Evolvulins I and II, Resin Glycosides with a Trihydroxy Aglycone Unit from Evolvulus alsinoides

Isolation of pentasaccharide resin glycosides from the whole plants of Ipomoea biflora and their cytotoxic activities

A total of eight previously undescribed pentasaccharide resin glycosides, named ipomofins I-VIII (1-8), along with five known ones (9-13), were isolated from the whole plants of Ipomoea biflora. Their structural elucidation was achieved through a comprehensive application of spectroscopic and chemical techniques. All these resin glycosides were characterized as partially acylated pentasaccharides, originating from operculinic acids A or D, containing l-rhamnose, d-glucose, d-xylose or d-fucose units, and 11S-hydroxyhexadecanoic acid serving as the aglycone. Notably, compounds 1 and 2 represent the first resin glycosides with operculinic acid D as their core structure, while compounds 3 and 4 are the first derivatives of operculinic acid A featuring a 23-membered ring. Compounds 1, 2, and 4-6 exhibited apparent cytotoxic effects against certain cancer cell lines. Particularly, compound 5 demonstrated the ability to impair colony formation, reduce the proportion of EdU-positive cells, and enhance the expression of proteins related to endoplasmic reticulum stress (ERS) in HCT-15 cells, indicating that its cytotoxicity might be driven by the activation of ERS pathways. Collectively, this research identified 13 resin glycosides from I. biflora, including eight previously undescribed compounds, with compound 5 emerging as a potential anticancer agent due to its induction of ERS.

Controlins I-X, Resin Glycosides from the Seeds of Convolvulus tricolor and Their Biological Activities

Ten new resin glycosides, controlins I-X (1-10), were isolated from the seeds of Convolvulus tricolor. Their structures were established by spectroscopic analysis as well as by chemical means. Compounds were identified as glycosidic acid methyl esters, considered as artifacts generated via transesterification with MeOH from natural resin glycosides. Compound 1 is the first nonasaccharide resin glycoside, while compounds 2-7 are rare octasaccharide resin glycosides. Compounds 5, 6, and 8 could inhibit the nitric oxide production in lipopolysaccharide-induced BV-2 cells, while compounds 3, 5, and 7 exhibited neuroprotective effects on H2O2-induced damage in PC12 cells. Compounds 6 and 7 could dose-dependently alleviate the dyskinesia in the UM0001 strain of Caenorhabditis elegans, a double transgenic line of Aβ and pro-aggregation tau, suggesting an anti-Alzheimer's activity, reported for resin glycosides for the first time.

Assimiloside A, a Glycolipid with Immunomodulatory Activity from the Northwestern Pacific Marine Sponge Hymeniacidon assimilis

Assimiloside A (1), an unprecedented marine glycolipid containing a γ-lactone of 4R,16,26R-trihydroxy C28 fatty acid as an aglycon and a trisaccharide carbohydrate moiety, was isolated from the marine sponge Hymeniacidon assimilis. Its structure was elucidated by NMR spectroscopy, mass spectrometry, chemical transformations, and ECD spectroscopy combined with time-dependent density functional theory calculations. Assimiloside A at nontoxic concentrations of 0.01-0.1 μM was shown to present lysosomal activity stimulation and intracellular reactive oxygen species level elevation in RAW 264.7 murine macrophages.

Resin Glycosides from Convolvulaceae Family: An Update

Resin glycoside is a type of secondary metabolite isolated commonly from the Convolvulaceae family. It consists of oligosaccharides conjugated to organic acids with a larger percentage having a macrocyclic structure. The resin glycosides reported in this review is classified mostly based on the number of sugar units constructing the structure, which is correlated to the biological properties of the compounds. According to preliminary reviews, the protocols to isolate the compounds are not straightforward and require a special technique. Additionally, the structural determination of the isolated compounds needs to minimize the structure for the elucidation to become easier. Even though resin glycosides have a complicated structural skeleton, several total syntheses of the compounds have been reported in articles published from 2010 to date. This review is an update on the prior studies of the resin glycosides reported in 2010 and 2017. The review includes the classification, isolation techniques, structural determination, biological properties, and total synthesis of the resin glycosides.

