Current advances in acteoside biosynthesis pathway elucidation and biosynthesis

Plantaginis semen ameliorates diabetic kidney disease via targeting the sphingosine kinase 1/sphingosine-1-phosphate pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Plantaginis Semen (PS) is widely utilized as a common herb in several Asian countries, particularly China, due to its diuretic, anti-hypertensive, anti-hyperlipidemic, and anti-hyperglycemic properties. Furthermore, it is acknowledged for its ability to mitigate renal complications associated with metabolic syndrome. Despite its extensive usage, there is limited systematic literature elucidating its therapeutic mechanisms, thus emphasizing the necessity for comprehensive investigations in this field.

AIM

This study aims to comprehensively evaluate the therapeutical potential of PS in treating diabetic kidney disease (DKD) and to elucidate the underlying mechanisms through in vivo and in vitro models.

METHODS

The main composition of PS were characterized using the UPLC-QTOF-MS method. For the in vivo investigation, a mouse model mediated by streptozocin (STZ) associated with a high-fat diet (HFD) and unilateral renal excision was established. The mice were split into 6 groups (n = 8): control group (CON group), DKD group, low-dose of Plantago asiatica L. seed extract group (PASE-L group, 3 g/kg/d), medium-dose of PASE group (PASE-M, 6 g/kg/d), high-dose of PASE group (PASE-H, 9 g/kg/d), and positive drug group (valsartan, VAS group, 12 mg/kg/d). After 8 weeks of treatment, the damage induced by DKD was evaluated by using relevant parameters of urine and blood. Furthermore, indicators of inflammation and factors associated with the SphK1-S1P signaling pathway were investigated. For the in vitro study, the cell line HBZY-1 was stimulated by high glucose (HG), they were then co-cultured with different concentrations of PASE, and the corresponding associated inflammatory and sphingosine kinase 1/sphingosine-1-phosphate (SphK1-S1P) factors were examined.

RESULTS

A total of 59 major components in PS were identified, including flavonoids, iridoids, phenylethanol glycosides, guanidine derivatives, and fatty acids. In the mouse model, PS was found to significantly improve body weight, decrease fasting blood glucose (FBG) levels, increased glucose tolerance and insulin tolerance, improved kidney-related markers compared to the DKD group, pathological changes in the kidneys also improved dramatically. These effects showed a dose-dependent relationship, with higher PASE concentrations yielding significantly better outcomes than lower concentrations. However, the effects of the low PASE concentration were not evident for some indicators. In the cellular model, the high dose of PASE suppressed high glucose (HG) stimulated renal mesangial cell proliferation, suppressed inflammatory factors and NF-κB, and decreased the levels of fibrillin-1(FN-1) and collagen IV(ColIV).

CONCLUSION

Our results indicate that PS exerts favorable therapeutic effects on DKD, with the possible mechanisms including the inhibition of inflammatory pathways, suppression of mRNA levels and protein expressions of SphK1 and S1P, consequently leading to reduced overexpression of FN-1 and ColIV, thereby warranting further exploration.

Genome-Wide Analysis of the Polyphenol Oxidase Gene Family in Olea europaea Provides Insights into the Mechanism of Enzymatic Browning in Olive Fruit

Browning of olive (Olea europaea L.) fruit reduces the sensory and nutritional qualities of olive oil, thereby increasing production costs. Polyphenol oxidases (PPOs) are the key enzymes that catalyze phenolic substance oxidation and mediate enzymatic browning in olive fruit, but the exact regulatory mechanism remains unclear. The main challenge is the lack of comprehensive information on OePPOs at the genome-wide level. In this study, 18 OePPO genes were identified. Subsequently, we performed a bioinformatic analysis on them. We also analyzed the expression patterns and determined the relationship among browning degree, PPO activity, and expression of OePPOs in the fruits of three olive varieties. Based on our analysis, we identified the four most conserved motifs. OePPOs were classified into two groups, with OePPOs from Group 1 showing only diphenolase activity and OePPOs from Group 2 exhibiting both mono-/diphenolase activities. Seven pairs of gene duplication events were identified, and purifying selection was found to have played a critical role in the evolution of the OePPO gene family. A positive correlation was observed between the browning degree of olive fruit and PPO activity across different olive varieties. Moreover, two important genes were found: OePPO-5 the main effector gene responsible for fruit browning, and OePPO-8, a key gene associated with specialized metabolite synthesis in the olive fruit. In short, our discoveries provide a basis for additional functional studies on OePPO genes and can help elucidate the mechanism of enzymatic browning in olive fruit in the future.

