Acylated flavonoids and phenol glycosides from Veronica thymoides subsp. pseudocinerea

Chemical Constituents of Thesium chinense Turcz and Their In Vitro Antioxidant, Anti-Inflammatory and Cytotoxic Activities

Three novel compounds (1–3) along with twenty-six known compounds, two known steroids (4–5) and twenty-four known phenylpropanoids (6–29) were isolated from the whole plant of Thesium chinense Turcz. The structures of the three new compounds were elucidated on the basis of ESI-MS, HR-ESIMS, 1D and 2D NMR, IR, UV spectroscopic data. The absolute stereochemistry of compound 1 was determined by the Gauge-Including Atomic Orbitals (GIAO) method. The in vitro antioxidant, anti-inflammatory and cytotoxic activities of the isolated compounds were evaluated by DPPH radical-scavenging assay, LPS-activated RAW 264.7 cells model and CCK-8 kit, respectively. Compound 11 showed high antioxidant activity with an SC50 value of 16.2 ± 1.6 μM. Compound 21 showed considerable anti-inflammatory activity with an IC50 value of 28.6 ± 3.0 μM. Compounds 4 and 5 displayed potent cytotoxic activity against human NCI-H292, SiHa, A549, and MKN45 cell lines, with the compound 4 having IC50 values of 17.4 ± 2.4, 22.2 ± 1.1, 9.7 ± 0.9, 9.5 ±0.7 μM, and the compound 5 having all IC50 values less than 0.1 μM in vitro.

A new monoterpenoid glycoside and a new phenolic glycoside isolated from Dracocephalum moldavica and their anti-complementary activity

A new monoterpenoid glycoside (1 R, 2 R, 4S)-1,8-epoxy-p-menthan-2-O-β-D-glucopyranosyl-(1→4)-β-D-glucopyranoside (1) and a new phenolic glycoside, cis-1-(3-hydroxy-4-methoxyphenyl)-2-butene-4-O-α-L-rhamnopyranosyl-(1→3)-O-β-D-glucopyranoside (2) were isolated from the dried aerial parts of Dracocephalum moldavica, together with 12 known compounds. Compound 5 was isolated from the Lamiaceae family for the first time, compounds 3, 4, 6 and 8-12 were identified from the genus Dracocephalum for the first time and compounds 7 and 13-14 were reported from the D. moldavica for the first time. All the compounds were evaluated for anti-complementary activity against the classical and alternative pathways. Compounds 2-4, 8 and 11 showed anti-complementary activity to different extents, with CH₅₀ and AP₅₀ values ranging from 0.78-1.24 and 1.52-1.84 mM, respectively. The targets of compounds 2-4, 8 and 11 in complement activation cascade were identified as well.

Luteolin: A promising natural agent in management of pain in chronic conditions

Pain due to chronic conditions is a frequent and insufficiently addressed problem. Current drug options for pain management (either in cases of chronic inflammatory conditions or neuropathy) do not adequately treat pain. Moreover, they are associated with important adverse events in long term use. Luteolin is a flavonoid widely present in the plant kingdom and its sources have been assembled in a comprehensive list of this paper. Luteolin has shown in several research studies a range of pharmacological properties; anti-inflammatory, antioxidant, neuroprotective, and analgesic. In this article, we summarize the effects and potential benefits from introducing luteolin as an adjuvant agent in established protocols for pain management. We review the most indicative in vivo and in vitro evidence of how luteolin can target the molecular pathways involved in pathogenesis of chronic inflammatory and neuropathic pain. The data reviewed strongly support luteolin's promising benefits in pain management and raise the need for further clinical trials that can establish its role in clinical practice.

Bioprospecting the Metabolome of Plant Urtica dioica L.: A Fast Dereplication and Annotation Workflow in Plant Metabolomics

Plants have a pivotal role in ethnopharmacology, and their preparations are in use globally. However, getting down to the structure requires an effective workflow and mostly requires a time-consuming isolation process. Although bioassay-guided approaches are widely popular, they face a massive problem of rediscovery in recent times, especially in plant metabolomics. Mass spectrometry (MS)-based approach incorporated molecular networking via Global Natural Product Social Molecular Networking (GNPS) is considered here for the benefit of the fast screening of secondary metabolites. This study uses direct crude extracts obtained from various parts of the Urtica dioica plant for the characterization of secondary metabolites. The crude extract of the plant initially displayed promising antioxidant and anti-diabetic activities. Then, we employed mass spectrometry-based dereplication to identify the phytochemical components in the extracts. This led to the discovery of 7 unknown and 17 known secondary metabolites, which were further verified with the SIRIUS 4 platform, a computational tool for the annotation of compounds using tandem MS data. On the other hand, chasing the antioxidant activity of methanolic extract of U. dioica leaves, we employed a bioassay-guided isolation approach. With this method, we isolated and characterized compound 13, a known molecule, which possessed strong antioxidant activity without showing much toxicity in the brine shrimp lethality test at the test concentration of 1 mg/mL. With our results, we advocate the MS-based approach as a good starting point for the dereplication of compounds from the complex crude extracts of plants.

