Bioassay-guided isolation of iridoid glucosides with antinociceptive and anti-inflammatory activities from Veronica anagallis-aquatica 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.

Plant-derived and dietary phenolic cinnamic acid derivatives: Anti-inflammatory properties

Cinnamic acids are aromatic acids primarily found in plants and plant-derived food. Phenolic cinnamic acids, with one or more hydroxyl groups in the aromatic ring, often contribute to the biological activities attributed to these compounds. The presence of hydroxyl groups and a carboxyl group makes cinnamic acids very hydrophilic, preventing them from crossing biological membranes and exerting their biological activities. To alleviate this condition, a panel of synthetic modifications have been made leading to a diverse set of phenolic cinnamic structures. In this review, an overview of the natural phenolic cinnamic acid derivatives and their plant sources (more than 200) is described. The synthetic approaches to obtain the referred derivatives (more than 200) namely esters and amides are reviewed. Further, their anti-inflammatory activity (more than 70 compounds) is scrutinized. Finally, future directions will be indicated to translate the research on phenolic cinnamic derivatives into potentially effective anti-inflammatory drugs.

Identification of Phenolic Compounds Present in Three Speedwell (Veronica L.) Species and Their Antioxidant Potential

Extracts from Veronica species (speedwells) are known for the various biological activities they show, such as cytotoxic, antimicrobial, anti-inflammatory, and antioxidant activities. Also, the plants from this genus are known as medicinal plants used in traditional medicine worldwide. Phenolic compounds are specialized metabolites that contribute to biological activity the most. Therefore, the aim of this research is identification and quantification of phenolic compounds present in three Veronica species (Veronica anagallis-aquatica L., Veronica persica Poir., and Veronica polita Fr.) using the liquid chromatography-mass spectrometry (LC-MS/MS) technique. All extracts were tested for antioxidant activity with two methods: DPPH (2,2-diphenyl-1-picrylhydrazyl) and ORAC (oxygen radical absorbance capacity). Also, standards for compounds that were detected in the highest amount in all species were also tested for antioxidant activity. Three different solvents (pure methanol, 80% ethanol, and water) were used for the extraction of phenolic components and their comparison in order to test their antioxidant activity as a final goal. The main compounds present in the tested Veronica extracts were: p-hydroxybenzoic acid, vanillic acid, caffeic acid, gentisic acid, and apigenin. V. anagallis-aquatica contained the highest amount of phenolic components in comparison with the two other tested species, V. persica and V. polita. Caffeic acid showed the highest antioxidant activity in both studied methods with an IC50 value for DPPH activity of 1.99 µg/mL. For the plant extracts, in general, methanolic/ethanolic extracts showed higher activity than water extracts in both methods which was expected, as organic solutions extract more phenolic compounds. This research points to the potential application of extracts of different Veronica species for antioxidant activity.

Anti-inflammatory effect and mechanism of catalpol in various inflammatory diseases

Catalpol is a kind of iridoid glucoside, widely found in a variety of plants, mostly extracted from the rhizome of the traditional medicinal herb rehmanniae. It has various biological activities such as anti-inflammatory, antioxidant, and antitumor. The anti-inflammatory effects of catalpol have been demonstrated in a variety of diseases, such as neurological diseases, atherosclerosis, renal diseases, respiratory diseases, digestive diseases, bone and joint diseases, eye diseases, and periodontitis. The purpose of this review is to summarize the existing literature on the anti-inflammatory effects of catalpol in a variety of inflammatory diseases over the last decade and to focus on the anti-inflammatory mechanisms of catalpol.

Isolation of Volatile Compounds by Microwave-Assisted Extraction from Six Veronica Species and Testing of Their Antiproliferative and Apoptotic Activities

This study was conducted to determine the differences in the chemical composition of the essential oils and hydrosols of six different Veronica species (V. agrestis, V. anagalloides, V. austriaca ssp. jacquinii, V. beccabunga, Veronica cymbalaria, and V. officinalis) and to test their antiproliferative and apoptotic activities, according to the authors' knowledge, because of insufficient research and lack of information. Also, the goal was to determine which obtained samples were better in achieving antiproliferative and apoptotic activities and due to which volatile components. Therefore, essential oils (EOs) and hydrosols (HYs) were isolated from the above-mentioned Veronica species by microwave-assisted extraction (MAE). Phytochemical identification of the free volatile compounds was performed using a GC equipped with a flame ionization detector and a mass spectrometer. Their antiproliferative and apoptotic activities against two human cancer cell lines, breast cancer cell line MDA-MB-231 and bladder cancer cell line T24, were determined. The main compounds identified in the studied Veronica EOs and HYs were terpinen-4-ol (0.34-6.49%), linalool (0.34-6.61%), (E)-caryophyllene (0.97-7.55%), allo-aromadendrene (0.18-2.21%), caryophyllene oxide (1.42-23.83%), benzene acetaldehyde (0.26-13.34%), and β-ionone (1.08-16.53%). In general, HYs of the tested Veronica species showed higher antiproliferative activity (IC50 13.41-42.05%) compared to EOs (IC50 158.1-970.4 µg/mL) on MDA-MB-231 and T24 cancer cell lines after 48 and 72 h. V. agrestis EO showed the best apoptotic effect among the EOs on the MDA-MB-231 cancer cell line (10.47 ± 0.53% and 9.06 ± 0.74% of early/late apoptosis, compared with control 3.61 ± 0.62% and 0.80 ± 0.17% of early/late apoptosis, respectively) and among the HYs V. cymbalaria showed 9.95 ± 1.05% and 3.06 ± 0.28% of early/late apoptosis and V. anagalloides 8.29 ± 1.09% and 1.95 ± 0.36% of early/late apoptosis compared with control (for EO was 7.45 ± 1.01% and 0.54 ± 0.25%, and for HY was 4.91 ± 1.97% and 0.70 ± 0.09% of early/late apoptosis, respectively) on the T24 cancer cell line. Future research will include other Croatian species of the genus Veronica to gain a more complete insight into the biological activity of the volatile products of this genus for potential discovery of drugs based on natural plant extracts.

