The paradox of Picroside II: As a natural antioxidant, but may instead futher aggravate liver injury by exacerbating mitochondrial oxidative stress.

Background: Picroside II (PII), an iridoid glycoside extracted from the rhizomes and stems of the genus Picroside, exhibits pronounced hepatoprotective properties. Pre-administration of PII protects against acute liver injury caused by D-galactosamine (D-Gal), carbon tetrachloride (CCl4), and acetaminophen (APAP). This study aimed to elucidate the ramifications of PII administration subsequent to the initiation of acute hepatic injury. Methods: Exploring the role of PII treatment in APAP-treated cell and rat models and in D-Gal and CCl4-treated rat models. Results: In rats, APAP treatment increased serum aspartate transaminase, alanine transaminase, and alkaline phosphatase levels and decreased glutathione activity and the fluidity of the liver mitochondrial membrane. In L-02 cells, APAP exposure resulted in a decrement in membrane potential, an augmentation in the liberation of reactive oxygen species, and an acceleration of apoptotic processes. Moreover, PII pre-administration protected against D-Gal-induced acute hepatic injury and CCl4-induced chronic hepatic injury in rodent models, whereas PII administration post-injury aggravated CCl4-induced chronic hepatic injury. Conclusions: Our results suggest that the effects of PII depend on the hepatic physiological or pathological state at the time of intervention. While PII possesses the potential to avert drug-induced acute hepatic injury through the mitigation of oxidative stress, its administration post-injury may exacerbate the hepatic damage, underscoring the critical importance of timing in therapeutic interventions.

Hepatoprotective Principles from the Rhizomes of Picrorhiza kurroa.

A methanol extract of rhizomes of Picrorhiza kurroa Royle ex Benth. (Plantaginaceae) showed hepatoprotective effects against D-galactosamine (D-GalN)/lipopolysaccharide (LPS)-induced liver injury in mice. We had previously isolated 46 compounds, including several types of iridoid glycosides, phenylethanoid glycosides, and aromatics, etc., from the extract. Among them, picroside II, androsin, and 4-hydroxy-3-methoxyacetophenone exhibited active hepatoprotective effects at doses of 50-100 mg/kg, per os (p.o.) To characterize the mechanisms of action of these isolates and to clarify the structural requirements of phenylethanoid glycosides for their hepatoprotective effects, their effects were assessed in in vitro studies on (i) D-GalN-induced cytotoxicity in mouse primary hepatocytes, (ii) LPS-induced nitric oxide (NO) production in mouse peritoneal macrophages, and (iii) tumor necrosis factor-α (TNF-α)-induced cytotoxicity in L929 cells. These isolates decreased the cytotoxicity caused by D-GalN without inhibiting LPS-induced macrophage activation and also reduced the sensitivity of hepatocytes to TNF-α. In addition, the structural requirements of phenylethanoids for the protective effects of D-GalN-induced cytotoxicity in mouse primary hepatocytes were evaluated.

Evaluation potential effects of Picroside II on cytochrome P450 enzymes in vitro and in vivo.

ETHNOPHARMACOLOGY RELEVANCE: Picrorhiza scrophulariiflora Pennell, a well-known Chinese herb, has been traditionally utilized as an antioxidant and anti-inflammatory agent. One of its main bioactive components is Picroside II, a glycoside derivative. However, there is limited information on the effects of Picroside II on the activity of cytochrome P450 (CYP) enzymes nor on potential herb-drug interactions are rarely studied. AIM OF THE STUDY: The purpose of the study was to investigate the effects of Picroside II on the activity of cytochrome P450 enzymes in vitro and in vivo and its potential herb-drug interactions. MATERIALS AND METHODS: Specific probe substrates were employed to assess the effect of Picroside II on the activity of P450 enzymes. The inhibitory effects of Picroside II on CYP enzymes were assayed both in human (i.e., 1A, 2C9, 2C19, 2D6, 2E1, and 3A) and rat (i.e., 1A, 2C6/11, 2D1, 2E1, and 3A) liver microsomes in vitro. The inductive effects were investigated in rats following oral gavage of 2.5 mg/kg and 10 mg/kg Picroside II. A specific Ultra Performance Liquid Chromatography-Tandem Mass Spectrometry (UPLC-MS/MS) method was developed to determine the formation of specific metabolites. RESULTS: Enzyme inhibition results showed that Picroside II (0.5-200 µM) had no evident inhibitory effects on rat and human liver microsomes in vitro. Interestingly, the administration of multiple doses of 10 mg/kg Picroside II inhibited the activity of CYP2C6/11 by reducing the rate of formation of 4-hydroxydiclofenac and 4-hydroxymephenytoin, while Picroside II at 2.5 mg/kg increased the activity of CYP3A by promoting the formation of 1-hydroxymidazolam and 6-hydroxychlorzoxazone in rats. In addition, there were negligible effects on CYP1A, CYP2D1, and CYP2E1 in rats. CONCLUSIONS: The results indicated that Picroside II modulated the activities of CYP enzymes and was involved in CYP2C and CYP3A medicated herb-drug interactions. Therefore, careful monitoring is necessary when Picroside II is used in combination with related conventional drugs.