Acteoside improves adipocyte browning by CDK6-mediated mTORC1-TFEB pathway

Adipocyte browning increases energy expenditure by thermogenesis, which has been considered a potential strategy against obesity and its related metabolic diseases. Phytochemicals derived from natural products with the ability to improve adipocyte thermogenesis have aroused extensive attention. Acteoside (Act), a phenylethanoid glycoside, exists in various medicinal or edible plants and has been shown to regulate metabolic disorders. Here, the browning effect of Act was evaluated by stimulating beige cell differentiation from the stromal vascular fraction (SVF) in the inguinal white adipose tissue (iWAT) and 3 T3-L1 preadipocytes, and by converting the iWAT-SVF derived mature white adipocytes. Act improves adipocyte browning by differentiation of the stem/progenitors into beige cells and by direct conversion of mature white adipocytes into beige cells. Mechanistically, Act inhibited CDK6 and mTOR, and consequently relieved phosphorylation of the transcription factor EB (TFEB) and increased its nuclear retention, leading to induction of PGC-1α, a driver of mitochondrial biogenesis, and UCP1-dependent browning. These data thus unveil a CDK6-mTORC1-TFEB pathway that regulates Act-induced adipocyte browning.

Combined Metabolome and Transcriptome Analysis Highlights the Host's Influence on Cistanche deserticola Metabolite Accumulation

The medicinal plant Cistanche deserticola Ma (Orobanchaceae) is a holoparasitic angiosperm that takes life-essential materials from Haloxylon ammodendron (C. A. Mey.) Bunge (Amaranthaceae) roots. Although many experiments have been conducted to improve the quality of C. deserticola, little attention has been paid to the host's influence on metabolite accumulation. In this study, transcriptomic and metabolomic analyses were performed to unveil the host's role in C. deserticola's metabolite accumulation, especially of phenylethanoid glycosides (PhGs). The results indicate that parasitism by C. deserticola causes significant changes in H. ammodendron roots in relation to metabolites and genes linked to phenylalanine metabolism, tryptophan metabolism and phenylpropanoid biosynthesis pathways, which provide precursors for PhGs. Correlation analysis of genes and metabolites further confirms that C. deserticola's parasitism affects PhG biosynthesis in H. ammodendron roots. Then we found specific upregulation of glycosyltransferases in haustoria which connect the parasites and hosts. It was shown that C. deserticola absorbs PhG precursors from the host and that glycosylation takes place in the haustorium. We mainly discuss how the host resists C. deserticola parasitism and how this medicinal parasite exploits its unfavorable position and takes advantage of host-derived metabolites. Our study highlights that the status of the host plant affects not only the production but also the quality of Cistanches Herba, which provides a practical direction for medicinal plant cultivation.

Identification of potential light deficiency response regulators in endangered species Magnolia sinostellata

Magnolia sinostellata is one of the endangered species in China and largely suffers light deficiency stress in the understory of forest. However, the weak light response molecular mechanism remains unclear. More importantly, hub genes in the molecular network have not been pinpointed. To explore potential regulators in the mechanism, weighted gene co-expression network analysis (WGCNA) was performed to analysis the trancriptome data of M. sinostellata leaves subjected to weak light with different time points. Gene co-expression analysis illustrated that module 1, 2 and 3 were closely associated with light deficiency treatment, which. Gene ontology and KEGG analyses showed that genes in module 1 mainly participated in amino and nucleotide metabolism, module 2 mostly involved in carbon fixation and module 3 mostly regulated photosynthesis related pathways, among which 6, 7 and 8 hub genes were identified, respectively. Hub genes isoform_107196 in module 1 and isoform_55976 in module 2 were unique to M. sinostellata. This study found that light deficiency inhibited photosynthesis and stress tolerance, while improved carbon metabolism and flowering related pathways in M. sinostellata, which can impact its accumulation reserves of growth and reproduction in the next season. In addition, key shade response regulators identified in this study have laid a firm foundation for further investigation of shade response molecular mechanism and protection of other shade sensitive plants.

