Bioassay-guided isolation and UHPLC-DAD-ESI-MS/MS quantification of potential anti-inflammatory phenolic compounds from flowers of Inula montana L

Ethnobotany and phytochemistry of plants used to treat musculoskeletal disorders among Skaw Karen, Thailand

CONTEXT

Musculoskeletal system disorders (MSD) are prevalent around the world affecting the health of people, especially farmers who work hard in the field. Karen farmers use many medicinal plants to treat MSD.

OBJECTIVE

This study collects traditional plant-based remedies used by the Skaw Karen to treat MSD and evaluates their active phytochemical compounds.

MATERIALS AND METHODS

The ethnobotanical study was conducted in six Karen villages in Chiang Mai province using semi-structured interviews were of 120 informants. The data were analyzed using ethnobotanical indices including use values (UV), choice value (CV), and informant consensus factor (ICF). Consequently, the 20 most important species, according to the indices, were selected for phytochemical analysis using LC-MS/MS.

RESULTS

A total of 3731 use reports were obtained for 139 species used in MSD treatment. The most common ailments treated with those plants were muscular pain. A total of 172 high-potential active compounds for MSD treatment were identified. Most of them were flavonoids, terpenoids, alkaloids, and steroids. The prevalent phytochemical compounds related to treat MSD were 9-hydroxycalabaxanthone, dihydrovaltrate, morroniside, isoacteoside, lithocholic acid, pomiferin, cucurbitacin E, leonuriside A, liriodendrin, and physalin E. Sambucus javanica Reinw. ex Blume (Adoxaceae), Betula alnoides Buch.-Ham. ex D.Don (Betulaceae), Blumea balsamifera (L.) DC. (Asteraceae), Plantago major L. (Plantaginaceae) and Flacourtia jangomas (Lour.) Raeusch. (Salicaceae) all had high ethnobotanical index values and many active compounds.

DISCUSSION AND CONCLUSIONS

This study provides valuable information, demonstrating low-cost medicine plants that are locally available. It is a choice of treatment for people living in remote areas.

An innovative UPLC-MS/MS method for the quantitation and pharmacokinetics of eupafolin in rat plasma

In this experiment, a rapid and highly sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) technology was established and validated for the quantitation and pharmacokinetic analysis of eupafolin in rat plasma, utilizing licochalcone B as internal standard (IS). After liquid-liquid extraction of the analyte samples by ethyl acetate, chromatographic separation was achieved using a UPLC HSS T3 column under gradient elution conditions, with the mobile phase consisting of acetonitrile and water (with 0.1 % formic acid). Eupafolin was quantified by multiple reaction monitoring (MRM) in electrospray positive-ion mode (ESI+), employing the mass transition m/z 315.2 → 300.3 for eupafolin and m/z 285.4 → 270.3 for IS. Eupafolin demonstrated excellent linear relationship (r > 0.99) over the concentration range of 1.25-1250 ng/mL, with the lower limit of quantification (LLOQ) of the UPLC-MS/MS assay determined as 1.25 ng/mL. Method validation followed the bioanalytical method validation criteria outlined by the FDA. The accuracy of eupafolin ranged from 86.7 % to 111.2 %, and the precision was less than 12 %. The matrix effect was observed at 92.8 %-98.6 %, while the recoveries exceeded 83.2 %. The established UPLC-MS/MS assay was successfully employed for the pharmacokinetic evaluation of eupafolin in rats. The half-lives (t1/2z) were determined to be 1.4 ± 0.4 h and 2.5 ± 1.4 h for intravenous and oral administration, respectively. Notably, the bioavailability of eupafolin was relatively low (8.3 %). The optimized UPLC-MS/MS technology showed highly sensitive, selective, and effective, rendering it suitable for the pharmacokinetics of eupafolin in preclinical practice.

