New lignans and their biological activities

Efficacy of Aster chinensis aerial parts metabolites in BALB/c mice model of Imiquimod-induced psoriasis skin inflammation

Using a bioassay-guided fractionation approach, the most potent anti-psoriatic components of Aster squamatus herb, Aster chinensis stalks, and Aster chinensis flowers, cultivated in Egypt, were identified and evaluated against Imiquimod (IMQ)-induced psoriasis in female BALB/c mice and compared to standard drug, mometasone. The topical application of A. chinensis stalk methanolic extract exhibited the strongest anti-psoriatic effects against IMQ-induced psoriasis model, as evidenced by improvements in psoriasis area severity index (PASI) score, histopathological analysis, and spleen index. Further fractionation of A. chinensis stalk methanolic extract using petroleum ether, methylene chloride, ethyl acetate, and n-butanol revealed that the methylene chloride fraction (MCF) was the most potent. Indeed, MCF significantly reduced the PASI score, alleviated histopathological changes, and restored spleen index. Mechanistically, MCF exerted its anti-psoriatic effects by suppressing inflammation, evidenced by decreased TLR-4 gene expression and lower levels of HMGB1 and NFκBp65 protein contents. Additionally, MCF reduced serum levels of pro-inflammatory cytokines interleukin (IL)-1β, IL-6, IL-23, and IL-17 while mitigating oxidative stress through increased superoxide dismutase (SOD) activity and reduced malondialdehyde (MDA) content. Notably, the efficacy of MCF was comparable to that of mometasone, with no significant differences observed. In parallel, the chemical profile of the MCF was analyzed using UHPLC-MS/MS techniques in negative and positive ionization full scan modes. MCF of A. chinensis stalk could be used a potential therapeutic agent for psoriasis.

Novel lignans from Syringa pinnatifolia and protective effect against H2O2-induced oxidative injury through regulating the expression of Nrf2/HO-1 in H9c2 cells

Phytochemical analysis of the peeled stems of Syringa pinnatifolia Hemsl. led to the discovery of 13 undescribed lignans, namely helanols A and B (1 and 2) and alashanenols W-G1 (3-13), as well as four known analogues, of which helanols A and B were lignans with novel skeleton of α-β' linkage. The structures were unambiguously established by extensive spectroscopic analyses, NMR calculations, ECD calculations, and single crystal X-ray crystallography. Five lignans (1, 2, 5, 11 and 13) exhibited a moderate protective effect against H2O2-induced oxidative injuries in H9c2 cells with the protective rates of 11.3-20.6 % at the concentration of 0.3-20 μM, while the positive control quercetin showed protective rates of 58.7 % at 10 μM. Further mechanism investigation suggested that 1 and 2 exerted the protective effect by regulating the expression of Nrf2/HO-1.

The promising antioxidant effects of lignans: Nrf2 activation comes into view

Lignans are biologically active compounds widely distributed, recognized, and identified in seeds, fruits, and vegetables. Lignans have several intriguing bioactivities, including anti-inflammatory, antioxidant, and anticancer activities. Nrf2 controls the expression of many cytoprotective genes. Activation of Nrf2 is a promising therapeutic approach for treating and preventing diseases resulting from oxidative injury and inflammation. Lignans have been demonstrated to stimulate Nrf2 signaling in a variety of in vitro and experimental animal models. The review summarizes the findings of fourteen lignans (Schisandrin A, Schisandrin B, Schisandrian C, Magnolol, Honokiol, Sesamin, Sesamol, Sauchinone, Pinoresinol, Phyllanthin, Nectandrin B, Isoeucommin A, Arctigenin, Lariciresinol) as antioxidative and anti-inflammatory agents, affirming how Nrf2 activation affects their pharmacological effects. Therefore, lignans may offer therapeutic candidates for the treatment and prevention of various diseases and may contribute to the development of effective Nrf2 modulators.

Neolignans in Magnolia officinalis as natural anti-Alzheimer's disease agents: A systematic review

BACKGROUND

Magnolia officinalis, a traditional herbal medicine widely used in clinical practice, exerts antibacterial, anti-tumor, anti-inflammatory, antioxidant, and anti-aging activities. Neolignans are the main active ingredients of M. officinalis and exert a wide range of pharmacological effects, including anti-Alzheimer's disease (AD) activity.

OBJECTIVE

To summarize the published data on the therapeutic effect and mechanism of neolignans on AD in vivo and in vitro.

METHODS

PubMed, Web of Science, Google Scholar, and Scopus were systematically reviewed (up to March 1, 2024) for pre-clinical studies.

RESULTS

M. officinalis-derived neolignans (honokiol, magnolol, 4-O-methylhonokiol, and obovatol) alleviated behavioral abnormalities, including learning and cognitive impairments, in AD animal models. Mechanistically, neolignans inhibited Aβ generation or aggregation, neuroinflammation, and acetylcholinesterase activity; promoted microglial phagocytosis and anti-oxidative stress; alleviated mitochondrial dysfunction and energy metabolism, as well as anti-cholinergic deficiency; and regulated intestinal flora. Furthermore, neolignans may achieve neuroprotection by regulating different molecular pathways, including the NF-κB, ERK, AMPK/mTOR/ULK1, and cAMP/PKA/CREB pathways.

CONCLUSIONS

Neolignans exert anti-AD effects through multiple mechanisms and pathways. However, the exact targets, pharmacokinetics, safety, and clinical efficacy in patients with AD need further investigation in multi-center clinical case-control studies.