Veronica persica Ethanol Extract Ameliorates Dinitrochlorobenzene-Induced Atopic Dermatitis-like Skin Inflammation in Mice, Likely by Inducing Nrf2/HO-1 Signaling

Atopic dermatitis (AD) is chronic allergic contact dermatitis with immune dysregulation. Veronica persica has pharmacological activity that prevents asthmatic inflammation by ameliorating inflammatory cell activation. However, the potential effects of the ethanol extract of V. persica (EEVP) on AD remain elusive. This study evaluated the activity and underlying molecular pathway of EEVP in two AD models: dinitrochlorobenzene (DNCB)-induced mice and interferon (IFN)-γ/tumor necrosis factor (TNF)-α-stimulated human HaCaT keratinocytes. EEVP attenuated the DNCB-induced increase in serum immunoglobulin E and histamine levels, mast cell counts in toluidine-blue-stained dorsal skin, inflammatory cytokine (IFN-γ, interleukin [IL]-4, IL-5, and IL-13) levels in cultured splenocytes, and the mRNA expression of IL6, IL13, IL31 receptor, CCR-3, and TNFα in dorsal tissue. Additionally, EEVP inhibited the IFN-γ/TNF-α-induced mRNA expression of IL6, IL13, and CXCL10 in HaCaT cells. Furthermore, EEVP restored the IFN-γ/TNF-α-induced downregulation of heme oxygenase (HO)-1 in HaCaT cells by inducing nuclear factor erythroid 2-related factor 2 (Nrf2) expression. A molecular docking analysis demonstrated that EEVP components have a strong affinity to the Kelch-like ECH-associated protein 1 Kelch domain. In summary, EEVP inhibits inflammatory AD by attenuating immune cell activation and inducing the Nrf2/HO-1 signaling pathway in skin keratinocytes.

Ethanol extract of Veronica persica ameliorates house dust mite-induced asthmatic inflammation by inhibiting STAT-3 and STAT-6 activation

Veronica persica is a flowering plant belonging to the family Scrophulariaceae. Here, we aimed to evaluate the pharmacological activity of the ethanol extract of Veronica persica (EEVP) in an airway inflammation model. We examined airway responsiveness to aerosolized methacholine, serum immunoglobulin (Ig)E levels, and total cell numbers in the lung and bronchoalveolar lavage fluid (BALF). Histological analysis of the lung tissue was performed using hematoxylin-eosin, Masson trichrome, or periodic acid-Schiff staining. Fluorescence-activated cell sorting analysis in the lung and BALF was applied to clarify the changes in immune cell types. Enzyme-linked immunosorbent assay and quantitative real-time polymerase chain reaction were applied to investigate cytokine levels and gene expression related to airway inflammation. STAT-3/6 phosphorylation was examined in primary bronchial/tracheal epithelial cells using western blot analysis. EEVP significantly suppressed total IgE levels and methacholine-induced increase of Penh value in the HDM-challenged mouse model. EEVP also attenuated the severity of airway remodeling in lung tissues and decreased eosinophil and neutrophil infiltration in the lungs and BALF. EEVP significantly reduced the production of cytokines in BAL and splenocyte culture medium, and the expression of mRNAs related to airway inflammation in the lung tissue. EEVP suppressed IL-4/13-induced STAT-3/6 phosphorylation in the epithelial cells. We showed for the first time that EEVP effectively inhibits eosinophilic airway inflammation by suppressing the expression of inflammatory factors for T cell activation and polarization, and inhibits MCP-1 production of bronchial/tracheal epithelial cells by suppressing STAT-3/6 activation. EEVP may be a potential pharmacological agent to prevent inflammatory airway diseases.

Phytochemical analysis on the aerial parts of Teucrium capitatum L. with aspects of chemosystematics and ethnobotany

The phytochemical analysis on the aerial parts of Teucrium capitatum L. collected from a new population in Central Italy, led to the identification of eight compounds, i.e. pheophytin a (1), poliumoside (2), apigenin (3), luteolin (4), cirsimaritin (5), cirsiliol (6), 8-O-acetyl-harpagide (7) and teucardoside (8) belonging to four different classes of secondary metabolites. Pheophytin a (1) represents a newly identified compound in the genus whereas compounds (7-8) are newly identified compound in the species. The chemotaxonomic and ethnobotanical aspects relative to the presence of these compounds were widely discussed suggesting important conclusions for both.

In Vitro Multiplication and NMR Fingerprinting of Rare Veronica caucasica M. Bieb

Micropropagation of rare Veronica caucasica M. Bieb. was achieved by successful in vitro cultivation of mono-nodal segments on MS medium supplemented with 1.0 mg L^–1 6-benzylaminopurine (BA) and then transferring the regenerated plants on hormone free basal MS medium for root development. In vitro multiplicated plants were successively acclimated in a growth chamber and a greenhouse with 92% survival. The number of plastid pigments and the total phenolics content in in vitro cultivated and ex vitro adapted plants were unchanged, and no accumulation of reactive oxygen species (ROS) was detected by staining with 3-3′-diaminobenzidine (DAB) and 2′,7′-dichlorofluorescein diacetate (DCF-DA). Nuclear Magnetic Resonance (NMR) fingerprinting allowed for the identification of the major alterations in metabolome of V. caucasica plants during the process of ex situ conservation. Iridoid glucosides such as verproside, aucubin and catalpol were characteristic for in vitro cultivated plants, while in ex vitro acclimated plants phenolic acid–protocatechuic acid and caffeic acid appeared dominant. The successful initiation of in vitro and ex vitro cultures is an alternative biotechnological approach for the preservation of V. caucasica and would allow for further studies of the biosynthetic potential of the species and the selection of lines with a high content of pharmaceutically valuable molecules and nutraceuticals.