Chemistry and biological activity of resin glycosides from Convolvulaceae species

Carbohydrate-based drug discovery has gained more and more attention during the last few decades. Resin glycoside is a kind of novel and complex glycolipids mainly distributed in plants of the family Convolvulaceae. Over the last decade, a number of natural resin glycosides and derivatives have been isolated and identified, and exhibited a broad spectrum of biological activities, such as cytotoxic, multidrug-resistant reversal on both microbial pathogens and mammalian cancer cells, antivirus, anticonvulsant, antidepressant, sedative, vasorelaxant, laxative, and α-glucosidase inhibitory effects, indicating their potential as lead compounds for drug discovery. A systematic review of the literature studies was carried out to summarize the chemistry and biological activity of resin glycosides from Convolvulaceae species, based on various data sources such as PubMed, Web of Science, Scopus, and Google scholar. The keyword "Convolvulaceae" was paired with "resin glycoside," "glycosidic acid," "glycolipid," or "oligosaccharide," and the references published between 2009 and June 2021 were covered. In this article, we comprehensively reviewed the structures of 288 natural resin glycoside and derivatives newly reported in the last decade. Moreover, we summarized the biological activities and mechanisms of action of the resin glycosides with pharmaceutical potential. Taken together, great progress has been made on the chemistry and biological activity of resin glycosides from Convolvulaceae species, however, more exploratory research is still needed, especially on the mechanism of action of the biological activities.

Mass Defect Filtering-Oriented Identification of Resin Glycosides from Root of Convolvulus scammonia Based on Quadrupole-Orbitrap Mass Spectrometer

This work aimed to develop and evaluate a post-acquisition data processing strategy, referred to as a mass defect filter (MDF), for rapid target the resin glycosides in root of Convolvulus scammonia by setting mass rang and mass defect range from high-resolution MS data. The full-scan mass data were acquired by high-performance liquid chromatography coupled with Q Exactive Plus hybrid quadrupole-orbitrap mass spectrometer that featured high resolution, mass accuracy, and sensitivity. To screen resin glycosides, three parent filter m/z 871, m/z 853, and m/z 869 combined with diagnostic fragment ions (DFIs) approach were applied to remove the interference from complex herbal extract. The targeted components were characterized based on detailed fragment ions. Using this approach, 80 targeted components, including 22 glycosidic acids and 58 resin glycosides were tentatively identified. The present results suggested that the proposed MDF strategy would be adaptable to the analysis of complex system in relevant filed.

Bioactive Compounds from the Aerial Parts of Evolvulus linarioides

Three new caryophyllane-type sesquiterpenoids, linariophyllenes A-C (1-3), two new hamamelitol derivatives, linaritols A (4) and B (5), two new chromones, linariosides A (6) and B (7), and three known chromones, cnidimol C (8), monnieriside A (9), and undulatoside A (10), were identified from the aerial parts of Evolvulus linarioides. The structures of these compounds were elucidated by NMR, MS, and IR data. The absolute configurations of compounds 1-5 and 7 were established via electronic circular dichroism data. The anti-inflammatory potential of compounds 1-5 and 7-10 was evaluated by determining their ability to inhibit the production of nitric oxide (NO) and proinflammatory cytokine IL-1β by stimulated J774 macrophages. Compounds tested at noncytotoxic concentrations inhibited NO production by macrophages, exhibiting IC₅₀ values between 17.8 and 66.2 μM, and inhibited IL-1β production by stimulated macrophages by 72.7-96.2%.

Isolation of evolvulic acids B and C, two new components of crude resin glycoside fraction from Evolvulus alsinoides

Two new glycosidic acids, evolvulic acids B and C (1 and 2), along with a known one, evolvulic acid A (3), were isolated from the glycosidic acid fraction afforded by alkaline hydrolysis of crude resin glycosides from Evolvulus alsinoides whole plants. Their structures were characterized by the spectroscopic data and chemical evidences. Compounds 1 and 2 are both defined as tetrasaccharides, composed of D-fucose, D-glucose, L-rhamnose or D-galactose units. Their aglycones are identified to be a distinctive 3S,11R,14R-trihydroxyhexadecanoic acid, which is only discovered from E. alsinoides up to now. The cytotoxic and anti-migration activities of compounds 1-3 were also tested.