Comparative Analysis and Phylogeny of the Complete Chloroplast Genomes of Nine Cynanchum (Apocynaceae) Species

Cynanchum belongs to the Apocynaceae family and is a morphologically diverse genus that includes around 200 shrub or perennial herb species. Despite the utilization of CPGs, few molecular phylogenetic studies have endeavored to elucidate infrafamilial relationships within Cynanchum through extensive taxon sampling. In this research, we constructed a phylogeny and estimated divergence time based on the chloroplast genomes (CPGs) of nine Cynanchum species. We sequenced and annotated nine chloroplast (CP) genomes in this study. The comparative analysis of these genomes from these Cynanchum species revealed a typical quadripartite structure, with a total sequence length ranging from 158,283 to 161,241 base pairs (bp). The CP genome (CPG) was highly conserved and moderately differentiated. Through annotation, we identified a total of 129-132 genes. Analysis of the boundaries of inverted repeat (IR) regions showed consistent positioning: the rps19 gene was located in the IRb region, varying from 46 to 50 bp. IRb/SSC junctions were located between the trnN and ndhF genes. We did not detect major expansions or contractions in the IR region or rearrangements or insertions in the CPGs of the nine Cynanchum species. The results of SSR analysis revealed a variation in the number of SSRs, ranging from 112 to 150. In five types of SSRs, the largest number was mononucleotide repeats, and the smallest number was hexanucleotide repeats. The number of long repeats in the cp genomes of nine Cynanchum species was from 35 to 80. In nine species of Cynanchum, the GC3s values ranged from 26.80% to 27.00%, indicating a strong bias towards A/U-ending codons. Comparative analyses revealed four hotspot regions in the CPG, ndhA-ndhH, trnI-GAU-rrn16, psbI-trnS-GCU, and rps7-ndhB, which could potentially serve as molecular markers. In addition, phylogenetic tree construction based on the CPG indicated that the nine Cynanchum species formed a monophyletic group. Molecular dating suggested that Cynanchum diverged from its sister genus approximately 18.87 million years ago (Mya) and species diversification within the Cynanchum species primarily occurred during the recent Miocene epoch. The divergence time estimation presented in this study will facilitate future research on Cynanchum, aid in species differentiation, and facilitate diverse investigations into this economically and ecologically important genus.

Synthesis and Monoamine Oxidase Inhibitory Activity of Halogenated Flavones

Small molecule neurotransmitters containing amines are metabolized by monoamine oxidase (MAO) in the nervous system. Monoamine oxidase inhibitors are a valuable class of drugs prescribed for the management of neurological disorders, including depression. A series of halogenated flavonoids similar to the dietary flavonoid acacetin were designed as selective MAO-B inhibitors. MAO-A and -B inhibition of 36 halogenated flavones were tested. The halogens (fluorine and chlorine) were placed at positions 5 and 7 on ring A of the flavone scaffold. All compounds were selective MAO-B inhibitors with micro- and nanomolar IC50 values. Compounds 9f, 10a-c, 11a-c, 11g,h, and 11l displayed inhibitory activity toward MAO-B with IC50 values between 16 to 74 nM. We conclude that halogenated flavonoids are promising molecules in pursuit of developing new agents for neurological disorders.

Dietary Phenolic Compounds-Wellbeing and Perspective Applications

Contemporary living is continuously leading to poor everyday choices resulting in the manifestation of various diseases. The benefits of plant-based nutrition are undeniable and research on the topic is rising. Modern man is now aware of the possibilities that plant nutrition can provide and is seeking ways to benefit from it. Dietary phenolic compounds are among the easily accessible beneficial substances that can exhibit antioxidant, anti-inflammatory, antitumor, antibacterial, antiviral, antifungal, antiparasitic, analgesic, anti-diabetic, anti-atherogenic, antiproliferative, as well as cardio-and neuroprotective activities. Several industries are exploring ways to incorporate biologically active substances in their produce. This review is concentrated on presenting current information about the dietary phenolic compounds and their contribution to maintaining good health. Additionally, this content will demonstrate the importance and prosperity of natural compounds for various fields, i.e., food industry, cosmetology, and biotechnology, among others.

Aerosolomics based approach to discover source molecular markers: A case study for discriminating residential wood heating vs garden green waste burning emission sources

Biomass burning is a significant source of particulate matter (PM) in ambient air and its accurate source apportionment is a major concern for air quality. The discrimination between residential wood heating (RWH) and garden green waste burning (GWB) particulate matter (PM) is rarely achieved. The objective of this work was to evaluate the potential of non-targeted screening (NTS) analyses using HRMS (high resolution mass spectrometry) data to reveal discriminating potential molecular markers of both sources. Two residential wood combustion appliances (wood log stove and fireplace) were tested under different output conditions and wood moisture content. GWB experiments were carried out using two burning materials (fallen leaves and hedge trimming). PM samples were characterized using NTS approaches with both LC- and GC-HRMS (liquid and gas chromatography-HRMS). The analytical procedures were optimized to detect as many species as possible. Chemical fingerprints obtained were compared combining several multivariate statistical analyses (PCA, HCA and PLS-DA). Results showed a strong impact of the fuel nature and the combustion quality on the chemical fingerprints. 31 and 4 possible markers were discovered as characteristic of GWB and RWH, respectively. Complementary work was attempted to identify potential molecular formulas of the different potential marker candidates. The combination of HRMS NTS chemical characterization with multivariate statistical analyses shows promise for uncovering organic aerosol fingerprinting and discovering potential PM source markers.

Comprehensive review of dibenzocyclooctadiene lignans from the Schisandra genus: anticancer potential, mechanistic insights and future prospects in oncology

Cancer remains one of the leading causes of mortality worldwide. The search for novel and effective anticancer agents has been a significant area of research. Dibenzocyclooctadiene lignans (DBCLS), derived from the Schisandra genus plants like: S. chinensis, S. sphenanthera, S. henryi, S. rubriflora, S. grandiflora, S. propinqua, and S. glabra, have been traditionally used in various medicinal systems and are known for their myriad health benefits, including anticancer properties. This comprehensive review aimed to collate and critically analyse the recent literature on the anticancer properties of DBCLS, focusing on their mechanistic approaches against different cancer types. An exhaustive literature search was performed using databases like PubMed/MedLine, Scopus, Web of Science, Embase, TRIP database and Google Scholar from 1980 to 2023. Peer-reviewed articles that elucidated the mechanistic approach of these lignans on cancer cell lines, in vivo models and preliminary clinical studies were included. Studies were assessed for their experimental designs, cancer types studied, and the mechanistic insights provided. The studies demonstrate that the anticancer effects of DBCLS compounds are primarily driven by their ability to trigger apoptosis, arrest the cell cycle, induce oxidative stress, modulate autophagy, and disrupt essential signaling pathways, notably MAPK, PI3K/Akt, and NF-κB. Additionally, these lignans have been shown to amplify the impact of traditional chemotherapy treatments, suggesting their potential role as supportive adjuncts in cancer therapy. Notably, several studies also emphasise their capacity to target cancer stem cells and mitigate multi-drug resistance specifically. DBCLS from the Schisandra genus have showcased significant potential as anticancer agents. Their multi-targeted mechanistic approach makes them promising candidates for further research, potentially leading to developing of new therapeutic strategies in cancer management.

