Related Lignans Research Articles

Justicidin B and related lignans from two South African Monsonia species with potent activity against HeLa cervical cancer cells

Cervical cancer is a deadly malignancy, one of the most common for women, evidencing the need for effective new chemotherapeutic agents to treat the disease. Lignans are widely occurring natural products with important pharmacological effects, including anticancer activities. Five arylnaphthalene lignans, isolated from Monsonia angustifolia and M. glauca (Geraniaceae), were investigated for their cytotoxicity against HeLa human cervical cancer cells. The best activity (IC50 1.2 μM) was exerted by justicidin B (4). The presence of additional methoxy groups in the “northern part” of the arylnaphthalene scaffold, at C-6 and/or C-7, lowered the cytotoxicity. Even more significantly, a free hydroxy group at C-7, leads to a drastic decrease in potency, by two orders of magnitude. Live-cell imaging experiments revealed that 4 induces changes in cancer cells morphology, effecting their elongation and eventual death. Justicidin B (4) inhibited formation of HeLa cell colonies in a dose-dependent manner. Mechanistic investigations showed that 4 modulates the expression of key proteins involved in apoptosis, suggesting that it induces cell death through several mechanisms.

Arctium lappa Lam. and Its Related Lignans Improve Hyperglycemia and Dyslipidemia in Diabetic Rodent Models: A Systematic Review and Meta-Analysis

Research on nutraceuticals has focused on reducing the onset, progression, and significant consequences of diabetes mellitus. Arctium lappa Lam. is a great source of plant fibers and polyphenols that have anti-disease benefits, including those for diabetes mellitus. This study sought to determine the impact of Arctium lappa Lam. extracts and its associated lignans on diabetic hyperglycemia and dyslipidemia by conducting meta-analyses of the available research using diabetic rodents. English-language peer-reviewed articles were searched by PubMed and Embase up until 10 August 2022. Included were studies comparing the blood glucose and/or lipid levels of diabetic rodents given either extracts of Arctium lappa Lam. and its related lignans or vehicles. Blood glucose levels were reported in 16 studies involving 168 diabetic mice or rats treated with Arctium lappa Lam. and 168 diabetic controls. The pooled effect size was −1.42 [95% CI: −1.84 to −1.00] with significant heterogeneity. Type of diabetic model was found to be the prominent covariate that explained, at least partially, the heterogeneity. Moreover, diabetic rodents treated with Arctium lappa Lam. showed a notable improvement in their hypertriglyceridemia and hypercholesterolemia.

(+)-Sesamin, a sesame lignan, is a potent inhibitor of gut bacterial tryptophan indole-lyase that is a key enzyme in chronic kidney disease pathogenesis

The progression of chronic kidney disease (CKD) increases the risks of cardiovascular morbidity and end-stage kidney disease. Indoxyl sulfate (IS), which is derived from dietary l-tryptophan by the action of bacterial l-tryptophan indole-lyase (TIL) in the gut, serves as a uremic toxin that exacerbates CKD-related kidney disorder. A mouse model previously showed that inhibition of TIL by 2-aza-l-tyrosine effectively reduced the plasma IS level, causing the recovery of renal damage. In this study, we found that (+)-sesamin and related lignans, which occur abundantly in sesame seeds, inhibit intestinal bacteria TILs. Kinetic studies revealed that (+)-sesamin and sesamol competitively inhibited Escherichia coli TIL (EcTIL) with Ki values of 7 μM and 14 μM, respectively. These Ki values were smaller than that of 2-aza-l-tyrosine (143 μM). Molecular docking simulation of (+)-sesamin- (or sesamol-)binding to EcTIL predicted that these inhibitors potentially bind near the active site of EcTIL, where the cofactor pyridoxal 5′-phosphate is bound, consistent with the kinetic results. (+)-Sesamin is a phytochemical with a long history of consumption and is generally regarded as safe. Hence, dietary supplementation of (+)-sesamin encapsulated in enteric capsules could be a promising mechanism-based strategy to prevent CKD progression. Moreover, the present findings would provide a new structural basis for designing more potent TIL inhibitors for the development of mechanism-based therapeutic drugs to treat CKD.

