Arvensic acids K and L, components of resin glycoside fraction from Convolvulus arvensis

Phytoconstituent analysis, anti-inflammatory, antimicrobial and anticancer effects of nano encapsulated Convolvulus arvensis L. extracts

BACKGROUND

The Convolvulus genus is distributed all over the world and has a long history in traditional medicine. As nanotechnology expands its reach into areas like drug delivery and biomedicine, this study intends to assess the potential of Convolvulus arvensis L. extracts as anti-bacterial, anti-inflammatory and anti-cancer agents, along with chemical profiling of the methanolic (MeOH) extract active ingredients.

METHODS

The chemical composition of an 85% MeOH extract was investigated by liquid chromatography with an electrospray source connected to mass spectrometry (LC-ESI-MS). Both the 85% MeOH extract and n-butanol fraction of C. arvensis were loaded for the first time on alginate/chitosan nanoparticles. The 85% MeOH extract, n-butanol fraction and their loaded nanoparticles were tested for their cytotoxicity, anticancer, anti-inflammatory and antibacterial activity (against pathogenic bacteria, E. coli and S. aureus).

RESULTS

The chemical investigation of 85% MeOH extract of C. arvensis underwent LC-ESI-MS analysis, revealing twenty-six phenolic substances, of which 16 were phenolic acids, 6 were flavonoids, 1 glycolipid, 1 sesquiterpene and 2 unknown compounds. The FT-IR spectra confirmed the encapsulation of the 85% MeOH extract and n-butanol fraction onto alginate/chitosan nanoparticles and small size obtained by TEM maintained them nontoxic and enhanced their anti-inflammatory activity (the IC50 was decreased from 1050 to 175 µg/ml). The anti-cancer activity against HepG2 was increased and the cell viability was decreased from 28.59 ± 0.52 to 20.80 ± 0.27 at a maximum concentration of 1000 µg/ml. In addition, the MIC of encapsulated extracts was decreased from 31.25 to7.78 µg/ml in E. coli (Gm-ve) and from 15.56 to 7.78 µg/ml in S. aureus (Gm + ve) bacteria.

CONCLUSION

Both alginate and chitosan are excellent natural polymers for the encapsulation process, which affects positively on the bioactive constituents of C. arvensis extracts and improves their biological properties.

Four new resin glycosides, calyhedins VII-X, from the rhizomes of Calystegia hederacea

Four new resin glycosides with macrolactone structures (jalapins), namely, calyhedins VII (1)-X (4), were isolated from the rhizomes of Calystegia hederacea Wall. (Convolvulaceae). The structures of 1-4 were determined based on spectroscopic data. They were classified into three ring types: a 27-membered ring (1), a 22-membered ring (2, 3), and a 23-membered ring (4). Their sugar moieties were partially acylated using five organic acids, including (E)-2-methylbut-2-enoic acid, 2S-methylbutyric acid, and 2 R-methyl-3R-hydroxybutyric acid. Compound 4 was the first genuine resin glycoside with calyhedic acid F as the glycosidic acid component. Additionally, the cytotoxic activities of 1, 2, and 4 towards HL-60 human promyelocytic leukaemia cells were evaluated. All compounds demonstrated almost the same activity as the positive control, cisplatin.

New coumarin glycosides from endemic Prangos heyniae H. Duman & M.F. Watson

Two new coumarin glycosides, named 7-methoxy isoarnottinin 4'-O-β-ᴅ-glucopyranoside and 7-methoxy isoarnottinin 4'-O-rutinoside (1 and 2) along with six known compounds (3-8) were isolated from the roots of Prangos heyniae, an endemic plant of Turkey. 1-methylethyl 6-O-D-apio-β-ᴅ-furanosyl-β-ᴅ-glucopyranoside (7) and cnidioside A (8) have been obtained from the genus Prangos for the first time. Structures of isolated compounds were established using spectroscopic methods (1 D and 2 D NMR, HR-MS, UV and IR). Moreover, all extracts and isolated compounds were evaluated for their cytotoxic activity against NIH/3T3, HK-2, A-549, MCF-7, PC-3 and SH-SY5Y cell lines by WST-1 method. One of the new coumarin glycosides, 7-methoxy isoarnottinin 4'-O-β-ᴅ-glucopyranoside (1) exhibited selective cytotoxic activity against SH-SY5Y cells with IC₅₀ value of 31.41 ± 1.04 μM.

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.

Illuminating the lineage-specific diversification of resin glycoside acylsugars in the morning glory (Convolvulaceae) family using computational metabolomics

Acylsugars are a class of plant defense compounds produced across many distantly related families. Members of the horticulturally important morning glory (Convolvulaceae) family produce a diverse sub-class of acylsugars called resin glycosides (RGs), which comprise oligosaccharide cores, hydroxyacyl chain(s), and decorating aliphatic and aromatic acyl chains. While many RG structures are characterized, the extent of structural diversity of this class in different genera and species is not known. In this study, we asked whether there has been lineage-specific diversification of RG structures in different Convolvulaceae species that may suggest diversification of the underlying biosynthetic pathways. Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) was performed from root and leaf extracts of 26 species sampled in a phylogeny-guided manner. LC-MS/MS revealed thousands of peaks with signature RG fragmentation patterns with one species producing over 300 signals, mirroring the diversity in Solanaceae-type acylsugars. A novel RG from Dichondra argentea was characterized using Nuclear Magnetic Resonance spectroscopy, supporting previous observations of RGs with open hydroxyacyl chains instead of closed macrolactone ring structures. Substantial lineage-specific differentiation in utilization of sugars, hydroxyacyl chains, and decorating acyl chains was discovered, especially among Ipomoea and Convolvulus - the two largest genera in Convolvulaceae. Adopting a computational, knowledge-based strategy, we further developed a high-recall workflow that successfully explained ~72% of the MS/MS fragments, predicted the structural components of 11/13 previously characterized RGs, and partially annotated ~45% of the RGs. Overall, this study improves our understanding of phytochemical diversity and lays a foundation for characterizing the evolutionary mechanisms underlying RG diversification.

Polysaccharide Based Polymers Produced by Scabby Cankered Cactus Pear (Opuntia ficus-indica L.) Infected by Neofusicoccum batangarum: Composition, Structure, and Chemico-Physical Properties

Neofusiccocum batangarum is the causal agent of scabby canker of cactus pear (Opuntia ficus-indica L.). The symptoms of this disease are characterized by crusty, perennial cankers, with a leathery, brown halo. Characteristically, a viscous polysaccharide exudate, caking on contact with air, leaks from cankers and forms strips or cerebriform masses on the surface of cactus pear cladodes. When this polysaccharide mass was partial purified, surprisingly, generated a gel. The TLC analysis and the HPLC profile of methyl 2-(polyhydroxyalkyl)-3-(o-tolylthiocarbomoyl)-thiazolidine-4R-carboxylates obtained from the mixture of monosaccharides produced by acid hydrolysis of the three EPSs examined in this research work [the polysaccharide component of the exudate (EPSC) and the EPSs extracted from asymptomatic (EPSH) and symptomatic (EPSD) cladodes] showed the presence of d-galactose, l-rhamnose, and d-glucose in a 1:1:0.5 ratio in EPSC while d-galactose, l-rhamnose, d-glucose, and d-xylose at the same ratio were observed in EPSH and EPSD. The presence of uronic acid residues in EPSC was also showed by solid state NMR and IR investigation. Furthermore, this manuscript reports the chemical-physical characterization of the gel produced by the infected cactus pear.