Anti-allergic and anti-inflammatory effects of bakkenolide B isolated from Petasites japonicus leaves

Valeriana jatamansi: Bioactive Compounds and their Medicinal Uses

Valeriana jatamansi is a reputed perennial medicinal herb distributed throughout the world, where it is used in cytotoxicity, neuronal problems, insomnia, leishmania and acetylcholinesterase inhibitor, antioxidant, antiviral and α-glucosidase inhibition activities. This review describes the current state of chemical characterization of isolated metabolites, which are well accepted for the treatment of various ailments in the indigenous system of medicine. This comprehensive review covers previously published research articles and reviews up to 2023 with an emphasis on the structural characterization of isolated bioactive compounds using different analytical techniques. Furthermore, the present review also focuses on the detailed medicinal and pharmacological properties of isolated compounds from this threatened herb.

Phytochemicals as treatment for allergic asthma: Therapeutic effects and mechanisms of action

BACKGROUND

Allergic asthma is an inflammatory disease caused by the immune system's reaction to allergens, inflammation and narrowing of the airways, and the production of more than normal mucus. One of the main reasons is an increased production of inflammatory cytokines in the lungs that leads to the appearance of symptoms of asthma, including inflammation and shortness of breath. On the other hand, it has been proven that phytochemicals with their antioxidant and anti-inflammatory properties can be useful in improving allergic asthma.

PURPOSE

Common chemical treatments for allergic asthma include corticosteroids, which have many side effects and temporarily relieve symptoms but are not a cure. Therefore, taking the help of natural compounds to improve the quality of life of asthmatic patients can be a valuable issue that has been evaluated in the present review.

STUDY DESIGN AND METHODS

In this study, three databases (Scopus, PubMed, and Cochrane) with the keywords: allergic asthma, phytochemical, plant, and herb were evaluated. The primary result was 5307 articles. Non-English, repetitive, and review articles were deleted from the study.

RESULTS AND DISCUSSION

Finally, after carefully reading the articles, 102 were included in the study (2006-2022). The results of this review state that phytochemicals suppress the inflammatory pathways via inhibition of inflammatory cytokines production/secretion, genes, and proteins involved in the inflammation process, reducing oxidative stress indicators and symptoms of allergic asthma, such as cough and mucus production in the lungs.

CONCLUSION

With their antioxidant effects, this study concluded that phytochemicals suppress cytokines and other inflammatory indicators and thus can be considered an adjunctive treatment for improving allergic asthma.

Inflammatory signaling pathways in the treatment of Alzheimer's disease with inhibitors, natural products and metabolites (Review)

The intricate nature of Alzheimer's disease (AD) pathogenesis poses a persistent obstacle to drug development. In recent times, neuroinflammation has emerged as a crucial pathogenic mechanism of AD, and the targeting of inflammation has become a viable approach for the prevention and management of AD. The present study conducted a comprehensive review of the literature between October 2012 and October 2022, identifying a total of 96 references, encompassing 91 distinct pharmaceuticals that have been investigated for their potential impact on AD by inhibiting neuroinflammation. Research has shown that pharmaceuticals have the potential to ameliorate AD by reducing neuroinflammation mainly through regulating inflammatory signaling pathways such as NF‑κB, MAPK, NLRP3, PPARs, STAT3, CREB, PI3K/Akt, Nrf2 and their respective signaling pathways. Among them, tanshinone IIA has been extensively studied for its anti‑inflammatory effects, which have shown significant pharmacological properties and can be applied clinically. Thus, it may hold promise as an effective drug for the treatment of AD. The present review elucidated the inflammatory signaling pathways of pharmaceuticals that have been investigated for their therapeutic efficacy in AD and elucidates their underlying mechanisms. This underscores the auspicious potential of pharmaceuticals in ameliorating AD by impeding neuroinflammation.

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.

Petasites for Migraine Prevention: New Data on Mode of Action, Pharmacology and Safety. A Narrative Review