Preparation of Lignan-Rich Extract from the Aerial Parts of Phyllanthus niruri Using Nonconventional Methods.

Phyllanthin and related lignans were found to be responsible, at least in part, for most of the activity of Phyllanthus species. This observation encouraged the authors to develop methods for the preparation of an extract rich in phyllanthin and related lignans from the aerial parts of P. niruri L. Direct extraction with solvents produced extracts with variable yields and contents of lignans. Lignans were identified by LC-ESI-MS analysis as phyllanthin (used as marker substance), hypophyllanthin, phylltetralin, nirtetralin, and niranthin. Extraction with boiling water produced 18.10 g% (w/w) extract with a trace amount of lignans (phyllanthin content of 0.33 ± 0.10 mg/g extract), while extraction with MeOH gave 3.6 g% w/w extract with a low phyllanthin content (3.1 mg/g extract), as determined by HPLC. However, Soxhlet extraction with hexane, CH2Cl2, or acetone gave extracts with low yields (0.82, 1.12, and 3.40 g% w/w, respectively) and a higher phyllanthin contents (36.2 ± 2.6, 11.7 ± 1.68, and 11.7 ± 1.10 mg/g extract, respectively). Extraction quality and efficiency were optimized by adopting the following three different approaches: (1) Alkaline digestion of the plant material with 30% potassium hydroxide yielded 3.1 g% w/w of purified extract with high phyllanthin content (22.34 ± 0.13 mg/g); (2) microwave-assisted extraction using 80% MeOH gave an extract with a better yield (8.13 g% w/w) and phyllanthin content (21.2 ± 1.30 mg/g) (after filtration through a Diaion HP-20 column); and (3) treatment of the ground plant material at 50 °C with two hydrolytic enzymes, cellulase (9 U/g for 12 h) and then, protease (4 U/g up to 72 h) optimized the yield of extract (13.92 g% w/w) and phyllanthin content (25.9 mg/g extract and total lignans content of 85.87 mg/g extract). In conclusion, the nonconventional methods presented here are superior for optimizing the yield of extract and its lignan contents from the aerial parts of P. niruri.

Assaying Chlamydia pneumoniae Persistence in Monocyte-Derived Macrophages Identifies Dibenzocyclooctadiene Lignans as Phenotypic Switchers.

Antibiotic-tolerant persister bacteria involve frequent treatment failures, relapsing infections and the need for extended antibiotic treatment. The virulence of an intracellular human pathogen C. pneumoniae is tightly linked to its propensity for persistence and means for its chemosensitization are urgently needed. In the current work, persistence of C. pneumoniae clinical isolate CV6 was studied in THP-1 macrophages using quantitative PCR and quantitative culture. A dibenzocyclooctadiene lignan schisandrin reverted C. pneumoniae persistence and promoted productive infection. The concomitant administration of schisandrin and azithromycin resulted in significantly improved bacterial eradication compared to sole azithromycin treatment. In addition, the closely related lignan schisandrin C was superior to azithromycin in eradicating the C. pneumoniae infection from the macrophages. The observed chemosensitization of C. pneumoniae was associated with the suppression of cellular glutathione pools by the lignans, implying to a previously unknown aspect of chlamydia–host interactions. These data indicate that schisandrin lignans induce a phenotypic switch in C. pneumoniae, promoting the productive and antibiotic-susceptible phenotype instead of persistence. By this means, these medicinal plant -derived compounds show potential as adjuvant therapies for intracellular bacteria resuscitation.

Effect of in vitro morphogenesis on the production of podophyllotoxin derivatives in callus cultures of Linum album

The anticancer compound podophyllotoxin and other related lignans can be produced in Linum album in vitro cultures, although their biosynthesis varies according to the degree of differentiation of the plant material. In general, L. album cell cultures do not form the same lignans as roots or other culture systems. Our aim was to explore how the lignan-producing capacity of organogenic cell masses is affected by the conditions that promote their formation and growth. Thus, L. album biomass obtained from plantlets was cultured in darkness or light, with or without the addition of plant growth regulators, and the levels of podophyllotoxin, methoxypodophyllotoxin and other related lignans were determined in each of these conditions. The organogenic capacity of the cell biomass grown in the different conditions was studied directly and also with light and scanning electronic microscopy, leading to the observation of.several somatic embryos and well-formed shoots. The main lignan produced was methoxypodophyllotoxin, whose production was clearly linked to the organogenic capacity of the cell biomass, which to a lesser extent was also the case for podophyllotoxin.

