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Type 2 diabetes mellitus is a major health problem and a societal burden. Individuals with prediabetes are at increased risk of type 2 diabetes mellitus. Catalpol, an iridoid glycoside, has been reported to exert a hypoglycaemic effect in db/db mice, but its effect on the progression of prediabetes is unclear. In this study, we established a mouse model of prediabetes and examined the hypoglycaemic effect, and the mechanism of any such effect, of catalpol. Catalpol (200 mg/(kg·day)) had no effect on glucose tolerance or the serum lipid level in a mouse model of impaired glucose tolerance-stage prediabetes. However, catalpol (200 mg/(kg·day)) increased insulin sensitivity and decreased the fasting glucose level in a mouse model of impaired fasting glucose/impaired glucose tolerance-stage prediabetes. Moreover, catalpol increased the mitochondrial membrane potential (1.52-fold) and adenosine triphosphate content (1.87-fold) in skeletal muscle and improved skeletal muscle function. These effects were mediated by activation of the insulin receptor-1/glucose transporter type 4 (IRS-1/GLUT4) signalling pathway in skeletal muscle. Our findings will facilitate the development of a novel approach to suppressing the progression of diabetes at an early stage. Novelty Catalpol prevents the progression of prediabetes in a mouse model of prediabetes. Catalpol improves insulin sensitivity in skeletal muscle. The effects of catalpol are mediated by activation of the IRS-1/GLUT4 signalling pathway.

Gaultheria berries (Ericaceae) are consumed as food or used in folk medicine throughout the world. In the present study, Gaultheria tenuifolia berries were studied to describe their polyphenol and iridoid composition, aroma volatiles, and cytoprotective effects. In total, 14 metabolites were isolated using a combination of countercurrent chromatography and Sephadex LH-20, namely, cyanidin-3-O-β-galactoside, cyanidin-3-O-β-arabinoside, 3-O-caffeoylquinic acid, 5-O-caffeoylshikimic acid, quercetin, quercetin-3-O-β-glucuronide, quercetin-3-O-β-rutinoside, quercetin-3-O-β-glucoside, quercetin-3-O-β-arabinoside, quercetin-3-O-β-rhamnoside, 6α-hydroxydihydromonotropein-10-trans-cinnamate, monotropein-10-trans-cinnamate, and an (epi)-catechin dimer and trimer. Other flavan-3-ols, proanthocyanidins, and iridoids were tentatively identified by spectroscopic and spectrometric means in the fruit extracts. The tentative volatile organic compound characterization pointed to methyl salicylate as responsible for the aroma of this species. The extracts showed significant cytoprotective effects in an oxidative stress model in human gastric epithelial cells. This is the first report on the isolation, characterization, and potential biological activity of secondary metabolites from G. tenuifolia berries and insights on its possible application as a functional food. PRACTICAL APPLICATION: Berries are desirable fruit species because of their phytochemical composition and pleasant taste. Gaultheria berries are special due to their high content of iridoids and the presence of salicylic acid derivatives. Aroma of native berries is relevant for the development of new products reflecting the local identity and use of fruits. The present work involves cooperation of academia and industry on the constituents of the native products. The results provided in this article could be useful for the introduction of this species in the food and nutraceutical industries.

Ligustri Lucidi Fructus (LLF) is a traditional Chinese medicine to treat osteopathic and hepatic diseases. Wine steaming is the major processing method for LLF in Chinese Pharmacopoeia, but the chemical changes involved are still unclear. In this study, a research strategy was proposed to reveal the chemical changes during wine steaming processing of LLF. Firstly, in total 104 compounds were tentatively identified using UHPLC/Orbitrap-MS. Secondly, potential chemical changes were revealed by comparing the peak areas of the 104 compounds between LLF and the corresponding wine-steamed LLF (WLLF). The results indicated that iridoid and phenylethanoid esters were readily hydrolyzed during wine steaming processing, while organic acids, flavonoids, and triterpenes were stable. Finally, 7 selected compounds were simultaneously determined in 21 batches of LLF/WLLF samples using a 10-min UPLC/UV method. The contents of 4 esters decreased from 3.64% to 2.71%, and the contents of 3 potential hydrolysis products increased from 0.27% to 0.88% after processing. Our study indicated that hydrolysis of iridoid and phenylethanoid esters such as specneuzhenide was responsible for the chemical changes during the wine processing of LLF. The proposed strategy could be employed to investigate the chemical changes of other herbs during processing.