Characterization and phylogenetic analysis of the complete plastome of Veronica undulata (Plantaginaceae)

Veronica undulata is a perennial herb, and the complete chloroplast genome (plastome) of V. undulata was determined in this study. The results showed that the plastome size of V. undulata was 151,178 bp, including a large single-copy region (68,533 bp), a small single-copy region (21,403 bp), and two inverted repeat regions (25,566 bp). The total GC content of the plastome was 38.1%. We annotated 115 unique genes in the plastome, including 81 protein-coding genes (PCGs), 30 tRNAs, and four rRNAs. Phylogenetic analysis showed that the species of V. undulata and Veronica clustered together.

Anti-rheumatoid arthritis effects of iridoid glucosides from Lamiophlomis rotata (Benth.) kudo on adjuvant-induced arthritis in rats by OPG/RANKL/NF-κB signaling pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Lamiophlomisrotata (Benth.) Kudo. has been used to treat trauma bleeding, rheumatism, yellow water disease in traditional Chinese medicine.

AIM

The aim of this work was to evaluate the anti-rheumatoid arthritis (RA) activities and underlying mechanisms of the total iridoid glucosides (TIG) from Lamiophlomisrotata (Benth.) Kudo.

METHODS

The chemical constituents of TIG was analyzed by high-performance liquid chromatography (HPLC) with seven reference compounds (penstemonoside, chlorotuberside, shanzhiside methyl ester, phloyoside, 7-epliamalbide, phlorigidoside C and lamalbide). The anti-rheumatoid arthritis effects of TIG were investigated by arthritis indexes and paw swelling degrees, as well as histopathological and Micro-CT analysis in adjuvant-induced arthritis (AIA) rats. The impacts of TIG on the level of inflammatory cytokines (IL-1β, TNF-α, IL-6, IFN-γ, IL-17 and IL-10), and the regulation of OPG/RANKL/NF-κB pathways were determined by the ELISA and western blot, respectively.

RESULTS

TIG significantly reduced the arthritis indexes and paws swelling in AIA rats, attenuated the inflammation and bone destruction in joint tissues, reduced the generation of pro-inflammatory cytokines IL-1β, TNF-α, IL-6, IFN-γ and IL-17, as well as increased the generation of anti-inflammatory cytokine IL-10 in serum. Moreover, TIG markedly inhibited the expression of p-IKK-α, p-IκB and p-p65, and decreased the ratio of OPG/RANKL in the synovial tissues.

CONCLUSION

TIG possessed significant anti-RA activities on adjuvant-induced arthritis, which might be ascribed to the regulation of inflammatory cytokines IL-1β, TNF-α, IL-6, IFN-γ IL-17 and IL-10, as well as inhibition of OPG/RANKL/NF-κB signaling pathways.

Beneficial effects of Ajuga chamaepitys (L.) Schreber subsp. chia (Schreber) and its iridoids on the colitis model: Histopathological and biochemical evidence

In Turkish folk medicine, aerial parts of Ajuga chamaepitys (L.) Schreber subsp. chia (Schreber) are used for the treatment of diarrhea. The crude methanolic extract of aerial parts of A. chamaepitys subsp. chia was sequentially fractionated into five subextracts; n-hexane, dichloromethane, ethyl acetate, n-butanol and aqueous extracts. Effects of the methanol extract, subextracts and fractions were investigated in acetic acid-induced rat colitis model. The MeOH extract and n-BuOH subextract have regulated the caspase-3, myeloperoxidase, TNF-α, IL-6 levels and antioxidant parameters. After confirmation of the activity against ulcerative colitis, n-BuOH subextract was subjected to more chromatographic separation for the isolation of compounds ajugoside (1), asperulosidic acid (2) and deacetyl-asperulosidic acid (3). As a conclusion, A. chamaepitys subsp. chia can be used in cell, tissue, or individual-specific treatments that will be developed in the future treatment of IBD, or as a complementary therapeutic agent that contributes to these treatments.

Scrophularia Tenuipes Coss and Durieu: Phytochemical Composition and Biological Activities

Scrophularia tenuipes is an Algerian-Tunisian endemic species, which has not been studied yet. Ethyl acetate (EA) and n-butanol (Bu) fractions obtained from Scrophularia tenuipes were investigated for their health benefit properties, in particular with respect to in vivo/in vitro anti-inflammatory and antioxidant activities, as well as their potential to inhibit key enzymes with impact in diabetes (α-glucosidase and α-amylase). The fractions had a distinct phytochemical composition, of which EA was richer in total phenolic compounds (225 mg GAE/g) and mostly composed of the phenylethanoid acetyl martynoside. Compared to EA, Bu had higher amounts of total flavonoids, and according to the result obtained from UHPLC-DAD-ESI-MSn analysis, harpagoside (iridoid) was its major phytochemical. EA fraction was quite promising with regard to the in vivo (at 200 mg/kg, po) anti-inflammatory effect (62% and 52% for carrageenan-induced rat paw edema and xylene-induced ear edema tests, respectively), while Bu fraction exhibited a stronger antioxidant capacity in all tests (IC50 = 68 µg/mL, IC50 = 18 µg/mL, IC50 = 18 µg/mL and A0.50 = 43 µg/mL for DPPH●, ABTS•+, O2•- scavenging assays and cupric-reducing antioxidant capacity method, respectively). Both fractions also showed a strong effect against α-amylase enzyme (IC50 = 8 µg/mL and 10 µg/mL for EA and Bu fraction, respectively).

Review of the Ethnopharmacology, Phytochemistry, and Pharmacology of the Genus Veronica

Veronica is the largest genus in the flowering plant family Plantaginaceae and comprises approximately 500 species. The genus was formerly placed in the Scrophulariaceae family, some species of which have been used in traditional medicine for the treatment of influenza, respiratory diseases, hemoptysis, laryngopharyngitis, cough, hernia, cancer, edema, and wounds. This review comprehensively summarizes the current information on the traditional uses, phytochemistry, and pharmacology of the genus Veronica on the basis of articles published from 1970 to 2018. More than 260 compounds have been isolated, and chemotaxonomic investigations of Veronica have revealed that iridoid glucosides - including aucubin, catalpol, and 6-O-catalpol derivatives - are characteristic of this genus. Modern pharmacological studies and clinical practice have demonstrated that extracts or monomeric compounds from Veronica have several pharmacological actions, such as anti-inflammatory, anti-oxidative, anticancer, antibacterial, anti-angiogenic, antineurodegenerative, neuroprotective, and hepatoprotective effects both in vivo and in vitro.

