Antioxidant lignans sesamin and sesamolin in sesame(Sesamum indicum L.):a comprehensive review and future prospects

Sesame(Sesamum indicum L.)is a significantly lucrative cash crop for millions of small-holder farmers.Its seeds are an important source of a highly appreciated vegetable oil globally and two clinically essential antioxidant lignans,sesamin and sesamolin.Accordingly,many countries import millions of tons of sesame seed every year.The demand for lignan-rich sesame seeds has been increasing in recent years due to the continuous discovery of several pharmacological attributes of sesamin and sesamolin.To meet this demand,the sesame breeder’s primary objective is to release sesame cultivars that are enriched in oil and lignans.Thus,it is necessary to summarize the information related to the sesamin and sesamolin contents in sesame in order to promote the joint efforts of specialized research teams on this important oilseed crop.In this article,we present the current knowledge on the sesamin and sesamolin contents in S.indicum L.with respect to the updated biosynthesis pathway,associated markers,governing loci,available variability in sesame germplasm,the in planta potential roles of these compounds in sesame,and the newly discovered pharmacological attributes.In addition,we propose and discuss some required studies that might facilitate genomics-assisted breeding of high lignan content sesame varieties.

Flaxseed Lignans Promoted the Growth of Skeletal Muscle in Male Rats and Its Possible Mechanism

This study was aimed to determine whether flaxseed lignans could affect the growth of skeletal muscle in male animals and its possible mechanisms. The impact of flaxseed lignans on the skeletal muscle in male rats was determined in vivo. Flaxseed lignans （50 ppm） and daidzein （5 ppm） were added into the basal diets, respectively. The concentrations of serum lignans and daidzein were measured by high performance liquid chromatography （HPLC）, and the serum growth hormone and testosterone （T） levels were analyzed by radioimmunoassay （RIA）, and the expression of estrogen receptor β （ER β） in the soleus muscle and hypothalamus were determined by reverse-transcription polymerase chain reaction （RT-PCR）. Flaxseed lignans and daidzein could significantly improve the feed efficiency and facilitate the weight gain of the femoral muscle in male rats. The ratio of RNA to DNA in the muscles and serum T levels was remarkably increased, whereas, the urea nitrogen concentrations were significantly decreased by flaxseed lignan and/or its metabolites and daidzein. Meanwhile, the expression of ER β in soleus muscle and hypothalamus were both upgraded by the two phytoestrogens. Flaxseed lignan promoted the growth of male rats, and it might be by regulating serum T levels by binding to ER β in the hypothalamus. In turn, it depressed the catabolism of protein and promoted the hypertrophy of skeletal muscle ceils.

Two new lignans from Dipteronia dyeriana

A new sesquilignan, 7＇,8＇-didehydroherpetotriol （1）, and a new lignan glycoside, （＋）-isolariciresinol-9＇-O-α-L-rhamnopyra- nosy1-（1→6）-[3-D-glucopyranoside （2）, were isolated from the branches of Dipteronia dyeriana. Their structures were elucidated by spectroscopic methods and chemical evidence. Compound 1 possessed inhibitory activity against human leukaemia K562 cells with an IC50 value of 39 μmol/L.

Neolignans and Norlignans from Insect Medicine Polyphaga plancyi and Their Biological Activities

Ten neolignans or norlignans(1-10)including eight new compounds were isolated from the whole bodies of Polyphaga plancyi Bolivar.Their structures were identified by spectroscopic data.Compounds 3,4,8,and 9 are racemates indicated by chiral HPLC analysis.Chiral separation followed by ECD calculations allowed to clarify the absolute configurations of all the antipodes.All the new compounds were evaluated for their biological properties toward extracellular matrix in rat renal proximal tubular cells,human cancer cells(K562,A549,and Huh7),EV71,ROCK2,JAK3,DDR1,and coagulation.