Toxicity and Larvicidal Activity of Podophyllum-Based Lignans Against Aedes aegypti (Diptera: Culicidae).

Aedes aegypti L. (Diptera: Culicidae) is a mosquito species that has adapted to urban environments and is the main vector of dengue viruses. Because of the increasing incidence of dengue, a more environmentally acceptable insecticide needs to be found. Natural products have been and continue to be an important source of leading compounds that can be modified in order to develop new drugs. The lignan family of natural products includes compounds with a diverse spectrum of biological activity. Podophyllotoxin and its related lignans represent an exciting class of natural products that can be targeted at different types of biological activity and are therefore worth exploring further. This study had the aim of evaluating the larvicidal activity of an ethanolic extract from the rhizomes and roots of Podophyllum hexandrum (PM-3) and its isolated lignans, podophyllotoxone (1) and desoxypodophyllotoxin (2), on the larvae of the mosquito vector Ae. aegypti. The PM-3 extract and the compounds (1) and (2) were dissolved in a mixture of acetone and dimethylsulfoxide at final concentrations of 1, 10, 30, 50, 100, and 200 μg/ml. After dilution, the solutions were applied (μg/ml) to the larvae-rearing medium. Overall, the ethanolic extract from the rhizomes and roots of P. hexandrum and the compounds (1) and (2) showed larvicidal activity against the larvae of Ae. aegypti According to the results from this study, it can be concluded that podophyllotoxone (1) and desoxypodophyllotoxin (2) exhibited significant toxicity toward Ae. aegypti larvae.

Synthesis of furofuran lignans as antidiabetic agents simultaneously achieved by inhibiting α-glucosidase and free radical.

Furofuran lignans such as sesamin have been recognized as promising antidiabetic agents as they possess curative as well as preventive effects toward diabetes complications. However, to date the structure-activity relationship has not been investigated due to the lack of a practical synthetic route capable of producing diverse furofuran lignans. Herein, we first introduced a single-step synthesis of these compounds starting from samin (4). Reaction of samin with a variety of electron-rich phenolics under acidic conditions afforded a total of 23 diverse furofuran lignans. On examination their inhibitions against α-glucosidase and free radicals, lignans having a free hydroxy group showed considerably enhanced inhibition, compared with their corresponding starter 4 and related lignans sesamin (1) and sesamolin (3). In addition, the mechanism underlying the α-glucosidase inhibition of a particular active lignan (epi -6) was verified to be mixed manner between competitive and noncompetitive inhibition.

Identification of key structural characteristics of Schisandra chinensis lignans involved in P-glycoprotein inhibition.

The aim of the present study was to determine the structural requirements for dibenzocyclooctadiene lignans essential for P-glycoprotein inhibition. Altogether 15 structurally related lignans isolated from Schisandra chinensis or prepared by modification of their backbone were investigated, including three pairs of enantiomers. P-Glycoprotein inhibition was quantified using a doxorubicin accumulation assay in human promyelotic leukemia HL60/MDR cells overexpressing P-glycoprotein. A preliminary quantitative structure-activity relationship analysis revealed three main structural features involved in P-glycoprotein inhibition: a 1,2,3-trimethoxy moiety, a 6-acyloxy group, and the absence of a 7-hydroxy group. The most effective inhibitors, (-)-gomisin N (1) and (+)-deoxyschizandrin [(+)-2], were selected for further evaluation of their effects. Both these lignans restored the cytotoxic effect of doxorubicin in HL60/MDR cells and when combined with a subtoxic concentration of this compound increased the proportion of G2/M cells significantly, which is a usual response to treatment with this anticancer drug.