Acteoside Alleviates Renal Fibrosis by Inhibiting β-Catenin/CTGF Signaling Pathway in UUO Rats

Objective: Acteoside (ACT) has been reported to regulate the inflammation and immune response. The study aims to explore the effect of ACT on renal fibrosis in unilateral ureteral obstruction (UUO) rats. Methods: Eighteen Sprague-Dawley rats were randomly divided into 3 groups: sham group, opened the abdominal cavity and sutured abdominal; UUO group, performed UUO surgery; and ACT + UUO group, ACT (40 mg/kg) was given by gavage every day after UUO surgery. After 2 weeks of rat model construction, urine and blood samples were collected for biochemical analysis, while kidney tissues were harvested for hematoxylin and eosin (H&E), Masson's trichrome, and immunohistochemistry staining. The expression of connective tissue growth factor (CTGF), alpha smooth muscle actin (α-SMA), collagen III, heat shock protein 47 (HSP47), and β-catenin in the renal tissue was detected and the correlation between these proteins was analyzed. Results: ACT improved the parameters of renal function in UUO rats, including decreased creatinine and urea nitrogen, and declined urinary protein. Pathological analysis suggested that ACT improved the conditions of renal tubule lesion (including structure destruction, atrophy and lumen obstruction), renal interstitial fibrosis and inflammatory cell infiltration in UUO rats. It also down-regulated the expressions of fibrin-related proteins β-catenin, CTGF, α-SMA, collagen III, and HSP47. Correlation analysis found that β-catenin and CTGF were correlated with the expressions of α-SMA, collagen III, and HSP47. Conclusions: ACT could alleviate renal fibrosis in UUO rats probably via inhibiting β-catenin/CTGF signaling pathway.

De novo full length transcriptome analysis and gene expression profiling to identify genes involved in phenylethanol glycosides biosynthesis in Cistanche tubulosa

Background

The dried stem of Cistanche, is a famous Chinese traditional medicine. The main active pharmacodynamic components are phenylethanol glycosides (PhGs). Cistanche tubulosa produces higher level of PhGs in its stems than that of Cistanche deserticola. However, the key genes in the PhGs biosynthesis pathway is not clear in C. tubulosa.

Results

In this study, we performed the full-length transcriptome sequencing and gene expression profiling of C. tubulosa using PacBio combined with BGISEQ-500 RNA-seq technology. Totally, 237,772 unique transcripts were obtained, ranging from 199 bp to 31,857 bp. Among the unique transcripts, 188,135 (79.12%) transcripts were annotated. Interestingly, 1080 transcripts were annotated as 22 enzymes related to PhGs biosynthesis. We measured the content of echinacoside, acteoside and total PhGs at two development stages, and found that the content of PhGs was 46.74% of dry matter in young fleshy stem (YS1) and then decreased to 31.22% at the harvest stage (HS2). To compare with YS1, 13,631 genes were up-regulated, and 15,521 genes were down regulated in HS2. Many differentially expressed genes (DEGs) were identified to be involved in phenylpropanoid biosynthesis pathway, phenylalanine metabolism pathway, and tyrosine metabolism pathway.

Conclusions

This is the first report of transcriptome study of C. tubulosa which provided the foundation for understanding of PhGs biosynthesis. Based on these results, we proposed a potential model for PhGs biosynthesis in C. tubulosa.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-022-08921-x.

Therapeutic effects and mechanisms of plant-derived natural compounds against intestinal mucositis

Intestinal mucositis is a clinically related adverse reaction of antitumor treatment. Majority of patients receiving high-dose chemical therapy, radiotherapy, and bone-marrow transplant suffer from intestinal mucositis. Clinical manifestations of intestinal mucositis mainly include pain, body-weight reduction, inflammatory symptom, diarrhea, hemoproctia, and infection, which all affect regular nutritional input and enteric function. Intestinal mucositis often influences adherence to antitumor treatment because it frequently restricts the sufferer’s capacity to tolerate treatment, thus resulting in schedule delay, interruption, or premature suspension. In certain circumstances, partial and general secondary infections are found, increasing the expenditures on medical care and hospitalization. Current methods of treating intestinal mucositis are provided, which do not always counteract this disorder. Against this background, novel therapeutical measures are extremely required to prevent and treat intestinal mucositis. Plant-derived natural compounds have lately become potential candidates against enteric injury ascribed to the capacity to facilitate mucosal healing and anti-inflammatory effects. These roles are associated with the improvement of intestinal mucosal barrier, suppression of inflammatory response and oxidant stress, and modulation of gut microflora and immune system. The present article aims at systematically discussing the recent progress of plant-derived natural compounds as promising treatments for intestinal mucositis.