ABC transporters mined through comparative transcriptomics associate with organ-specific accumulation of picrosides in a medicinal herb, Picrorhiza kurroa.

Picrorhiza kurroa Royle ex Benth is a valuable medicinal herb of North-Western Himalayas due to presence of two major bioactive compounds, picroside-I and picroside-II used in the preparation of several hepatoprotective herbal drugs. These compounds accumulate in stolons/rhizomes; however, biosynthesized in different organs, viz., picroside-I in shoots and picroside-II in roots. As of today, no information exists on what transporters are transporting these metabolites from shoots and roots to the final storage organ, stolon, which ultimately transforms into rhizome. The ATP-binding cassette (ABC) transporters are reported to transport majority of secondary metabolites, including terpenoids in plants, therefore, we mined P. kurroa transcriptomes to identify and shortlist potential candidates. A total of 99 ABC transporter-encoding transcripts were identified in 3 differential transcriptomes, PKSS (shoots), PKSTS (stolons), and PKSR (roots) of P. kurroa, based on in silico comparative analysis and transcript abundance. 15 of these transcripts were further validated for their association using qRT-PCR in shoots, roots and stolon tissues in P. kurroa accessions varying for picroside-I and picroside-II contents. Organ-specific expression analysis revealed that PkABCA1, PkABCG1, and PkABCB5 had comparatively elevated expression in shoots; PkABCB2 and PkABCC2 in roots; PkABCB3 and PkABCC1 in stolon tissues of P. kurroa. Co-expression network analysis using ABC genes as hubs further unravelled important interactions with additional components of biosynthetic machinery. Our study has provided leads, first to our knowledge as of today, on putative ABC transporters possibly involved in long distance and local transport of picrosides in P. kurroa organs, thus opening avenues for designing a suitable genetic intervention strategy.

Capturing acyltransferase(s) transforming final step in the biosynthesis of a major Iridoid Glycoside, (Picroside-II) in a Himalayan Medicinal Herb, Picrorhiza kurroa.

BACKGROUND: Picrorhiza kurroa has been reported as an age-old ayurvedic hepato-protection to treat hepatic disorders due to the presence of iridoids such as picroside-II (P-II), picroside-I, and kutkoside. The acylation of catalpol and vanilloyl coenzyme A by acyltransferases (ATs) is critical step in P-II biosynthesis. Since accumulation of P-II occurs only in roots, rhizomes and stolons in comparison to leaves uprooting of this critically endangered herb has been the only source of this compound. Recently, we reported that P-II acylation likely happen in roots, while stolons serve as the vital P-II storage compartment. Therefore, developing an alternate engineered platform for P-II biosynthesis require identification of P-II specific AT/s. METHODS AND RESULTS: In that direction, egg-NOG function annotated 815 ATs from de novo RNA sequencing of tissue culture based 'shoots-only' system and nursery grown shoots, roots, and stolons varying in P-II content, were cross-compared in silico to arrive at ATs sequences unique and/or common to stolons and roots. Verification for organ and accession-wise upregulation in gene expression of these ATs by qRT-PCR has shortlisted six putative 'P-II-forming' ATs. Further, six-frame translation, ab initio protein structure modelling and protein-ligand molecular docking of these ATs signified one MBOAT domain containing AT with preferential binding to the vanillic acid CoA thiol ester as well as with P-II, implying that this could be potential AT decorating final structure of P-II. CONCLUSIONS: Organ-wise comparative transcriptome mining coupled with reverse transcription real time qRT-PCR and protein-ligand docking led to the identification of an acyltransferases, contributing to the final structure of P-II.