Biosynthesis of (1R,4aS,7S,7aR)-nepetalactol (1) and (4aS,7S,7aR)-nepetalactone (2) in plants involves iridoid synthase (ISY), an atypical reductive cyclase that catalyses the reduction of 8-oxogeranial into the reactive enol of (S)-8-oxocitronellal, and cyclization of this enol intermediate, either non-enzymatically or by a nepetalactol-related short chain dehydrogenase enzyme (NEPS) that yields the nepetalactols. In this study, we investigated the biosynthesis in vivo of 1 and 2 in the pea aphid, Acyrthosiphon pisum, using a library of isotopically-labelled monoterpenoids as molecular probes. Topical application of deuterium-labelled probes synthesized from geraniol and nerol resulted in production of 2 H4 -lactol 1 and 2 H4 -lactone 2. However, deuterium incorporation was not evident using labelled probes synthesized from (S)-citronellol. These results suggest that iridoid biosynthesis in animals, specifically aphids, may follow a broadly similar route to that characterised for plants.

Viburnumfocesides A - D, four undescribed 1-O-isovaleroylated iridoid 11-O-allosides modified with (Z / E)-p-coumaric acid, were isolated from the aqueous EtOH extract of the twigs of Viburnum foetidum var. ceanothoides, together with seven known natural products. Their structures were identified on the basis of the spectroscopic data interpretation and chemical derivation studies. Cell-based estrogen biosynthesis assays indicated that viburnumfoceside D (4), (2S,3R)-2,3-dihydro-3-hydroxymethyl-7-methoxy-2-(4-hydroxy-3-methoxyphenyl)-5-benzofuranpropanol-3a-O-α-L-rhamnopyranoside (8), and (-)-eriodictyol (11) inhibit estrogen biosynthesis with IC50 values of 5.8, 1.5, and 1.1 μM, respectively, in human ovarian granulosa-like KGN cells via decreasing the expression level of aromatase.

Our group has been investigating the anti-inflammatory and antidepressant-like effects of plumieride (PLU 0.5, 1, 2 µg/Kg). However, there is no record in the literature about the in vivo antioxidant activity of PLU at very low doses, which could be linked with pharmacology effects. Here, we administered mice with vehicle and PLU 0.5, 1, or 2 µg/Kg for 7 days. Subsequently, we evaluated the modulation of lipoperoxidation, nitrite, protein carbonylation, and non-protein thiols triggered by PLU in mice’s brain, plasma, liver, and kidneys. Our results support, at least in part, the pharmacological potential that has been attributed to iridoid.

The aim of this study was to determine the chemical variability of Allamanda cathartica flowers collected in different localities of Santa Catarina State, Brazil. Extractive solutions (25 samples) were analyzed by HPLC-DAD for the qualitative and quantitative profiles of the iridoid plumieride, the flavonoid rutin as well as total flavonoid content expressed in rutin. The chemical variability was evaluated by Principal Component Analysis (PCA) and Hierarchical Clustering Analysis (HCA). The samples demonstrated similar chromatographic profiles. In PCA analysis, Araquari samples AC01, AC08 and AC25 did not group with other samples obtained from other locations. In the HCA analysis, it was possible to observe hierarchially similar groups, generating 5 clusters. Group 5 (samples AC01, AC08 and AC25) presented lower similarity compared to the other groups. This dissimilarity can be explained by the amount of metabolites from each collection. Regarding the content of markers, it was observed a variation between 27 to 230 mg/g, 2.7 to 9.5 mg/g and 7.14 to 17.8 mg/g for plumieride, rutin, and total flavonoids, respectively. The samples from Araquari (AC01, AC08, AC25) presented the highest concentrations of chemical markers. Therefore, for reproducibility and standardization of A. cathartica flower extracts, it is important to determine the location and the plant cultivation conditions.

The new 2,3-secoiridoids morisecoiridoic acids A (1) and B (2), the new iridoid 8-acetoxyepishanzilactone (3), and four additional known iridoids (4–7) were isolated from the leaf and stem bark methanol extracts of Morinda asteroscepa using chromatographic methods. The structure of shanzilactone (4) was revised. The purified metabolites were identified using NMR spectroscopic and mass spectrometric techniques, with the absolute configuration of 1 having been established by single-crystal X-ray diffraction analysis. The crude leaf extract (10 μg/mL) and compounds 1–3 and 5 (10 μM) showed mild antiplasmodial activities against the chloroquine-sensitive malaria parasite Plasmodium falciparum (3D7). peerReviewed

Iridoids are secondary metabolites with several biological activities. They are often found in species of the genus Tabebuia Gomes ex A.P. de Candolle. Tabebuia aurea (Silva Manso) Benth. & Hook. F. ex S. Moore, Bignoniaceae, is used to treat snake bites in traditional medicine. This study aimed to isolate the specioside - an the iridoid glycoside - from T. aurea, as well as investigate its potential biological properties, including anti-inflammatory, antibacterial, antibiofilm, cytotoxic, anti-Trichomonas vaginalis and antitrypanosomal activities. Specioside inhibited leucocyte recruitment into the peritoneal cavity in mice injected with carrageenan, data that demonstrated its anti-inflammatory potential. However, the additional evaluated biological properties were negligible.