The investigation of epigenetic modifiers in cultures of an endophytic fungus to enhance PPT production

Podophyllotoxin (PPT) is a natural plant lignan used for the semi-synthesis of anti-cancer drugs. Due to a variety of factors, PPT is becoming less available. An endophytic fungus, PPE7, from Podophyllum peltatum, can serve as an alternate source of PPT, but production declined over several generations of subculture, perhaps due to gene silencing. Small molecule epigenetic modifiers, such as DNA methyl transferase (DNMT) and histone deacytelase (HDAC) inhibitors, can activate silent fungal pathways and enhance the production of fungal metabolites. Re-activation of the PPT pathway may make it possible to identify the genes involved in PPT synthesis through cDNA analysis. The HDAC inhibitor, suberoylanilide hydroxamic acid (SAHA) and the DNMT inhibitor 5-azacytidine (5-aza) were used to treat cultures of PPE7. Extracts were prepared by solid phase extraction (SPE) and analyzed by HPLC. Cultures treated with SAHA and 5-aza showed gain of peaks, loss of peaks and altered amounts of individual peaks compared to the untreated cultures. Thus, both epigenetic modifiers are capable of affecting the compounds produced in cultures of PPE7. LC-MS analysis is in progress to further confirm these findings and explore the production of PPT and related lignans in the treated cultures.

Design and validation of a novel immunological test for enterolactone

Enterolactone (ENL) is produced by the gut microflora from lignans found in edible plants. ENL is estrogenic with no effect on the E-screen test and is a natural Selected Estrogen Receptor Modulator (SERM) with health interests that have to be checked in clinical studies with bioavailability assessment. Two haptens of ENL were synthesized, with a spacer arm at the C5 position having either 2 or 4 carbon atoms (ENLΔ2 and ENLΔ4, respectively). Hapten coupling to bovine serum albumin (BSA) was characterized by MALDI mass spectrometry. Polyclonal antibodies were obtained against the BSA conjugates. Additional conjugates were generated by coupling to swine thyroglobulin (Thyr). Homologous and heterologous competitive ELISAs were developed with Thyr or BSA conjugates as coating. The best assays were validated on biological samples from mice. Both antibodies exhibited the same IC50 at 1.5 ng mL(-1) with a detection limit below 0.5 ng mL(-1). Most cross-reactions with structurally related lignans were lower than 0.03%. This new assay type is faster, more specific and more reliable than existing ones.

Induction of lignans and phenolic compounds in cell culture of Linum album by culture filtrate of Fusarium graminearum

Cell suspension cultures of Linum album Kotschy ex Boiss. have been reported to produce anticancer podophyllotoxin and its related lignans. In the present study, we investigated the effect of culture filtrate of Fusarium graminearumon growth, and lignan and phenolic compounds in L. album cell culture. After 7 days of pre-culture, the cells were treated with 1% (v/v) of the culture filtrate. Cell growth was reduced, while phodophyllotoxin and lariciresinol production was stimulated reaching a maximum 0.0187 mg/g fresh weight (FW) and 0.0136 mg/g FW 5 days after the treatment, respectively. Also, our results provide evidence that the culture filtrate of F. graminearum can be effective on phenylalanine ammonia-lyase activity and phenolic compounds.

Relationship between podophyllotoxin accumulation and soil nutrients and the influence of Fe2+ and Mn2+ on podophyllotoxin biosynthesis in Podophyllum hexandrum tissue culture

Podophyllotoxin (PDT) and its derivatives, which are isolated from the Podophyllum species, are widely used in the clinical setting. The present study was designed to analyze the correlation between PDT levels in the rhizomes of Podophyllum hexandrum (P. hexandrum) and Dysosma versipellis (D. versipellis) and the nutrients in soil. We also aimed to investigate the influence of Fe(2+) and Mn(2+) on the enzyme activity of phenylalanine ammonia lyase (PAL), cinnamyl alcohol-dehydrogenase (CAD), and deoxypodophyllotoxin 6-hydroylase (DOP6H) and PDT accumulation via P. hexandrum tissue culture. The results showed that PDT accumulation was positively correlated with the NO3(-), PO4(3-), Na(+), Fe, and Mn levels and was negatively correlated with the SO4(2-) and K(+) levels, while the correlation with the Mg(2+), Ca(2+), Cu and Zn levels was not significant. The Fe(2+) and Mn(2+) levels were associated with the increased activity of PAL and CAD at 3-18 days; Fe(2+) enhanced the activity levels by 2.66- and 1.76-fold, respectively, and Mn(2+) was associated with a 1.68- and 1.10-fold increase in activity levels, respectively, compared with the control (CK) at 18 days. DOP6H activity was enhanced by Mn(2+), but it was not significantly affected by Fe(2+). Finally, PDT production was enhanced approximately 60% and 34% by Fe(2+) and Mn(2+), respectively, compared with CK at 16 days. These observations may be useful for the generation of PDT and related lignans via commercial cultivation as well as cell and tissue culture of P. hexandrum and other related plant resources.