Picroside II alleviates DSS-induced ulcerative colitis by suppressing the production of NLRP3 inflammasomes through NF-κB signaling pathway.

CONTEXT: Ulcerative colitis (UC) is a common acute or chronic intestinal disease with an imbalance of inflammation. Picroside II (P-II) exerts a protective role in various inflammation-related diseases. However, the effect of P-II on UC is still unclear. OBJECTIVE: To explore the effect of P-II on UC and its potential mechanism. MATERIALS AND METHODS: Human monocytic leukemia cell line THP-1 was treated with phorbol ester (PMA) to differentiate into a macrophage. The differentiated THP-1 cells were hatched with LPS combined with ATP or Nigericin to activate the NLRP3 inflammasome in vitro. The UC model was constructed by injection of DSS into mice. RESULTS: The maximum nontoxic concentration of P-II on THP-1 cells was 60 µM. LPS combined with ATP or Nigericin stimulated the production of IL-1ß, which was antagonized by P-II treatment. Meanwhile, P-II administration interfered with the aggregation of ASC and the assembly of NLRP3 inflammasomes. Also, P-II treatment reduced the LPS and ATP-induced elevation of the relative protein expression of NLRP3, pro-caspase-1, IL-1ß and p-p65/p65, and the concentration of TNF-α and IL-6. Besides, the NF-κB specific inhibitor BAY-117082 notably repressed the LPS together with ATP-enhanced the relative protein expression of NLRP3, caspase-1 and IL-1ß. Moreover, in vivo results showed that P-II relieved the DDS-induced UC, as evidenced by the improvement of mice weight, DAI and pathological scores. In addition, P-II treatment notably decreased DDS-promoted expression of NLRP3 inflammasomes and inflammatory factors in vivo. CONCLUSION: P-II alleviated DSS-induced UC by repressing the production of NLRP3 inflammasomes via the NF-κB signaling pathway.

Intervention by picroside II on FFAs induced lipid accumulation and lipotoxicity in HepG2 cells.

BACKGROUND: Accumulation of free fatty acids (FFAs) in hepatocytes is a hallmark of liver dysfunction and non-alcoholic fatty liver disease (NAFLD). Excessive deposition of FFAs alters lipid metabolism pathways increasing the oxidative stress and mitochondrial dysfunction. Attenuating hepatic lipid accumulation, oxidative stress, and improving mitochondrial function could provide potential targets in preventing progression of non-alcoholic fatty liver (NAFL) to non-alcoholic steatohepatitis (NASH). Earlier studies with Picrorhiza kurroa extract have shown reduction in hepatic damage and fatty acid infiltration in several experimental models and also clinically in viral hepatitis. Thus, the effect of P. kurroa's phytoactive, picroside II, needed mechanistic investigation in appropriate in vitro liver cell model. OBJECTIVE(S): To study the effect of picroside II on FFAs accumulation, oxidative stress and mitochondrial function with silibinin as a positive control in in vitro NAFLD model. MATERIALS AND METHODS: HepG2 cells were incubated with FFAs-1000µM in presence and absence of Picroside II-10 µM for 20 hours. RESULTS: HepG2 cells incubated with FFAs-1000µM lead to increased lipid accumulation. Picroside II-10µM attenuated FFAs-induced lipid accumulation (33%), loss of mitochondrial membrane potential (ΔΨm), ATP depletion, and production of reactive oxygen species (ROS). A concomitant increase in cytochrome C at transcription and protein levels was observed. An increase in expression of MnSOD, catalase, and higher levels of tGSH and GSH:GSSG ratios underlie the ROS salvaging activity of picroside II. CONCLUSION: Picroside II significantly attenuated FFAs-induced-lipotoxicity. The reduction in ROS, increased antioxidant enzymes, and improvement in mitochondrial function underlie the mechanisms of action of picroside II. These findings suggest a need to develop an investigational drug profile of picroside II for NAFLD as a therapeutic strategy. This could be evaluated through the fast-track path of reverse pharmacology.

Advances in Ethnobotany, Synthetic Phytochemistry and Pharmacology of Endangered Herb Picrorhiza kurroa (Kutki): A Comprehensive Review (2010-2020).