A new hexenoic acid glycoside (1) together with known compounds, flavonol glycosides (2–4), iridoid glycoside (5), megastigmane glycoside (6), and amino acid (7) were isolated from the leaves of P. luzoniensis by resin column chromatography and preparative HPLC. Their structures were determined based on spectroscopic analysis, including HRFABMS and NMR (1H and 13C, 1H−1H COSY, HMQC, and HMBC) data. All compounds tested for cytotoxicity were active (IC50 < 50 μM) with IC50 values ranging from 1.97 to 32.85 μM against human colon adenocarcinoma cell line, compared to etoposide (IC50 1.19 μM).

A new bis-iridoid glucoside minutifloroside (1) was isolated from Palicourea minutiflora, together with asperuloside, (-)-epicatechin, catechin, quercetin, rutin, ursolic acid, oleanolic acid, daucosterol and two monoterpenic indole alkaloids strictosidinic acid and vincosamine. Structural characterization of the compounds was established on their spectral data basis, mainly mass spectrometry (MS) and 1D and 2D nuclear magnetic resonance (NMR). The bis-iridoid showed high activity against Candida albicans strain and antioxidant activity.

In this work, the first phytochemical analysis on Cephalanthus glabratus (Spreng.) K.Schum. regarding its composition in iridoids was reported. The analysis was carried out by following current usual methodologies in the extraction, separation and identification procedures. Four compounds were isolated, i.e., the iridoid loganin (1) and the seco-iridoids sweroside (2), secologanin (3) and secoxyloganin (4). Their presence allowed to provide important confirmations about the chemotaxonomy of the genus and the family this species belongs to.

International audience; Iridoids are monoterpenes that are produced by various plants as chemical defense molecules. Lichman et al. recently described the timeline of molecular events that underpin the re-emergence of iridoid biosynthesis in an independent lineage of aromatic plants (catnip). This study represents a benchmark for studying enzyme and metabolite evolution in different clades across the tree of life.

The aim of the study was to identify and evaluate the content of iridoids and phenolic compounds in the leaves and roots of Dipsacus fullonum L. They were identified and quantified by UPLC-PDA-MS/MS. Five iridoid compounds (loganic acid, loganin, sweroside, cantleyoside, and sylvestroside III) were identified in Dipsacus fullonum L. leaves and roots. Seven phenolic acids and three flavones were identified in the leaves, and seven phenolic acids were detected in the roots. The leaves contained more iridoids and phenolic compounds than the roots. We also evaluated the antimicrobial (anti-bacterial and anti-yeast), antioxidant (ORAC methods), and antiacetylcholinesterase (AChE) activities of Dipsacus fullonum L. leaves and roots. Leaf extract demonstrated the strongest antioxidant activity, but roots showed stronger antiacetylcholinesterase activity than leaves. The study also confirmed antibacterial activity of root-derived compounds against Staphylococcus aureus DSM 799 and Escherichia coli ATCC 10536.

Iridoids are a class of active compounds that widely exist in the plant kingdom. In recent years, with advances in phytochemical research, many compounds with novel structure and outstanding activity have been identified. Iridoid compounds have been confirmed to mainly exist as the prototype and aglycone and Ι and II metabolites, by biological transformation. These metabolites have been shown to have neuroprotective, hepatoprotective, anti-inflammatory, antitumor, hypoglycemic, and hypolipidemic activities. This review summarizes the new structures and activities of iridoids identified locally and globally, and explains their pharmacokinetics from the aspects of absorption, distribution, metabolism, and excretion according to the differences in their structures, thus providing a theoretical basis for further rational development and utilization of iridoids and their metabolites.