Petasins are the pharmacologically active ingredients of butterbur and of therapeutic benefit in the treatment of migraine and tension headaches. Here, we summarize the pharmacology, safety and clinical efficacy of butterbur in the prevention of migraine attacks and present new data on its mode of action. We review published literature and study reports on the safety and clinical efficacy of the butterbur root extract Petadolex® and report new findings on petasins in dampening nociception by desensitizing calcium-conducting TRP ion channels of primary sensory neurons. Importantly, butterbur diminishes the production of inflammatory mediators by inhibiting activities of cyclooxygenases, lipoxygenases and phospholipase A2 and desensitizes nociception by acting on TRPA1 and TRPPV1 ion channels. It inhibits the release of calcitonin-gene related peptide (CGRP) of meningeal afferents during migraine attacks. We also evaluated the safety of a butterbur root extract in repeated dose studies for up to 6 months. A no-observable-adverse-effect-level at 15-fold of the maximal clinical dose (3 mg/kg/day MCD) was established for rats. At supratherapeutic doses, i.e., 45–90-fold MCD, we observed bile duct hyperplasia, and mechanistic studies revealed regulations of solute carriers to likely account for bile duct proliferations. Additionally, liver function tests were performed in cultures of primary human hepatocytes and did not evidence hepatotoxicity at therapeutic butterbur level and with migraine co-medications. Lastly, in randomized, double-blinded and placebo-controlled trials with Petadolex® migraine attack frequency was reduced significantly at 150 mg/day, and no relevant abnormal liver function was reported. Together, butterbur is effective in the prevention of migraine attacks by blocking CGRP signaling.

The Complexity of Sesquiterpene Chemistry Dictates Its Pleiotropic Biologic Effects on Inflammation

Sesquiterpenes (SQs) are volatile compounds made by plants, insects, and marine organisms. SQ have a large range of biological properties and are potent inhibitors and modulators of inflammation, targeting specific components of the nuclear factor-kappaB (NF-κB) signaling pathway and nitric oxide (NO) generation. Because SQs can be isolated from over 1600 genera and 2500 species grown worldwide, they are an attractive source of phytochemical therapeutics. The chemical structure and biosynthesis of SQs is complex, and the SQ scaffold represents extraordinary structural variety consisting of both acyclic and cyclic (mono, bi, tri, and tetracyclic) compounds. These structures can be decorated with a diverse range of functional groups and substituents, generating many stereospecific configurations. In this review, the effect of SQs on inflammation will be discussed in the context of their complex chemistry. Because inflammation is a multifactorial process, we focus on specific aspects of inflammation: the inhibition of NF-kB signaling, disruption of NO production and modulation of dendritic cells, mast cells, and monocytes. Although the molecular targets of SQs are varied, we discuss how these pathways may mediate the effects of SQs on inflammation.

Aqueous extract of Petasites japonicus leaves promotes osteoblast differentiation via up-regulation of Runx2 and Osterix in MC3T3-E1 cells

BACKGROUND/OBJECTIVES

Petasites japonicus Maxim (P. japonicus) has been used as an edible and medicinal plant and contains many bioactive compounds. The purpose of this study is to investigate the effect of P. japonicus on osteogenesis.

MATERIALS/METHODS

The leaves and stems of P. japonicus were separated and extracted with hot water or ethanol, respectively. The total phenolic compound and total polyphenol contents of each extract were measured, and alkaline phosphatase (ALP) activity of each extract was evaluated to determine their effect on bone metabolism. To investigate the effect on osteoblast differentiation of the aqueous extract of P. japonicus leaves (AL), which produced the highest ALP activity among the tested extracts, collagen content was measured using the Sirius Red staining method, mineralization using the Alizarin Red S staining method, and osteocalcin production through enzyme-linked immunosorbent assay analysis. Also, real-time reverse transcription polymerase chain reaction was performed to investigate the mRNA expression levels of Runt-related transcriptional factor 2 (Runx2) and Osterix.

RESULTS

Among the 4 P. japonicus extracts, AL had the highest values in all of the following measures: total phenolic compounds, total polyphenols, and ALP activity, which is a major biomarker of osteoblast differentiation. The AL-treated MC3T3-E1 cells showed significant increases in induced osteoblast differentiation, collagen synthesis, mineralization, and osteocalcin production. In addition, mRNA expressions of Runx2 and Osterix, transcription factors that regulate osteoblast differentiation, were significantly increased.

CONCLUSIONS

These results suggest that AL can regulate osteoblasts differentiation, at least in part through Runx2 and Osterix. Therefore, it is highly likely that P. japonicus will be useful as an alternate therapeutic for the prevention and treatment of osteoporosis.