Time-course changes in fungal elicitor-induced lignan synthesis and expression of the relevant genes in cell cultures of Linum album

Linum album has been shown to accumulate anti-tumor podophyllotoxin (PTOX) and its related lignans. In the present study, we examined the effects of five fungal extracts on the production of lignans in L. album cell cultures. Fusarium graminearum extract induced the highest increase of PTOX [140μgg(-1) dry weight (DW) of the L. album cell culture] which is seven-fold greater than the untreated control, while Rhizopus stolonifer extract enhanced the accumulation of lariciresinol, instead of PTOX, up to 365μgg(-1) DW, which was 8.8-fold greater than the control. Quantitative PCR analyses showed that expression of the enzyme genes responsible for the PTOX biosynthesis cascade, such as pinoresinol-lariciresinol reductase (PLR), phenylalanine ammonia-lyase (PAL), cinnamoyl-CoA reductase (CCR) and cinnamyl-alcohol dehydrogenase (CAD) genes, were also up-regulated in a fungal extract-selective fashion. These results provide evidence that the fungal extracts used in this study differentially increase the production of PTOX or larisiresinol via the up-regulation of the genes in lignan biosynthesis in L. album cell cultures, and suggest that such selective actions of fungal elicitors on the lignan synthesis will lead to more efficient metabolic engineering-based production of PTOX and other beneficial lignans using L. album cell cultures.

Increased lignan biosynthesis in the suspension cultures of Linum album by fungal extracts

Linum album accumulates anti-tumor podophyllotoxin (PTOX) and its related lignans, which were originally isolated from an endangered species Podophyllum. In the present study, we examined the effects of five fungal extracts on the production of lignans in L. album cell cultures. Fusarium graminearum extract induced the highest increase of PTOX [143 μg g−1 dry weight (DW) of the L. album cell culture], while Rhizopus stolonifer extract enhanced the accumulation of lariciresinol up to 364 μg g−1 DW, instead of PTOX. Typical elicitors, such as chitin, chitosan, or methyl jasmonate (MeJA), were shown to be less effective in lignan production in L. album cell cultures. These results verified the advantages of fungal extracts to increase lignan production in L. album cell culture, and suggested potential on-demand metabolic engineering of lignan biosynthesis using differential fungal extracts.

Molecular and functional characterization of novel furofuran-class lignan glucosyltransferases from Forsythia

Lignan is a large class of plant secondary metabolites, which has long attracted pharmacological interest because of its anti-tumor and estrogenic activities. Forsythia plants are known to produce a wide variety of lignans, such as (−)-matairesinol, (−)-secoisolariciresinol, (+)-pinoresinol, and (+)-phillygenin. The majority of such lignans are accumulated in glucoside forms. However, their glucosylation mechanisms largely remain to be elucidated. Here we describe the sequence, enzymatic activities, and gene expression profiles of UDP-sugar dependent-glycosyltransferases (UGT) from Forsythia koreana through a reverse-genetic approach. A Forsythia UGT, UGT71A18 protein, expressed in E. coli, preferentially glucosylated furofuran-class lignans, including (+)-pinoreisnol, (+)-epipinoreisnol, and (+)-phylligenin. Moroeover, the recombinant UGT71A18 exhibited specificity to UDP-glucose as a glycosyl donor. Gene expression analysis revealed that UGT71A18 is expressed predominantly in leaves and the suspension cell culture of F. koreana, and that the UGT71A18 transcript is upregulated in the transgenic cell culture expressing the RNAi construct of the pinoresinol lariciresinol reductase (PLR) gene, compared to non-transformants. These results are consistent with the remarkable elevation of pinoresinol glucosides in the PLR-RNAi lines. Collectively, the present data strongly suggests that UGT71A18, in part, is responsible for glucosylation of furofuran-class lignans, including (+)-pinoresinol and/or structurally related lignans in vivo.