Patulinervones A and B, two novel α-glucosidase inhibitory spiro-lignans from Melicope patulinervia (Merr. & Chun) C.C. Huang

(±)-Patulinervones A (1) and B (2), two diastereomers of spiro-lignans sharing an unprecedented dimethyl-spiro[furan-2,2'-furo[2,3-b]furan] 5/5/5 tricyclic moiety were isolated from the leaves of Melicope patulinervia (Merr. & Chun) C.C. Huang. Their structures were established by extensive spectroscopic data and electronic circular dichroism (ECD) analyses. The racemates (±)-1 and 2 and their enantiomers exhibited α-glucosidase inhibitory effect with IC50 values range of 10.08 ± 1.24 - 25.58 ± 1.97 µM.

How do cultivar origin and stepwise industrial processing impact Sesamum indicum seeds' metabolome and its paste and in relation to their antioxidant effects? A case study from the sesame industry

Sesame is a valuable crop recognized for its rich composition and myriad of health benefits. The current study attempts to characterize sesame seeds' metabolome in relation to geographical origins i.e., Egypt, Sudan, Nigeria, in addition to samples from paste production lines along its different steps. UPLC-PDA-ESI-qTOF-MS was employed for untargeted profiling and in correlation to antioxidant capacity using DPPH, FRAP and β-carotene-lineolate assays. 139 Peaks were identified, including novel phospholipids and catechol lignan in sesame. Furthermore, discriminatory markers belonging to coumarins, lignans, phenolic and organic acids were revealed among raw accessions, whereas roasted and unroasted seeds were distinguished by sugar, peptide/amino acid, and organic acid contents. Negative processing impact was observed in the loss of lignans during dehulling and decreased antioxidant capacity in sesame paste. However, malic acid in roasted seeds and verbascoside in Nigerian sesame could account for their improved antioxidant effects as revealed using chemometrics.

Structural Features of Small Molecule Antioxidants and Strategic Modifications to Improve Potential Bioactivity

This review surveys the major structural features in various groups of small molecules that are considered to be antioxidants, including natural and synthetic compounds alike. Recent advances in the strategic modification of known small molecule antioxidants are also described. The highlight is placed on changing major physicochemical parameters, including log p, bond dissociation energy, ionization potential, and others which result in improved antioxidant activity.

Addition of a Blend Based on Zinc Chloride and Lignans of Magnolia in the Diet of Broilers to Substitute for a Conventional Antibiotic: Effects on Intestinal Health, Meat Quality, and Performance

This study aimed to determine whether adding a blend based on zinc chloride and lignans from magnolia to the diet of broilers could replace conventional performance enhancers. For this study, 360 chickens were divided into four groups, with six repetitions per group (n = 15), as follows: CN, without promoter; GPC, control, 50 mg/kg of enramycin growth promoter; T-50, additive blend at a dose of 50 g/ton; and T-100, additive blend at a dose of 100 g/ton. Chickens fed with the additive blend at 50 g/ton showed a production efficiency index equal to that in the GPC group (p < 0.05). At 42 days, the lowest total bacterial count (TBC) was found in the T-100 group, followed by that in the GPC group (p < 0.001). For E. coli, the lowest count was observed in the T-100 group, followed by that in the CP and T-50 groups (p < 0.001). Higher villus/crypt ratios were observed in birds belonging to the T-100 and T-50 groups than in the GPC and NC groups (p < 0.001). Greater water retention was found in the T-50 group than in NC and T-100 groups (p < 0.048). The lowest water loss during cooking was also noted in the T-50 group (p < 0.033). We concluded that adding the antimicrobial blend, primarily at 50 g/ton, maintains the efficiency of the index of production and improves the intestinal health and meat quality of the birds.

Effects of non-covalent binding of lignans with rice starch driven by high-pressure homogenization on the starch structure and in vitro nutritional characteristics

As a type of phytoestrogen, lignans have attracted attention in recent years for their nutritional functions. To investigate the effects of lignans on the structural and nutritional functions of starch, honokiol (HK) and arctiin (AC) were complexed with rice starch respectively under high-pressure homogenization (UHPH) (UHPHRS/HK and UHPHRS/AC). The results showed that both HK and AC could form inclusive complexes with rice starch via non-covalent bonding (hydrophobic interaction and hydrogen bonds), and these complexes could further form V-type crystals and aggregates, which reduced the starch digestibility as well as endowing them with the ability to retard glucose release and bind sodium cholate. Interestingly, due to its smaller molecular size, HK could induce starch to form a more compact structure than AC, leading to better nutritional functions. When the addition of HK/AC reached 8%, the resistant starch content could reach 26% and 19.8%, respectively. Meanwhile, the glucose dialysis retardation index could increase to 17.2% and 14.8%, respectively, and the sodium cholate-binding capacity could increase to 33.1 mg g^-1 and 21.8 mg g^-1, respectively. These results demonstrated that UHPH with lignans' molecular interaction could be beneficial for controlling the nutritional functions of starch products with the desired digestibility.

Phylogeny and functional characterization of the cinnamyl alcohol dehydrogenase gene family in Phryma leptostachya

Phryma leptostachya has attracted increasing attention because it is rich in furofuran lignans with a wide range of biological activities. Biosynthesis of furofuran lignans begins with the dimerization of coniferyl alcohol, one of the monolignol. Cinnamyl alcohol dehydrogenase (CAD) catalyzes the final step of monolignol biosynthesis, reducing cinnamyl aldehydes to cinnamyl alcohol. As it is in the terminal position of monolignol biosynthesis, its type and activity can cause significant changes in the total amount and composition of lignans. Herein, combined with bioinformatics analysis and in vitro enzyme assays, we clarified that CAD in P. leptostachya belonged to a multigene family, and identified nearly the entire CAD gene family. Our in-depth characterization about the functions and structures of two major CAD isoforms, PlCAD2 and PlCAD3, showed that PlCAD2 exhibited the highest catalytic activity, and coniferyl aldehyde was its preferred substrate, followed by PlCAD3, and sinapyl aldehyde was its preferred substrate. Considering the accumulation patterns of furofuran lignans and expression patterns of PlCADs, we speculated that PlCAD2 was the predominant CAD isoform responsible for furofuran lignans biosynthesis in P. leptostachya. Moreover, these CADs found here can also provide effective biological parts for lignans and lignins biosynthesis.