A yeast-based screening system identified bakkenolide B contained in Petasites japonicus as an inhibitor of interleukin-2 production in a human T cell line

Ca2+ signaling is related to various diseases such as allergies, diabetes, and cancer. We explored Ca2+ signaling inhibitors in natural resources using a yeast-based screening method and found bakkenolide B from the flower buds of edible wild plant, Petasites japonicus, using the YNS17 strain (zds1Δ erg3Δ pdr1/3Δ). Bakkenolide B exhibited growth-restoring activity against the YNS17 strain and induced Li+ sensitivity of wild-type yeast cells, suggesting that it inhibits the calcineurin pathway. Additionally, bakkenolide B inhibited interleukin-2 production at gene and protein levels in Jurkat cells, a human T cell line, but not the in vitro phosphatase activity of human recombinant calcineurin, an upstream regulator of interleukin-2 production. Furthermore, bakkenolide A showed weak activity in YNS17 and Jurkat cells compared with bakkenolide B. These findings revealed new biological effects and the structure-activity relationships of bakkenolides contained in P. japonicus as inhibitors of interleukin-2 production in human T cells.

Single and Repeated Oral Dose Toxicity and Genotoxicity of the Leaves of Butterbur

Butterbur (Petasites japonicus (Siebold & Zucc.) Maxim) leaves are available to consumers in the marketplace, but there is no guarantee that they are safe for human consumption. Previously, we demonstrated that hot water extracts of P. japonicus leaves (KP-1) had anti-inflammatory properties and attenuated memory impairment. However, data regarding KP-1 toxicity are lacking. This study assessed the safety of KP-1 by examining oral and genotoxic effects using in vivo and in vitro tests, respectively. In a single oral dose toxicity and two-week repeated oral dose toxicity study, we observed no toxicologically significant clinical signs or changes in hematology, blood chemistry, and organ weights at any dose during the experiment. Following a thirteen-week repeated oral dose, toxicity, hyperkeratosis, and squamous cell hyperplasia of the limiting ridge in the stomach were observed. The no observable adverse effect level (NOAEL) was found to be 1250 mg/kg/day in male and female rats. However, hyperkeratosis and hyperplasia were not considered to be of toxicological significance when extrapolating the NOAEL to humans because the limiting ridge in the stomach is species-specific to rats. Therefore, in our study, the NOAEL was considered to be 5000 mg/kg/day when the changes in the stomach’s limiting ridge were discounted. Moreover, in vitro bacterial reverse mutations and chromosomal aberrations in Chinese hamster lung (CHL) cells and the in vivo micronucleus in Institute of cancer research (ICR) mice assays showed that KP-1 possessed no mutagenicity. Although additional research is required, these toxicological evaluations suggest that KP-1 could be safe for human consumption.

O-1602 Promotes Hepatic Steatosis through GPR55 and PI3 Kinase/Akt/SREBP-1c Signaling in Mice

Non-alcoholic fatty liver disease is recognized as the leading cause of chronic liver disease. Overnutrition and obesity are associated with hepatic steatosis. G protein-coupled receptor 55 (GPR55) has not been extensively studied in hepatic steatosis, although its endogenous ligands have been implicated in liver disease progression. Therefore, the functions of GPR55 were investigated in Hep3B human hepatoma cells and mice fed high-fat diets. O-1602, the most potent agonist of GPR55, induced lipid accumulation in hepatocytes, which was reversed by treatment with CID16020046, an antagonist of GPR55. O-1602 also induced intracellular calcium rise in Hep3B cells in a GPR55-independent manner. O-1602-induced lipid accumulation was dependent on the PI3 kinase/Akt/SREBP-1c signaling cascade. Furthermore, we found increased levels of lysophosphatidylinositol species of 16:0, 18:0, 18:1, 18:2, 20:1, and 20:2 in the livers of mice fed a high-fat diet for 4 weeks. One-week treatment with CID16020046 suppressed high-fat diet-induced lipid accumulation and O-1602-induced increase of serum triglyceride levels in vivo. Therefore, the present data suggest the pro-steatotic function of GPR55 signaling in hepatocytes and provide a potential therapeutic target for non-alcoholic fatty liver disease.

S-petasin induces apoptosis and inhibits cell migration through activation of p53 pathway signaling in melanoma B16F10 cells and A375 cells

Melanoma is a dangerous type of skin cancer that develops from the melanocytes. Activation of p53 in melanoma cells has been validated as a strategy for melanoma therapy. S-Petasin, a dietary sesquiterpene isolated from Petasites japonicus, has been shown to possess multiple biological effects. However, no studies have reported that s-petasin exerted anti-melanoma or inhibited activity in melanoma cells. We investigated the effect of s-petasin in B16F10 cells and A375 cells and the underlying molecular mechanism. S-Petasin exerted a significant anti-proliferation effect on B16F10 cells and A375 cells as measured by the MTT assay and crystal violet staining assay. S-Petasin induced cell apoptosis in B16F10 cells and A375 cells as evidenced by flow cytometry assay and western blot assay. Wound healing assay and transwell cell migration and invasion assay revealed that s-petasin suppressed B16F10 cells and A375 cells migration in vitro. For mechanism study, western blot assay indicated that s-petasin activated the p53 pathway signaling. Furthermore, expression of Bcl-2, Bcl-_XL, Bax, MMP-2, MMP-9, p21, CDK4 and cyclin D₁ were regulated by s-petasin. Taken together, our data suggest that s-petasin is a novel compound which can induce apoptosis and inhibit cell migration through activation of the p53 pathway signaling in melanoma B16F10 cells and A375 cells.