The crude drug ysyp&oacute, h&ucirc, (Adenocalymma marginatum DC., Bignoniaceae) is used traditionally by the Guarani of Eastern Paraguayan as a male sexual enhancer. The aim of the present study was to identify the main constituents of the crude drug and to evaluate the in vitro inhibitory activity towards the enzyme phosphodiesterase-5 (PDE-5). The main compounds were isolated by counter-current chromatography (CCC). The metabolites were identified by spectroscopic and spectrometric means. The chemical profiling of the extracts was assessed by high-performance liquid chromatography coupled to mass spectrometry (HPLC-MS/MS). The crude extract and main isolated compounds were tested for their PDE-5 inhibitory activity using commercial kits. The iridoid theviridoside and 4-hydroxy-1-methylproline were isolated as the main constituent of the crude drug. Four chlortheviridoside hexoside derivatives were detected for the first time as natural products. Chemical profiling by HPLC-MS/MS led to the tentative identification of nine iridoids, six phenolics, and five amino acids. The crude extracts and main compounds were inactive towards PDE-5 at concentrations up to 500 &micro, g/mL. Iridoids and amino acid derivatives were the main compounds occurring in the Paraguayan crude drug. The potential of ysyp&oacute, as a male sexual enhancer cannot be discarded, since other mechanisms may be involved.

Three new iridoid glycosides, namely umbrosides A–C (1–3); ten known iridoid glycosides (4–8 and 16–20); and seven known phenylethanoid glycosides (9–15) were isolated from Scrophularia umbrosa Dumortier, and their structures were established through spectroscopic methods including 1D and 2D NMR experiments and ESIMS analysis. The inhibitory activities of the isolated compounds on LPS-stimulated nitric oxide (NO) production in RAW 264.7 cells were investigated. Compounds 1–3, 7, 9–10, 13–16, and 19–20 inhibited NO production, with IC50 values ranging from 9.0 to 40.3 μM. Their structure–activity relationships are preliminarily discussed in this paper.

Three hitherto unknown valeriana-type iridoid glycosides (1−3) were isolated from Viburnum punctatum, and their structures were elucidated by extensive spectroscopic analysis. The new compounds, designated as viburpunosides A − C (1−3), are characterized by having a mono- or triacylated α- l -rhamnopyranosyl-(1→2)-β- d -glucopyranosyl moiety linked to C-11. This is the second report of an iridoid attached to a disaccharide other than glucose in this genus. The absolute configuration of new compounds was briefly discussed.

Caryopincaolide M (1), a new rearranged abietane diterpenoid with an unusual pent-4-enoic acid group on a 6/6/5 tricyclic ring system, and 7-epi-8-dehydroxypatriscabrol (3), a new iridoid, together with 17 known compounds, have been isolated from the whole plant of Caryopteris incana (Thunb.) Miq. Their structures were elucidated on the basis of 1-D and 2-D NMR, IR, and mass spectroscopic data. Compounds 1–5 were evaluated for their inhibitory activities against enzyme α-glucosidase, and the results showed that only 1 has moderate inhibitory activity against enzyme α-glucosidase with IC50 at 528.3 ± 12.37 mg/L.

Six metabolites (1-6) were isolated from the aerial parts of Anarrhinum pubescens Fresen. (Plantaginaceae) growing in Saint Catherine region in Egypt; two of them (1 and 4) are here reported to be newly identified naturally occurring iridoids. The isolated metabolites were identified as 6-O-foliamenthoyl-(6'-O-cinnamoyl)-antirrhinoside (1), 6'-O-cinnamoyl-antirrhinoside (2), the iridoid dimer, pubescensoside (4), antirrhinoside (5), 10-hydroxy-antirrhinoside (6), and the flavonoid, diosmin (3). Identification of the new metabolites was based on analysis of their collected spectroscopic data (NMR and HR-ESI-MS). Furthermore, compounds (1, 4, and 5) were subjected to cytotoxic testing against the human lung carcinoma cell line (A-549); compound 4 showed better cytotoxic activity as indicated by the obtained (IC50).

Fadogia erythrophloea (K. Schum. & K. Krause) Hutch and Dalziel is a specie from the family of Rubiaceae. The plant materials of Fadogia erythrophloea have been used in Africa in alternative medicine to remedy dysentery, malaria, childhood fever, as antidotes (venomous stings, bites, etc.), emetics, vermifuge, colic and constipation. Therefore, this study was designed to isolate active principle(s) present in the leaves extract of Fadogia erythrophloea and to test for possible in-vitro antimicrobial activity. Isolation works were carried out using various chromatographic techniques on the n-butanol fraction; this yielded a pure compound labelled as ‘F.e’. From the data obtained through spectroscopic techniques using 1H NMR, 13C NMR, DEPT, COSY, NOESY, HMBC and HSQC Nuclear Magnetic Resonances (NMR),the compound ‘F.e’ was identified to be an ipolamiide(an iridoid glycoside). Based on the findings in this research work, it can be concluded that the leaves of the plant Fadogia erythrophloea (K.Schum. & K.Krause) Hutch. & Dalziel possess measurable in-vitro antimicrobial activity against many of the microorganisms implicated in the pathogenesis of human infections.Keywords: Fadogia erythrophloea, Rubiaceae, Isolation, spectroscopic techniques, iridoid glycoside, ipolamiide, in-vitro antimicrobial activity