Identification of Catalposide Metabolites in Human Liver and Intestinal Preparations and Characterization of the Relevant Sulfotransferase, UDP-glucuronosyltransferase, and Carboxylesterase Enzymes

Catalposide, an active component of Veronica species such as Catalpa ovata and Pseudolysimachion lingifolium, exhibits anti-inflammatory, antinociceptic, anti-oxidant, hepatoprotective, and cytostatic activities. We characterized the in vitro metabolic pathways of catalposide to predict its pharmacokinetics. Catalposide was metabolized to catalposide sulfate (M1), 4-hydroxybenzoic acid (M2), 4-hydroxybenzoic acid glucuronide (M3), and catalposide glucuronide (M4) by human hepatocytes, liver S9 fractions, and intestinal microsomes. M1 formation from catalposide was catalyzed by sulfotransferases (SULTs) 1C4, SULT1A1*1, SULT1A1*2, and SULT1E1. Catalposide glucuronidation to M4 was catalyzed by gastrointestine-specific UDP-glucuronosyltransferases (UGTs) 1A8 and UGT1A10; M4 was not detected after incubation of catalposide with human liver preparations. Hydrolysis of catalposide to M2 was catalyzed by carboxylesterases (CESs) 1 and 2, and M2 was further metabolized to M3 by UGT1A6 and UGT1A9 enzymes. Catalposide was also metabolized in extrahepatic tissues; genetic polymorphisms of the carboxylesterase (CES), UDP-glucuronosyltransferase (UGT), and sulfotransferase (SULT) enzymes responsible for catalposide metabolism may cause inter-individual variability in terms of catalposide pharmacokinetics.

Veronica Plants-Drifting from Farm to Traditional Healing, Food Application, and Phytopharmacology

The Veronica genus, with more than 200 species, belongs to the Plantaginaceae family and is distributed over most of the Northern Hemisphere and in many parts of Southern Hemisphere. These plants are traditionally used in medicine for wound healing, in the treatment of rheumatism, and in different human diseases. This paper reviews the chemical composition of some valuable Veronica species, the possibilities Veronica extracts have in food preservation and as food ingredients, and their functional properties. Veronica species represent a valuable source of biological active secondary metabolites, including iridoid glycosides and phenolic compounds. In particular, due to presence of these phytochemicals, Veronica species exhibit a wide spectrum of biological activities, including antimicrobial and antioxidant. In fact, some studies suggest that some Veronica extracts can inhibit foodborne pathogens, such as Listeria monocytogenes, but only a few of them were performed in food systems. Moreover, anticancer, anti-inflammatory, and other bioactivities were reported in vitro and in vivo. The bioactivity of Veronica plants was demonstrated, but further studies in food systems and in humans are required.

Bioactivities of Natural Catalpol Derivatives

Catalpol, a famous molecule of iridoids, possesses extensive pharmacological activities. Our studies found that compounds with low-polarity substituents at the 6-O position of catalpol exhibited higher NF-κB inhibitory potency than catalpol. However, catalpol derivatives are not much focused. Here this review provides extensive coverage of naturally occurring catalpol derivatives discovered from 1888 until 2018. It covers their distribution, chemotaxonomic significance, chemical structures, and bioactivities from more than 200 peer-reviewed articles, and highlights the structure-activity relationship of catalpol derivatives.

Bioactive Constituents of Lamium album L. as Inhibitors of Cytokine Secretion in Human Neutrophils

The traditional role of Lamium album L. (white dead nettle, Lamiaceae) in providing relief from pain in rheumatism as well as vaginal and cervical inflammation was described. The aim of the study was to screen for the anti-inflammatory bioactivity of compounds isolated from aqueous-methanolic extract of Lamium album herb in human neutrophils (PMNs). The effect of the compounds on the inhibition of selected inflammatory markers released by neutrophils, such as cytokines (IL-8, TNF-α), was studied. The molecular masses and the purity of compounds were determined using high-performance liquid chromatography coupled with diode array detection and mass spectrometry (HPLC-DAD-MSⁿ). The level of cytokines production after incubation with the compounds (1–25 µM) was measured by ELISA. Two derivatives of quercetin, not previously described, were isolated in this study. Phenylpropanoids (verbascoside and phlinoside D), as well as iridoids (lamalbid, and shanzhiside methyl ester), and flavonoids revealed to be more significant inhibitors of IL-8 secretion than TNF-α. The compounds at a concentration of 25 µM, except for shanzhiside methyl ester (6), inhibited secretion of IL-8 in the range from 29.1 to 50.0%. In conclusion, L. album might be a valuable source of bioactive compounds and may provide constituents to limit noninfectious inflammation associated with the aforementioned diseases.

Chemical Profiling and Assessment of Antineurodegenerative and Antioxidant Properties of Veronica teucrium L. and Veronica jacquinii Baumg

Neuroprotective potential of V. teucrium and V. jacquinii methanol extracts was analyzed. Chemical analysis of investigated extracts showed the presence of phenolic acid derivatives, flavonoids and one secoiridoid. The detected flavonoids derived from flavones (luteolin and isoscutellarein in V. jacquinii; apigenin, isoscutellarein and luteolin in V. teucrium) and flavonol (quercetin in V. jacquinii). Acteoside was the dominant compound in V. jacquinii, while plantamajoside and isoscutellarein 7-O-(6‴-O-acetyl)-β-allosyl (1‴→2‴)-β-glucoside were the major phenolics in V. teucrium. Additionally, the antineurodegenerative activity was tested at concentrations of 25, 50, and 100 μg/ml using acetylcholinesterase (AChE) and tyrosinase (TYR) assays. The inhibition of both enzymes was achieved with the investigated extracts, ranging from 22.78 to 35.40% for AChE and from 9.57 to 16.38% for TYR. There was no statistical difference between the activities of the analyzed extracts. Our data indicate that V. teucrium and V. jacquinii may have beneficial effects against Alzheimer's and Parkinson's disease.