Picrorhiza kurroa Royle ex Benth. (Family: Plantaginaceae) is a well-recognized Ayurvedic herb. It is commonly called "Kutki" or "Kurro" and 'Indian gentian'. Iridoid glycosides are the plant's bioactive constituents accountable for the bitter taste and medicinal properties of the plant. The iridoid glycosides such as picrosides and other active metabolites of the plant exhibit many pharmacological activities like hepatoprotective, antioxidant, anti-inflammatory, anticancer, immunomodulator, anti-ulcerative colitis, antimicrobial, etc. This review aims to provide updated information on the ethnobotany, synthetic phytochemistry, pharmacological potential, safety and toxicology of P. kurroa and its active metabolites. Indiscriminate exploitation, ecological destruction of natural habitats, slower plant growth and unawareness regarding cultivation and uprooting of plants have brought kutki an endangered status. Therefore, various techniques used for the conservation and production of bioactive metabolites from P. kurroa have also been reported. Information on the plant has been collected from Science Direct, Google Scholar, PubMed, Scopus using 'Picrorhiza kurroa', 'Picroside-', 'Picroside-II', 'Picroliv', 'Immunomodulator' keywords. All studies on ethnobotany, phytochemistry and pharmacology of plant from 2010- 2020 were comprised in this review article. The possible directions for future research have also been outlined briefly in this review article.

Effect and mechanism of picroside n on p38 mitogen activated protein kinase signal transduction pathway after cerebral ischemia/reperfusion in rats / 解剖学报

Objective To explore the neuroprotective effect and mechanism of picroside II on p38 mitogen activated protein kinase (p38 MAPK) signal transduction pathway after cerebral ischemia/reperfusion injury in rats. Methods A total of 150 healthy male Wistar rats were subject to establish middle cerebral artery occlusion/reperfusion (MCAO/R) models by inserting a monofilament thread. All rats were randomly divided into sham group, model group, picroside (Pier) group, anisomycin (Anis, agonist of p38 MAPK) group, Anis+Picr group, SB203580 (SB, inhibitor of p38 MAPK) group and SB+Picr group. The neurobehavioral function was evaluated by modified neurological severity score points (mNSS) test. The structure of neuron was observed using HE staining. The apoptotic cells were counted using TUNEL assay. The expression of phosphorylated p38 MAPK (p-p38 MAPK) in cortex was determined using the immunohistochemistry. And the expressions of p-p38 MAPK, phosphorylated MAPK activated protein kinase-2 (p-MK2), phosphorylated cytoplasm phospholipase A2 (p-cPLA2), interleukin-6 (IL-6) and tumor necrotic factor a (TNF-α) were determined by Western blotting. Results No neurological behavioral malfunction was found in sham group. In model group, the damage of neuron was worsened, while the neurobehavioral function score, apoptotic cell index and the expressions of p-p38 MAPK, p-MK2, p-cPLA2,IL-6 and TNF-α increased significantly than those in control group. No significant difference was found in TNF-α. In Pier group, SB group and SB+Picr group, the damage of neuron was lighter, the neurological behavioral function was improved, the number of apoptotic cells and the expressions of p-p38 MAPK, p- MK2, p-cPLA2 and IL-6 decreased significantly than those in model group. In Anis group and Anis + Pier group, the damage was worsen, the cerebral infarction was larger, and the expressions of p-p38 MAPK, p-MK2, p-cPLA2 and IL-6 increased significantly than those in control group. Conclusion Picroside II can protect the neuron from the apoptosis and inflammation reaction after MCAO/R by inhibiting p38 MAPK signal transduction pathway in rats.

Picroside II alleviates liver injury induced by alpha-naphthylisothiocyanate through AMPK-FXR pathway.

