Combined Metabolome and Transcriptome Analysis Highlights the Host's Influence on Cistanche deserticola Metabolite Accumulation

The medicinal plant Cistanche deserticola Ma (Orobanchaceae) is a holoparasitic angiosperm that takes life-essential materials from Haloxylon ammodendron (C. A. Mey.) Bunge (Amaranthaceae) roots. Although many experiments have been conducted to improve the quality of C. deserticola, little attention has been paid to the host's influence on metabolite accumulation. In this study, transcriptomic and metabolomic analyses were performed to unveil the host's role in C. deserticola's metabolite accumulation, especially of phenylethanoid glycosides (PhGs). The results indicate that parasitism by C. deserticola causes significant changes in H. ammodendron roots in relation to metabolites and genes linked to phenylalanine metabolism, tryptophan metabolism and phenylpropanoid biosynthesis pathways, which provide precursors for PhGs. Correlation analysis of genes and metabolites further confirms that C. deserticola's parasitism affects PhG biosynthesis in H. ammodendron roots. Then we found specific upregulation of glycosyltransferases in haustoria which connect the parasites and hosts. It was shown that C. deserticola absorbs PhG precursors from the host and that glycosylation takes place in the haustorium. We mainly discuss how the host resists C. deserticola parasitism and how this medicinal parasite exploits its unfavorable position and takes advantage of host-derived metabolites. Our study highlights that the status of the host plant affects not only the production but also the quality of Cistanches Herba, which provides a practical direction for medicinal plant cultivation.

New lignans and phenylethanoid with antioxidant activity from aerial parts of Forsythia suspensa (Thunb.) Vahl

Two new lignans, phillyroside A(1) and phillyroside B(2), together with three new phenylethanoid glycoside, forsythoside K(3), forsythoside L(5) and forsythol L (4), while compounds 4 was an aglycon of forsythoside L(5), were isolated from the aerial parts of Forsythia suspensa (Thunb.) Vahl. Their structures were elucidated by comprehensive analyses of standard spectroscopic data (MS, IR, and NMR) and the in vitro antioxidant activity of five new compounds were evaluated in DPPH and ABTS radical scavenging experiment and ferric reducing ability of plasma (FRAP) experiment. Compounds 4 and 5 exhibited antioxidant activity with IC₅₀ values ranging from 112.49 to 153.58 μM in DPPH experiment and 45.43 to 64.09 μM in ABTS experiment.

Inhibition of α-Glycosidase by Lippia dulcis Trevir. (Verbenaceae) Preparations, Quantification of Verbascoside, and Study of Its Molecular Docking

This study aimed to quantify verbascoside (VEB), perform molecular docking studies of VEB with the α-glucosidase (GL) of Bacillus stearothermophilus, and evaluate the inhibition of the enzyme by L. dulcis preparations. The substrate concentration and presence of reduced glutathione were evaluated for their effect on the in vitro inhibition of the GL enzyme. Assays were also performed in the presence and absence of simulated gastric fluid. The antidiabetic fractions 2 and 3 were the most inhibited GL, but their activity were significantly decreased in the presence of gastric fluid. Chromatographic analyses confirmed the predominant presence of VEB in the samples. The samples had VEB concentrations between 49.9 and 243.5 mg/g. Simulation of the molecular docking of VEB were consistent with its GL-inhibitory activity. It can conclude that the crude ethanol extract and fractions show inhibitory activity against the GL enzyme.

Hepatoprotective Principles from the Rhizomes of Picrorhiza kurroa

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

Phenylethanoid and Phenylmethanoid Glycosides from the Leaves of Ligustrum robustum and Their Bioactivities