Veronica officinalis Product Authentication Using DNA Metabarcoding and HPLC-MS Reveals Widespread Adulteration with Veronica chamaedrys

Studying herbal products derived from local and traditional knowledge and their value chains is one of the main challenges in ethnopharmacology. The majority of these products have a long history of use, but non-harmonized trade and differences in regulatory policies between countries impact their value chains and lead to concerns over product efficacy, safety and quality. Veronica officinalis L. (common speedwell), a member of Plantaginaceae family, has a long history of use in European traditional medicine, mainly in central eastern Europe and the Balkans. However, no specified control tests are available either to establish the quality of derived herbal products or for the discrimination of its most common substitute, V. chamaedrys L. (germander speedwell). In this study, we use DNA metabarcoding and high performance liquid chromatography coupled with mass spectrometry (HPLC-MS) to authenticate sixteen V. officinalis herbal products and compare the potential of the two approaches to detect substitution, adulteration and the use of unreported constituents. HPLC-MS showed high resolution in detecting phytochemical target compounds, but did not enable detection of specific plant species in the products. DNA metabarcoding detected V. officinalis in only 15% of the products, whereas it detected V. chamaedrys in 62% of the products. The results confirm that DNA metabarcoding can be used to test for the presence of Veronica species, and detect substitution and/or admixture of other Veronica species, as well as simultaneously detect all other species present. Our results confirm that none of the herbal products contained exactly the species listed on the label, and all included substitutes, contaminants or fillers. This study highlights the need for authentication of raw herbals along the value chain of these products. An integrative methodology can assess both the quality of herbal products in terms of target compound concentrations and species composition, as well as admixture and substitution with other chemical compounds and plants.

Multiple UDP-Glucuronosyltransferase and Sulfotransferase Enzymes are Responsible for the Metabolism of Verproside in Human Liver Preparations

Verproside, an active iridoid glycoside component of Veronica species, such as Pseudolysimachion rotundum var. subintegrum and Veronica anagallis-aquatica, possesses anti-asthma, anti-inflammatory, anti-nociceptive, antioxidant, and cytostatic activities. Verproside is metabolized into nine metabolites in human hepatocytes: verproside glucuronides (M1, M2) via glucuronidation, verproside sulfate (M3) via sulfation, picroside II (M4) and isovanilloylcatalpol (M5) via O-methylation, M4 glucuronide (M6) and M4 sulfate (M8) via further glucuronidation and sulfation of M4, and M5 glucuronide (M7) and M5 sulfate (M9) via further glucuronidation and sulfation of M5. Drug-metabolizing enzymes responsible for verproside metabolism, including sulfotransferase (SULT) and UDP-glucuronosyltransferase (UGT), were characterized. The formation of verproside glucuronides (M1, M2), isovanilloylcatalpol glucuronide (M7), and picroside II glucuronide (M6) was catalyzed by commonly expressed UGT1A1 and UGT1A9 and gastrointestinal-specific UGT1A7, UGT1A8, and UGT1A10, consistent with the higher intrinsic clearance values for the formation of M1, M2, M6, and M7 in human intestinal microsomes compared with those in liver microsomes. The formation of verproside sulfate (M3) and M5 sulfate (M9) from verproside and isovanilloylcatalpol (M5), respectively, was catalyzed by SULT1A1. Metabolism of picroside II (M4) into M4 sulfate (M8) was catalyzed by SULT1A1, SULT1E1, SULT1A2, SULT1A3, and SULT1C4. Based on these results, the pharmacokinetics of verproside may be affected by the co-administration of relevant UGT and SULT inhibitors or inducers.

Bioactivity-guided isolation of antioxidant and anti-hepatocarcinoma constituents from Veronica ciliata

Background

Veronica ciliata Fisch., widely distributed in western China, has been traditionally used in Tibetan Medicine as a treatment for hepatitis, cholecystitis, rheumatism, and urticaria. However, V. ciliata Fisch. has not been subjected to detailed chemical constitution analysis and the bioactive studies were restricted to its crude extracts. It is necessary to investigate the active chemical components of these extracts and identify their biological effects.

Results

Four iridoid glycosides, (veronicoside, cataposide, amphicoside, and verminoside) were isolated from the ethyl acetate fraction. Among these compounds, veronicoside and verminoside were isolated for the first time from this plant. These compounds exhibited strong antioxidant activity and inhibitory activity on HepG2 cell proliferation. The antioxidant activity of verminoside was equal to Vc. Cataposide, amphicoside and verminoside had stronger anti-hepatocarcinoma activity than 5-fluorouracil.

Conclusions

Four iridoid glycosides,(veronicoside, cataposide, amphicoside and verminoside) were isolated from the extract of V. ciliata Fisch. using bioassay-guided screening.Among these compounds, veronicoside and verminoside were isolated for the first time from this plant. The above results indicated that these compounds were the active chemical components responsible for the antioxidant and anti-hepatocarcinoma properties of V. ciliata Fisch. The underlying mechanism of their bioactivity is worthy of further investigation.

Ethnopharmacological in vitro studies on Austria's folk medicine--an unexplored lore in vitro anti-inflammatory activities of 71 Austrian traditional herbal drugs

ETHNOPHARMACOLOGICAL RELEVANCE

In Austria, like in most Western countries, knowledge about traditional medicinal plants is becoming scarce. Searching the literature concerning Austria's ethnomedicine reveals its scant scientific exploration. Aiming to substantiate the potential of medicinal plants traditionally used in Austria, 63 plant species or genera with claimed anti-inflammatory properties listed in the VOLKSMED database were assessed for their in vitro anti-inflammatory activity.