Inula salicina L.: Insights into Its Polyphenolic Constituents and Biological Activity

In this study, UHPLC-HRMS analysis of the defatted methanol extract obtained from Inula salicina L. led to the identification of 58 compounds-hydroxycinnamic and hydroxybenzoic acids and their glycosides, acylquinic and caffeoylhexaric acids, and flavonoids and their glycosides. In addition, a new natural compound, N-(8-methylnepetin)-3-hydroxypiperidin-2-one was isolated and its structure was elucidated by NMR spectroscopy. The presence of a flavoalkaloid in genus Inula is described now for the first time. Chlorogenic acid was the main compound followed by 3,5-, 1,5- and 4,5-dicaffeoylquinic acids. The methanol extract was studied for its antioxidant potential by DPPH, ABTS, and FRAP assays and sun protective properties. In addition, a study was conducted to assess the effectiveness of the tested extract in inhibiting biofilm formation by Gram-positive and Gram-negative strains. Results from crystal violet tests revealed a notable decrease in biofilm mass due to the extract. The anti-biofilm efficacy was confirmed through the observation of the biofilm viability by live/dead staining. The obtained results showed that this plant extract could be used in the development of cosmetic products with antibacterial and sun protection properties.

Polyphenols of the Inuleae-Inulinae and Their Biological Activities: A Review

Polyphenols are ubiquitous plant metabolites that demonstrate biological activities essential to plant-environment interactions. They are of interest to plant food consumers, as well as to the food, pharmaceutical and cosmetic industry. The class of the plant metabolites comprises both widespread (chlorogenic acids, luteolin, quercetin) and unique compounds of diverse chemical structures but of the common biosynthetic origin. Polyphenols next to sesquiterpenoids are regarded as the major class of the Inuleae-Inulinae metabolites responsible for the pharmacological activity of medicinal plants from the subtribe (Blumea spp., Dittrichia spp., Inula spp., Pulicaria spp. and others). Recent decades have brought a rapid development of molecular and analytical techniques which resulted in better understanding of the taxonomic relationships within the Inuleae tribe and in a plethora of data concerning the chemical constituents of the Inuleae-Inulinae. The current taxonomical classification has introduced changes in the well-established botanical names and rearranged the genera based on molecular plant genetic studies. The newly created chemical data together with the earlier phytochemical studies may provide some complementary information on biochemical relationships within the subtribe. Moreover, they may at least partly explain pharmacological activities of the plant preparations traditionally used in therapy. The current review aimed to systematize the knowledge on the polyphenols of the Inulae-Inulinae.

Probiotic-fermented edible herbs as functional foods: A review of current status, challenges, and strategies

Recently, consumers have become increasingly interested in natural, health-promoting, and chronic disease-preventing medicine and food homology (MFH). There has been accumulating evidence that many herbal medicines, including MFH, are biologically active due to their biotransformation through the intestinal microbiota. The emphasis of scientific investigation has moved from the functionally active role of MFH to the more subtle role of biotransformation of the active ingredients in probiotic-fermented MFH and their health benefits. This review provides an overview of the current status of research on probiotic-fermented MFH. Probiotics degrade toxins and anti-nutritional factors in MFH, improve the flavor of MFH, and increase its bioactive components through their transformative effects. Moreover, MFH can provide a material base for the growth of probiotics and promote the production of their metabolites. In addition, the health benefits of probiotic-fermented MFH in recent years, including antimicrobial, antioxidant, anti-inflammatory, anti-neurodegenerative, skin-protective, and gut microbiome-modulating effects, are summarized, and the health risks associated with them are also described. Finally, the future development of probiotic-fermented MFH is prospected in combination with modern development technologies, such as high-throughput screening technology, synthetic biology technology, and database construction technology. Overall, probiotic-fermented MFH has the potential to be used in functional food for preventing and improving people's health. In the future, personalized functional foods can be expected based on synthetic biology technology and a database on the functional role of probiotic-fermented MFH.

Combining the In Silico and In Vitro Assays to Identify Strobilanthes cusia Kuntze Bioactives against Penicillin-Resistant Streptococcus pneumoniae

Leaves of Strobilanthes cusia Kuntze (S. cusia) are a widely used alexipharmic Traditional Chinese Medicine (TCM) in southern China for the prevention of cold and respiratory tract infectious diseases. One of the most common bacterial pathogens in the respiratory tract is the gram-positive bacterium Streptococcus pneumoniae. The antibiotic resistance of colonized S. pneumoniae makes it a more serious threat to public health. In this study, the leaves of S. cusia were found to perform antibacterial effects on the penicillin-resistant S. pneumoniae (PRSP). Confocal assay and Transmission Electron Microscopy (TEM) monitored the diminished cell wall integrity and capsule thickness of the PRSP with treatment. The following comparative proteomics analysis revealed that the glycometabolism-related pathways were enriched for the differentially expressed proteins between the samples with treatment and the control. To further delve into the specific single effective compound, the bio-active contents of leaves of S. cusia were analyzed by UPLC-UV-ESI-Q-TOF/MS, and 23 compounds were isolated for anti-PRSP screening. Among them, Tryptanthrin demonstrated the most promising effect, and it possibly inhibited the N-glycan degradation proteins, as suggested by reverse docking analysis in silico and further experimental verification by the surface plasmon resonance assay (SPR). Our study provided a research foundation for applications of the leaves of S. cusia as a TCM, and supplied a bio-active compound Tryptanthrin as a candidate drug skeleton for infectious diseases caused by the PRSP.