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.

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.

Ferulic Acid and Naturally Occurring Compounds Bearing a Feruloyl Moiety: A Review on Their Structures, Occurrence, and Potential Health Benefits

The ubiquitous compound 4-hydroxy-3-methoxycinnamic acid, also known as ferulic acid (FA), constitutes a bioactive ingredient of many foods that may offer beneficial effects against disorders related to oxidative stress, including cancer, diabetes, and neurodegenerative diseases. This review discusses the antioxidant properties of FA, establishing relationships to several biological activities already described for this natural product. Next, 387 naturally occurring compounds, all isolated from plants and published between 1990 and 2015, the structures of which bear 1 or more feruloyl moieties, are covered in this review along with their structural formulas, botanical sources, and bioactivities. The compounds' distribution, structural patterns, bioactivities, and perspectives on food research are also succinctly discussed.

Anti-Inflammatory Constituents from Bidens frondosa

A new polyacetylene glucoside (3E,5E,11E)-tridecatriene-7,9-diyne-1,2,13-triol-2-O-β-D-glucopyranoside (1), a new phenylpropanoid glucoside 2'-butoxyethylconiferin (2), and a new flavonoid glycoside 8,3',4'-trihydroxyflavone-7-O-(6''-O-p-coumaroyl)-β-D-glucopyranoside (3), have been isolated from Bidens frondosa together with fifty-three known compounds 4-56. The structures of these compounds were established by spectroscopic methods. mainly ESIMS, 1D- and 2D-NMR spectroscopic data. and comparison with literature data. Compounds 1-34, 36, 39, 43, 47, 51, and 52 were tested for inhibition of nuclear factor kappa B (NF-κB) in 293-NF-κB-luciferase report cell line induced by lipopolysaccharide (LPS), and compounds 1, 2, 3, 9, 15, 21, 24 and 51 were tested for the production of TNF-α, IL-1β, IL-6, IL-10 in RAW 264.7 macrophages induced by LPS. In conclusion, the isolated compounds 1, 2, 3, 9, 15, 21, 24 and 51 exhibited significant activity in anti-inflammatory activity assays.

NMR spectroscopic method for the assignment of 3,5-dioxygenated aromatic rings in natural products

In recent years, certain "new" naturally occurring compounds (1-28) with 3,5-dioxygenated aromatic rings have been reported. A comparison of the NMR data of these compounds with the data of four model compounds (A-D) indicated that the structures of these "new" compounds were erroneous. The reason for the incorrect elucidation of the structures of 1-28 was attributed to "deceptively simple" (1)H NMR spectra, which displayed two broad singlets with integrations of 1:2 for H-2 and H-5, H-6, respectively. To expose the misleading results from the spectra, serial (1)H NMR experiments on compounds A-D were performed using various deuterated solvents and temperatures. The results revealed separated proton signals for the ABX system in certain deuterated solvents. Additionally, the characteristic differences between 3,4- and 3,5-dioxygenated aromatic rings in their (13)C NMR spectra are summarized based on our experiment and data reported. This approach is useful for analyzing the patterns of dioxygenated aromatic rings in natural products, especially when "deceptively simple" (1)H NMR spectra are displayed.

Chemical profile and biological activities of Veronica thymoides subsp. pseudocinerea

CONTEXT

In Turkey, Veronica species (Plantaginaceae) have been used as a diuretic and for wound healing in traditional medicine.

OBJECTIVE

To examine the fatty acid and essential oil profiles, the antioxidant, anticholinesterase, antimicrobial, and DNA damage effects of Veronica thymoides P.H. Davis subsp. pseudocinerea M.A. Fischer as a potential source of natural active compounds.

MATERIALS AND METHODS

GC/MS was used to analyze essential oil and fatty acid obtained from whole plant. The antioxidant activity was evaluated by the β-carotene-linoleic acid test system, DPPH-free and ABTS cation radicals scavenging, and cupric reducing antioxidant capacity assays. The anticholinesterase and antimicrobial activities were determined by Ellman and broth macrodillution methods, respectively. The effect of the methanol extract on DNA cleavage was investigated.

