Sucrose diester of aryldihydronaphthalene-type lignans from Echium angustifolium Mill. and their antitumor activity

Sucrose esters of aryldihydronaphthalene-type lignans, and antitumor activity of extracts of Moltkiopsis ciliata (Forssk.) aerial parts

One new compound (3f-[(7'R,8'R)-4,4'-dihydroxy-5-methoxy-2,7'-cycloligna-7-en-9-methoxycarbonyl, 9'-carbonyl-O-] -β- D-fructofuranosyl- (2→1)-α- D-glucopyranoside) (Moltkiopsin A) (2) was isolated and identified from the extract of aerial parts of the wild Egyptian plant Moltkiopsis ciliata (Frossk.), family Boraginaceae, for the first time, along with two aryldihydronaphthalene lignans 3f→9':6f→9-[(7'R,8'R)-4,4'- dihydroxy-3,3',5-trimethoxy-2,7'-cycloligna-7-en-9,9'-dicarbonyl]-6g-acetyl-α-D-gluco pyranosyl-(1→2) -β-D-fructofuranoside (Trigonotin A) (1) which was reported for the first time from this plant species and a known compound 3f→9':6f→9-[(7'R,8'R)-4,4'- dihydroxy-3,3',5-trimethoxy-2,7'-cycloligna-7-en-9,9'-dicarbonyl]-α-D-gluco pyranosyl - (1→2)- β-D- fructofuranoside (Trigonotin C) (3). These compounds were separated and purified using different chromatographic techniques and their structures were elucidated by extensive 1D (1H and 13C NMR), and 2D NMR (COSY, HSQC, and HMBC), besides ESI-MS spectral methods. Extracts were screened as antioxidant, antitumor and antibacterial. The different extracts showed moderate to strong antioxidant capacities in DPPH assays. Ethyl acetate, methylene chloride and crude methanol extracts exhibited the most significant free radicals scavenging activity when compared to the standard antioxidant vitamin C. Hexane and butanol fractions showed the highest cytotoxicity against the cancer cell lines HepG2 and MCF-7.

Exploring pharmaphylogeny from multiple perspectives: a case study on Lithospermeae

Lithospermeae Dumort., a tribe under the subfamily Boraginoidae, is a perennial herb containing approximately 470 species under 26 genera, primarily distributed in temperate and tropical regions. To gain a deeper understanding of the medicinal plants of Lithospermeae and better protect and develop plant medicinal resources, the phytochemistry, pharmacology, and traditional use of Lithospermeae with medicinal value were analyzed. Phylogenetic analysis was carried out based on the internal transcribed spacer sequence. Through spatial analysis and the species distribution model, the spatial distribution pattern of Lithospermeae medicinal plants was analyzed. Meanwhile, the relevant targets and pathways involved in the pharmacological effects of commonly used medicinal plants were predicted using network pharmacology to further explore the genetic origin of Lithospermeae and enrich the pharmaphylogeny of medicinal plants. In this study, the chemical composition, traditional efficacy, and modern pharmacological activity of Lithospermeae were collected for the first time and analyzed in combination with the geographical distribution model, molecular phylogeny, and network pharmacology. Based on our findings, the pharmaphylogeny of Lithospermeae was preliminarily discussed, providing the scientific basis for basic research regarding Lithospermeae. Concurrently, this study explored the relationship between the development of the regional medicinal plant industry and the protection of biodiversity. Furthermore, our findings provide direction and theoretical guidance for the study of the phylogenetic relationships in medicinal plants and the development of Lithospermeae medicinal plant resources.