Neolignans from Selaginella moellendorffii

Two new neolignans selaginellol(1)and selaginellol 4'-O-β-D-glucopyranoside(2),together with seven known compounds(3–9),were isolated from the whole plant of Selaginella moellendorffii.The structures of the new isolates were determined through spectroscopic data analysis.Compounds 1–9,as well as compounds 10–18 previously isolated from the species,were measured for the activity against platelet aggregation induced by ADP or collagen.Three neoligans(8,11,and 12),one flavanone(14),and one alkaloid(16)showed inhibitory activity against ADP-or collagen-induced platelet aggregation as compared with tirofiban.The dihydrobenzofuran neolignans(8,11,and 12)are more potent than the benzofuran neolignan(13)and other types of neolignans(1–7).Glucosidation of the dihydrobenzofuran neolignans(11 and 12)is helpful for the activity.Graphical Abstract Two new neolignans selaginellol(1)and selaginellol 40-O-b-D-glucopyranoside(2)were isolated from the whole plant of Selaginella moellendorffii.Several compounds from this plant showed the activity against platelet aggregation induced by ADP or collagen.

CARBONIUM CYCLIZATION--STUDIES ON LIGNANS CONTAINING THE DIBENZOCYCLOOCTADIENE SYSTEM.Ⅱ

The major products of carbonium cyclization of 1 are 2 and 3;2 is unstable and undergoes aerial oxidation to give 4.A similar product(6)from 5 is somehow stabilized by the extra ben- zoyloxy group(or OH)and can be stored without deterioration.

Lignans and sesquiterpenoids from the stems of Schisandra bicolor var. tuberculata

A pair of new tetrahydrofuran lignan enantiomers,(±)-schibiculatin A[(±)-1],a new enedione lignan,schibiculatin B(2),two new cadinane-type sesquiterpenoids,schibiculatins C(3)and D(4),along with two known seco-cadinane-type sesquiterpenoids(5 and 6)and seven known miscellaneous lignans(7-13)were isolated from the stems of Schisandra bicolor var.tuberculata.The structures of 1-4 were elucidated by comprehensive analysis of their spectro-scopic data,quantum chemical calculations,as well as single-crystal X-ray diffraction.A few isolated compounds were tested for their protective activities against corticosterone-induced apoptosis in PC12 cells.Among them,compounds 5 and 6 showed moderate activities.

CARBONIUM CYCLIZATION—STUDIES ON LIGNANS CONTAINING THE DIBENZOCYCLOOCTADIENE SYSTEM.Ⅰ

Schisandrin(1)under the Ritter reaction conditions (conc.H_2SO_4/CH_3CN)gave trace amounts of the expected acetamido derivatives(2a,2b).The main product is 5a,from intramolecular car- bonium cyclization.

STUDIES ON SEPARATION AND DETERMIINATION OF THE LIGNANS IN DIPHYLLEIA SIENSIS LI BY RP-HPLC

A simple,sensitive and accurate RP-HPLC method for the separation and determination of eight lignans in Diphylleia sinensis was described.The method has been applied to the analysis of different samples.

Studies on the Synthesis of Sesamin-Group Lignans Ⅷ. A Simplified Sythesis of 2-Aryl-4-phenyloxazoles and 2-Alkyl-4-phenyloxazoles

The reaction of phenacyl benzoate derivatives with acetamide at about 140°in the presence of BF3 catalyst gave 2-aryl-4-phenyloxazoles. This method can be applied to the preparation of 2-alkyl-4-phenyloxazoles as well.

Isolation and characterization of lignans from the leaves of Isatis indigotica Fortune

A phytochemical investigation of 80%EtOH exact of Isatis indigotica Fortune leaves yielded ten lignans(1-10),including six furofurans lignans(1-6),one arylnaphthalenes lignans(7)and three tetrahydrofurans lignans(8-10).Their structures were determined by HRESIMS spectroscopic data and extensive NMR analyses.Among them,compounds 6,9 and 10 were isolated from the genus oi Isatis for the first time.

Research progress on the lignans from the genus Schisandra and their biological activities

The plants of the genus Schisandra belong to the Schisandraceae family.As one of the main active components of genus Schisandra,lignans have rich biological activities,including anti-inflammatory,anti-tumor,anti-HIV and PAF antagonism.This article summarizes and classifies the types and activities of lignans isolated from the genus Schisandra in the past ten years.

Four new lignans from the leaves and stems of Schisandra propinqua var.sinensis

Four new tetrahydrofuran lignans,schpropinrins A-D(1-4),together with five known ones,were isolated from the leaves and stems of Schisandra propinqua var.sinensis.Their structures,including absolute configurations,were characterized by means of spectroscopic analysis and ECD calculation.Compounds 1-4 featured a ketal or hemiketal substructure at C-7 and all of the isolates were tested for their anti-HIV integrase activity.