Complete sequence of Cynanchum rostellatum (Apocynaceae: Asclepiadoideae) chloroplast genome and its phylogenetic analysis

Cynanchum rostellatum (Turcz.) Liede and Khanum 2016 is a perennial herbaceous twining vine that is widely distributed in Japan, South Korea, the United States of America, and China. In this study, the complete chloroplast (cp) genome of C. rostellatum was sequenced using the Illumina platform and assembled for the first time. This plastome has a circular structure with a length of 160,641 bp. The GC content of the plastome was 37.82%. The cp genome contained 113 unique genes, including 79 protein-coding, 30 transfer RNA, and four ribosomal RNA genes. Phylogenetic analysis based on the complete cp genome sequences of the Asclepiadoideae subfamily showed that C. rostellatum was closely related to C. bungei in the genus Cynanchum. These results provide useful information for both phylogenetic research and the utilization of C. rostellatum.

Natural Antioxidant Evaluation: A Review of Detection Methods

Antioxidants have drawn the attention of the scientific community due to being related to the prevention of various degenerative diseases. The antioxidant capacity has been extensively studied in vitro, and different methods have been used to assess its activity. However, the main issues related to studying natural antioxidants are evaluating whether these antioxidants demonstrate a key role in the biological system and assessing their bioavailability in the organism. The majority of outcomes in the literature are controversial due to a lack of method standardization and their proper application. Therefore, this study aims to compile the main issues concerning the natural antioxidant field of study, comparing the most common in vitro methods to evaluate the antioxidant activity of natural compounds, demonstrating the antioxidant activity in biological systems and the role of the main antioxidant enzymes of redox cellular signaling and explaining how the bioavailability of bioactive compounds is evaluated in animal models and human clinical trials.

Paving the way towards effective plant-based inhibitors of hyaluronidase and tyrosinase: a critical review on a structure-activity relationship

Human has used plants to treat many civilisation diseases for thousands of years. Examples include reserpine (hypertension therapy), digoxin (myocardial diseases), vinblastine and vincristine (cancers), and opioids (palliative treatment). Plants are a rich source of natural metabolites with multiple biological activities, and the use of modern approaches and tools allowed finally for more effective bioprospecting. The new phytochemicals are hyaluronidase (Hyal) inhibitors, which could serve as anti-cancer drugs, male contraceptives, and an antidote against venoms. In turn, tyrosinase inhibitors can be used in cosmetics/pharmaceuticals as whitening agents and to treat skin pigmentation disorders. However, the activity of these inhibitors is stricte dependent on their structure and the presence of the chemical groups, e.g. carbonyl or hydroxyl. This review aims to provide comprehensive and in-depth evidence related to the anti-tyrosinase and anti-Hyal activity of phytochemicals as well as confirming their efficiency and future perspectives.

Using α- and β-Epimerizations of cis-2,3-Bis(hydroxymethyl)-γ-butyrolactone for the Synthesis of Both Enantiomers of Enterolactone

In the context of asymmetric synthesis, epimerization is usually problematic. Here, we describe the use of the epimerization of cis-2,3-bis(hydroxymethyl)-γ-butyrolactone for the synthesis of enterolactones with anti-carcinogenic, anti-inflammatory, anti-angiogenic, and antioxidant activity. Selective α- or β-epimerization of a γ-butyrolactone was used to selectively synthesize both enantiomers of enterolactone. Theoretical and kinetic studies were performed to elucidate the epimerization mechanism.

A comprehensive review of ethnopharmacology, phytochemistry, pharmacology, and pharmacokinetics of Schisandra chinensis (Turcz.) Baill. and Schisandra sphenanthera Rehd. et Wils

ETHNOPHARMACOLOGICAL RELEVANCE

Schisandra chinensis (called bei-wuweizi in Chinese, S. chinensis) and Schisandra sphenanthera (called nan-wuweizi in Chinese, S. sphenanthera) are two highly similar plants in the Magnoliaceae family. Their dried ripe fruits are commonly used as traditional Chinese medicine in the treatment of coughs, palpitation, spermatorrhea, and insomnia. They also are traditionally used as tonics in Russia, Japan, and Korea.

AIM OF THE REVIEW

S. chinensis and S. sphenanthera are similar in appearance, traditional applications, ingredient compositions, and therapeutic effects. This review, therefore, aims to provide a systematic insight into the botanical background, ethnopharmacology, phytochemistry, pharmacology, pharmacokinetics, quality control, and toxicology of S. chinensis and S. sphenanthera, and to explore and present the similarities and differences between S. chinensis and S. sphenanthera.

MATERIALS AND METHODS

A comprehensive literature search regarding S. chinensis and S. sphenanthera was collected by using electronic databases including PubMed, SciFinder, Science Direct, Web of Science, CNKI, and the online ethnobotanical database.

RESULTS

In the 2020 Edition of Chinese Pharmacopoeia (ChP), there were 100 prescriptions containing S. chinensis, while only 11 contained S. sphenanthera. Totally, 306 and 238 compounds have been isolated and identified from S. chinensis and S. sphenanthera, respectively. Among these compounds, lignans, triterpenoids, essential oils, phenolic acid, flavonoids, phytosterols are the major composition. Through investigation of pharmacological activities, S. chinensis and S. sphenanthera have similar therapeutic effects including hepatoprotection, neuroprotection, cardioprotection, anticancer, antioxidation, anti-inflammation, and hypoglycemic effect. Besides, S. chinensis turns out to have more effects including reproductive regulation and immunomodulatory, antimicrobial, antitussive and antiasthmatic, anti-fatigue, antiarthritic, and bone remodeling effects. Both S. chinensis and S. sphenanthera have inhibitory effects on CYP3A and P-gp, which can mediate metabolism or efflux of substrates, and therefore interact with many drugs.