MATERIAL AND METHODS

71 herbal drugs from 63 plant species or genera were extracted using solvents of varying polarities and subsequently depleted from the bulk constituents, chlorophylls and tannins to avoid possible interferences with the assays. The obtained 257 extracts were assessed for their in vitro anti-inflammatory activity. The expression of the inflammatory mediators E-selectin and interleukin-8 (IL-8), induced by the inflammatory stimuli tumor necrosis factor alpha (TNF-α) and the bacterial product lipopolysaccharide (LPS) was measured in endothelial cells. The potential of the extracts to activate the nuclear factors PPARα and PPARγ and to inhibit TNF-α-induced activation of the nuclear factor-kappa B (NF-κB) in HEK293 cells was determined by luciferase reporter gene assays.

RESULTS

In total, extracts from 67 of the 71 assessed herbal drugs revealed anti-inflammatory activity in the applied in vitro test systems. Thereby, 30 could downregulate E-selectin or IL-8 gene expression, 28 were strong activators of PPARα or PPARγ (inducing activation of more than 2-fold at a concentration of 10µg/mL) and 21 evoked a strong inhibition of NF-κB (inhibition of more than 80% at 10µg/mL).

CONCLUSION

Our research supports the efficacy of herbal drugs reported in Austrian folk medicine used for ailments associated with inflammatory processes. Hence, an ethnopharmacological screening approach is a useful tool for the discovery of new drug leads.

Anti-inflammatory activity of iridoids and verbascoside isolated from Castilleja tenuiflora

Castilleja tenuiflora (Orobanchaceae) has been used in Mexican traditional medicine as a treatment for cough, dysentery, anxiety, nausea and vomiting as well as hepatic and gastrointestinal diseases. The ethanolic extract of the aerial parts of Castilleja tenuiflora was separated by silica gel column chromatography. The fractions were evaluated using the induced edema acetate 12-O-tetradecanoylphorbol (TPA) anti-inflammatory activity model. The most active fraction was subjected to medium-pressure liquid chromatography (MPLC) with UV detection at 206 and 240 nm. The following iridoids were isolated: geniposidic acid, aucubin, bartioside, 8-epi-loganin, mussaenoside, and the phenylpropanoid verbascoside. The most active iridoid was geniposidic acid, which was more active than the control (indomethacin), and the least active iridoid was mussaenoside. 8-epi-Loganin, and mussaenoside have not been previously reported to be anti-inflammatory compounds. The results of these investigations confirm the potential of Mexican plants for the production of bioactive compounds and validate the ethnomedical use of Castilleja tenuiflora-like anti-inflammatory plants.

Antibacterial activity of Veronica montana L. extract and of protocatechuic acid incorporated in a food system

This study was designed to evaluate the antibacterial activity of the Veronica montana L. water extract and its main phenolic compound, protocatechuic acid. The antibacterial activity was determined by microdilution assay against six strains of Gram-positive and Gram-negative bacteria. Listeria monocytogenes was the most sensitive of the tested bacterial species. Antibacterial preserving properties of protocatechuic acid were also evaluated after its incorporation in cream cheese, using L. monocytogenes as commonly cheese contaminant. The compound successfully inhibited L. monocytogenes development in cream cheese, at room temperature and in refrigerator (25°C and 4°C, respectively), after 3days of inoculation. Sensory evaluation was carried out in order to validate the mentioned food system. A possible mode of action of the tested compound towards bacterial cells was assessed and appears to be direct lysis of pathogenic cytoplasmic membrane. Prediction of pharmacokinetic properties was also performed using computational analyzes. The obtained results can serve as an important platform for the development of effective natural preservatives.

Traditionally used Veronica officinalis inhibits proinflammatory mediators via the NF-κB signalling pathway in a human lung cell line

ETHNOPHARMACOLOGICAL RELEVANCE

Extracts from Veronica officinalis L. are traditionally used for the treatment of lung diseases; however, the effective compounds and the mode of action are still unknown.

AIM OF THE STUDY

Here we analyzed the effects of a standardized Veronica extract on genes expression and signalling protein production associated with the development of inflammatory lung diseases.

MATERIAL AND METHODS

The degranulation capacity of primary mast cells, as well as gene expression and release of inflammatory mediators from human lung epithelial cells (A549 cells) were analyzed in relation to the synthetic drugs azelastine and dexamethasone. Gene and protein expression of cyclooxygenase-2 were investigated by semi-quantitative RT-PCR and western blotting, respectively. The involvement of phosphorylated mitogen-activated protein kinases and NF-κB signaling in regulation of these molecules were characterized by western blotting and electrophoretic mobility shift assays. Characteristic extract components were identified by LC-MS and verminoside was quantified by HPLC analysis.

RESULTS

We demonstrated that Veronica officinalis has a small influence on the degranulation capacity of mast cells but rather inhibits gene and protein expression of the chemokine eotaxin in A549 lung epithelial cells, which is essential for recruitment of inflammatory-associated cells in lung diseases. Furthermore, release of the inflammatory mediator PGE(2) was diminished through inhibition of COX-2 expression via the NF-κB signaling pathway in TNF-α-activated A549 cells. Phytochemical analysis identified verproside and verminoside as the most abundant iridoid glycosides.

CONCLUSION

Our results are a contribution to explaining the observed anti-inflammatory effects of Veronica offcinalis extract on a molecular level. However, its clinical potency has at first to be proven in animals and subsequently in clinical trials.

In vitro and in vivo metabolism of verproside in rats

Verproside, a catalpol derivative iridoid glycoside isolated from Pseudolysimachion rotundum var. subintegrum, is a biologically active compound with anti-inflammatory, antinociceptic, antioxidant, and anti-asthmatic properties. Twenty-one metabolites were identified in bile and urine samples obtained after intravenous administration of verproside in rats using liquid chromatography-quadrupole Orbitrap mass spectrometry. Verproside was metabolized by O-methylation, glucuronidation, sulfation, and hydrolysis to verproside glucuronides (M1 and M2), verproside sulfates (M3 and M4), picroside II (M5), M5 glucuronide (M7), M5 sulfate (M9), isovanilloylcatalpol (M6), M6 glucuronide (M8), M6 sulfate (M10), 3,4-dihydroxybenzoic acid (M11), M11 glucuronide (M12), M11 sulfates (M13 and M14), 3-methyoxy-4-hydroxybenzoic acid (M15), M15 glucuronides (M17 and M18), M15 sulfate (M20), 3-hydroxy-4-methoxybenzoic acid (M16), M16 glucuronide (M19), and M16 sulfate (M21). Incubation of verproside with rat hepatocytes resulted in thirteen metabolites (M1–M11, M13, and M14). Verproside sulfate, M4 was a major metabolite in rat hepatocytes. After intravenous administration of verproside, the drug was recovered in bile (0.77% of dose) and urine (4.48% of dose), and O-methylation of verproside to picroside II (M5) and isovanilloylcatalpol (M6) followed by glucuronidation and sulfation was identified as major metabolic pathways compared to glucuronidation and sulfation of verproside in rats.