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.

Bakkenolides and Caffeoylquinic Acids from the Aerial Portion of Petasites japonicus and Their Bacterial Neuraminidase Inhibition Ability

Petasites japonicus have been used since a long time in folk medicine to treat diseases including plague, pestilential fever, allergy, and inflammation in East Asia and European countries. Bioactive compounds that may prevent and treat infectious diseases are identified based on their ability to inhibit bacterial neuraminidase (NA). We aimed to isolate and identify bioactive compounds from leaves and stems of P. japonicas (PJA) and elucidate their mechanisms of NA inhibition. Key bioactive compounds of PJA responsible for NA inhibition were isolated using column chromatography, their chemical structures revealed using ¹ H NMR, ¹³ C NMR, DEPT, and HMBC, and identified to be bakkenolide B (1), bakkenolide D (2), 1,5-di-O-caffeoylquinic acid (3), and 5-O-caffeoylquinic acid (4). Of these, 3 exhibited the most potent NA inhibitory activity (IC₅₀ = 2.3 ± 0.4 μM). Enzyme kinetic studies revealed that 3 and 4 were competitive inhibitors, whereas 2 exhibited non-competitive inhibition. Furthermore, a molecular docking simulation revealed the binding affinity of these compounds to NA and their mechanism of inhibition. Negative-binding energies indicated high proximity of these compounds to the active site and allosteric sites of NA. Therefore, PJA has the potential to be further developed as an antibacterial agent for use against diseases associated with NA.

Anti-Obesity Effects of Petasites japonicus (Meowi) Ethanol Extract on RAW 264.7 Macrophages and 3T3-L1 Adipocytes and Its Characterization of Polyphenolic Compounds

Koreans have been consuming Petasites Japonicus (PJ) as food. Although the therapeutic effect of PJ on allergic or inflammatory reactions associated with asthma has been proven, its effect on obesity is unclear. Therefore, the present study was aimed to assess the obesity related anti-inflammatory and anti-adipogenic effects of ethanol extract PJ (EPJ) on the inflammatory response in RAW 264.7 macrophages and on differentiation in 3T3-L1 adipocytes. In addition, the polyphenolic compound was quantitatively characterized from the EPJ using ultra performance liquid chromatography coupled with diode array detector, quadrupole time-of-flight-mass spectrometry (UPLC-DAD-QToF-MS). In RAW 264.7 or 3T3-L1, reduction of nitric oxide (in macrophages) production as well as monocyte chemoattractant protein-1 and tumor necrosis factor-α were observed. Treatment of EPJ in adipocyte differentiation showed an improvement in adiponectin and lipid accumulation and a significant reduction of PPARγ and FABP-4 mRNA expression levels. On the other hand, mRNA expression of UCP-1, PPARα, and ACO increased in the EPJ treated group. In addition, a total of 26 polyphenolic compounds were detected and of which 12 are reported for the first time from PJ. The higher content of diverse polyphenolic compounds presented in EPJ might be responsible for the observed anti-inflammatory and anti-adipogenic effect. These results suggest that PJ is valuable in improving obesity-related inflammatory responses.

S-petasin inhibits lipid accumulation in oleic acid-induced HepG2 cells through activation of the AMPK signaling pathway

S-petasin inhibits lipid accumulation in oleic acid-induced HepG2 cells.

Blockage of sphingosine-1-phosphate receptor 2 attenuates allergic asthma in mice

BACKGROUND AND PURPOSE

Sphingosine-1-phosphate 2 (S1P₂ ) receptors have been implicated in degranulation of mast cells. However, functions of S1P₂ receptors have not been investigated in an in vivo model of allergic asthma.

EXPERIMENTAL APPROACH

Using an ovalbumin (OVA)-induced asthma model, the function of S1P₂ receptors was evaluated in S1P₂ -deficient mice or in mice treated with JTE-013, a selective S1P₂ antagonist. Bone marrow-derived dendritic cells (BMDCs) were used to investigate the roles of S1P₂ receptors in dendritic cell maturation and migration.