Characterization of Sideritis clandestina subsp. peloponnesiaca Polar Glycosides and Phytochemical Comparison to Other Mountain Tea Populations

Sideritis clandestina (Bory & Chaub.) Hayek subsp. peloponnesiaca (Boiss. & Heldr.) Baden (SCP) is endemic to the mountains of the Northern Peloponnese (Greece). This and other Sideritis taxa, collectively known as mountain tea, are widely ingested as beverages for refreshment or medicinal purposes. We describe a methodology for the characterization of SCP. Four iridoid glycosides (monomelittoside, melittoside, ajugoside, and 7-O-acetyl-8-epiloganic acid), two phenolic acid glycosides (vanillic and salicylic acid glycosides), and three caffeoyl ester glycosides (chlorogenic acid, verbascoside, and isoverbascoside) were isolated from SCP for the first time. We used ultrasound-assisted extraction of 3 g of plant material to produce petroleum ether and aqueous extracts, which we then analyzed using GC/MS and LC/MS. This was applied to eight samples from four different taxa. In total, 70 volatile and 27 polar metabolites were determined. The S. clandestina samples had a lower phenolic content and weaker antioxidant properties than S. raeseri and S. scardica. However, S. clandestina ssp. clandestina seemed to be the most aromatic taxon, with almost double the number of volatiles as the others. Τhis study could contribute to authentication and chemotaxonomic studies of Sideritis taxa.

Development of Evaluation Methods for Anti-Glycation Activity and Functional Ingredients Contained in Coriander and Fennel Seeds

Spices are known to have various physiological functions. We focused on the anti-glycation effects of spices, researched anti-glycation active ingredients in coriander (Coriandrum sativum L.) and fennel (Foeniculum vulgare) seeds, and conducted experiments using human skin-derived fibroblast TIG-110 cells as a model of glycation. We isolated 11 compounds from two spice seeds and found several substances that showed anti-glycation activity. A new compound (5,5′-diallyl-2,2′-diglucopyranosyl-3,3′-dimethoxy diphenyl ether) was isolated from fennel seeds and showed high anti-glycation activity with an IC50 value of 0.08 mM, thereby indicating a high anti-glycosylation activity. In this study, we established a glyoxal (GO)-induced glycation test method for human skin cells, confirmed the anti-glycation effect of spice seeds using this glycation induction model, and found that the exposure of TIG-110 human skin-derived fibroblast cells to GO reduced cell viability. The most stable conditions for cell viability were found to be a GO concentration of 1.25 mM and a culture time of 48 h. We evaluated extracts and isolates of spice seeds using this model as a model test for glycation induction. We conducted qualitative and quantitative analyses of carboxymethyl lysine (CML), a type of AGE, to determine the relationship between cell viability and AGEs. The relationship between cell viability and the amount of CML was correlated. Establishing a glycation induction model test using skin cells makes it possible to quickly screen extracts of natural ingredients in the future. Moreover, the results of this model showed that extracts of two spice seeds and their isolates have high anti-glycation activity, and they are expected to be used as cosmetics, health foods, and pharmaceutical ingredients.

Ingredients with anti-inflammatory effect from medicine food homology plants

Inflammation occurs when the immune system responses to external harmful stimuli and infection. Chronic inflammation induces various diseases. A variety of foods are prescribed in the traditional medicines of many countries all over the world, which gave birth to the concept of medicine food homology. Over the past few decades, a number of secondary metabolites from medicine food homology plants have been demonstrated to have anti-inflammatory effects. In the present review, the effects and mechanisms of the medicine food homology plants-derived active components on relieving inflammation and inflammation-mediated diseases were summarized and discussed. The information provided in this review is valuable to future studies on anti-inflammatory ingredients derived from medicine food homology plants as drugs or food supplements.