Integrating transcriptome and chemical analyses to reveal the anti-Alzheimer's disease components in Verbena officinalis Linn

Verbena officinalis Linn. is a kind of traditional Chinese medicine, which has a long history of application and shows good effects on neuroprotection. Therefore, we consider that V. officinalis may be a potential drug for treating Alzheimer's disease (AD). First, ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) pointed out that the main chemical components in V. officinalis were iridoid glycosides, phenylethanoid glycosides, and flavonoids. These compounds were used for molecular docking and the results showed that these compounds had good anti-AD activity. To explore the biosynthetic pathway of anti-AD components in V. officinalis, UPLC and ultraviolet (UV) spectrophotometry were used for contents determination and the result was leaf > stem > root. At the same time, 92,867 unigenes were annotated in V. officinalis transcriptome; 206, 229, 115 related unigenes were, respectively, annotated in iridoid glycoside, phenylethanoid glycoside, and flavonoid pathway, of which 61, 73, and 35 were differential expression genes. The components had relatively high expression in leaves, which was consistent with the quantitative results. In addition, the tissue distribution particularity of verbenalin may be related to the branching of pathways. Meanwhile transcription factors VoWRKY6 and VoWRKY7 may be involved in the regulation of iridoid glycoside biosynthesis. Further, VoWRKY3, VoWRKY9, and VoWRKY12 may be related to flavonoid biosynthesis. The above research is helpful to explore the biosynthetic pathway of anti-AD components and the regulation mechanism of active components and to further explore the anti-AD effect of V. officinalis.

Duranta erecta Linn: A critical review on phytochemistry, traditional uses, pharmacology, and toxicity from phytopharmaceutical perspective

ETHNOPHARMACOLOGICAL RELEVANCE

Duranta erecta Linn. belonging to the Verbenaceae family is widely used in the traditional systems of medicines practiced in Bangladesh, India, Nigeria, the Philippines, and Brazil. The ethnomedicinal application as vermifuge, febrifuge, diuretic, anti-parasitic, and anti-malarial are well documented. D. erecta is also a significant source of phenylethanoid glycoside known as acteoside-a drug in clinical trials for IgA nephropathy patients.

AIM OF THIS REVIEW

This review aims to critically highlight the existing studies on D. erecta, including its botanical authentication, geographical distribution, ethnomedicinal uses, phytochemistry, and pharmacological properties. Critical discussion is focused on the overview and gap in knowledge for future research. Additionally, the clinical significance of its major secondary metabolite, i.e., acteoside, has also been discussed with emphasis on biosynthesis, distribution, pre-clinical, and clinical outcomes.

MATERIALS AND METHODS

Professional research data from 1963 to 2021 appeared in scholarly journals, and books were retrieved from scientific database platforms viz. Sci-Finder, PubMed, CNKI, Science Direct, Web of Science, Wiley, Google Scholar, Taylor and Francis, Springer, and Scopus. The chemical structures for all the phytomolecules were validated using Sci-finder and first-hand references. While plant name and synonyms were corroborated by "The Plant List" (www.theplantlist.org).

RESULTS

D. erecta and its key metabolite acteoside display various biological actions like antimalarial, antimicrobial, antioxidant, anticancer, antinephritic, hepatoprotective, neuroprotective, and antiviral properties. Acteoside literature analysis shows its presence in different stages of clinical trials for anti-nephritic, hepatoprotective, and osteoarthritic activity. The phytochemical review of D. erecta exhibited 64 compounds that have been isolated and identified from D. erecta, such as iridoid glycosides, phenylethanoid glycosides, flavonoids, steroids, phenolics, terpenoids, and saponins. The other significant secondary metabolites responsible for its medicinal properties are acteoside, durantol, pectolinaringenin, repenins, scutellarein, and repennoside.

CONCLUSION

Duranta erecta is one of the Verbenaceae plants, widely used in ethnomedicines having various phytochemicals with understandable pharmacological actions mainly confined at the crude extract level. However, further bioactivity-guided or fingerprint-assisted studies are required to validate the ethnomedicinal uses, concerning cellular and molecular mechanisms, quality standardization, and safety with respect to its bioactive constituent(s). Therefore, the present review identified the gap in the research on scientific validation of Duranta based ethnomedicines and may provide critical information for the development of phytopharmaceuticals/Phyto-cosmeceuticals.