In vivo and in vitro antioxidant effects of three Veronica species

The aim of the present study was to examine the antioxidant activity of three Veronica species (Plantaginaceae). The antioxidant potential of various extracts obtained from aerial flowering parts was evaluated by DPPH-free (1,1-diphenyl-2-picrylhydrazyl-free) radical scavenging activity and ferric-reducing antioxidant power assays. Considerable antioxidant activity was observed in the plant samples (FRAP values ranged from 0.97 to 4.85 mmol Fe2+/g, and DPPH IC50 values from 12.58 to 66.34 µg/ml); however, these levels were lower than the activity of the control compound butylated hydroxytoluene (BHT) (FRAP: 10.58 mmol Fe2+/g; DPPH IC50: 9.57 µg/ml). Also, the in vivo antioxidant effects were evaluated in several hepatic antioxidant systems in rats (activities of glutathione peroxidase, glutathione reductase, peroxidase, catalase, xanthine oxidase, glutathione content and level of thiobarbituric acid reactive substances) after treatment with different Veronica extracts, or in combination with carbon tetrachloride (CCl4). Pretreatment with 100 mg/kg b.w. of Veronica extracts inhibited CCl4-induced liver injury by decreasing TBA-RS level, increasing GSH content, and bringing the activities of CAT and Px to control levels. The present study suggests that the extracts analyzed could protect the liver cells from CCl4-induced liver damage by their antioxidative effect on hepatocytes.

Anti-inflammatory iridoids of botanical origin

Inflammation is a manifestation of a wide range of disorders which include; arthritis, atherosclerosis, Alzheimer's disease, inflammatory bowel syndrome, physical injury and infection amongst many others. Common treatment modalities are usually nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin, paracetamol, indomethacin and ibuprofen as well as corticosteroids such as prednisone. These however, may be associated with a host of side effects due to non-selectivity for cyclooxygenase (COX) enzymes involved in inflammation and those with selectivity may be highly priced. Thus, there is a continuing search for safe and effective antiinflammatory molecules from natural sources. Research has confirmed that iridoids exhibit promising anti-inflammatory activity which may be beneficial in the treatment of inflammation. Iridoids are secondary metabolites present in various plants, especially in species belonging to the Apocynaceae, Lamiaceae, Loganiaceae, Rubiaceae, Scrophulariaceae and Verbenaceae families. Many of these ethnobotanicals have an illustrious history of traditional use alluding to their use to treat inflammation. Although iridoids exhibit a wide range of pharmacological activities such as cardiovascular, hepatoprotection, hypoglycaemic, antimutagenic, antispasmodic, anti-tumour, antiviral, immunomodulation and purgative effects this review will acutely focus on their anti-inflammatory properties. The paper aims to present a summary for the most prominent iridoid-containing plants for which anti-inflammatory activity has been demonstrated in vitro and / or in vivo.

In vitro cytotoxic activity and structure activity relationships of iridoid glucosides derived from Veronica species

This study was an investigation of the cytotoxic activity of iridoid glucosides, including aucubin, catalpol, 6-O-acetylcatalpol, veronicoside, catalposide, verproside, amphicoside, veratroylcatalposide, verminoside, aquaticosides B and C isolated from different Veronica species. The cytotoxic activity was determined against Hep-2 (human epidermoid carcinoma), RD (human rhabdomyosarcoma), L-20B (transgenic murine L-cells) cancer cell lines and Vero (African green monkey kidney cells) non-cancerous cell line using the MTT method. While verminoside, amphicoside and veronicoside were found to exhibit cytotoxic activity in the concentration range of 70-355 µM, acetylcatalpol, aquaticosides B and C, catalposide, veratroylcatalposide and verproside showed cytostatic activity. Apoptotic cell death was observed as the effect of verminoside in the histological analysis of the tested cell lines. In conclusion, iridoid glucosides are considered to show a biphasic effect on cancer cells that is both cytostatic and cytotoxic, depending on the chemical structure and the type of cancer cell.

Liquid chromatography-mass spectrometry for the simultaneous determination of the catalpol-related iridoid glucosides, verproside, isovanilloylcatalpol, catalposide and 6-O-veratroyl catalpol in rat plasma

Verproside, isovanilloylcatalpol, catalposide and 6-O-veratroyl catalpol are bioactive iridoid glucosides isolated from in a number of folk medicinal plants. A rapid, sensitive and selective liquid chromatography/mass spectrometric (LC/MS) method for the simultaneous determination of verproside, isovanilloylcatalpol, catalposide and 6-O-veratroyl catalpol in rat plasma was developed. The analytes were extracted from 50 microL of rat plasma with ethyl acetate using 7-carboxymethyloxy-3',4',5-trimethoxyflavone as internal standard and analyzed on an X-Bridge C(18) column within 6.5 min with 40% methanol in 10 mm ammonium formate (pH 3.0). The analytes were quantified using an electrospray ionization mass spectrometry in the selected ion monitoring mode. The standard curves were linear over the concentration ranges of 10-2000 ng/mL for verproside, isovanilloylcatalpol and catalposide and 20-2000 ng/mL for 6-O-veratroyl catalpol. The coefficients of variation and relative errors of verproside, isovanilloylcatalpol, catalposide and 6-O-veratroyl catalpol for intra- and inter-assay at four quality control levels were 2.5-8.0 and-4.0-6.6%, respectively. This method was successfully applied to the pharmacokinetic study of verproside and its possible metabolite isovanilloylcatalpol after intravenous administration of verproside, a candidate anti-asthma drug, in male Sprague-Dawley rats.

