Dracotanosides A-D, spermidine glycosides from Dracocephalum tanguticum: structure and amide rotational barrier

Polyamine-containing natural products: structure, bioactivity, and biosynthesis

Covering: 2005 to August, 2023Polyamine-containing natural products (NPs) have been isolated from a wide range of terrestrial and marine organisms and most of them exhibit remarkable and diverse activities, including antimicrobial, antiprotozoal, antiangiogenic, antitumor, antiviral, iron-chelating, anti-depressive, anti-inflammatory, insecticidal, antiobesity, and antioxidant properties. Their extraordinary activities and potential applications in human health and agriculture attract increasing numbers of studies on polyamine-containing NPs. In this review, we summarized the source, structure, classification, bioactivities and biosynthesis of polyamine-containing NPs, focusing on the biosynthetic mechanism of polyamine itself and representative polyamine alkaloids, polyamine-containing siderophores with catechol/hydroxamate/hydroxycarboxylate groups, nonribosomal peptide-(polyketide)-polyamine (NRP-(PK)-PA), and NRP-PK-long chain poly-fatty amine (lcPFAN) hybrid molecules.

Dracotangusions A and B, two new sesquiterpenes from Dracocephalum tanguticum Maxim. with anti-inflammatory activity

Two new guaiane sesquiterpenoids were isolated from the dried aerial parts of Dracocephalum tanguticum Maxim., named as dracotangusions A (1) and B (2), together with four known sesquiterpenoids, which were identified as Curcumenone (3), (4Z,7Z,9Z)-11-Hydroxy-4,7,9-germacratriene-1,6-dione (4), Kobusone (5), and (1S,10S), (4S, 5S)-(+)-germacrone-1(10)-4-diepoxide (6). The structures of isolates were determined by UV, IR, HR-ESI-MS, and NMR analysis. What is noteworthy is that four known sesquiterpenoids were isolated for the first time from the genus of Dracocephalum L. All compounds inhibited the extremely significant difference (p < 0.01) in anti-inflammatory activity, suggesting that these compounds may be promising candidates as an anti-inflammatory agent.

The untapped potential of spermidine alkaloids: Sources, structures, bioactivities and syntheses

Spermidine alkaloids are a kind of natural products possessing an aliphatic triamine structure with three or four methylene groups between two N-atoms. Spermidine alkaloids exist in plants, microorganisms, and marine organisms, which usually form amide structures with cinnamic acid or fatty acid derivatives. Their unique structures showed a wide range of biological activities such as neuroprotective, anti-aging, anti-cancer, antioxidant, anti-inflammatory, and antimicrobial. In order to better understand the research status of spermidine alkaloids and promote their applications in human health, this paper systematically reviewed the biological sources, structures, pharmacological actions, and synthetic processes of spermidine alkaloids over the past two decades. This will help to open up new pharmacological investigation fields and better drug design based on these spermidine alkaloids.

HSCCC Separation of Three Main Compounds from the Crude Extract of Dracocephalum Tanguticum by Using Dimethyl Sulfoxide as Cosolvent

Separation of natural compounds directly from the crude extract is a challenging work for traditional column chromatography. In the present study, an efficient method for separation of three main compounds from the crude extract of Dracocephalum tanguticum has been successfully established by high-speed counter-current chromatography (HSCCC). The crude extract was directly introduced into HSCCC by using dimethyl sulfoxide as cosolvent. Ethyl acetate/n-butyl alcohol/0.3% glacial acetic acid (4: 1: 5, v/v) system was used and three target compounds with purity higher than 80% were obtained. Preparative HPLC was used for further purification and three target compounds with purity higher than 98% were obtained. The compounds were identified as chlorogenic acid, pedaliin and pedaliin-6″-acetate.

Interaction of Flavonoids from Woodwardia unigemmata with Bovine Serum Albumin (BSA): Application of Spectroscopic Techniques and Molecular Modeling Methods