The contents of sesamol and related lignans in sesame, tahina and halva as determined by a newly developed polarographic and stripping voltammetric analysis

The contents of antioxidant lignans (Sesamol) in sesame, commercial formulations of tahina and halva, which are processed tahina foods, were determined by Differential Pulse Polarography (DPP) with a capillary hanging mercury drop electrode (HMDE). A platinum wire was used as the counter electrode and Ag/AgCl was the reference electrode. Samples have been analyzed by standard addition procedures and found to be quantitative (p 2 =0.9999) (p<0.01). The proposed Differential Pulse Polarographic (DPP) method is a rapid, reproducible procedure for the simultaneous determination of phenolic lignans in sesame and food products with sesame. It provides an adequate, sensitive, quantitative detection of these nutraceuticals in the commercial food industry.

Machilin A Isolated fromMyristica fragransStimulates Osteoblast Differentiation

This study evaluated the stimulatory effects of machilin A and structurally related lignans isolated from Myristica fragrans on osteoblast differentiation. In two IN VITRO osteoblast differentiation models, machilin A stimulated osteoblast differentiation via activation of p38 MAP kinase. Lignans isolated from Myristica fragrans also stimulated osteoblast differentiation in MC3T3-E1 cells; the lignans included macelignan, machilin F, nectandrin B, safrole, licarin A, licarin B, myristargenol, and meso-dihydroguaiaretic acid. These data suggest that lignans isolated from Myristica fragrans have anabolic activity in bone metabolism.

Selection methodology with scoring system: Application to Mexican plants producing podophyllotoxin related lignans

As most anticancer drugs are derived from natural sources, the screening of local medicinal flora should be considered a primary step in the search for new sources for antineoplastic agents. In Mexico, more than 6000 medicinal plant species are used for the treatment of various diseases, including cancer. A multifactorial plant selection method, employing various criteria was designed and applied in order to select alternative sources of podophyllotoxin lignan analogues. For each criterion (chemotaxonomy, traditional medical uses and published scientific data), an arbitrary score system was ascribed to the species and the sum of these enabled us to compare potential candidates. The resulting selected plants were tested for cytotoxic activity and the compounds responsible for this activity were evaluated by liquid chromatography–mass spectroscopy (LC–MS). Around 50 species from the Mexican flora were initially considered. From these, six species were selected by referring to the results from the scoring system and these were then collected. Three extracts were evaluated as being highly cytotoxic against three different cancer cell lines. Finally, podophyllotoxin-like lignans could be identified by observing the fragmentation pattern on mass spectra, obtained from the LC–MS in two species: Linum scabrellum and Hyptis suaveolens.

UDP-glucose:(6-methoxy)podophyllotoxin 7- O-glucosyltransferase from suspension cultures of Linum nodiflorum

Cell cultures of Linum species store 6-methoxypodophyllotoxin (MPTOX), podophyllotoxin (PTOX) and related lignans as O-glucosides. UDP-glucose:(M)PTOX 7- O-glucosyltransferase has been detected and characterised in protein preparations of suspension-cultured cells of Linum nodiflorum L. (Linaceae). The maximal lignan glucoside contents in the cells are preceded by a rapid increase of the specific glucosyltransferase activity on day six of the culture period. MPTOX glucoside is the major lignan with up to 1.18 mg g −1 of the cell dry wt which is more than 30-fold of the PTOX glucoside content. Of the three aryltetralin lignans tested as substrates, PTOX and MPTOX display comparable apparent K m values of 4.7 and 5.4 μM, respectively. 5′-Demethoxy-6-methoxypodophyllotoxin is converted with the highest velocity of 25.2 pkat mg −1 while also possessing a higher K m of 14.7 μM. Two-substrate test series indicate that all three compounds compete for the active site of a single protein. The structurally similar lignan β-peltatin acts as competitive inhibitor as well. However, the 6- O-glucosidation is most likely catalysed by a separate enzyme. The (M)PTOX 7- O-glucosyltransferase works best at a pH around 9 and a temperature around 35 °C. A 15–30% increase of the reaction rate is effected by the addition of 0.9 mM Mn 2+.