Alpha-naphthylisothiocyanate (ANIT) is a typical hepatotoxicant that causes cholestasis, which causes toxic bile acid accumulation in the liver and leads to liver injury. Picroside II (PIC), one of the dominant effective components extracted from Picrorhiza scrophulariiflora Pennell, exhibits many pharmacological effects. However, the role of AMP-activated protein kinase (AMPK)-Farnesoid X receptor (FXR) pathway in the hepatoprotective effect of PIC against ANIT-induced cholestasis remains largely unknown. This study aimed to investigate the mechanisms of PIC on ANIT-induced cholestasis in vivo and in vitro. Our results showed that PIC protected against ANIT-induced liver injury in primary mouse hepatocytes, and decreased serum biochemical markers and lessened histological injuries in mice. ANIT inhibited FXR and its target genes of bile acid synthesis enzymes sterol-12α-hydroxylase (CYP8B1), and increase bile acid uptake transporter Na + -dependent taurocholate transporter (NTCP), efflux transporter bile salt export pump (BSEP) and bile acid metabolizing enzymes UDP-glucuronosyltransferase 1a1 (UGT1A1) expressions. PIC prevented its downregulation of FXR, NTCP, BSEP and UGT1A1, and further reduced CYP8B1 by ANIT. Furthermore, ANIT activated AMPK via ERK1/2-LKB1 pathway. PIC inhibited ERK1/2, LKB1 and AMPK phosphorylation in ANIT-induced cholestasis in vivo and in vitro. AICAR, an AMPK agonist, blocked PIC-mediated changes in FXR, CYP8B1 and BSEP expression in vitro. Meanwhile, U0126, an ERK1/2 inhibitor, further repressed ERK1/2-LKB1-AMPK pathway phosphorylation. In conclusion, PIC regulated bile acid-related transporters and enzymes to protect against ANIT-induced liver injury, which related to ERK1/2-LKB1-AMPK pathway. Thus, this study extends the understanding of the anti-cholestasis effect of PIC and provides new therapeutic targets for cholestasis treatment.

The beneficial pharmacological effects and potential mechanisms of picroside II: Evidence of its benefits from in vitro and in vivo.

Picrorhiza kurroa, the dried rhizome of Picrorhiza kurroa Royle ex Benth, is a famous Chinese herb that has been traditionally used in China. Picroside II (PII), a glycoside derivative, is the main bioactive constituent of Picrorhiza kurroa. In the past several decades, bioactive components from Picrorhiza kurroa have attracted the attention of researchers due to their promising therapeutic effects. A large number of studies have demonstrated the therapeutic potential of PII for the prevention and treatment of some diseases, such as organic ischemia/reperfusion (I/R) injury, liver damage, inflammation, cancer metastasis and angiogenesis. In the present paper, we aimed to provide an overview of the pharmacology of PII, focusing on its anti-oxidant, anti-inflammatory and anti-apoptotic activities. Meanwhile, the plant tissue distribution and pharmacokinetic properties were also described. Due to its beneficial pharmacological effects in I/R injury, PII may serve as a promising therapeutic agent for organic I/R injury prevention.

Nose to brain drug delivery - A promising strategy for active components from herbal medicine for treating cerebral ischemia reperfusion.

Cerebral ischemia reperfusion injury (CIRI), one of the major causes of death from stroke in the world, not only causes tremendous damage to human health, but also brings heavy economic burden to society. Current available treatments for CIRI, including mechanical therapies and drug therapies, are often accompanied by significant side-effects. Therefore, it is necessary to discovery new strategies for treating CIRI. Many studies have confirmed that the herbal medicine has the advantages of abundant resources, good curative effect and little side effects, which can be used as potential drug for treatment of CIRI through multiple targets. It's known that oral administration commonly has low bioavailability, and injection administration is inconvenient and unsafe. Many drugs can't delivery to brain through routine pathways due to the blood-brain-barrier (BBB). Interestingly, increasing evidences have suggested the nasal administration is a potential direct route to transport drug into brain avoiding the BBB and has the characteristics of high bioavailability for treating brain diseases. Therefore, intranasal administration can be treated as an alternative way to treat brain diseases. In the present review, effective methods to treat CIRI by using active ingredients derived from herbal medicine through nose to brain drug delivery (NBDD) are updated and discussed, and some related pharmacological mechanisms have also been emphasized. Our present study would be beneficial for the further drug development of natural agents from herbal medicines via NBDD.

Picroside II protects against cholestatic liver injury possibly through activation of farnesoid X receptor.