KEY RESULTS

Eosinophil accumulation and elevated Th2 cytokine levels in bronchoalveolar lavage fluid and inflamed lung tissues were strongly inhibited by administration of JTE-013 before OVA sensitization, before OVA challenge, and before both events. In S1P₂ -deficient mice, allergic responses were significantly lower than in wild-type mice. LPS- and OVA-induced maturation of BMDCs was significantly blunted in dendritic cells from S1P₂ -deficient mice and by treatment with JTE-013. Migrations of immature and mature BMDCs were also dependent on S1P₂ receptors. It was found that OVA-challenged mice into which in vitro OVA primed BMDCs from S1P₂ -deficient mice were adoptively transferred, had less severe asthma responses than OVA-challenged mice into which OVA-primed BMDCs from wild-type mice were adoptively transferred.

CONCLUSIONS AND IMPLICATIONS

Pro-allergic functions of S1P₂ receptors were elucidated in a murine asthma model. S1P₂ receptors were involved not only in maturation and migration of dendritic cells in the sensitization phase but also in mast cell degranulation in the challenge phase. These results suggest S1P₂ receptor as a therapeutic target for allergic asthma.

S-Petasin isolated from Petasites japonicus exerts anti-adipogenic activity in the 3T3-L1 cell line by inhibiting PPAR-γ pathway signaling

S-Petasin from Petasites japonicus exerts anti-adipogenic activity in 3T3-L1 cells through inhibition of the expression of PPAR-γ.

Bicyclic eremophilane-type petasite sesquiterpenes potentiate peroxisome proliferator-activated receptor γ activator-mediated inhibition of dendritic cells

Dendritic cell (DC) activation induces expression of co-stimulatory surface molecules, as well as migration into secondary lymphoid organs, where they activate naïve T-cells. A family of plant derivatives, eremophilane-type petasite sesquiterpenes, can regulate the immune system through DC targeting due to their anti-inflammatory effects. Peroxisome proliferator–activated receptor gamma (PPARγ) is involved in inhibition of inflammatory responses and induction of DCs to acquire a mucosal phenotype. Since mucosal DCs are central in innate immune responses, we hypothesized that eremophilane-type petasite sesquiterpenes exerted their anti-inflammatory effects by inhibiting DC maturation and activation through PPARγ. This study assessed the bicyclic eremophilane-type petasite sesquiterpene compounds Fukinone and 10βH-8α,12-Epidioxyeremophil-7(11)-en-8β-ol (ZYFDC21 and ZYFDC22) in the maturation and activation of mouse DC. We measured surface expression of co-stimulatory molecules by flow cytometry and cell-free supernatant cytokine production upon lipopolysaccharide stimulation by enzyme-linked immunosorbent assays (ELISAs) in the presence or absence of PPARγ agonists. DCs were generated from C57BL/6 mice bone marrow cells and harvested. Cells were exposed to bicyclic eremophilane-type petasite sesquiterpenes ZYFDC21 or ZYFDC22 in the presence or absence of synthetic PPARγ agonists (GW1929 and TGZ) or the natural PPARγ ligand 15d-PGJ₂, followed by overnight activation with LPS. We observed differences in the upregulation of surface expression of CD86, along with TNF, IL-6, and IL-12p70 released by DCs stimulated with LPS, when using combinations of bicyclic eremophilane-type petasite sesquiterpenes ZYFDC21 or ZYFDC22, and PPARγ agonists, in particular the PPARγ ligand 15d-PGJ₂. Our results indicate that bicyclic eremophilane-type petasite sesquiterpenes ZYFDC21 or ZYFDC22 inhibit maturation and activation of DC, and this activity is augmented upon PPARγ activation.

Suppressive Effect of 4-Hydroxy-2-(4-Hydroxyphenethyl) Isoindoline-1,3-Dione on Ovalbumin-Induced Allergic Asthma

4-Hydroxy-2-(4-hydroxyphenethyl)isoindoline-1,3-dione (PD1) is a synthetic phthalimide derivative of a marine compound. PD1 has peroxisome proliferator-activated receptor (PPAR) γ agonistic and anti-inflammatory effects. This study aimed to investigate the effect of PD1 on allergic asthma using rat basophilic leukemia (RBL)-2H3 mast cells and an ovalbumin (OVA)-induced asthma mouse model. In vitro, PD1 suppressed β-hexosaminidase activity in RBL-2H3 cells. In the OVA-induced allergic asthma mouse model, increased inflammatory cells and elevated Th2 and Th1 cytokine levels were observed in bronchoalveolar lavage fluid (BALF) and lung tissue. PD1 administration decreased the numbers of inflammatory cells, especially eosinophils, and reduced the mRNA and protein levels of the Th2 cytokines including interleukin (IL)-4 and IL-13, in BALF and lung tissue. The severity of inflammation and mucin secretion in the lungs of PD1-treated mice was also less. These findings indicate that PD1 could be a potential compound for anti-allergic therapy.