UPLC-PDA-ESI-QTOF-MS/MS fingerprint of purified flavonoid enriched fraction of Bryophyllum pinnatum; antioxidant properties, anticholinesterase activity and in silico studies

CONTEXT

Bryophyllum pinnatum (Lam.) Oken (Crassulaceae) is used traditionally to treat many ailments.

OBJECTIVES

This study characterizes the constituents of B. pinnatum flavonoid-rich fraction (BPFRF) and investigates their antioxidant and anticholinesterase activity using in vitro and in silico approaches.

MATERIALS AND METHODS

Methanol extract of B. pinnatum leaves was partitioned to yield the ethyl acetate fraction. BPFRF was isolated from the ethyl acetate fraction and purified. The constituent flavonoids were structurally characterized using UPLC-PDA-MS². Antioxidant activity (DPPH), Fe²⁺-induced lipid peroxidation (LP) and anticholinesterase activity (Ellman's method) of the BPFRF and standards (ascorbic acid and rivastigmine) across a concentration range of 3.125-100 μg/mL were evaluated in vitro for 4 months. Molecular docking was performed to give insight into the binding potentials of BPFRF constituents against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE).

RESULTS

UPLC-PDA-MS² analysis of BPFRF identified carlinoside, quercetin (most dominant), luteolin, isorhamnetin, luteolin-7-glucoside. Carlinoside was first reported in this plant. BPFRF significantly inhibited DPPH radical (IC₅₀ = 7.382 ± 0.79 µg/mL) and LP (IC₅₀ = 7.182 ± 0.60 µg/mL) better than quercetin and ascorbic acid. Also, BPFRF exhibited potent inhibition against AChE and BuChE with IC₅₀ values of 22.283 ± 0.27 µg/mL and 33.437 ± 1.46 µg/mL, respectively compared to quercetin and rivastigmine. Docking studies revealed that luteolin-7-glucoside, carlinoside and quercetin interact effectively with crucial amino acid residues of AChE and BuChE through hydrogen bonds.

DISCUSSION AND CONCLUSIONS

BPFRF possesses an excellent natural source of cholinesterase inhibitor and antioxidant. The material could be further explored for the potential treatment of oxidative damage and cholinergic dysfunction in Alzheimer's disease.

1β-Hydroxyalantolactone from Inulae Flos alleviated the progression of pulmonary fibrosis via inhibiting JNK/FOXO1/NF-κB pathway

Inulae Flos was widely distributed throughout Europe, Africa, and Asia, and was commonly used as a folk medicine in clinic for treating various respiratory diseases, including cough, asthma, bronchitis, pulmonary fibrosis, and pneumonia. However, the ingredients responsible for the pharmacology effects of I. Flos and the underlying mechanisms remain unclear. In this study, the effects of 16 known sesquiterpene lactones and flavonoids from I. Flos on TGF-β1-induced fibroblast activation were assessed by phenotypic high-content screening. Among those sixteen compounds, 1β-hydroxy alantolactone (HAL), the main characteristic sesquiterpene lactone from I. Flos, exhibited remarkable inhibitory activity. The further studies showed that HAL significantly inhibited the proliferation and induced the apoptosis of human fibroblast cell lines HELF and MRC-5 in a concentration-dependent manner. It also reduced intracellular ROS production, suppressed the mRNA expressions of E-cad, TGF-β1, Smad3, Col I, α-SMA and TNF-α, and downregulated protein expressions of α-SMA and F-actin. Furthermore, HAL significantly reduced the levels of HA, LN, PC-III and IV-C in serum, TNF-α and IL-6 in BALF, and TGF-β1, HYP and Col I in lung tissues of bleomycin (BLM)-treated rats. HAL significantly downregulated the expressions of p-JNK, FOXO1, p-p65, α-SMA, p-smad3 and Col I but upregulated p-FOXO1, which could be reversed by JNK agonist anisomycin. These results demonstrated that HAL induced the apoptosis of lung fibroblast cells activated by TGF-β1 and improved BLM-induced lung fibrosis in rats via inhibiting JNK/FOXO1/NF-κB pathway.