Oleanolic acid isolated from Oldenlandia diffusa exhibits a unique growth inhibitory effect against ras-transformed fibroblasts

AIMS

Oldenlandia diffusa (Willd.) Roxb. (O. diffusa) is a commonly used traditional Chinese medicine for treating cancer. Its pharmacological activities and anti-cancer effects have been the focus of intense research in recent years. In the present study, we aim to investigate whether the five major compounds from O. diffusa possess a unique inhibitory activity against ras-transformed cells in a well-established cell model.

MAIN METHODS

The anti-cancer effects of O. diffusa were assessed in a co-culture system containing normal and transformed Rat 6 (R6) fibroblasts. In addition, a transwell assay was used to examine the interaction between the drugs and the co-cultivated cells.

KEY FINDINGS

Our data showed that among the samples tested, oleanolic acid (OA), but not the structural isomer ursolic acid (UA), inhibits the growth of ras oncogene-transformed R6 cells at a dosage that is not toxic to the co-cultivated normal fibroblasts. A significant inhibitory effect was also observed in the transwell experiments, indicating that the mode of action for OA-mediated growth inhibition of transformed cells does not require direct cell-to-cell contact between normal and ras-transformed cells. Data obtained from experiments conducted with the conditioned medium that was collected from normal R6 cells treated with OA also suggest that OA might cause normal cells to secrete inhibitory factor(s) against the transformed cells. The enhanced ability of OA to cause cytotoxicity in transformed cells in the presence of normal fibroblasts is also observed with the human hepatocellular carcinoma cell line, SMMC-7721.

SIGNIFICANCE

The present study demonstrates that OA may possess both cancer chemotherapeutic and chemopreventive activities. Thus, it may have great potential for clinical application as a novel anti-cancer drug.

Alternative and complementary antileishmanial treatments: assessment of the antileishmanial activity of 27 Lebanese plants, including 11 endemic species

Aqueous, methanolic, and dichloromethane extracts from 27 Lebanese plants were investigated for their in vitro immunomodulatory and antileishmanial activities as compared to their toxicity against human cells. Extracts from yellow chamomile (Anthemis tinctoria), white larkspur (Consolida rigida), Syrian broom (Cytisus syriacus), coast spurge (Euphorbia paralias), shield fibigia (Fibigia clypeata), Auchers golden-drop (Onosma aucheriana), shell-flower sage (Salvia multicaulis), snowy woundwort (Stachys nivea), Palestine woundwort (Stachys palaestina), and polium-leaved speedwell (Veronica polifolia) exhibited interesting antileishmanial activities on the intracellular amastigote form of the parasite, while several extracts from A. tinctoria, F. clypeata, and O. aucheriana were shown to induce nitrous oxide (NO) production by human macrophages. Further experiments should be performed in order to purify and characterize the chemical compounds responsible for these activities.

Phenolic compounds of Sideritis ozturkii and their in vivo anti-inflammatory and antinociceptive activities

Acetone extract from aerial parts of Sideritis ozturkii Aytaç & Aksoy and its fractions were investigated for its in vivo anti-inflammatory and antinociceptive activities. For the anti-inflammatory activity assessment, carrageenan-induced hind paw edema and for the antinociceptive activity, p-benzoquinone-induced abdominal constriction tests were used. Acetone extract of the plant and its phenolic fraction were found to possess significant inhibitory activity on these in vivo models in mice. Ozturkoside A (chrysoeriol 7-O-[2'''-O-caffeoyl-6'''-O-acetyl-beta-d-glucopyranosyl-(1-->2)-beta-d-glucopyranoside]); ozturkoside B (chrysoeriol 7-O-[2'''-O-caffeoyl-beta-d-glucopyranosyl-(1-->2)-beta-d-glucopyranoside]); and ozturkoside C (chrysoeriol 7-O-[2'''-O-p-coumaroyl-6'''-O-acetyl-beta-d-glucopyranosyl-(1-->2)-beta-d-glucopyranoside]) were isolated from the active phenolic fraction. The structures of isolated compounds were elucidated by spectroscopic techniques (UV, IR, 1D- and 2D-NMR, MS). Ozturkoside C showed notable antinociceptive and anti-inflammatory activities without inducing any apparent acute toxicity or gastric damage. Although the activity of ozturkosides A and B were found insignificant in statistical analysis, some inhibitory effect was observed. Accordingly, it is suggested that these components in phenolic fraction might possibly share the antinociceptive and anti-inflammatory activities together.

Determination of iridoid glucosides for quality assessment of Herba Oldenlandiae by high-performance liquid chromatography

Herba Oldenlandiae, the dried herb of Oldenlandia diffusa (WILLD.) ROXB. (Family Rubiaceae), is officially listed in the Chinese Pharmacopoeia. In the herbal market, two substitutes originated from O. corymbosa (L.) LAM and O. tenelliflora BL. are commonly used. In light of this, the target in setting up a method for quality assessment of Herba Oldenlandiae is urgently needed. In this article, a simple and reliable high-performance liquid chromatographic (HPLC) method was developed for quantifying asperuloside (1), E-6-O-p-coumaroyl scandoside methyl ester (2) and E-6-O-p-coumaroyl scandoside methyl ester-10-methyl ether (3) in Herba Oldenlandiae derived from O. diffusa. Among them, compound 3 is a new compound isolated from O. diffusa. All these unique compounds were used as markers for the first time in the quality assessment of Herba Oldenlandiae. The results showed that the contents of compounds 1-3 were significantly varied among different samples whilst those of compounds 2 and 3 were found to be lower in contents in the two substitutes of O. diffusa. The analytical method is suitable for quality control of Herba Oldenlandiae and useful in differentiation from its confusable species. The method has been fully validated with satisfactory linearity, accuracy, precision and stability.