Butterbur Leaves Attenuate Memory Impairment and Neuronal Cell Damage in Amyloid Beta-Induced Alzheimer's Disease Models

Alzheimer’s disease (AD) is the most prevalent neurodegenerative disease, and is characterized by the accumulation of amyloid beta (Aβ) as a pathological hallmark. Aβ plays a central role in neuronal degeneration and synaptic dysfunction through the generation of excessive oxidative stress. In the present study, we explored whether leaves of Petasites japonicus (Siebold & Zucc.) Maxim. (PL), called butterbur and traditionally used in folk medicine, show neuroprotective action against Aβ_25–35 plaque neurotoxicity in vitro and in vivo. We found that PL protected Aβ_25–35 plaque-induced neuronal cell death and intracellular reactive oxygen species generation in HT22 cells by elevating expression levels of phosphorylated cyclic AMP response element-binding protein, heme oxygenase-1, and NAD(P)H quinine dehydrogenase 1. These neuroprotective effects of PL were also observed in Aβ_25–35 plaque-injected AD mouse models. Moreover, administration of PL diminished Aβ_25–35 plaque-induced synaptic dysfunction and memory impairment in mice. These findings lead us to suggest that PL can protect neurons against Aβ_25–35 plaque-induced neurotoxicity and thus may be a potential candidate to regulate the progression of AD.

Petasites japonicus bakkenolide B inhibits lipopolysaccharide‑induced pro‑inflammatory cytokines via AMPK/Nrf2 induction in microglia

Abnormal neuroinflammatory responses have diverse roles in neuronal death, oxidative stress and neurodegenerative diseases, such as Alzheimer's and Parkinson's disease. Microglia regulate these responses via molecular signaling cascades that involve inflammatory cytokines and complement proteins. Bakkenolide B from Petasites japonicus exhibits significant anti‑inflammatory and anti‑allergic bioactivities. The present study investigated the anti‑neuroinflammatory effects and underlying molecular mechanisms of bakkenolide B on the lipopolysaccharide (LPS)‑mediated neuroinflammatory response in microglia. The results indicated that bakkenolide B pretreatment significantly reduced microglial production of interleukin (IL)‑1β, IL‑6, IL‑12, and tumor necrosis factor (TNF)‑α. Furthermore, this effect was associated with reduced production of reactive oxygen species. The role of bakkenolide B was then evaluated in the upregulation of nuclear factor erythroid 2‑related factor 2 (Nrf2)/antioxidant response element (ARE) signaling pathways. The results suggested that bakkenolide B significantly upregulated Nrf2/ARE pathway‑related downstream factors, such as NADPH dehydrogenase quinone‑1 (NQO‑1) and heme oxygenase‑1 (HO‑1). Silencing of Nrf2, HO‑1 and NQO‑1 diminished the anti‑neuroinflammatory properties of bakkenolide B. AMP‑activated protein kinase (AMPK) activates the Nrf2/ARE signaling pathway, and the results of the present study demonstrated that bakkenolide B increased AMPK phosphorylation in microglia. In addition, an AMPK inhibitor abolished the bakkenolide B‑induced increase in nuclear Nrf2, NQO‑1 and HO‑1 protein expression. Finally, an AMPK inhibitor diminished the bakkenolide B‑mediated inhibition of LPS‑stimulated TNF‑α production. Taken together, the present results demonstrate that bakkenolide B may be an effective and therapeutically relevant AMPK/Nrf2 pathway activator for suppressing abnormal neuro-inflammation in neurodegenerative diseases.