BACKGROUD: Cholestasis, accompanied by the accumulation of bile acids in body, may ultimately cause liver failure and cirrhosis. There have been limited therapies for cholesteric disorders. Therefore, development of appropriate therapeutic drugs for cholestasis is required. Picroside II is a bioactive component isolated from Picrorhiza scrophulariiflora Pennell, its mechanistic contributions to the anti-cholestasis effect have not been fully elucidated, especially the role of picroside II on bile acid homeostasis via nuclear receptors remains unclear. PURPOSE: This study was designed to investigate the hepatoprotective effect of picroside II against alpha-naphthylisothiocyanate (ANIT)-induced cholestatic liver injury and elucidate the mechanisms in vivo and in vitro. METHODS: The ANIT-induced cholestatic mouse model was used with or without picroside II treatment. Serum and bile biochemical indicators, as well as liver histopathological changes were examined. siRNA, Dual-luciferase reporter, quantitative real-time PCR and Western blot assay were used to demonstrate the farnesoid X receptor (FXR) pathway in the anti-cholestasis effects of picroside II in vivo and in vitro. RESULTS: Picroside II exerted hepatoprotective effect against ANIT-induced cholestasis by impaired hepatic function and tissue damage. Picroside II increased bile acid efflux transporter bile salt export pump (Bsep), uptake transporter sodium taurocholate cotransporting polypeptide (Ntcp), and bile acid metabolizing enzymes sulfate transferase 2a1 (Sult2a1) and UDP-glucuronosyltransferase 1a1 (Ugt1a1), whereas decreased the bile acid synthesis enzymes cholesterol 7α-hydroxylase (Cyp7a1) and oxysterol 12α-hydroxylase (Cyp8b1). In addition, expression of FXR and the target gene Bsep was increased, whereas aryl hydrocarbon receptor (AhR), pregnane X receptor (PXR), peroxisome proliferator-activated receptor alpha (PPARα) and their corresponding target genes were not significantly influenced by picroside II under cholestatic conditions. Furthermore, regulation of transporters and enzymes involved in bile acid homeostasis by picroside II were abrogated by FXR silencing in mouse primary cultured hepatocytes. Dual-luciferase reporter assay performed in HepG2 cells demonstrated FXR activation by picroside II. CONCLUSION: Our findings demonstrate that picroside II exerts protective effect on ANIT-induced cholestasis possibly through FXR activation that regulates the transporters and enzymes involved in bile acid homeostasis. Picroside II might be an effective approach for the prevention and treatment of cholestatic liver diseases.

Picroside II, an iridoid glycoside from Picrorhiza kurroa, suppresses tumor migration, invasion, and angiogenesis in vitro and in vivo.

Cancer is one of the leading causes of death worldwide. The development of novel anti-cancer agents from natural products is a promising approach to reduce cancer mortality. In this study, we investigated the anti-metastatic and anti-angiogenic activities of picroside II (PII) in human breast cancer cells both in vitro and in vivo. Our results demonstrated that PII significantly inhibited the migration and invasion of MDA-MB-231 cancer cells. With the treatment of PII, the activity of matrix metalloproteinase 9 (MMP-9) in MDA-MB-231 cancer cells was significantly inhibited both in vitro and in vivo. Meanwhile, PII showed effective anti-metastatic activity in an experimental lung metastasis model. Interestingly, cluster of differentiation 31 (CD31), a marker of angiogenesis, was significantly downregulated in the PII-treated tumor samples, indicating the anti-angiogenic activity of PII. Furthermore, we demonstrated that PII significantly inhibited the migration, invasion, and tube formation of human umbilical vein endothelial cells (HUVECs). The inhibition of MMP-9 activity in PII-treated HUVECs was also demonstrated. Finally, the suppression of angiogenesis by PII in the chick embryo chorioallantoic membrane (CAM) was observed. In conclusion, our results demonstrated that PII effectively inhibited the metastasis and angiogenesis of cancer cells both in vitro and in vivo, and thus, might be a novel candidate for cancer therapy.

Picroside II Protects SH-SY5Y Cells From Autophagy and Apoptosis Following Oxygen Glucose Deprivation/Reoxygen Injury by Inhibiting JNK Signal Pathway.