CONCLUSIONS

S. chinensis and S. sphenanthera have great similarities. Dibenzocyclooctadiene lignans are regarded to contribute to most of the bioactivities. Schisandrin A-C, schisandrol A-B, and schisantherin A, existing in both S. chinensis and S. sphenanthera but differing in the amount, are the main active components, which may contribute to the similarities and differences. Study corresponding to the traditional use is needed to reveal the deep connotation of the use of S. chinensis and S. sphenanthera as traditional Chinese medicine. In addition, a joint study of S. chinensis and S. sphenanthera can better show the difference between them, which can provide a reference for clinical application. It is worth mentioning that the inhibition of S. chinensis and S. sphenanthera on CYP3A and P-gp may lead to undesirable drug-drug interactions.

Liriodendrin, ameliorates hypertension by calcium channel blockade and enhancing enos expression in wistar rats

Introduction: Hypertension is found to be the prime cause ofdeath worldwide in spite of a number of available treatmentswhich suggests that there is a need of discovering new leadmolecules that would be more effective to treat cardiovasculardisease (CVD). Liriodendrin, the lignan phytoconstituent possessespotential pharmacological effects. Literature survey suggeststhat liriodendrin could be effective in mitigating hypertensionconsidering its structural similarity with reported cardiovascularprotective drugs. Hence liriodendrin is investigated to reveal itsmechanism of actions to support its antihypertensive property.Methods: Hypertension was induced in male wistar rats withDOCA salt. Hypertensive rats were treated with liriodendrin for4 weeks. Blood pressure, heart rate, body weight, lipid profile,serum nitrite levels, vascular reactivity to various catecholamines,in-vitro calcium channel blocking assays, antioxidantassay, determination of aortic calcium level, endothelial function,expression of eNOS analysis were studied.Result: Liriodendrin was found safe orally up to 2000 mg/kg. Itshowed a significant decrease in heart rate, blood pressure andmean arterial pressure. In-vitro study on the isolated rat aorta revealedthe calcium channel blocking potential of liriodendrin. Vascularreactivity to various catecholamines was normalized. Vascularendothelium was significantly protected by the enhancedrelease of nitric oxide and eNOS expression by the western blottechnique. Oxidative stress was also significantly reduced.Conclusion: Liriodendrin was found to be beneficial in hypertensionas it produced vasorelaxation by blocking calciumchannels, enhancing nitric oxide release, and reducing oxidativestress. Thus, liriodendrin may be useful to relieve hypertensionand cardiovascular complications.

The ethnopharmacology, phytochemistry, pharmacology and toxicology of the genus Erycibe (Convolvulaceae)

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Erycibe belongs to the Convolvulaceae family that contains approximately 70 species mainly distributed from tropical and subtropical Asia to north of Australia. Several Erycibe species are traditionally used in folk medicine for the treatment of various ailments, including rheumatic arthralgia, primary glaucoma, hepatopathies, and infectious and malignant diseases.

AIM OF THE REVIEW

This review aims to summarize comprehensive and updated information on traditional medicinal uses, phytochemistry, pharmacology, and toxicology of Erycibe species to provide a reference for the further research and application of the Erycibe genus.

MATERIALS AND METHODS

The scientific and extensive literatures between 1975 and 2020 were systematically gathered from scientific databases such as SciFinder Scholar, Science Direct, Web of Science, PubMed, Google Scholar, Scopus, Springer Link and China National Knowledge Infrastructure (CNKI), as well as Chinese herbal classic books, PhD and MSc theses, and several official websites.

RESULTS

Erycibe species have been used for the treatment of various rheumatoid diseases, glaucoma, a variety of hepatic diseases, infectious diseases and various malignancies in the traditional and local medicine. Since the 1970s, 153 compounds, including coumarins, quinic acid derivatives, flavonoids, alkaloids, lignans, and others have been isolated from five species of the Erycibe genus. Pharmacological studies have shown that these extracts and compounds from the Erycibe genus have extensive activities consistent with the traditional and local applications, such as anti-glaucoma, anti-arthritic, hepatoprotective and anti-cancer activities, as well as anti-inflammatory, anti-respiratory syncytial virus (RSV), and neuroprotective properties.

CONCLUSIONS

Although there are extensive data on the genus Erycibe, certain specific gaps still exist. For herbal preparations containing Erycibe species, clinical toxicological investigation is required for the safety of these herbal preparation therapies, as well as further investigations on pharmacokinetics and bioavailability for guideline for clinical application. Furthermore, more detailed pharmacological, toxicological and clinical researches are needed to assess the alternatives to Erycibe species. Systematic and comprehensive pre-clinical studies are similarly required to estimate the possibility of extracts and compounds from the genus Erycibe with bioactivity developing into new drugs.

Filtration of Active Components with Antioxidant Activity Based on the Differing Antioxidant Abilities of Schisandrae Sphenantherae Fructus and Schisandrae Chinensis Fructus through UPLC/MS Coupling with Network Pharmacology

This study attempted to filter active components with antioxidant activities based on the differing antioxidant abilities of Schisandrae Sphenantherae Fructus (SSF) and Schisandrae Chinensis Fructus (SCF). First, the antioxidant activity of SSF and SCF was evaluated through the DPPH free radical scavenging method and compared with the half maximal inhibitory concentration (IC₅₀) value. Next, components of SSF and SCF were detected by employing ultrahigh-performance liquid chromatography-Q-Exactive Orbitrap mass spectrometry (UPLC-QEO/MS) technology, and differential compounds were screened out as potential antioxidant compounds by using Compound Discover 3.1 Software. After that step, in order to verify the antioxidant compounds, the network method was applied. Biological targets were searched in the GeneCards database, and that related to antioxidant ability were selected in the Comparative Toxicogenomics Database (CTD). Finally, the pharmacology network was constructed. Results showed that SSF and SCF possessed different compounds and antioxidant abilities. A total of 14 differential compounds such as γ-schizandrin, schisandrin B, schisandrin, and tigloylgomisin H between them were screened out and identified. Twenty targets associated with antioxidant activity contained MAP2K1, MAPK8, RPS6KB1, PRKCB, HIF1A, and so on were investigated. Thirty-six pathways contained HIF-1 signaling pathways, choline metabolism in cancer, serotonergic synapse, Fc epsilon RI signaling pathway, GnRH signaling pathway, and so on related to the above twenty targets were identified. The pharmacology network analysis indicated that the differential components may be helpful in treating various diseases, especially cancer, by exerting antioxidant activity. In conclusion, this study provided a novel method for identifying active components with antioxidant activity in SSF and SCF, and this method may be applicable for the filtration of bioactive components in other herbs.