Liquid chromatography-tandem mass spectrometry quantification of acetamiprid and thiacloprid residues in butterbur grown under regulated conditions

An analytical method was developed to quantify the residual levels of the neonicotinoid insecticides, acetamiprid and thiacloprid, in field-incurred butterbur samples using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Samples were extracted with acetonitrile and partitioned with dichloromethane. After partitioning, purification was conducted using a Florisil^® cartridge. Linearity of a matrix-matched calibration curve of the two compounds over a concentration range of 0.004-0.4μg/g was excellent, with determination coefficients (R²)≥0.9998. The limits of detection (LOD) and quantitation (LOQ) for both acetamiprid and thiacloprid were 0.0006 and 0.002mg/kg, respectively. The average recoveries for acetamiprid and thiacloprid at two spiking levels (0.02 and 0.1mg/kg, i.e., 10×LOQ and 50×LOQ) were between 78.23 to 82.17%, with relative standard deviations (RSDs)≤7.22%. The method was successfully applied to field-incurred samples treated with a commercial pesticide product, either once (zero or 7 days before harvest) or twice (0 and 7, 7 and 14, or 14 and 21 days before harvest). The highest and lowest residues were obtained for the 7 and 0 days' treatment and the 21 and 14 days' treatment, respectively. The developed method is simple and accurate and can be extrapolated to other leafy vegetables.

Herbal Medicines for Asthmatic Inflammation: From Basic Researches to Clinical Applications

Asthma is one of the most common chronic inflammatory disorders, associated with reversible airflow obstruction, airway hyperresponsiveness, and airway remodeling. This disease has a significant impact on individuals, their families, and society. Standardized therapeutics such as inhaled corticosteroid in combination with long acting β2 agonist have been applied for asthma control; however, complementary and alternative medicines, especially herbal medicines, are still widely used all over the world. A growing body of literature suggests that various herbals or related products might be effective in inhibiting asthmatic inflammation. In this review, we summarize recent advances about the mechanistic studies of herbal medicines on allergic airway inflammation in animal models and their potential application into clinic for asthma control.

Anti-Allergic Effect of Oroxylin A from Oroxylum indicum Using in vivo and in vitro Experiments

Oroxylum indicum has long been used in Asian traditional medicine to prevent and treat respiratory diseases, diabetes, diarrhea and other conditions. Oroxylin A is a flavone that is present in Oroxylum indicum and in Scutellaria baicalensis. Because the root extracts of both plants have been shown to have anti-allergic effects, the authors investigated whether oroxylin A is likely to have beneficial effects on allergic asthma using female Balb/c mice and rat RBL-2H3 mast cells. Antigen-induced degranulation was measured in vitro by measuring β-hexosaminidase activity. A murine ovalbumin-induced allergic asthma model was used to test the in vivo efficacy of oroxylin A. Sensitization and challenge of ovalbumin induced allergic asthma responses, the accumulations of eosinophils and Th2 cytokine levels in bronchoalveolar lavage fluid and lung tissues. Oroxylin A administration decreased numbers of inflammatory cells, especially eosinophils, and reduced the expression and secretion of Th2 cytokines, including IL-4 and IL-13, in lung tissues and bronchoalveolar lavage fluid. Histologic studies showed oroxylin A reduced inflammatory signs and mucin production in lungs. These findings provide evidence that oroxylin A has potential use as an anti-allergic therapeutic.

Petatewalide B, a novel compound from Petasites japonicus with anti-allergic activity

ETHNOPHARMACOLOGICAL RELEVANCE

The giant butterbur Petasites japonicus is used to treat asthma and allergic diseases in traditional Korean, Japanese, and Chinese medicine.

AIM OF THE STUDY

To elucidate the anti-allergic effect of Petasites genus, we studied effects of several compounds from Petasites japonicus leaves and found a novel bakkenolide-type sesquiterpine. In the present study, anti-allergic and anti-inflammatory effects of the new compound was examined using in vivo and in vitro experiments.

MATERIALS AND METHODS

The novel compound was isolated from Petasites japonicus leaves and named petatewalide B. Antigen-induced degranulation and Ca(2+) mobilization were measured in RBL-2H3 mast cells by measuring β-hexosaminidase activity and fluorescence change of Ca(2+) probe, fura-2. Induction of inducible nitric oxide synthase and cyclooxygenase 2 was measured by Western blotting in peritoneal macrophages. In addition, ovalbumin-induced asthma model was used for in vivo efficacy test of petatewalide B. Membrane potential was estimated by measuring fluorescence change of DiBAC in C6 glioma cells.

RESULTS

Petatewalide B inhibited the antigen-induced degranulation of β-hexosaminidase in RBL-2H3 mast cells, but did not affect antigen-induced Ca(2+) increase in the cells. Petatewalide B also showed inhibition of the LPS-induced induction of iNOS, but not COX-2 in mouse peritoneal macrophages. Nitric oxide production was also inhibited by petatewalide B in macrophages. In the ovalbumin-induced asthma model, petatewalide B strongly inhibited accumulations of eosinophils, macrophages, and lymphocytes in bronchoalveolar lavage fluid. Petatewalide B increased the membrane potential of C6 glioma cells in a concentration-dependent manner.

