Four new sesqui-lignans isolated from Acanthopanax senticosus and their diacylglycerol acyltransferase (DGAT) inhibitory activity

Sesquilignans: Current research and potential prospective

Lignans are widely distributed in nature, primarily found in the xylem and resins of plants, with the constituent units C6-C3, and their dimers are the most common in plants. In recent years, the trimeric sesquilignans have also received increasing attention from scholars. More than 200 derivatives have been isolated and identified from nearly 50 families, most of which are different types (monoepoxy lignans, bisepoxy lignans, benzofuran lignans) connected with simple phenylpropanoids through ether bonds, C-C bonds, and oxygen-containing rings to constitute sesquilignans. Some of them also possess pharmacological properties, including antioxidants, hepatoprotectives, antitumors, anti-inflammatory properties, and other properties. In addition, the chemical structure of sesquilignans is closely related to the pharmacological activity, and chemical modification of methoxylation enhances the pharmacological activity. In contrast, phenolic hydroxyl and hydroxyl glycosides reduce the pharmacological activity. Therefore, the present review aims to summarize the chemical diversity, bioactivities, and constitutive relationships to provide a theoretical basis for the more profound development and utilization of sesquilignans.

Triterpenoid Saponins From the Fruit of Acanthopanax senticosus (Rupr. & Maxim.) Harms

Five new oleanane-type triterpenoid saponins (1–5), together with 24 known saponins (6–29) were isolated from the fruit of Acanthopanax senticosus. Their structures were determined by extensive spectroscopic analysis, including 1D, 2D nuclear magnetic resonance (NMR), and high-resolution electrospray ionization mass spectrometry (HR-ESI-MS), in combination with chemical methods (acid hydrolysis). The neuroinflammation model was established by lipopolysaccharide (LPS)-induced BV2 microglia, and the neuroprotective effects of all compounds (1–29) were evaluated.

Antioxidant, Anti-Inflammatory, and Antidiabetic Activities of Bioactive Compounds from the Fruits of Livistona chinensis Based on Network Pharmacology Prediction

In this study, a chemical investigation on the fruits of Livistona chinensis (FLC) led to the isolation and identification of 45 polyphenols and 5 alkaloids, including two new compounds (Livischinol (1) and Livischinine A (46)), an undescribed compound (47) and 47 known compounds. FLC was predicted with novel potential antidiabetic function by collecting and analyzing the potential targets of the ingredients. Compound 32 exhibited significant α-glucosidase inhibitory activity (IC₅₀ = 5.71 μM) and 1, 6, and 44 showed the PTP1B inhibitory activity with IC₅₀ values of 9.41-22.19 μM, while that of oleanolic acid was 28.58 μM. The competitive inhibitors of PTP1B (compounds 1 and 44) formed strong binding affinity, with catalytic active sites, proved by kinetic analysis, fluorescence spectra measurements, and computational simulations, and stimulated glucose uptake in the insulin-resistant HepG2 cells at the dose of 50 μM. In addition, FLC was rich in antioxidant and anti-inflammatory bioactive compounds so that they could be developed as nutraceuticals against diabetes.

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.

Cornigerin, a new sesqui-lignan from the hepatoprotective fractions of Cynara cornigera L

The ethanol extract of Cynara cornigera L. was fractionated and the fractions were subjected to hepatoprotective assays using Wistar albino rats at a dose of 500 and 250mg/kg. The liver injury was induced in rats using carbon tetrachloride. Biochemical parameters such as aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and total bilirubin were estimated as reflections of the liver condition, with silymarin as a positive control. Phytochemical investigation and chromatographic separation of the hepatoprotective fractions led to the isolation of a new sesqui-lignan namely cornigerin (1), along with eight known compounds: apigenin (2), luteolin (3), β-sitosterol glycoside (4), apigenin 7-O-β-D-glucopyranoside (5), luteolin-7-O-β-D-glucopyranoside (6), apigenin-7-O-rutinoside (7), cynarin 1,5-di-O-caffeoylquinic acid (8), and apigenin-7-O-β-D-glucuronide (9). This is the first report for the isolation of 8 and 9 from this plant.