Enzyme inhibitory function and phytochemical profile of Inula discoidea using in vitro and in silico methods

Many plant species have a large diversity of secondary metabolites with different biological activities. This study aims to assess the phenolic constituent, enzyme inhibitory and antioxidant activities of the aqueous (water) and methanol extracts of Inula discoidea. The enzyme assays showed effective enzyme inhibition of the methanol extract against acetylcholinesterase (AChE), butyrylcholinesterase (BChE), glutathione S-transferase (GST), and α-glycosidase (α-Gly) enzymes. The IC50 values for AChE, BChE, GST, and α-Gly were found as 38.5 mg/mL, 34.65 mg/mL, 77.0 mg/mL, and 40.76 mg/mL, respectively. Antioxidant properties of the aqueous and methanol extracts of I. discoidea were determined by four well-known in vitro techniques (ABTS, CUPRAC, DPPH, and FRAP methods). The antioxidant values of both water and methanol extracts were found to be better than the standard antioxidants (BHA, BHT, ascorbic acid, and α-tocopherol) in ABTS and CUPRAC methods. According to an updated LC-MS/MS technique analysis, quinic acid (21.08 mg/g), protocatechuic acid (4.49 mg/g), and gallic acid (0.48 mg/g) were found as major phenolic compounds of the plant extract. The binding interactions of major phenolic compounds of I. discoidea with the AChE, BChE, GST, and α-Gly enzymes were investigated by the molecular docking studies.

Phytochemical Profile, Antioxidant Capacity, α-Amylase and α-Glucosidase Inhibitory Potential of Wild Moroccan Inula viscosa (L.) Aiton Leaves

Medicinal plants offer imperative sources of innovative chemical substances with important potential therapeutic effects. Among them, the members of the genus Inula have been widely used in traditional medicine for the treatment of several diseases. The present study investigated the antioxidant (DPPH, ABTS and FRAP assays) and the in vitro anti-hyperglycemic potential of aerial parts of Inula viscosa (L.) Aiton (I. viscosa) extracts through the inhibition of digestive enzymes (α-amylase and α-glucosidase), responsible of the digestion of poly and oligosaccharides. The polyphenolic profile of the Inula viscosa (L.) Aiton EtOAc extract was also investigated using HPLC-DAD/ESI-MS analysis, whereas the volatile composition was elucidated by GC-MS. The chemical analysis resulted in the detection of twenty-one polyphenolic compounds, whereas the volatile profile highlighted the occurrence of forty-eight different compounds. Inula viscosa (L.) Aiton presented values as high as 87.2 ± 0.50 mg GAE/g and 78.6 ± 0.55mg CE/g, for gallic acid and catechin, respectively. The EtOAc extract exhibited the higher antioxidant activity compared to methanol and chloroform extracts in different tests with (IC50 = 0.6 ± 0.03 µg/mL; IC50 = 8.6 ± 0.08 µg/mL; 634.8 mg ± 1.45 AAE/g extract) in DPPH, ABTS and FRAP tests. Moreover, Inula viscosa (L.) Aiton leaves did show an important inhibitory effect against α-amylase and α-glucosidase. On the basis of the results achieved, such a species represents a promising traditional medicine, thanks to its remarkable content of functional bioactive compounds, thus opening new prospects for research and innovative phytopharmaceuticals developments.

In vitro anti-inflammatory properties of honey flavonoids: A review

Honey is a natural ready-to-eat product rich in flavonoids, which is known by the wound healing properties due to both antibacterial and antioxidant activity. Flavonoids mitigate inflammatory processes, and thus it could currently support studies of anti-inflammatory potential of honeys. In this review, in vitro anti-inflammatory properties of flavonoids found in honey were prioritized. Mechanistic information of specific isolated flavonoids as modulators of inflammatory processes are summarized aiming to stimulate studies regarding the action of honey in inflammatory events. Lastly, a structure-activity relationship (SAR) of flavonoids was also included. Flavonoids found in honey have demonstrated antioxidant properties and ability to inhibit pro-inflammatory enzymes such as COX, LOX, iNOS, and pro-inflammatory mediators, including nitric oxide, cytokines and chemokines. Transcriptional factors such as NF-κB are also modulated by flavonoids, controlling the expression of several inflammatory mediators. SAR studies demonstrate the effect of flavonoids in the prevention of inflammatory cascades. Despite the promising reports of in vitro anti-inflammatory activity, well-designed clinical trials need yet to be performed to confirm the benefits of honeys from different botanical sources in diseases that include episodes of inflammation.