The phytochemical study on the leaves of Ligustrum robustum, which have been used as Ku-Ding-Cha, led to the isolation and identification of three new phenylethanoid glycosides and three new phenylmethanoid glycosides, named ligurobustosides R₁ (1b), R_2-3 (2), R₄ (3), S₁ (4b), S₂ (5), and S₃ (6), and five reported phenylethanoid glycosides (7-11). In the bioactivity test, (Z)-osmanthuside B₆ (11) displayed strong fatty acid synthase (FAS) inhibitory activity (IC₅₀: 4.55 ± 0.35 μM) as the positive control orlistat (IC₅₀: 4.46 ± 0.13 μM), while ligurobustosides R₄ (3) and S₂ (5), ligupurpuroside B (7), cis-ligupurpuroside B (8), ligurobustoside N (9), osmanthuside D (10), and (Z)-osmanthuside B₆ (11) showed stronger ABTS radical scavenging activity (IC₅₀: 2.68 ± 0.05~4.86 ± 0.06 μM) than the positive control L-(+)-ascorbic acid (IC₅₀: 10.06 ± 0.19 μM). This research provided a theoretical basis for the leaves of L. robustum as a tea with function in treating obesity and diabetes.

[One new phenylethanoid glycoside from Forsythiae Fructus]

One new phenylethanoid glycoside was isolated from the ethyl acetate fraction of the 75% EtOH extract of Forsythiae Fructus by various column chromatographies(HP20, silica gel, ODS) and preparative HPLC.Its structure was identified as forsythiayanoside E(1) by physicochemical properties and extensive spectroscopic analysis(HR-ESI-MS, 1 D and 2 D NMR).Compound 1 was evaluated for cytotoxic activities by MTT assay and showed weak cytotoxic activity against MCF-7 and A-375 cell lines with inhibition rates of 39.85% and 43.38% at 40 μmol·L~(-1), and no cytotoxic activity against PC-3 and HepG2 cell lines at 100 μmol·L~(-1).

Research Progress and Trends of Phenylethanoid Glycoside Delivery Systems

Background: Phenylethanoid glycosides (PhGs) are obtained from a wide range of sources and show strong biological and pharmacological activities, such as antioxidant, antibacterial and neuroprotective effects. However, intestinal malabsorption and the low bioavailability of PhGs seriously affect their application. Delivery systems are an effective method to improve the bioavailability of active substances. Scope and approach: In this article, the biological activities of and delivery systems for PhGs are introduced. The application statuses of delivery systems for echinacoside, acteoside and salidroside are reviewed. Finally, the problems of the lack of uniform standards for delivery systems and the poor targeted delivery accuracy of PhGs in the current research are proposed and suggestions for future research are put forward based on those problems. Key findings and conclusions: Although there are still some problems in the delivery system of phenylethanoside, such as inconsistent standards and inaccurate delivery, phenylethanoside itself has been proven to have a variety of physiological activities. Therefore, the action mechanism and application of phenylethanoside and its delivery system should be studied further.

[A new phenylethanol glycoside from Baphicacanthis Cusiae Rhizoma et Radix]

The 95% ethanol extract of Baphicacanthis Cusiae Rhizoma et Radix was purified by multi-chromatographic methods including microporous resin, silica gel, Sephadex LH-20, and C_(18) reversed-phase column chromatography. Fourteen compounds were isolated and structurally identified, including five phenylethanoid glycosides, five phenylpropanoids, one lupinane triterpene, two alkaloids, and one flavonoid, listed as follows: 2-(4-hydroxy-3-methoxyphenyl)-3-(2-hydroxy-5-methoxyphenyl)-3-oxo-1-propanol B(1), threo-2,3-bis-(4-hydroxy-3-methoxybenzene)-3-methoxypropanol(2), 2-(3-hydroxy-4-methoxyphenyl)-ethanol-1-O-[3,4-O-di-acetyl-(1→3)-O-α-L-rhamnopyranosyl]-β-D-glucopyranoside(3), verbascoside(4), 2″,3″-di-O-acetyl martynoside(5),(+)-pinore-sinol(6), diospyrosin(7), daidzein(8), wiedemannioside B(9), buddlenol A(10), 2″-O-acetyl martyonside(11), lupeol(12), indirubin(13), and tryptanthrin(14). Compound 3 was a new phenylethanoid glycoside, and the other 10 compounds were isolated for the first time from Baphicacanthis Cusiae Rhizoma et Radix except compounds 12, 13, and 14.