An effective screening method for inhibitors of NO production in natural products using LC-QTOF MS/MS coupled with a cell-based assay was proposed. The ethyl acetate fraction of Catalpa ovata exhibited a strong inhibitory effect on NO production in lipopolysaccharide-induced BV2 microglia cells. We attempted to identify the active constituents of C. ovata by using LC-QTOF MS/MS coupled with a cell-based assay. Peaks at approximately 14–15 min on the MS chromatogram were estimated to be the bioactive constituents. A new iridoid compound, 6-O-trans-feruloyl-3β-hydroxy-7-deoxyrehamaglutin A (4), and nine known compounds (1–3, 5–10) were isolated from the ethyl acetate fraction of C. ovata by repeated column chromatography. Compounds 3, 4, 5, 7, and 8 significantly attenuated lipopolysaccharide-stimulated NO production in BV2 cells. Our results indicate that LC-QTOF MS/MS coupled with a cell-based NO production inhibitory assay successfully predicted active compounds without a time-consuming isolation process.

Iridoid blue-based pigments (IBBP) extract of Genipa americana L. represents a natural alternative additive for food applications and also exerts desirable biological effects on human health. In this study the iridoids present in the extract were identified, the influence of pH and temperature on color difference (ΔE) of IBBP was evaluated using a central composite design (CCD) and finally the antioxidant capacity was monitored before and after its in vitro digestion. Ten glucoside iridoids were detected and the main compounds identified were genipin, genipin 1-β-gentiobioside and geniposide. It was also observed an increase of 17–18% of antioxidant capacity after the in vitro digestion, respectively. Among the conditions tested, the color of extract was more stable at 12–20 °C and low pH (3.0–4.0), suggesting that it is compatible for coloring acidic foods. Finally, the in vitro digestion also increased the antioxidant capacity (ORAC assay) by 39%.

The checkerspot butterfly, Euphydryas anicia (Nymphalidae), specializes on plants containing iridoid glycosides and has the ability to sequester these compounds from its host plants. This study investigated larval preference, performance, and sequestration of iridoid glycosides in a population of E. anicia at Crescent Meadows, Colorado, USA. Although previous studies showed that other populations in Colorado use the host plant, Castilleja integra (Orobanchaceae), we found no evidence for E. anicia ovipositing or feeding on C. integra at Crescent Meadows. Though C. integra and another host plant, Penstemon glaber (Plantaginaceae), occur at Crescent Meadows, the primary host plant used was P. glaber. To determine why C. integra was not being used at the Crescent Meadows site, we first examined the host plant preference of naïve larvae between P. glaber and C. integra. Then we assessed the growth and survivorship of larvae reared on each plant species. Finally, we quantified the iridoid glycoside concentrations of the two plant species and diapausing caterpillars reared on each host plant. Our results showed that E. anicia larvae prefer P. glaber. Also, larvae survive and grow better when reared on P. glaber than on C. integra. Castilleja integra was found to contain two primary iridoid glycosides, macfadienoside and catalpol, and larvae reared on this plant sequestered both compounds; whereas P. glaber contained only catalpol and larvae reared on this species sequestered catalpol. Thus, although larvae are able to use C. integra in the laboratory, the drivers behind the lack of use at the Crescent Meadows site remain unclear.

Fructus Gardeniae-Fructus Forsythiae herb pair is an herbal formula used extensively to treat inflammation and fever, but few systematic identification studies of the bioactive components have been reported. Herein, the unknown analogues in the first-step screening were rapidly identified from representative compounds in different structure types (geniposide as iridoid type, crocetin as crocetin type, jasminoside B as monocyclic monoterpene type, oleanolic acid as saponin type, 3-caffeoylquinic acid as organic acid type, forsythoside A as phenylethanoid type, phillyrin as lignan type and quercetin 3-rutinoside as flavonoid type) by UPLC-Q-Tof/MS combined with mass defect filtering (MDF), and further confirmed with reference standards and published literatures. Similarly, in the second step, other unknown components were rapidly discovered from the compounds identified in the first step by MDF. Using the two-step screening method, a total of 58 components were characterized in Fructus Gardeniae-Fructus Forsythiae (FG-FF) decoction. In rat's blood, 36 compounds in extract and 16 metabolites were unambiguously or tentatively identified. Besides, we found the principal metabolites were glucuronide conjugates, with the glucuronide conjugates of caffeic acid, quercetin and kaempferol confirmed as caffeic acid 3-glucuronide, quercetin 3-glucuronide and kaempferol 3-glucuronide by reference standards, respectively. Additionally, most of them bound more strongly to human serum albumin than their respective prototypes, predicted by Molecular Docking and Simulation, indicating that they had lower blood clearance in vivo and possibly more contribution to pharmacological effects. This study developed a novel two-step screening method in addressing how to comprehensively screen components in herbal medicine by UPLC-Q-Tof/MS with MDF.