Phytochemical investigation on the methanol extract of Woodwardia unigemmata resulted in the isolation of seven flavonoids, including one new flavonol acylglycoside (1). The structures of these compounds were elucidated on the basis of extensive spectroscopic analysis and comparison of literature data. The multidrug resistance (MDR) reversing activity was evaluated for the isolated compounds using doxorubicin-resistant K562/A02 cells model. Compound 6 showed comparable MDR reversing effect to verapamil. Furthermore, the interaction between compounds and bovine serum albumin (BSA) was investigated by spectroscopic methods, including steady-state fluorescence, synchronous fluorescence, circular dichroism (CD) spectroscopies, and molecular docking approach. The experimental results indicated that the seven flavonoids bind to BSA by static quenching mechanisms. The negative ΔH and ΔS values indicated that van der Waals interactions and hydrogen bonds contributed in the binding of compounds 2–6 to BSA. In the case of compounds 1 and 7 systems, the hydrophobic interactions play a major role. The binding of compounds to BSA causes slight changes in the secondary structure of BSA. There are two binding sites of compound 6 on BSA and site I is the main site according to the molecular docking studies and the site marker competitive binding assay.

Indoline Amide Glucosides from Portulaca oleracea: Isolation, Structure, and DPPH Radical Scavenging Activity

A polyamide column chromatography method using an aqueous ammonia mobile phase was developed for large-scale accumulation of water-soluble indoline amide glucosides from a medicinal plant, Portulaca oleracea. Ten new [oleraceins H, I, K, L, N, O, P, Q, R, S (1-10)] and four known [oleraceins A-D (11-14)] indoline amide glucosides were further purified and structurally characterized by various chromatographic and spectroscopic methods. The DPPH radical scavenging activities of oleraceins K (5) and L (6), with EC50 values of 15.30 and 16.13 μM, respectively, were twice that of a natural antioxidant, vitamin C; the EC50 values of the 12 other indoline amides, which ranged from 29.05 to 43.52 μM, were similar to that of vitamin C. Structure-activity relationships indicated that the DPPH radical scavenging activities of these indoline amides correlate with the numbers and positions of the phenolic hydroxy groups.

Macrocyclic spermidine alkaloids from Androya decaryi L. Perrier

Three new spermidine alkaloids and two known compounds were isolated from the leaves of Androya decaryi. Their structures were elucidated on the basis of their spectroscopic data (NMR and mass spectrometry), by X-Ray diffraction and by comparison with literature values. Evaluation of the in vitro antiplamosdial properties of the isolated compounds revealed they did not possess any significant activity.

Phenolic alkaloids from the aerial parts of Dracocephalum heterophyllum

Chemical examination of aerial parts of Dracocephalum heterophyllum resulted in isolation of phenolic alkaloids, including two flavonoidal alkaloids, drahebephins A and B, one imidazole alkaloid with a phenolic substituent, drahebenine, together with 15 other known compounds. Their structures were established by extensive spectroscopic data analyses. Due to the stereogenic center in the pyrrolidin-2-one ring, the flavonoidal alkaloids are chiral, although they were isolated as racemates. The enantiomers were separated by HPLC using a chiral phase and stereochemically characterized by circular dichroism (CD) spectroscopy. The structure of compound drahebenine was established by X-ray crystallography.

New glycosides from Dracocephalum tanguticum maxim

Four new glycosides, luteolin-7-methoxy-3'-O-(3″-O-acetyl)-β-D-gluco pyranuronic acid-6″-methyl ester (1), benzyl-6-[(2E)-2-butenoate]-β-D-glucopyranoside (2), 2-methoxy-4-(2-propen-1-yl)penyl-6-acetate-β-D-glucopyranoside (3), and 2-methoxy-4-(2-propen-1-yl)penyl-6-[(2E)-2-butenoate]-β-D-glucopyranoside (4), along with benzyl-β-D-glucopyranoside (5), 2-methoxy-4-(2-propen-1-yl)penyl-β-D-glucopyranoside (6), and pectolarigenin (7), were isolated from the whole plant of Dracocephalum tanguticum Maxim. The structures of 1-4 were elucidated by detailed spectroscopic analyses, including HR-ESI-MS and 2D NMR spectroscopic data. The inhibitory effects against nitric oxide production in LPS-stimulated RAW264.7 cells of all seven compounds were also evaluated.

Chemical constituents of Equisetum debile

Three new compounds, debilitriol (1), debilignanoside (2), and equisetumine (3), along with nine known compounds, were isolated from the whole plant of Equisetum debile. Their structures were elucidated by spectral and chemical methods.

Meehanines L-W, spermidine alkaloidal glycosides from Meehania urticifolia

Twelve new spermidine alkaloidal glycosides, meehanines L-W (1-12), were isolated from the whole plant Meehania urticifolia. The structures of these new compounds were elucidated on the basis of spectroscopic data analyses.