Highly Oxygenated Limonoids and Lignans from Phyllanthus flexuosus

Two new highly oxygenated limonoids,flexuosoids A(1)and B(2),and three new arylnaphthalene lignan glycosides,phyllanthusmins D–F(3–5),were isolated from the roots of Phyllanthus flexuosus,in addition to three known lignans,phyllanthusmin C,arabelline,and(?)-diasyringaresinol.Their structures were elucidated on the basis of detailed spectroscopic analysis and chemical methods.Compounds 1 and 2,two new decaoxygenated limonoids with a C-19/29 lactol bridge and heptaoxygenated substituents at C-1,C-2,C-3,C-7,C-11,C-17,and C-30,represent the second example of limonoids in the Euphorbiaceae family.Most of the isolates were tested for their antifeedant,anti-herpes simplex virus 1,and cytotoxic activities.The new limonoids 1 and 2 showed promising antifeedant activity against the beet army worm(Spodoptera exigua)with EC50 values of 25.1 and 17.3 lg/cm2,respectively.In addition,both of them displayed moderate cytotoxicity against the ECA109 human esophagus cancer cell line,along with the known lignan glycoside,phyllanthusmin C,with the IC50 values of 11.5(1),8.5(2),and 7.8(phyllanthusmin C)lM,respectively.

Lignans from Seeds of Herpetospermum caudigerum Wall.Protect Against Alcoholic Liver Injury via TGF-β/Smads Pathway in Rats

[Objectives]This study aimed to investigate the effects of lignans from seeds of Herpetospermum caudigerum Wall.(SHC)on expression of TGF-β/Smads in liver tissue of hepatic alcohol-injuried rats,and to explore its protective mechanism.[Methods]A total of 60 SD rats were randomly divided into six groups.The rats in all the groups except those in the normal group were given with white spirit by gavage for 8 weeks to establish alcoholic liver injury models.After rat models were established successfully,they were administered intragastrically with 400,200 and 100 mg/kg of lignans,respectively.The rats in the normal group were administered intragastrically with 50 mg/kg of silymarin.The administration lasted for 8 weeks,once a day.The changes in the general state,liver tissue pathology and collagen deposition of the rats were observed.The expression of TGF-β,TGF-β1 receptor 1(TβR-I),TGF-β1 receptor 2(TβR-II),Smad2/p-Smad2 and Smad3/p-Smad3 in the hepatic tissue was detected.[Results]The expression levels of TGF-β1,Smad2,p-Smad2,and p-Smad3 significantly declined,and the expression levels of TβR-I,TβR-II and Smad3 did not change significantly in the liver tissue of rats in the lignans groups and the expression levels of TGF-β,Smad2,and p-Smad3 significantly declined.Meanwhile,the expression levels of TβR-I,TβR-II,p-Smad2 and Smad3 did not change significantly in the silymarin group.[Conclusions]The lignans from SHC have significant intervention effects on alcoholic livery injury.The mechanism may be related to the inhibition of hepatic stellate cell(HSC)activation,TGF-βsecretion and p-Smad2,p-Smad3 expression in the signaling pathway.

The ERF transcription factor LTF1 activates DIR1 to control stereoselective synthesis of antiviral lignans and stress defense in Isatis indigotica roots

Lignans are a powerful weapon for plants to resist stresses and have diverse bioactive functions to protect human health.Elucidating the mechanisms of stereoselective biosynthesis and response to stresses of lignans is important for the guidance of plant improvement.Here,we identified the complete pathway to stereoselectively synthesize antiviral(-)-lariciresinol glucosides in Isatis indigotica roots,which consists of three-step sequential stereoselective enzymes DIR1/2,PLR,and UGT71B2.DIR1 was further identified as the key gene in respoJanuary 2024nse to stresses and was able to trigger stress defenses by mediating the elevation in lignan content.Mechanistically,the phytohormone-responsive ERF transcription factor LTF1 colocalized with DIR1 in the cell periphery of the vascular regions in mature roots and helped resist biotic and abiotic stresses by directly regulating the expression of DIR1.These systematic results suggest that DIR1 as the first common step of the lignan pathway cooperates with PLR and UGT71B2 to stereoselectively synthesize(-)-lariciresinol derived antiviral lignans in I.indigotica roots and is also a part of the LTF1-mediated regulatory network to resist stresses.In conclusion,the LTF1-DIR1 module is an ideal engineering target to improve plant Defenses while increasing the content of valuable lignans in plants.