Herba Cistanche (Rou Cong Rong): A Review of Its Phytochemistry and Pharmacology

Herba Cistanche, known as Rou Cong Rong in Chinese, is a very valuable Chinese herbal medicine that has been recorded in the Chinese Pharmacopoeia. Rou Cong Rong has been extensively used in clinical practice in traditional herbal formulations and has also been widely used as a health food supplement for a long time in Asian countries such as China and Japan. There are many bioactive compounds in Rou Cong Rong, the most important of which are phenylethanoid glycosides. This article summarizes the up-to-date information regarding the phytochemistry, pharmacology, processing, toxicity and safety of Rou Cong Rong to reveal its pharmacodynamic basis and potential therapeutic effects, which could be of great value for its use in future research.

Bioactivity, Compounds Isolated, Chemical Qualitative, and Quantitative Analysis of Cymbaria daurica Extracts

Cymbaria daurica L. is widely used in traditional Mongolian medicine for the treatment of impetigo, psoriasis, pruritus, fetotoxicity, and diabetes. Therefore, the anti-inflammatory and α-glucosidase-inhibitory activities of four polar C. daurica extracts (water, n-butanol, ethyl acetate, and petroleum ether extract) were preliminarily evaluated to identify the active extracts. We also investigated the chemical composition of the active extracts by phytochemical analysis. The n-butanol and ethyl acetate extracts exhibited significant (p < 0.05) anti-inflammatory activities by inhibiting lipopolysaccharide-induced nitric oxide (NO) production in RAW 264.7 cells. None of the tested extracts exhibited cytotoxic effects at the effective concentrations. The ethyl acetate extract significantly inhibited α-glucosidase activity, and the inhibition potency was equivalent to that of acarbose (p > 0.05). The n-Butanol extract presented the second highest inhibitory activity. As the n-butanol and ethyl acetate extracts were found to have potent anti-inflammatory and α-glucosidase-inhibitory activities, we separated and identified 10 compounds from the extracts. Among them, vanillic acid, cistanoside F, echinacoside, arenarioside, verbascoside, isoacteoside, and tricin were isolated from C. daurica for the first time. Further, 30 compounds from the n-butanol and ethyl acetate extracts of C. daurica were identified using UHPLC-Q-Exactive. The present study demonstrates for the first time that C. daurica contains phenylethanoid glycosides. In addition, this novel HPLC method was subsequently used for simultaneous identification of five compounds in the n-butanol and ethyl acetate extracts of C. daurica. This study provides a chemical basis for further characterization and utilization of C. daurica, which could be a potential source of novel anti-diabetic and anti-inflammatory agents.

A Newly Discovered Phenylethanoid Glycoside from Stevia rebaudiana Bertoni Affects Insulin Secretion in Rat INS-1 Islet β Cells

The tea-like beverage Stevia rebaudiana Bertoni (Stevia) is popular in China because it reduces blood glucose and has a sweet taste. In this work, a comprehensive quality assessment of Stevia led to the discovery of five phenylethanoid glycosides, namely steviophethanoside (1), cuchiloside (2), salidroside (3), icariside D (4), and tyrosol (5). Of them, compound 1 is a novel compound. Mass spectrometry and NMR spectroscopy were employed to confirm the absolute configuration. A hydrolytic step with 4 N TFA at 95 °C for 4 h was used to confirm the monosaccharides. In addition, Discovery Studio 4.0 was used to predict the ADME and toxicity activity of compound 1. The results suggested that compound 1 was biocompatible and had poor toxicity, which was verified by rat INS-1 islet β cells through an MTT assay. Meanwhile, a significant stimulatory effect on INS-1 cells was observed, which indicated a hypoglycemic effect of compound 1. This is the first report that describes a natural, novel, and hypoglycemic phenylethanoid glycoside in Stevia.

A Review of Biologically Active Natural Products from a Desert Plant Cistanche tubulosa

An Orobanchaceae plant Cistanche tubulosa (SCHENK) WIGHT (Kanka-nikujuyou in Japanese), which is one of the authorized plant resources as Cistanches Herba in both Japanese and Chinese Pharmacopoeias, is a perennial parasitic plant growing on roots of sand-fixing plants. The stems of C. tubulosa have traditionally been used for treatment of impotence, sterility, lumbago, and body weakness as well as a promoting agent of blood circulation. In recent years, Cistanches Herba has also been widely used as a health food supplement in Japan, China, and Southeast Asian countries. Here we review our recent studies on chemical constituents from the stems of C. tubulosa as well as their bioactivities such as vasorelaxtant, hepatoprotective, and glucose tolerance improving effects.