Interaction of lignin dimers with model cell membranes: A quartz crystal microbalance and molecular dynamics simulation study

A study of the interaction between cell membranes and small molecules derived from lignin, a protective phenolic biopolymer found in vascular plants, is crucial for identifying their potential as pharmacological and toxicological agents. In this work, the interactions of model cell membranes [supported 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) lipid bilayers] are compared for three βO4 dimers of coniferyl alcohol (G lignin monomer): guaiacylglycerol guaiacol ester with a hydroxypropenyl (HOC₃H₄-) tail (G-βO4'-G), a truncated GG dimer without HOC₃H₄- (G-βO4'-truncG), and a benzylated GG dimer (benzG-βO4'-G). The uptake of the lignin dimers (per mass of lipid) and the energy dissipation (a measure of bilayer disorder) are higher for benzG-βO4'-G and G-βO4'-truncG than those for G-βO4'-G in the gel-phase DPPC bilayer, as measured using quartz crystal microbalance with dissipation (QCM-D). A similar uptake of G-βO4'-truncG is observed for a fluid-phase bilayer of 1,2-dioleoyl-sn-glycero-3-phosphocholine, suggesting that the effect of the bilayer phase on dimer uptake is minimal. The effects of increasing lignin dimer concentration are examined through an analysis of density profiles, potential of mean force curves, lipid order parameters, and bilayer area compressibilities (disorder) in the lipid bilayers obtained from molecular dynamics simulations. Dimer distributions and potentials of mean force indicate that the penetration into bilayers is higher for benzG-βO4'-G and G-βO4'-truncG than that for G-βO4'-G, consistent with the QCM-D results. Increased lipid tail disorder due to dimer penetration leads to a thinning and softening of the bilayers. Minor differences in the structure of lignin derivatives (such as truncating the hydroxypropenyl tail) have significant impacts on their ability to penetrate lipid bilayers.

Phyllanthin and hypophyllanthin, the isolated compounds of Phyllanthus niruri inhibit protein receptor of corona virus (COVID-19) through in silico approach

OBJECTIVES

Phyllanthus niruri has been known as an immunomodulator and also reported to possess an antiviral activity against several RNA viruses, such as hepatitis B virus and hepatitis C virus by inhibiting viral entry and replication. Since the current situation of Coronavirus Disease 2019 (COVID-19) which infected among the world and caused severe disease and high morbidity, it urgently needed to find new agents against COVID-19. Therefore, in silico screening against COVID-19 receptors is carried out as an initial stage of drug discovery by evaluating the activity of phyllanthin and hypophyllanthin, an isolated from Phyllanthus niruri, in inhibiting spike glycoprotein (6LZG) and main protease (5R7Y) which play as target receptors of COVID-19.

METHODS

Molegro Virtual Docker 6.0 used to determine the best binding energy through the rerank score which shows the total energy bonds calculation.

RESULTS

Phyllanthin and hypophyllanthin demonstrated to possess greater binding affinity toward the COVID-19 inhibition sites than their native ligand. The rerank score of phyllanthin and hypophyllanthin are lower than the native ligands 6LZG and 5R7Y. This result indicated that phyllanthin and hypophyllanthin have a stronger interaction than the native ligands both in spike glycoprotein (entry inhibitor) and main protease (translation and replication inhibitor).

CONCLUSIONS

In conclusion, phyllanthin and hypophyllanthin are predicted to have strong activity against COVID-19 through inhibiting spike glycoprotein and main protease under in silico study. Further research is needed to support the development of P. niruri as inhibitor agents of COVID-19 through bioassay studies.

Biomass-derived chemical substitutes for bisphenol A: recent advancements in catalytic synthesis

Bisphenol A is an oil-derived, large market volume chemical with a wide spectrum of applications in plastics, adhesives and thermal papers. However, bisphenol A is not considered safe due to its endocrine disrupting properties and reproductive toxicity. Several functional substitutes of bisphenol A have been proposed in the literature, produced from plant biomass. Unless otherwise specified, the present review covers the most significant contributions that appeared in the time span January 2015-August 2019, describing the sustainable catalytic synthesis of rigid diols from biomass derivatives. The focus is thereupon on heterogeneous catalysis, use of green solvents and mild conditions, cascade processes in one-pot, and continuous flow setups. More than 500 up-to-date references describe the various substitutes proposed and the catalytic methods for their manufacture, broken down according to the main biomass types from which they originate.

Design, synthesis, and evaluation of cytotoxic activities of arylnaphthalene lignans and aza-analogs

A concise and versatile synthetic strategy for the total synthesis of arylnaphthalene lignans and aza-analogs was developed. The main objective was to develop synthetic tactics for the creation of the lactone and lactam unit that would give access to an array of synthetic, natural, and/or bioactive compounds through rather simple chemical manipulation. The flexibility and potentiality of these new processes were further illustrated by the total synthesis of retrojusticidin B (13b), justicidin C (14b), and methoxy-vitedoamine A (22a). In this study, a series of novel aryl-naphthalene lignans and aza-analogs were synthesized, and the cytotoxic activities of all compounds on cancer cell growth were evaluated. The target compounds were structurally characterized by ¹ H NMR (nuclear magnetic resonance), ¹³ C NMR, infrared, high-resolution mass spectrometry, and X-ray crystallography. The IC₅₀ values of these compounds on five tumor cell lines (A549, HS683, MCF-7, SK-MEL-28, and B16-F1) were obtained by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) colorimetric assay. Five of the compounds exhibited excellent activity compared to 5-fluorouracil and etoposide against the five cell lines tested, with IC₅₀ values ranging from 1 to 10 μM.

Three new C21 steroidal glycosides isolated from Metaplexis japonica and their potential inhibitory effects on tyrosine protein kinases

Three new steroidal glycosides, metapregnoside A-C (II-IV), together with one known compound, byzantionoside B (I), were isolated from the fresh whole herb of Metaplexis japonica by using high-speed countercurrent chromatography and semi-preparative liquid chromatography. Their structures and relative configurations were elucidated by spectroscopic methods including 1D NMR, 2D NMR and HR-ESI-MS. The potential targets of compound I-IV were identified by virtual screening. And the potential inhibitory effects of these compounds on tyrosine protein kinases were compared by molecular docking. Byzantionoside B (I) was the first isolated compound from Metaplexis genus. The docking score of metapregnoside C (IV) was the highest. And the sugar chain residues at position C-20 in the pregn-4-en-3-one derivatives is the main factor affecting their docking scores on tyrosine protein kinases Fes/Fps.