The evolution of chemical complexity has been a major driver of plant diversification, with novel compounds serving as key innovations. The species-rich mint family (Lamiaceae) produces an enormous variety of compounds that act as attractants and defense molecules in nature and are used widely by humans as flavor additives, fragrances, and anti-herbivory agents. To elucidate the mechanisms by which such diversity evolved, we combined leaf transcriptome data from 48 Lamiaceae species and four outgroups with a robust phylogeny and chemical analyses of three terpenoid classes (monoterpenes, sesquiterpenes, and iridoids) that share and compete for precursors. Our integrated chemical–genomic–phylogenetic approach revealed that: (1) gene family expansion rather than increased enzyme promiscuity of terpene synthases is correlated with mono- and sesquiterpene diversity; (2) differential expression of core genes within the iridoid biosynthetic pathway is associated with iridoid presence/absence; (3) generally, production of iridoids and canonical monoterpenes appears to be inversely correlated; and (4) iridoid biosynthesis is significantly associated with expression of geraniol synthase, which diverts metabolic flux away from canonical monoterpenes, suggesting that competition for common precursors can be a central control point in specialized metabolism. These results suggest that multiple mechanisms contributed to the evolution of chemodiversity in this economically important family.

Phytochemical investigations of methanolic extracts obtained from leaves and stem bark of Carapichea affinis (Rubiaceae: Palicoureeae), a poorly known relative of the famous vomiting root ipecac (C. ipecacuanha), led to the isolation and identification of two new and five known dopamine-iridoid alkaloids. All of them are structurally related to the famous emetic and anti-amoebic compound emetine. The known glucosides borucoside, cephaeline, 6-O-methyl-trans-cephaeloside, ipecoside and 6-O-methyl-ipecoside were isolated together with two novel alkaloids: 7-O-methyl-alangine and the cephaeloside derivative 3 ''' -O-demethyl-borucoside. All alkaloid structures were confirmed on basis of 1D- and 2D-NMR spectroscopy and mass spectrometry. Additionally, the flavonoid glycoside nicotiflorine was identified on basis of UV spectrum and retention time in the leaf extract. Feeding assays against the insect pest Spodoptera littoralis were carried out with alkaloid-rich aqueous phases of leaf and stem bark extracts.

Possibility of pre-sowing seed treatment with growth regulators of steroid and iridoid nature has been studied while growing onions. In the experiment, an "ecostim" preparation has been used for the pre-sowing treatment of onion seeds, the active ingredient of which is the glycoside of the steroid nature of tomatosides isolated from the seeds of Solanum lycopersicum L., as well as the sum of iridoid glycosides (linarosides) from Linaria vulgaris Mill. To identify the technological parameters of the use of plant growth bio-regulators preliminary testing has been conducted in the Laboratory of Natural Bio-Regulators of the Institute of Genetics, Physiology and Plant Protection, A comparison of the effectiveness of the compounds obtained on the germination of onion seeds has shown that the greatest stimulation has been achieved by using low concentrations (0.0001% - 0.001%) of tomatoside solutions (eostimis preparation) and higher concentrations (0.005% - 0.01%0 of linarosides. Production tests have been carried out in the field in the Pridnestrovian Research Institute of Agriculture. Variety specificity of the impact of natural bio-regulators has been determined by the example of 3 varieties of onions, different in terms of maturation, resistance, etc. (Pinguin, Diamant and Chalcedon). It has been proved that the effect of the tested growth regulators has a pronounced varietal specificity and mainly is determined by the early maturity of the variety. It has been found that the compounds studied were most effective when growing onions under unfavorable conditions, and the amount of iridoid glycosides from the linaria had a greater stimulating effect compared with the tomatoside. Seed treatment with bio-regulators has provided the simultaneous emergence of seedlings, the leveling in growth and development of plants, as well as increased the yield of onions by 27.6% - 41.3%.

Iridoid synthases belong to the family of short-chain dehydrogenase/reductase involved in the biosynthesis of iridoids. Despite having high sequence and structural homology with progesterone 5β-reductase, these enzymes exhibit differential substrate specificities. Previously, two loops, L1 and L2 at substrate-binding pocket, were suggested to be involved in generating substrate specificity. However, the structural basis of specificity determinants was elusive. Here, combining sequence and structural analysis, site-directed mutagenesis, and molecular dynamics simulations, we have shown that iridoid synthase contains two channels for substrate entry whose geometries are altered by L1-L2 dynamics, primarily orchestrated by interactions of residues Glu161 and Gly162 of L1 and Asn358 of L2. A complex interplay of these interactions confer the substrate specificity to the enzyme.