High resolution UPLC-PDA-QTOF-ESI-MS/MS analysis of the flavonoid-rich fraction of Lasianthera africana leaves, and in vivo evaluation of its renal and cardiac function effects

Lasianthera africana P. Beauv. (Icacinaceae) is a traditional Nigerian medicinal plant used for treatment of ulcers, diarrhea, parasitic infections and diabetes. This study was aimed at characterizing the bioactive principles extractable from the flavonoid-rich fraction of L. africana leaves (LAFRF), and to evaluate its effects on renal and cardiac functions. Isolation, and purification of the LAFRF was achieved using standard methods. The in vitro antioxidant activity was evaluated on DPPH∗ and ferric reducing antioxidant potential (FRAP). The total flavonoids (281.05 ± 7.44 mg QE/g), were identified, structurally characterized and quantified using high resolution ultra-performance liquid chromatography, in tandem with quadrupole-time-of-flight electrospray ionization mass spectrometer (UPLC-PDA-QTOF-ESI-MS/MS). Fifty Wistar rats of both sexes (110-130 g), were distributed into 10 groups (n = 5). Groups 1 and 2 served as the normal and CCl4 controls respectively. Groups 3A-6B constituted the preventive and curative studies. The effects of the LAFRF at 3, 10, and 30 mg/kg body weight on urea and creatinine concentrations, lactate dehydrogenase (LDH), and creatine kinase (CK) activities of CCl4-intoxicated rats were assessed. The LAFRF displayed remarkable in vitro antioxidant property by scavenging the DPPH∗, with an IC50 of 5.40 ± 0.00 μg/ml which is more potent than the scavenging activity of the ascorbic acid (IC50 of 7.18 ± 0.00 μg/ml), and also effectively reduced Fe3+ to Fe2+ when compared to gallic acid. The UPLC-PDA-QTOF-ESI-MS/MS fingerprint of the LAFRF indicated presence of quercetin (758983.6 mg/kg), rutin (17540.4 mg/kg), luteolin (126524.3 mg/kg), isorhamnetin (197949.0 mg/kg), and other non-phenolic compounds. The LAFRF significantly (p < 0.05) improved renal function, and normalized cardiac enzyme activities in vivo. The ability of the LAFRF to scavenge the DPPH and Fe3+ radicals, improve renal and cardiac functions following CCl4 intoxication shows its potential in the development of alternative therapy for combating oxidative stress-related complications.

Caffeoylquinic Acids, Cytotoxic, Antioxidant, Acetylcholinesterase and Tyrosinase Enzyme Inhibitory Activities of Six Inula Species from Bulgaria

Chlorogenic (5-CQA), 1,5-, 3,5-, 4,5- and 3,4-dicaffeoylquinic (DCQA) acids were identified and quantified in the methanol extracts of Inula oculus-christi L., I. bifrons L., I. aschersoniana Janka var. aschersoniana, I. ensifolia L., I. conyza (Griess.) DC. and I. germanica L. by HPLC analysis. The amount of 5-CQA varied from 5.48 to 28.44 mg/g DE and the highest content was detected in I. ensifolia. 1,5-DCQA (4.05-55.25 mg/g DE) was the most abundant dicaffeoyl ester of quinic acid followed by 3,5-DCQA, 4,5-DCQA and 3,4-DCQA. The extract of I. ensifolia showed the highest total phenolic content (119.92±0.95 mg GAE/g DE) and exhibited the strongest DPPH radical scavenging activity (69.41±0.55 %). I. bifrons extract was found to be the most active sample against ABTS^.+ (TEAC 0.257±0.012 mg/mL) and the best tyrosinase inhibitor. The studied extracts demonstrated a low inhibitory effect towards acetylcholinesterase and possessed low cytotoxicity in concentration range from 10 to 300 μg/mL toward non-cancer (MDCK II) and cancer (A 549) cells.

Phytochemical composition, isolation and hepatoprotective activity of active fraction from Veronica ciliata against acetaminophen-induced acute liver injury via p62-Keap1-Nrf2 signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Veronica ciliata Fisch, a traditional Tibetan medicine, used to cure hepatitis and existed in lots of Tibetan medicine prescriptions owing to its hepatoprotective activity.