To explore the neuroprotective effect of picroside (Picr) II on C-Jun NH2-terminal kinase (JNK) signal pathway after oxygen glucose deprivation/reoxygen (OGD/R) in SH-SY5Y cells. In vitro, SH-SY5Y cells were used to establish the OGD/R model, which was divided into the control group, model group, Picr group, and SP600125 (SP) group. Cellular viability was measured by CCK8. Cytotoxicity was assessed with LDH assay kit. Ad-GFP-mRFP-LC3 was used to monitor autophagosome and autolysosome. Apoptoic cells were detected by Annexin V-FITC/PI apoptosis detection kit. The expressions of phospho-JNK and phospho-c-Jun were determined by western blot (WB) and immunofluorescence. The expressions of phospho-MKK4, phospho-Bcl-2, Bax, Beclin-1, and LC3 I/II were determined by WB. In the control group, only limited apoptosis and autophagy was observed, and the expression of associated proteins was very low. After OGD/R, the cellular viability of SH-SY5Y cells was reduced, whereas the cytotoxicity, apoptosis, and autophagy were increased, accompanied with an increase of phospho-MKK4, phospho-JNK, phospho-c-Jun, phospho-Bcl-2, LC3 II, Beclin-1, and Bax. During the reoxygen, treatment with Picr II or SP600125 could strengthen the cellular viability of SH-SY5Y cells, but repress the cytotoxicity, apoptosis, autophagy, and the expressions of associated protein. OGD/R could induce apoptosis and autophagy of SH-SY5Y cells by activating JNK signal pathway. Picr II could protect SH-SY5Y cells from autophagy and apoptosis following OGD/R by inhibiting JNK signal pathway. Anat Rec, 302:2245-2254, 2019. © 2019 American Association for Anatomy.

Picroside II Isolated from Pseudolysimachion rotundum var. subintegrum Inhibits Glucocorticoid Refractory Serum Amyloid A (SAA) Expression and SAA-induced IL-33 Secretion.

Chronic obstructive pulmonary disease (COPD) is a major inflammatory lung disease characterized by irreversible and progressive airflow obstruction. Although corticosteroids are often used to reduce inflammation, steroid therapies are insufficient in patients with refractory COPD. Both serum amyloid A (SAA) and IL-33 have been implicated in the pathology of steroid-resistant lung inflammation. Picroside II isolated from Pseudolysimachion rotundum var. subintegrum (Plantaginaceae) is a major bioactive component of YPL-001, which has completed phase-2a clinical trials in chronic obstructive pulmonary disease patients. In this study, we investigated whether picroside II is effective in treating steroid refractory lung inflammation via the inhibition of the SAA-IL-33 axis. Picroside II inhibited LPS-induced SAA1 expression in human monocytes, which are resistant to steroids. SAA induced the secretion of IL-33 without involving cell necrosis. Picroside II, but not dexamethasone effectively inhibited SAA-induced IL-33 expression and secretion. The inhibitory effect by picroside II was mediated by suppressing the mitogen-activated protein kinase (MAPK) p38, ERK1/2, and nuclear factor-κB pathways. Our results suggest that picroside II negatively modulates the SAA-IL-33 axis that has been implicated in steroid-resistant lung inflammation. These findings provide valuable information for the development of picroside II as an alternative therapeutic agent against steroid refractory lung inflammation in COPD.

Picroside II attenuates hyperhomocysteinemia-induced endothelial injury by reducing inflammation, oxidative stress and cell apoptosis.

Picroside II (P-II), one of the main active components of scrophularia extract, which have anti-oxidative, anti-inflammatory effects, but its effect on hyperhomocysteinemia (HHcy) induced endothelial injury remains to be determined. Here, we test whether P-II protects HHcy-induced endothelial dysfunction against oxidative stress, inflammation and cell apoptosis. In vitro study using HUVECs, and in hyperhomocysteinemia mouse models, we found that HHcy decreased endothelial SIRT1 expression and increased LOX-1 expression, subsequently causing reactive oxygen species generation, up-regulation of NADPH oxidase activity and NF-κB activation, thereby promoting pro-inflammatory response and cell apoptosis. Blockade of Sirt1 with Ex527 or siRNASIRT1 increased LOX-1 expression, whereas overexpression of SIRT1 decreased LOX-1 expression markedly. P-II treatment significantly increased SIRT1 expression and reduced LOX-1 expression, and protected against endothelial cells from Hcy-induced oxidative injury, inflammation and apoptosis. However, blockade of SIRT1 or overexpression of LOX-1 attenuated the therapeutic effects of P-II. In conclusion, our results suggest that P-II prevents the Hcy induced endothelial damage probably through regulating the SIRT1/LOX-1 signaling pathway.

Picroside II Attenuates CCI-Induced Neuropathic Pain in Rats by Inhibiting Spinal Reactive Astrocyte-Mediated Neuroinflammation Through the NF-κB Pathway.