A new iridoid glycoside, named physaloside A (1), together with one known iridoid glycoside (swertiamarin, 2), was isolated from the EtOAc extract of Physochlaina physaloides (L.) G. Don. The structure elucidation of 1 was carried out by 1D NMR (1H and 13C NMR) and 2D NMR (COSY, HSQC, HMBC, and NOESY) spectral analysis. Antibacterial activities of the compounds were evaluated against various bacteria.

The ether extract ofArtemisia integrifoliawas separated by chromatography and afforded a new iridoid, arteintegin A (6), together with five known compounds, namely chamazulene (1) , acetylenes (E)-2, (E)-3, (Z)-4, eugenol (5). The structure elucidation of the new compound was carried out by 1D ( 1H NMR and 13C NMR) and 2D-NMR (COSY, HSQC and NOESY) spectral analysis .

White-flesh guava is widely planted in tropical or subtropical areas of Southeast Asia. Despite of folk statements on specific function, few researches are focused on the description of its plant secondary metabolites. In the present work, contents of total phenolics and flavonoids as well as antioxidant activity from different parts (peel, flesh, and seed) were determined. The constituents of ethanol extracts were characterized by HPLC-QTOF-MS. A total of 69 phenolic compounds as well as nine polar compounds were detected, with flavonoids, hydrolyzable tannins, phenolic acid derivatives, and benzophenones of the four predominant phenolic compounds. Moreover, the presence of other phenolics (lignan, phenylethanoid, stilbenoid, and dihydrochalcones) was revealed. Simultaneously, the polar compounds, such as triterpenoids, iridoid were identified. Benzophenones and triterpenoids were proved to be marked constitutes of peel and flesh, respectively. The existence of isoflavonoids, lignan, phenylethanoid were firstly reported for edible parts or by-products of guava. The results showed that white-flesh guavas, particularly peel parts, were superior resources of antioxidant compounds, with exploitation value.

Two new (1 and 2) and 10 known (3−12) acylated iridoid diglycosides were isolated from the twigs and leaves of the cultivated endangered ornamental plant Gmelina hainanensis. Based on spectroscopic data interpretation and chemical transformation, the new triacyl and the new diacyl iridoid diglycosides were established to be 6-O-α-L-(2″,3″-di-O-acetyl-4″-O-cis-cinnamoyl)rhamnopyranosylcatalpol (1) and 6-O-α- l -(2″,4″-di-O-trans-cinnamoyl)rhamnopyranosylcatalpol (2), respectively. All the isolates were evaluated for their inhibitory effects against the protein tyrosine phosphatase 1 B (PTP1B) enzyme.

An expedient approach toward the unified total syntheses of (+)-iridomyrmecin, (−)-isoiridomyrmecin, (+)-7-epi-boschnialactone, (+)-teucriumlactone, and (−)-dolichodial in chirally pure forms starting from readily available (+)-β-citronellene is delineated combining step economy and simplicity. Highlights include a Ti(III)-mediated reductive epoxide opening-cyclization for the construction of the core cyclopenta[c]pyran skeleton of the iridoid lactones with complete diastereoselectivity for the newly created bridgehead stereogenic centers. Subsequent transformations facilitate a short access to (+)-teucriumlactone and (−)-dolichodial and formal access to potentially other iridoids.

New iridoid glycoside derivatives from durantoside I, the latter from the dried flowers and leaves of Citharexylum spinosum, were synthesized by variously modifying a sugar moiety by silylation or acetylation and/or removal of cinnamate group at C-7 position and subsequent screening for comparative cytotoxicity against several cancer cell lines. Addition of alkylsilane to durantoside I and removal of cinnamate group were most effective in improving cytotoxicity.

Morinda citrifolia L. (Noni) is an annual plant, distributed in the tropical parts of the world. Chemical constituents such as flavonoids, alkaloids, terpenoids, sterols, and minerals have been isolated from this plant. The pharmacological properties, based on scientific research, claimed as antibacterial, antiulcerogenic, anti-inflammatory, antioxidant, and especially for antimelanogenesis therapy. Iridoid, a flavonoid compound, is the main component found in the Noni leaves extract. Screening of Noni leaves extract possessed flavonoid and steroid content with the concentration of 2.82% and 0.14%, respectively. Therefore, the Noni leaves extract was potential used for sunscreen, based on antimelanogenesis activity.