Enantioselective total synthesis of furofuran lignans via Pd-catalyzed asymmetric allylic cycloadditon of vinylethylene carbonates with 2-nitroacrylates

Herein, a practical and efficient approach to tetrahydrofurans with three-stereocenters has been developed through Pd-catalyzed asymmetric allylic cycloaddition of vinylethylene carbonates (VECs) with 2-nitroacrylates under mild conditions. By using this asymmetric catalytic reaction as a key step, several furofuran lignans with stereodivergency have been effectively synthesized through 5- or 6-step sequences from readily available starting materials.

Antimicrobial Capacity of Plant Polyphenols against Gram-positive Bacteria: A Comprehensive Review

BACKGROUND

Multi-drug-resistant bacteria such as Methicillin-Resistant Staphylococcus aureus (MRSA) disseminate rapidly amongst patients in healthcare facilities and suppose an increasingly important cause of community-associated infections and associated mortality. The development of effective therapeutic options against resistant bacteria is a public health priority. Plant polyphenols are structurally diverse compounds that have been used for centuries for medicinal purposes, including infections treatment and possess, not only antimicrobial activity, but also antioxidant, anti-inflammatory and anticancer activities among others. Based on the existing evidence on the polyphenols' antibacterial capacity, polyphenols may be postulated as an alternative or complementary therapy for infectious diseases.

OBJECTIVE

To review the antimicrobial activity of plant polyphenols against Gram-positive bacteria, especially against S. aureus and its resistant strains. Determine the main bacterial molecular targets of polyphenols and their potential mechanism of action.

METHODOLOGY

The most relevant reports on plant polyphenols' antibacterial activity and their putative molecular targets were studied. We also performed virtual screening of thousand different polyphenols against proteins involved in the peptidoglycan biosynthesis to find potential valuable bioactive compounds. The bibliographic information used in this review was obtained from MEDLINE via PubMed.

RESULTS

Several polyphenols: phenolic acids, flavonoids (especially flavonols), tannins, lignans, stilbenes and combinations of these in botanical mixtures, have exhibited significant antibacterial activity against resistant and non-resistant Gram-positive bacteria at low μg/mL range MIC values. Their mechanism of action is quite diverse, targeting cell wall, lipid membrane, membrane receptors and ion channels, bacteria metabolites and biofilm formation. Synergic effects were also demonstrated for some combinations of polyphenols and antibiotics.

CONCLUSION

Plant polyphenols mean a promising source of antibacterial agents, either alone or in combination with existing antibiotics, for the development of new antibiotic therapies.

Synthesis and Antibacterial Analysis of Analogues of the Marine Alkaloid Pseudoceratidine

In an effort to gain more understanding on the structure activity relationship of pseudoceratidine 1, a di-bromo pyrrole spermidine alkaloid derived from the marine sponge Pseudoceratina purpurea that has been shown to exhibit potent biofouling, anti-fungal, antibacterial, and anti-malarial activities, a large series of 65 compounds that incorporated several aspects of structural variation has been synthesised through an efficient, divergent method that allowed for a number of analogues to be generated from common precursors. Subsequently, all analogues were assessed for their antibacterial activity against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. Overall, several compounds exhibited comparable or better activity than that of pseudoceratidine 1, and it was found that this class of compounds is generally more effective against Gram-positive than Gram-negative bacteria. Furthermore, altering several structural features allowed for the establishment of a comprehensive structure activity relationship (SAR), where it was concluded that several structural features are critical for potent anti-bacterial activity, including di-halogenation (preferable bromine, but chlorine is also effective) on the pyrrole ring, two pyrrolic units in the structure and with one or more secondary amines in the chain adjoining these units, with longer chains giving rise to better activities.

Synthesis of Bisphenol Neolignans Inspired by Honokiol as Antiproliferative Agents

Honokiol (2) is a natural bisphenol neolignan showing a variety of biological properties, including antitumor activity. Some studies pointed out 2 as a potential anticancer agent in view of its antiproliferative and pro-apoptotic activity towards tumor cells. As a further contribution to these studies, we report here the synthesis of a small library of bisphenol neolignans inspired by honokiol and the evaluation of their antiproliferative activity. The natural lead was hence subjected to simple chemical modifications to obtain the derivatives 3–9; further neolignans (12a-c, 13a-c, 14a-c, and 15a) were synthesized employing the Suzuki–Miyaura reaction, thus obtaining bisphenols with a substitution pattern different from honokiol. These compounds and the natural lead were subjected to antiproliferative assay towards HCT-116, HT-29, and PC3 tumor cell lines. Six of the neolignans show GI₅₀ values lower than those of 2 towards all cell lines. Compounds 14a, 14c, and 15a are the most effective antiproliferative agents, with GI₅₀ in the range of 3.6–19.1 µM, in some cases it is lower than those of the anticancer drug 5-fluorouracil. Flow cytometry experiments performed on these neolignans showed that the inhibition of proliferation is mainly due to an apoptotic process. These results indicate that the structural modification of honokiol may open the way to obtaining antitumor neolignans more potent than the natural lead.

First total synthesis of mariamide A

Mariamide A, a lignanamide isolated from the seeds of Silybum marianum, has demonstrated potential utility as an antioxidant and antidiabetic agent and possesses an 8-O-4′ neolignan skeleton. Herein, a first total synthesis of mariamide A is presented that proceeds in nine steps using vanillin as the starting material. The key steps for the preparation of mariamide A involve an I2-catalyzed bromomethoxylation of an alkene group, a nucleophilic substitution followed by a sequential elimination and a monoacylation reaction.