Echiumin E, an Aryl Dihydronaphthalene Lignan from the Australian Invasive Plant Paterson's Curse (Echium plantagineum)

A new aryl dihydronaphthalene lignan, echiumin E (1), and four known compounds, echiumin A, globoidnan A, (-)-rabdosiin, and rosmarinic acid (2-5), were isolated from the Australian invasive plant Echium plantagineum (Paterson's curse) for the first time. Echiumin E (1) was characterized by 1D/2D NMR spectroscopy and MS spectrometry, with its absolute configuration assigned through comparison of experimental and TDDFT-calculated ECD data. Echiumin E (1) along with compounds 3-5 were screened in vitro against three cancer cell lines (SH-SY5Y, HeLa, and PC-3) and a prostate stromal (normal) cell line (WPMY-1) using a resazurin reduction assay. Echiumin E (1) was found to be active toward HeLa cells (IC₅₀ 0.21 μM).

Targeting Natural Plant Metabolites for Hunting SARS-CoV-2 Omicron BA.1 Variant Inhibitors: Extraction, Molecular Docking, Molecular Dynamics, and Physicochemical Properties Study

(1) Background: SARS-CoV-2 Omicron BA.1 is the most common variation found in most countries and is responsible for 99% of cases in the United States. To overcome this challenge, there is an urgent need to discover effective inhibitors to prevent the emerging BA.1 variant. Natural products, particularly flavonoids, have had widespread success in reducing COVID-19 prevalence. (2) Methods: In the ongoing study, fifteen compounds were annotated from Echium angustifolium and peach (Prunus persica), which were computationally analyzed using various in silico techniques. Molecular docking calculations were performed for the identified phytochemicals to investigate their efficacy. Molecular dynamics (MD) simulations over 200 ns followed by molecular mechanics Poisson–Boltzmann surface area calculations (MM/PBSA) were performed to estimate the binding energy. Bioactivity was also calculated for the best components in terms of drug likeness and drug score. (3) Results: The data obtained from the molecular docking study demonstrated that five compounds exhibited remarkable potency, with docking scores greater than −9.0 kcal/mol. Among them, compounds 1, 2 and 4 showed higher stability within the active site of Omicron BA.1, with ΔG_binding values of −49.02, −48.07, and −67.47 KJ/mol, respectively. These findings imply that the discovered phytoconstituents are promising in the search for anti-Omicron BA.1 drugs and should be investigated in future in vitro and in vivo research.

Phenylpropanoids from Brachybotrys paridiformis Maxim. ex Oliv. and their anti-HBV activities

Using chemical and spectroscopic data, this study on Brachybotrys paridiformis Maxim. ex Oliv. identified four undescribed phenylpropanoids, brachin A-C and brachoside A, together with nine other known compounds. The isolated compounds were tested for anti-hepatitis B virus activities in the HepG2.2.15 cell line. Among them, caffeic anhydride showed the most potent activity.

Natural sucrose esters: Perspectives on the chemical and physiological use of an under investigated chemical class of compounds

The present review describes the chemistry and physiological properties of the sucrose esters (SEs) obtained from natural or synthetic pathways, with emphasis on those that have aliphatic and phenylpropanoid substituents on their sucrose moiety. Synthesis, extraction and characterization methods for the SEs and NSEs are discussed in terms of synthetic procedures, separation techniques and spectroscopic methods. The physiological properties are discussed taking into account the nature of the substituent groups and their regiochemistry (position and number of substitutions) on the sucrose moiety.

A new synthetic methodology for pyridinic sucrose esters and their antibacterial effects against Gram-positive and Gram-negative strains

Described are the development of a new synthetic method using ultrasonic irradiation and sodium methoxide as catalyst for a series of pyridinic sucrose esters (py-SEs), derived from transesterification of sucrose with picolinic, nicotinic and isonicotinic methyl esters. The reaction was optimized using a 3² x 2 experimental design, the reaction time, temperature and sucrose: methyl ester molar ratio being evaluated. The method proved to be efficient for obtaining monosubstituted esters (≥83%) with high methyl ester consumption (≥79%). The monosubstituted py-SEs were isolated by semipreparative HPLC, characterized by high-resolution mass spectrometry, calorimetry, vibrational spectroscopy, and ¹H and ¹³C NMR. The py-SEs were tested against E. coli, S. aureos, and P. aeruginosa bacteria with minimum inhibitory concentration values equal or inferior to the reference drugs for both E. coli and P. aeruginosa.