Three new secoiridoids, nuezhenelenoliciside (1), isojaslanceoside B (2), 6'-O-trans-cinnamoyl-secologanoside (3), were isolated from the dried fruits of Ligustrum lucidum. Their structures were elucidated by comprehensive spectroscopic analysis. Among them, 1 featured a rare rearrangement product of secoiridoid, which underwent the cleavage of chemical bond between C-1 and O-2, and the reformation of a new iridoid ring between C-8 and O-2. In addition, all compounds were tested for their osteogenic activity on pre-osteoblastic MC3T3-E1 cells. As a result, 1 and 3 exhibited potent effects on promoting cell proliferation of pre-osteoblast cells.

Three new anthraquinones, 1-methyl-2,4-dimethoxy-3-hydroxyanthraquinone (6), 1-methoxy-3-hydroxy-2-ethoxymethylanthraquinone (7), and 2-methyl-3-O-β-D-primeveroside (14), together with 15 known compounds, including seven anthraquinones, one iridoid glucoside, three phenolic compounds, three flavone glucosides, and one flavone, were isolated from Paederia scandens. The isolated compounds were elucidated by extensive spectroscopic methods. To the best of our knowledge, six known anthraquinones (1, 2, 5, 9, 10, and 13) and two known phenolic acids (4, 11) were isolated from this plant for the first time.

The extract of the aerial and underground parts of Phlomis likiangensis afforded two new iridoid derivatives, namely as phloloside H (1) and phloline (2), along with four known compounds (3–6), and compound 2 was a novel normonoterpene. Their structures were elucidated on the basis of spectroscopic studies and chemical methods. Six compounds were assayed for cytotoxic, antibacterial and antioxidative activities, but were either inactive or very weakly active.

A new diterpenoid glucoside, (3S,5S,6S,8R,9R,10S)-3,6,9-trihydroxy-13(14)-labdean-16,15-olide 3-O-β-D-glucopyranoside (1), and a new iridoid glucoside, (1S, 5S,6R,9R)-10-O-p-hydroxybenzoyl-5,6β-dihydroxy iridoid 1-O-β-D-glucopyranoside (2), along with six known compounds (3-8) were isolated from Vitex trifolia L.. Their structures were elucidated by extensive spectroscopic analysis. All these isolated compounds were evaluated for their inhibitory effects on nitric oxide production in LPS-induced RAW 264.7 macrophages. Compounds 2, 4, 5, and 7 showed moderate inhibitory activities with IC50 values of 90.05, 88.51, 87.26, and 76.06 μM, respectively.

The aim of the study was to evaluate the effect of the different methods of preparation of the blue honeysuckle (Lonicera caerulea L. var. Kamtschatica) cv. 'Wojtek' and their influence on the iridoid content of fruit juices and fresh and freeze-dried pomaces. Compounds were identified by UPLC-ESI-qTOF-MS/MS in negative ion mode. Five iridoids - loganic acid, 7-epi-loganic acid 7-O-pentoside, loganin, sweroside, and secologanin - were determined in blue honeysuckle fruits and products. The results revealed no differences in iridoid content between the fresh pomace from skin and flesh, or between the juice from skin and flesh. A higher content of iridoids was obtained in juice from crushed than from whole berries, and in freeze-dried pomace from whole than from crushed berries. Freeze-dried pomace from blue honeysuckle can be an excellent source of bioactive iridoids.

Lamiophlomis rotata (L. rotata) is a Tibetan medicinal herb used for centuries that contains iridoid glycosides (IGs), which are pharmacologically active ingredients and can be used for quality control. The IG profiles of the underground and aerial parts of the plant were determined by UPLC-TOF-MS to evaluate the similarity and variability of the different herbal parts listed in the Chinese Pharmacopoeia. Twenty-six IGs were detected in the total ion current (TIC) profile of L. rotata, and twenty-two of these were identified by comparing the retention times and mass spectra of the compounds to those of authentic standards. Among these compounds, five IGs with the same molecular formula (C17H26O11) were identified for the first time by mass spectrometry based on their different hydroxyl group-substituted positions. The aerial part has a similar chemical profile to that of the roots. The difference between the two parts was determined by multivariate statistical analysis of the UPLC-TOF-MS data of 24 specimens. Sesamoside was explored as the most characteristic marker to distinguish the two parts of L. rotata. To further estimate the distinction between the two parts, the content of total IGs and the antioxidant capacity were investigated in samples from different locations. The aerial parts showed a high content of total IGs and high antioxidant capacity, although not higher than those of the roots. The results also suggest the dosage should be increased when the aerial parts are used as crude medicinal materials instead of the underground parts.