RESULTS

Hexatriacontene (21.0%) was found to be the main constituent in essential oil, and linoleic acid (25.2%) and palmitic acid (20.6%) in fatty acid. Methanol extract demonstrated the best IC50 values in lipid peroxidation (49.81 ± 0.31 µg/ml) and DPPH-free radical scavenging activity (15.32 ± 0.17 µg/ml). Methanol and water extracts possessed strong ABTS cation radical scavenging activity with IC50 values 9.15 ± 0.28 and 8.90 ± 0.1  µg/ml, respectively. The acetone extract exhibited moderate butyrylcholinesterase inhibitory activity. The highest antimicrobial activity was determined in methanol extract against Escherichia coli with 31.25 µg/ml MIC value. Inhibition of methanol extract on plasmid DNA cleavage by OH radicals was found to be 93.32% at 500 µg/ml.

CONCLUSION

The methanol extract having strong antioxidant and DNA damage effects could be investigated phytochemically to find natural active compounds.

Five new phenolic glycosides from Hedyotis scandens

Five new phenolic glycosides, hedyotosides A-E (1-5), including a new cyanogenic glycoside (1), along with 10 known compounds (6-15) were isolated from the whole plants of Hedyotis scandens. The structures of compounds 1-5 were established by extensive spectroscopic analyses and acid hydrolysis. All the isolated compounds were evaluated for their in vitro antiviral activity against respiratory syncytial virus (RSV) with cytopathic effect (CPE) reduction assay. Compounds 6 and 15 showed anti-RSV effects with IC(50) values of 20 and 25 μg/mL, respectively.

Anti-HBV active flavone glucosides from Euphorbia humifusa Willd

Thirteen flavone glucosides from the herb of Euphorbia humifusa were isolated and elucidated. Among them, five compounds including apigenin-7-O-β-D-glucopyranoside (2), apigenin-7-O-(6''-O-galloyl)-β-D-glucopyranoside (3), luteolin-7-O-β-D-glucopyranoside (7), luteolin-7-O-(6''-O-trans-feruloyl)-β-D-glucopyranoside (8) and luteolin-7-O-(6''-O-coumaroyl)-β-D-glucopyranoside (9) showed anti-HBV activity in vitro. The structure-activity relationship showed that the parent structure was closely relevant to the anti-HBV activity of these compounds (agigenin>luteolin>quercetin). It was found that the number of glucoside in the structure may significantly influence their activities (flavone monoglucoside>flavone diglucoside) and cytotoxicity (flavone>flavone monoglucoside>flavone diglucoside). In addition, the substitution of acyl group on glucoside may be important to keep the anti-HBV activities of these compounds (galloyl>feruloyl>coumaroyl).

New antioxidant phenylethanol glycosides from Torenia concolor

Two new phenylethanol glycosides, phenylethyl-O-alpha-l-rhamnopyranosyl-(1 --> 2)-beta-D-glucopyranoside (torenoside A, 1) and 2'-O-3,4-dihydroxy-beta-phenylethoxy-O-alpha-L-rhamnopyranosyl-(1'' --> 3')-(4'-O-caffeoyl)-beta-D-glucopyranoside (torenoside B, 2), along with the 17 known compounds (3-19) were isolated from Torenia concolor. Those structures were established on the basis of spectroscopic analysis including NMR spectroscopic techniques (13C, 1H, 1H-1H COSY, HMQC, HMBC, TOCSY, and NOESY). Moreover, phenylethanol glycosides 3-6 exhibited significant antioxidant activities in DPPH radical scavenging assay.

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.

An apigenin-derived xanthine oxidase inhibitor from Palhinhaea cernua

Fractionation of the ethanol extract of Palhinhaea cernua afforded a new (1) and two known p-coumaroylated apigenin glycosides (2, 3) in addition to dillenetin, rhamnazin, alpha-onocerin, beta-sitosterol, and (E)-2-hydroxy-5-methoxycinnamic acid. The structure of compound 1 was elucidated as apigenin-4'-O-(2' '-O-p-coumaroyl)-beta-D-glucopyranoside by a combination of its spectroscopic data. The new glycoside 1 inhibits xanthine oxidase (IC(50): 23.95 +/- 0.43 microM) in a competitive-noncompetitive manner with K(i) and K(I) values of 14.35 and 93.68 microM, whereas compounds 2 and 3 were inactive. The distribution and significance of acylated flavonoid glycosides are discussed.