The pharmacokinetic property and pharmacological activity of acteoside: A review

Acteoside (AC), a phenylpropanoid glycoside isolated from many dicotyledonous plants, has been demonstrated various pharmacological activities, including anti-oxidation, anti-inflammation, anti-cancer, neuroprotection, cardiovascular protection, anti-diabetes, bone and cartilage protection, hepatoprotection, and anti-microorganism. However, AC has a poor bioavailability, which can be potentially improved by different strategies. The health-promoting characteristics of AC can be attributed to its mediation in many signaling pathways, such as MAPK, NF-κB, PI3K/AKT, TGFβ/Smad, and AMPK/mTOR. Interestingly, docking simulation study indicates that AC can be an effective candidate to inhibit the activity of SARS-CoV2 main protease and protect against COVID-19. Many clinical trials for AC have been investigated, and it shows great potentials in drug development.

The chemical composition of different leaf extracts of Lantana fucata Lindl. influences its cytotoxic potential: A study using the Allium cepa model

ETHNOPHARMACOLOGICAL RELEVANCE

One of the most popular plants used to treat diseases in Brazil is Lantana fucata. Like most herbal medicines, its consumption is based on popular knowledge, which, despite being considered effective, may cause side effects.

AIM OF THE STUDY

Since the scientific data on the pharmacological properties of L. fucata are still incipient, this research aimed to evaluate the cytotoxic and genotoxic potential of different types of extracts (infusion, aqueous and hydroalcoholic), characterizing them chemically.

MATERIALS AND METHODS

The cytotoxicity assay was performed by the A. cepa model. The cytotoxicity parameters studied were number of dividing cells and percentage mitotic index (%MI).

RESULTS

The result of the A. cepa assay showed that there was a decrease in the number of dividing cells and the percentage mitotic index as concentrations increased, for all extracts, indicating cytotoxicity. However, the hydroalcoholic extract was the most cytotoxic. Chromatography analysis allowed the characterization of secondary metabolites in the extracts, which were very similar. However, a greater abundance of flavonoids and triterpenoids was observed in the hydroalcoholic extract, suggesting that these compounds are responsible for its greater toxicity.

CONCLUSIONS

Since the highest doses of extracts showed to have a cytotoxic effect, it is suggested that the ingestion of this species occurs in a moderate way.

Functional characterization of tyrosine decarboxylase genes that contribute to acteoside biosynthesis in Rehmannia glutinosa

The RgTyDCs possess typical decarboxylase functional activity in vitro and in vivo and participate in acteoside biosynthesis in R. glutinosa, positively controlling its production via activated acteoside/tyrosine-derived pathways. Acteoside is an important ingredient in Rehmannia glutinosa and an active natural component that contributes to human health. Tyrosine decarboxylase (TyDC) is thought to play an important role in acteoside biosynthesis. Several plant TyDC family genes have been functionally characterized and shown to play roles in some bioactive metabolites' biosynthesis by mediating the decarboxylation of L-tyrosine and L-dihydroxyphenylalanine (L-DOPA); however, one TyDC (named RgTyDC1) in R. glutinosa has been identified to date, but the family genes that contribute to acteoside biosynthesis remain largely characterized. Here, by in silico and experimental analyses, we isolated and identified three RgTyDCs (RgTyDC2 to RgTyDC4) in this species; these genes' sequences showed 50.92-82.55% identity, included highly conserved domains with homologues in other plants, classified into two subsets, and encoded proteins that localized to the cytosol. Enzyme kinetic analyses of RgTyDC2 and RgTyDC4 indicated that they both efficiently catalysed L-tyrosine and L-dopa. The overexpression of RgTyDC2 and RgTyDC4 in R. glutinosa, which was associated with enhanced TyDC activity, significantly increased tyramine and dopamine contents, which was positively correlated with improved acteoside production; moreover, the overexpression of RgTyDCs led to upregulated expression of some other genes-related to acteoside biosynthesis. This result suggested that the overexpression of RgTyDCs can positively activate the molecular networks of acteoside pathways, enhancing the accumulation of tyramine and dopamine, and promoting end-product acteoside biosynthesis. Our findings provide an evidence that RgTyDCs play vital molecular roles in acteoside biosynthesis pathways, contributing to the increase in acteoside yield in R. glutinosa.