Iridoid, phenylethanoid and flavonoid glycosides from Forsythia suspensa

As part of our continuing efforts to explore bioactive compounds from natural resources, a new iridoid glycoside, adoxosidic acid-6'-oleuroperic ester (1), together with one known phenylethanoid glycoside (2) and two known flavonoid glycosides (3-4) were isolated from the fruit of Forsythia suspensa. The structure of the new compound (1) was elucidated through 1D and 2D NMR spectroscopic data and HR-ESIMS. Interestingly, compound 1 was a monoterpene ester of one iridoid glycoside. Compounds 2-4 were identified as calceolarioside A (2), kaempferol-3-O-rutinoside (3), kampferol-3-O-robinobioside (4) on the basis of NMR spectroscopic data analyses and comparison with the data reported in the literature. The antiviral activity aganisist influenza A (H5N1) virus of compound 1 was studied as well.

Preparative Separation of Phenylethanoid and Secoiridoid Glycosides from Ligustri Lucidi Fructus by High-Speed Counter-Current Chromatography Coupled with Ultrahigh Pressure Extraction

Three phenylethanoid glycosides, echinacoside (1), salidroside (3), and acteoside (6), and three secoiridoid glycosides, isonuezhenide (2), nuezhenoside G13 (4), and specnuezhenide (5), have been extracted and separated by a combined method of ultrahigh pressure extraction (UPE) and high-speed counter-current chromatography (HSCCC) from Ligustri Lucidi Fructus. For the UPE, the optimal extraction was developed with conditions including solvent of 90% ethanol, sample to solvent ratio of 1:20 g/mL, pressure of 200 MPa, and time of 2 min, which rendered the yields of compounds 4 and 5 were 15.0 and 78.0 mg/g, respectively. For the HSCCC separation, the strategy of changing flow rates between 1.0 and 2.0 mL/min allowed the acquisition for 2.7 mg of compound 1, 4.5 mg of compound 2, 6.8 mg of compound 3, 5.9 mg of compound 4, 11.2 mg of compound 5, and 2.2 mg of compound 6 in one separation run under the solvent system of ethyl acetate:n-butanol:water (2:1:3, v/v) from 200 mg of the UPE extract. The structures of these phenylethanoid and secoiridoid glycosides were elucidated by extensive spectroscopic methods.

A new phenylethanoid glycoside from Incarvillea compacta

A new phenylethanoid glycoside, 3'''-O-methylcampneoside I (1), was isolated from the 90% ethanolic extract of the roots of Incarvillea compacta, together with three known compounds, campneoside I (2), ilicifolioside A (3), and campneoside II (4). Their structures were determined spectroscopically and compared with previously reported spectral data. Compound 1 existed as epimers and displayed better 1,1-diphenyl-2-picrylhydrazyl (DPPH)-free radical scavenging activity using di-tert-butyl-4-methylphenol (BHT) as the positive control. In addition, pretreatment of human HepG2 cells with compound 1 significantly increased the viability on CCl4-induced cell death.

Flowers by UPLC/PDA/MS and Simulated Digestion Model

Variations of phenylethanoid glycoside profiles and antioxidant activities in Osmanthus fragrans flowers through the digestive tract were evaluated by a simulated digestion model and UPLC/PDA/MS. Major phenylethanoid glycosides and phenolic acids, namely, salidroside, acteoside, isoacteoside, chlorogenic acid, and caffeic acid, were identified in four cultivars of O. fragrans flowers, and the concentration of acteoside was the highest, being up to 71.79 mg/g dry weight. After simulated digestion, total phenylethanoid glycoside contents and antioxidant activities were significantly decreased. Acteoside was identified as decomposing into caffeic acid, whereas salidroside was found to be stable during simulated digestion. According to Pearson's correlation analysis, acteoside contents showed good correlations with antioxidant activities during simulated digestion (R(2) = 0.994, P < 0.01). In conclusion, acteoside was the major contributor to the antioxidant activity of O. fragrans flowers, and salidroside was considered as the major antioxidant compound of O. fragrans flowers in vivo.