μM) resulted in a significant increase in cell viability (105.18 ± 7.48%) compared with the control (100.00 ± 3.05%), while glutamate (5 mM) reduced cell viability by 39.94 ± 1.61%. The glutamate-induced calcium (Ca(2+)) influx (1.93 ± 0.08-fold) was significantly reduced by 0.89 ± 0.02-fold following the administration of 25 μM KF. Additionally, when HT22 cells were stressed with excessive glutamate, there was a 3.70 ± 0.01-fold increase in intracellular ROS generation, even though this was effectively attenuated by KF (25 μM, 0.72 ± 0.01-fold). The protective effects of KF in HT22 cells were later confirmed using a lactate dehydrogenase (LDH) assay and a FITC-annexin V/propidium iodide double staining procedure. These findings also revealed that the neuroprotective effects of KF are a result of the regulation of the expression levels of proteins, such as Bcl-2, Bid, apoptosis-inducing factor (AIF), and mitogen-activated protein kinase (MAPK). This is the first report to investigate the neuroprotective influence of KF in glutamate-treated HT22 cells. These data demonstrate that KF may be a useful candidate for pharmacological therapies that can prevent and treat neurodegenerative diseases such as Alzheimer's disease (AD).