Reactive astrocyte-mediated neuroinflammatory responses in the spinal dorsal horn have been reported to play a pivotal role in pathological pain. Chronic constriction injury (CCI) enhances the activation of nuclear factor kappa B (NF-κB), which is involved in neuropathic pain (NP). Picroside II (PII), a major active component of Picrorhiza scrophulariiflora, has been investigated for its anti-oxidative, anti-inflammatory, and anti-apoptotic activities. Here, we explored the analgesic effects of PII on a model of CCI-induced NP and investigated the levels of the GFAP protein and the mRNA and protein levels of pro-inflammatory cytokines in the spinal cord, including interleukin-1ß (IL-1ß), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). CCI significantly induced mechanical allodynia and thermal hyperalgesia. Intraperitoneal administration of PII remarkably reversed the CCI-induced mechanical allodynia and thermal hyperalgesia and reduced the mRNA and protein levels of IL-1ß, IL-6, and TNF-α in the spinal cord. Additionally, according to the in vitro data, the PII treatment inhibited LPS-induced increases in the mRNA and protein levels of IL-1ß, IL-6, and TNF-α and suppressed the NF-κB pathway by inhibiting the phosphorylation of NF-κB/p65 and the degradation of inhibitor of NF-κB (IκB) in astrocytes without toxicity to astrocytes. Overall, the analgesic effect of PII correlated with the inhibition of spinal reactive astrocyte-mediated neuroinflammation through the NF-κB pathway in rats with NP.

Picroside II attenuates fatty acid accumulation in HepG2 cells via modulation of fatty acid uptake and synthesis.

BACKGROUND/AIMS: Hepatic steatosis is caused by an imbalance between free fatty acids (FFAs) uptake, utilization, storage, and disposal. Understanding the molecular mechanisms involved in FFAs accumulation and its modulation could drive the development of potential therapies for Nonalcoholic fatty liver disease. The aim of the current study was to explore the effects of picroside II, a phytoactive found in Picrorhiza kurroa, on fatty acid accumulation vis-à-vis silibinin, a known hepatoprotective phytoactive from Silybum marianum. METHODS: HepG2 cells were loaded with FFAs (oleic acid:palmitic acid/2:1) for 20 hours to mimic hepatic steatosis. The FFAs concentration achieving maximum fat accumulation and minimal cytotoxicity (500 µM) was standardized. HepG2 cells were exposed to the standardized FFAs concentration with and without picroside II pretreatment. RESULTS: Picroside II pretreatment inhibited FFAs-induced lipid accumulation by attenuating the expression of fatty acid transport protein 5, sterol regulatory element binding protein 1 and stearoyl CoA desaturase. Preatreatment with picroside II was also found to decrease the expression of forkhead box protein O1 and phosphoenolpyruvate carboxykinase. CONCLUSIONS: These findings suggest that picroside II effectively attenuated fatty acid accumulation by decreasing FFAs uptake and lipogenesis. Picroside II also decreased the expression of gluconeogenic genes.

Picroside II attenuates fatty acid accumulation in HepG2 cells via modulation of fatty acid uptake and synthesis

BACKGROUND/AIMS: Hepatic steatosis is caused by an imbalance between free fatty acids (FFAs) uptake, utilization, storage, and disposal. Understanding the molecular mechanisms involved in FFAs accumulation and its modulation could drive the development of potential therapies for Nonalcoholic fatty liver disease. The aim of the current study was to explore the effects of picroside II, a phytoactive found in Picrorhiza kurroa, on fatty acid accumulation vis-à-vis silibinin, a known hepatoprotective phytoactive from Silybum marianum. METHODS: HepG2 cells were loaded with FFAs (oleic acid:palmitic acid/2:1) for 20 hours to mimic hepatic steatosis. The FFAs concentration achieving maximum fat accumulation and minimal cytotoxicity (500 μM) was standardized. HepG2 cells were exposed to the standardized FFAs concentration with and without picroside II pretreatment. RESULTS: Picroside II pretreatment inhibited FFAs-induced lipid accumulation by attenuating the expression of fatty acid transport protein 5, sterol regulatory element binding protein 1 and stearoyl CoA desaturase. Preatreatment with picroside II was also found to decrease the expression of forkhead box protein O1 and phosphoenolpyruvate carboxykinase. CONCLUSIONS: These findings suggest that picroside II effectively attenuated fatty acid accumulation by decreasing FFAs uptake and lipogenesis. Picroside II also decreased the expression of gluconeogenic genes.