AIMS OF THIS STUDY

In this study, we are aimed to systematically analysis and isolate the chemical constituents of the ethyl acetate fraction from V. ciliata (EAFVC), and test the hepatoprotective effect and mechanism of EAFVC and its compounds on attenuating the liver injury induced by acetaminophen (APAP) in vivo and vitro.

MATERIALS AND METHODS

UPLC-PDA-ESI-MS method was established for the analysis of the components in EAFVC, which was further separated using multiple chromatographic techniques. The MS, ¹H and ¹³C NMR were applied to elucidate their structures. UPLC-PDA method was applied for the simultaneous quantification of major compounds of EAFVC. Furthermore, the protective effect of the EAFVC was determined using APAP-induced acute hepatotoxicity in mice and BRL-3A cells model, respectively. In addition, the hepatoprotective activity of two main compounds in EAFVC on relieving APAP-induced liver injury was further evaluated. Finally, we have some concerns about the protective mechanism of EAFVC via enzyme-linked immunosorbent assay (ELISA), reactive oxygen species (ROS) detection, quantitative real-time PCR (qPCR), western blot analysis and molecular docking.

RESULTS

Thirteen compounds were successfully identified using UPLC-PDA-ESI-MS for the first time. Meanwhile, other twelve compounds were separated from EAFVC. Eventually, twenty-five compounds were successfully identified from the EAFVC. Among these compounds, fourteen compounds (3, 8, 10, 14-17, 19-25) were separated from V.ciliata for the first time. In addition, UPLC-PDA analysis method was first to establish for simultaneous determination of the main compounds (1, 2, 4, 5, 7, 9, 12). Further assay indicated that the liver injury in mice induced by APAP showed a significant reversal by EAFVC, as evidenced by reducing the activities of liver function enzymes, suppressing the lipid peroxidation as well as increasing the serum total antioxidant capacity (T-AOC) and the activities of antioxidant enzymes. Pathological sections showed that the liver in the high dose has significant improvement in mice. In vitro experiment also showed that EAFVC elevate the viability, inhibiting the activities of liver function enzymes as well as the generation of ROS of BRL-3A cells. In addition, Catalposide and verproside could reverse the low cell viability of BRL-3A cells induced by APAP. The mechanism research in vitro demonstrated that EAFVC could promote the mRNA and protein expression of heme oxygenase-1 (HO-1), NAD(P) H dehydrogenase quinone 1 (NQO-1) and catalytic or modify subunit of glutamate-cysteine ligase (GCLC/GCLCM) via enhancing nuclear factor-E2-related factor 2 (Nrf2) and p62/SQSTM1 (p62) expression in protein level. Molecular docking results demonstrated that catalposide and verproside have strong affinity to the kelch-like ECH-associated protein-1(Keap1) Kelch domain.

CONCLUSION

This research is the first to clarify the substance basis of the hepatoprotective activity of the EAFVC and provide the further scientific data for the traditional use of this Tibetan Medicine. EAFVC is valuable to be further investigated as active preparations for application in liver protection via activating p62- Keap1-Nrf2 pathway.

Inula L. Secondary Metabolites against Oxidative Stress-Related Human Diseases

An imbalance in the production of reactive oxygen species in the body can cause an increase of oxidative stress that leads to oxidative damage to cells and tissues, which culminates in the development or aggravation of some chronic diseases, such as inflammation, diabetes mellitus, cancer, cardiovascular disease, and obesity. Secondary metabolites from Inula species can play an important role in the prevention and treatment of the oxidative stress-related diseases mentioned above. The databases Scopus, PubMed, and Web of Science and the combining terms Inula, antioxidant and secondary metabolites were used in the research for this review. More than 120 articles are reviewed, highlighting the most active compounds with special emphasis on the elucidation of their antioxidative-stress mechanism of action, which increases the knowledge about their potential in the fight against inflammation, cancer, neurodegeneration, and diabetes. Alantolactone is the most polyvalent compound, reporting interesting EC50 values for several bioactivities, while 1-O-acetylbritannilactone can be pointed out as a promising lead compound for the development of analogues with interesting properties. The Inula genus is a good bet as source of structurally diverse compounds with antioxidant activity that can act via different mechanisms to fight several oxidative stress-related human diseases, being useful for development of new drugs.

Anti-inflammatory effects of cinnamon extract and identification of active compounds influencing the TLR2 and TLR4 signaling pathways

Cinnamon extract and its active compounds attenuate TLR2-/TLR4-mediated inflammatory processes.