A Chemometric Analysis of Deep-Sea Natural Products

Deep-sea natural products have been created by unique marine organisms that thrive in a challenging environment of extreme conditions for its inhabitants. In this study, 179 deep-sea natural products isolated from 2009 to 2013 were investigated by analysing their physicochemical properties that are important indicators of the ADMET (Absorption, Distribution, Metabolism, Excretion and Toxicity) profile of a compound. The study and analysis of these molecular descriptors and characteristics enabled the defining of these compounds in various chemical spaces, particularly as an indication of their drug-likeness and position in chemical space and is the first to be conducted to analyse deep-sea derived natural products. It was found that ~40% of all deep-sea natural products were drug-like and 2/3 were within Known Drug Space (KDS), highlighting the high drug-likeness of a significant proportion of deep-sea natural products, most of which have already been shown to have notable biological activities, that should be further investigated as potential therapeutics. Furthermore, this study was able to reveal the general structural differences between compounds from Animalia, Bacteria and Fungi organisms where it was observed that natural products from members of the Animalia kingdom are structurally more varied than compounds from bacteria and fungi. It was also noted that, in general, fungi-derived compounds occupy a more favourable position in drug-like chemical space and are a rich and promising source of biologically-active natural products for the purposes of drug development and therapeutic application.

Insights into Lignan Composition and Biosynthesis in Stinging Nettle (Urtica dioica L.)

Stinging nettle (Urtica dioica L.) has been used as herbal medicine to treat various ailments since ancient times. The biological activity of nettle is chiefly attributed to a large group of phenylpropanoid dimers, namely lignans. Despite the pharmacological importance of nettle lignans, there are no studies addressing lignan biosynthesis in this plant. We herein identified 14 genes encoding dirigent proteins (UdDIRs) and 3 pinoresinol-lariciresinol reductase genes (UdPLRs) in nettle, which are two gene families known to be associated with lignan biosynthesis. Expression profiling of these genes on different organs/tissues revealed a specific expression pattern. Particularly, UdDIR7, 12 and 13 displayed a remarkable high expression in the top internode, fibre tissues of bottom internodes and roots, respectively. The relatively high expression of UdPLR1 and UdPLR2 in the young internodes, core tissue of bottom internode and roots is consistent with the high accumulation of lariciresinol and secoisolariciresinol in these tissues. Lignan quantification showed a high abundance of pinoresinol in roots and pinoresinol diglucosides in young internodes and leaves. This study sheds light on lignan composition and biosynthesis in nettle, providing a good basis for further functional analysis of DIRs and PLRs and, ultimately, engineering lignan metabolism in planta and in cell cultures.

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.

Naturally Lignan-Rich Foods: A Dietary Tool for Health Promotion?

Dietary guidelines universally advise adherence to plant-based diets. Plant-based foods confer considerable health benefits, partly attributable to their abundant micronutrient (e.g., polyphenol) content. Interest in polyphenols is largely focused on the contribution of their antioxidant activity to the prevention of various disorders, including cardiovascular disease and cancer. Polyphenols are classified into groups, such as stilbenes, flavonoids, phenolic acids, lignans and others. Lignans, which possess a steroid-like chemical structure and are defined as phytoestrogens, are of particular interest to researchers. Traditionally, health benefits attributed to lignans have included a lowered risk of heart disease, menopausal symptoms, osteoporosis and breast cancer. However, the intake of naturally lignan-rich foods varies with the type of diet. Consequently, based on the latest humans' findings and gathered information on lignan-rich foods collected from Phenol Explorer database this review focuses on the potential health benefits attributable to the consumption of different diets containing naturally lignan-rich foods. Current evidence highlight the bioactive properties of lignans as human health-promoting molecules. Thus, dietary intake of lignan-rich foods could be a useful way to bolster the prevention of chronic illness, such as certain types of cancers and cardiovascular disease.

Oxidative Transformations of Lignans

Numerous oxidative transformations of lignan structures have been reported in the literature. In this paper we present an overview on the current findings in the field. The focus is put on transformations targeting a specific structure, a specific reaction, or an interconversion of the lignan skeleton. Oxidative transformations related to biosynthesis, antioxidant measurements, and total syntheses are mostly excluded. Non-metal mediated as well as metal mediated oxidations are reported, and mechanisms based on hydrogen abstractions, epoxidations, hydroxylations, and radical reactions are discussed for the transformation and interconversion of lignan structures. Enzymatic oxidations, photooxidation, and electrochemical oxidations are also briefly reported.

Lignans: A Chemometric Analysis

The physicochemical properties of classical lignans, neolignans, flavonolignans and carbohydrate-lignan conjugates (CLCs) were analysed to assess their ADMET profiles and establish if these compounds are lead-like/drug-like and thus have potential to be or act as leads in the development of future therapeutics. It was found that while no studied compounds were lead-like, a very large proportion (>75%) fulfilled all the requirements to be deemed as present in drug-like space and almost all compounds studied were in the known drug space. Principal component analysis was an effective technique that enabled the investigation of the relationship between the studied molecular descriptors and was able to separate the lignans from their sugar derivatives and flavonolignans, primarily according to the parameters that are considered when defining chemical space (i.e., number of hydrogen bond donors, acceptors, rotatable bonds, polar surface area and molecular weight). These results indicate that while CLCs and flavonolignans are less drug-like, lignans show a particularly high level of drug-likeness, an observation that coupled with their potent biological activities, demands future pursuit into their potential for use as therapeutics.

Naturally occurring furofuran lignans: structural diversity and biological activities

Furofuran lignans containing the 2,6-diaryl-3,7-dioxabicyclo[3.3.0]octane skeleton, represent one of the major subclasses of the lignan family of natural products. Furofuran lignans feature a wide variety of structures due to different substituents at aryl groups and diverse configurations at furofuran ring. Moreover, they exhibit a wide range of significant biological activities, including antioxidant, anti-inflammatory, cytotoxic, and antimicrobial activities. This review summarizes source, phytochemistry, and biological activities of 137 natural furofuran lignans isolated from 53 species in 41 genera of 27 plant families for the last 20 years, which provides a comprehensive information for further research of these furofuran lignans as potential pharmaceutical agents.

Natural Products Research in China From 2015 to 2016

This review covers the literature published by chemists from China during the 2015-2016 on natural products (NPs), with 1,985 citations referring to 6,944 new compounds isolated from marine or terrestrial microorganisms, plants, and animals. The emphasis is on 730 new compounds with a novel skeleton or/and significant bioactivity, together with their source organism and country of origin.

Bioinspired total synthesis of tetrahydrofuran lignans by tandem nucleophilic addition/redox isomerization/oxidative coupling and cycloetherification reactions as key steps

Three steps suffice to complete a bioinspired total synthesis of tetrahydrofuran lignans using tandem addition/isomerization/dimerization and cycloetherification reactions.