Natural products inspired[3+2]cycloaddition enables efficient construction of hydroxylated tetrahydrofuran acetals and concise syntheses of lignans

Mimicking biosynthetic pathways of hongkonoids led to the development of a new Cu(Ⅰ)-catalyzed[3+2]cycloaddition ofα-hydroxyketone andβ-keto enol ethers,affording tetrahydrofuran acetals in a highly diastereoselective manner and 100%atom economy.Computational studies on the mechanism disclosed a concerted but asynchronous Michael addition/aldol reaction.Of the same importance,this methodology provides a practical biomimetic approach for one-step construction of the dibenzylbutyrolactol lignan backbone starting from two phenyl propane derivatives,opening up a powerful new approach for lignan synthesis,which is showcased by succinct total syntheses of two biologically important aryltetralin-type lignans,β-apopicropodophyllin and cycloolivil.Given the mild and operationally simple conditions,the developed chemistry might have a promising prospect in potential industrial applications.

Lignans are the main active components of Schisandrae Chinensis Fructus for liver disease treatment:a review

As a traditional Chinese herbal medicine,Schisandrae Chinensis Fructus(SC)has been used in medicine and food industry due to its health care and therapeutic effects.Over the past 20 years,the use of SC and its active ingredient lignans in the prevention and treatment of liver diseases has been increasing,and their hepatoprotective effects has increased the interest of the public and academia.Therefore,in the present work,we first determined the effectiveness of SC in the treatment of liver diseases such as metabolic associated fatty liver disease,alcoholic liver disease,cholestatic liver disease and acute liver injury.Subsequently,the pharmacological effects and molecular mechanisms of lignans,the active components of SC,for liver disease treatment were comprehensively summarized for the first time.The results showed that the lignans in SC could achieve hepatoprotective effects by regulating lipid metabolism,anti-fibrosis,anti-inflammation,anti-oxidation,anti-tumor and regulating bile acid metabolism.The mechanism mainly involved adenosine 5’-monophosphate-activated protein kinase,endoplasmic reticulum stress,sterol regulatory element binding protein 1c,autophagy,transforming growth factor-β,mitogen-activated protein kinase,microRNA,nuclear factor kappa-B,nuclear factor erythroid-2-related factor 2,heat shock proteins and pregnane X receptor signaling pathways.These results can lay a scientific foundation for the development of hepatoprotective drugs or functional foods from SC/lignans.

Eucommia lignans alleviate the progression of diabetic nephropathy through mediating the AR/Nrf2/HO-1/AMPK axis in vivo and in vitro

Lignans derived from Eucommia ulmoides Oliver(Eucommia lignans)inhibit the progression of inflammatory diseases,while their effect on the progression of diabetic nephropathy(DN)remained unclear.This work was designed to assess the function of Eucommia lignans in DN.The major constituents of Eucommia lignans were analyzed by UPLC-Q-TOF-MS/MS.The binding between Eucommia lignans and aldose reductase(AR)was predicted by molecular docking.Eucommia lignans(200,100,and 50 mg·kg^(-1))were used in model animals to evaluate their renal function changes.Rat glomerular mesangial cells(HBZY-1)were transfected with sh-AR,sh-AMPK,and oe-AR in the presence of high glucose(HG)or HG combined with Eucommia lignans to evaluate whether Eucommia lignans affected HG-induced cell injury and mitochondrial dysfunction through the AR/Nrf2/HO-1/AMPK axis.Eucommia lignans significantly attenuated the progression of DN in vivo.Eucommia lignans notably reversed HG-induced upregulation of inflammatory cytokines and mitochondrial injury,while downregulating the levels of Cyto c,caspase 9,AR,and NOX4 in HBZY-1 cells.In contrast,HG-induced downregulation of Nrf2,HO-1 and p-AMPKαlevels were abolished by Eucommia lignans.Meanwhile,knockdown of AR exerted similar therapeutic effect of Eucommia lignans on DN progression,and AR overexpression reversed the effect of Eucommia lignans.Eucommia lignans alleviated renal injury through the AR/Nrf2/HO-1/AMPK axis.Thus,these findings might provide evidence for the use of Eucommia lignans in treating DN.