CONCLUSION

Petatewalide B from Petasites genus not only has anti-allergic and anti-inflammatory effects but also induces a transient increase of membrane potential in C6 glioma cells.

Anti-allergic effect of α-cubebenoate isolated from Schisandra chinensis using in vivo and in vitro experiments

AIM OF THE STUDY

In Oriental countries, the dried fruits of Schisandra chinensis are extensively used in traditional medicine to treat asthma, gonorrhea, and other diseases. Recently, α-cubebenoate was isolated as an anti-inflammatory component from Schisandra chinensis. In the present study, the authors examined the anti-allergic effect of α-cubebenoate using in vivo and in vitro experiments.

MATERIALS AND METHODS

α-Cubebenoate was isolated from an extract of Schisandra chinensis fruits. Antigen-induced degranulation and Ca(2+) mobilization were measured in RBL-2H3 mast cells. In addition, BALB/c mice were sensitized with ovalbumin and aluminum hydroxide, and then challenged with ovalbumin for three consecutive days. α-Cubebenoate (1mg/kg) was administered intraperitoneally 30min before each ovalbumin challenge.

RESULTS

In RBL-2H3 mast cells, α-cubebenoate inhibited antigen-induced degranulation and increase of intracellular Ca(2+) concentrations. In the ovalbumin-induced asthma model, α-cubebenoate suppressed bronchiolar structural changes induced by ovalbumin challenge. Furthermore, α-cubebenoate strongly inhibited accumulations of eosinophils, macrophages, and lymphocytes in bronchoalveolar lavage fluid. α-Cubebenoate also suppressed Th2 cytokines (IL-4 and IL-13) and TGF-β1 in lung tissues and in immune cells at the mRNA and protein levels.

CONCLUSION

α-Cubebenoate has an inhibitory effect on allergic inflammation and could be utilized as an agent for the treatment of asthma.

Antiproliferative effect of the methanol extract from the roots of Petasites japonicus on Hep3B hepatocellular carcinoma cells in vitro and in vivo

Traditional medicinal plants have been used in the treatment of various diseases for centuries. A number of plant-derived compounds have been proposed as anticancer agents and are currently undergoing medical development. Petasites japonicus (PJ), also known as Butterbur, is a herb cultivated in East Asia that is used as a traditional herbal medicine. The aim of the present study was to investigate whether a methanol extract of PJ demonstrated anticancer activity against Hep3B hepatocellular carcinoma (HCC) cells. The anticancer property and underlying mechanism of the extract were evaluated by assessing the effect on cell viability, nuclear morphology and the expression of phosphorylated (p)-mTOR, p-Akt, β-catenin and p-glycogen synthase kinase-3β, which are markers for cancer cell proliferation and metastasis. These results were obtained by the MTT assay, fluorescence microscopy and Western blot analysis. The methanol extract of PJ was shown to decrease the cell viability in a concentration-dependent manner. In addition, the methanol extract of PJ was found to inhibit the growth of Hep3B HCC cells through inhibiting the Akt/mTOR and Wnt signaling pathways. These results suggest that the methanol extract of PJ exerts an anticancer effect on Hep3B HCC cells.

Therapeutic effects of s-petasin on disease models of asthma and peritonitis

To explore the anti-allergic and anti-inflammatory effects of extracts of Petasites genus, we studied the effects of s-petasin, a major sesquiterpene from Petasites formosanus (a butterbur species) on asthma and peritonitis models. In an ovalbumin-induced mouse asthma model, s-petasin significantly inhibited the accumulations of eosinophils, macrophages, and lymphocytes in bronchoalveolar fluids. S-petasin inhibited the antigen-induced degranulation of β-hexosamidase but did not inhibit intracellular Ca(2+) increase in RBL-2H3 mast cells. S-petasin inhibited the LPS induction of iNOS at the RNA and protein levels in mouse peritoneal macrophages. Furthermore, s-petasin inhibited the production of NO (the product of iNOS) in a concentration-dependent manner in the macrophages. Furthermore, in an LPS-induced mouse model of peritonitis, s-petasin significantly inhibited the accumulation of polymorpho nuclear and mononuclear leukocytes in peritoneal cavity. This study shows that s-petasin in Petasites genus has therapeutic effects on allergic and inflammatory diseases, such as, asthma and peritonitis through degranulation inhibition in mast cells, suppression of iNOS induction and production of NO in macrophages, and suppression of inflammatory cell accumulation.