Montbresides A-D: antibacterial p-coumaroyl esters of a new sucrose-based tetrasaccharide from Crocosmia × crocosmiiflora (montbretia) flowers

Crocosmia × crocosmiiflora (montbretia) flowers yielded four esters (montbresides A-D) of a new sucrose-based tetrasaccharide, 3-O-β-d-glucopyranosyl-4´-O-α-d-rhamnopyranosyl-sucrose [β-d-Glc-(1 → 3)-α-d-Glc-(1↔2)-β-d-Fru-(4 ← 1)-α-d-Rha]. All four possess O-p-coumaroyl residues on C-3 of fructose and C-4 of α-glucose, plus O-acetyl residues on C-2 and C-3 of rhamnose and C-6 of fructose. Montbresides A and B are additionally O-acetylated on C-1 of fructose. The p-coumaroyls are trans- in montbresides A and C and cis- in B and D. Elemental compositions were determined from MS data, and structures from 1D and 2D NMR spectra. Monosaccharide residues were identified from selective 1D TOCSY spectra and TLC, and acylation sites from 2D HMBC spectra. Enantiomers were distinguished by enzymic digestion. Montbretia flower extracts were cytotoxic against six human cancerous cell-lines, but purified montbresides lacked cytotoxicity. Each montbreside displayed antibacterial activity against Staphylococcus aureus (minimal inhibitory concentration ~6 μg/ml). Montbretia is a potential source of new cytotoxins and antibacterial agents.

Lignans and Neolignans: Plant secondary metabolites as a reservoir of biologically active substances

Lignans and neolignans are plant secondary metabolites derived from the oxidative coupling of phenylpropanoids. Biological activity of these phenolic compounds ranges from antioxidant, antitumor (terminaloside P, IC₅₀ = 10 nM), anti-inflammatory, anti-neurodegenerative (schibitubin B, IC₅₀ = 3.2 nM) and antiviral (patentiflorin A, IC₅₀ = 14-23 nM) to antimicrobial. In addition, it was observed that several members of this group, namely enterolactone and its biochemical precursors also known as phytoestrogens, possess important protective properties. Most of these lignans and neolignans are presented in reasonable amounts in one's diet and thus the protection they provide against the colon and breast cancer, to name a few, is even more important to note. Similarly, neuroprotective properties were observed (schisanwilsonin G, IC₅₀ = 3.2 nM) These structural motives also serve as an important starting point in the development of anticancer drugs. Presumably the most famous members of this family, etoposide and teniposide, synthetic derivatives of podophyllotoxin, are used in the clinical treatment of lymphocytic leukemia, certain brain tumors, and lung tumors already for nearly 20 years. This review describes 413 lignans and neolignans which have been isolated between 2016 and mid-2018 being reported in more than 300 peer-reviewed articles. It covers their source, structure elucidation, and bioactivity. Within the review, the structure-based overview of compounds as well as the bioactivity-based overview of compounds are described.

A new aryldihydronaphthalene-type lignan and other metabolites with potential anti-​inflammatory activities from Corispermum mongolicum Iljin

One new aryldihydronaphthalene-type lignan (1) together with eight known lignans (2-4, 7-11) as well as two caffeic-acid dimers (5, 6) were isolated from an ethanol extract of the whole plant of Corispermum mongolicum Iljin (Chenopodiaceae). The chemical structures of these compounds were determined from 1D and 2D NMR and HR-ESI-MS spectra, and results were compared with data from the literature. This study is the first demonstration of nine compounds (2 and 4-11) isolated from the Chenopodiaceae family, with one of these (3) from the genus Corispermum. Anti-inflammatory effects of the isolated compounds were evaluated in terms of inhibition of production of nitric oxide, tumour necrosis factor-α, and interleukin-6 in lipopolysaccharide-induced RAW 264.7 cells.