The Combination of Untargeted Metabolomics and Machine Learning Predicts the Biosynthesis of Phenolic Compounds in Bryophyllum Medicinal Plants (Genus Kalanchoe)

Phenolic compounds constitute an important family of natural bioactive compounds responsible for the medicinal properties attributed to Bryophyllum plants (genus Kalanchoe, Crassulaceae), but their production by these medicinal plants has not been characterized to date. In this work, a combinatorial approach including plant tissue culture, untargeted metabolomics, and machine learning is proposed to unravel the critical factors behind the biosynthesis of phenolic compounds in these species. The untargeted metabolomics revealed 485 annotated compounds that were produced by three Bryophyllum species cultured in vitro in a genotype and organ-dependent manner. Neurofuzzy logic (NFL) predictive models assessed the significant influence of genotypes and organs and identified the key nutrients from culture media formulations involved in phenolic compound biosynthesis. Sulfate played a critical role in tyrosol and lignan biosynthesis, copper in phenolic acid biosynthesis, calcium in stilbene biosynthesis, and magnesium in flavanol biosynthesis. Flavonol and anthocyanin biosynthesis was not significantly affected by mineral components. As a result, a predictive biosynthetic model for all the Bryophyllum genotypes was proposed. The combination of untargeted metabolomics with machine learning provided a robust approach to achieve the phytochemical characterization of the previously unexplored species belonging to the Bryophyllum subgenus, facilitating their biotechnological exploitation as a promising source of bioactive compounds.

Transcriptome-Wide Identification of WRKY Transcription Factor and Functional Characterization of RgWRKY37 Involved in Acteoside Biosynthesis in Rehmannia glutinosa

WRKYs play important roles in plant metabolism, but their regulation mechanism in Rehmannia glutinosa remains elusive. In this study, 37 putative WRKY transcription factors (TFs) with complete WRKY domain from R. glutinosa transcriptome sequence data were identified. Based on their conserved domains and zinc finger motif, the R. glutinosa WRKY TFs were divided into five groups. Structural feature analysis shows that the 37 RgWRKY proteins contain WRKYGQK/GKK domains and a C2H2/C2HC-type zinc finger structure. To identify the function of RgWRKY members involved in acteoside biosynthesis, transcriptional profiles of 37 RgWRKYs in hairy roots under salicylic acid (SA), methyl jasmonate (MeJA), and hydrogen peroxide (H₂O₂) treatments were systematically established using RNA-seq analysis. Based on the correlationship between the expression levels of RgWRKY genes and acteoside content, RgWRKY7, RgWRKY23, RgWRKY34, RgWRKY35, and RgWRKY37 were suggested to be involved in acteoside biosynthesis in R. glutinosa, and RgWRKY37 was selected for gene functional research. Overexpression of RgWRKY37 increased the content of acteoside and total phenylethanoid glycosides (PhGs) in hairy roots and enhanced the transcript abundance of seven enzyme genes involved in the acteoside biosynthesis pathway. These results strongly suggest the involvement of the WRKY transcription factor in the regulation of acteoside biosynthesis.

Comparative metabolomics analysis of different sesame (Sesamum indicum L.) tissues reveals a tissue-specific accumulation of metabolites

BACKGROUND

Sesame (Sesamum indicum L.) leaves, flowers, especially seeds are used in traditional medicine to prevent or cure various diseases. Its seed's market is expanding. However, the other tissues are still underexploited due to the lack of information related to metabolites distribution and variability in the plant. Herein, the metabolite profiles of five sesame tissues (leaves, fresh seeds, white and purple flowers, and fresh carpels) have been investigated using ultra-high-performance liquid chromatography-mass spectrometry (UPLC-MS/MS)-based widely targeted metabolomics analysis platform.

RESULTS

In total, 776 metabolites belonging to diverse classes were qualitatively and quantitatively identified. The different tissues exhibited obvious differences in metabolites composition. The majority of flavonoids predominantly accumulated in flowers. Amino acids and derivatives, and lipids were identified predominantly in fresh seeds followed by flowers. Many metabolites, including quinones, coumarins, tannins, vitamins, terpenoids and some bioactive phenolic acids (acteoside, isoacteoside, verbascoside, plantamajoside, etc.) accumulated mostly in leaves. Lignans were principally detected in seeds. 238 key significantly differential metabolites were filtered out. KEGG annotation and enrichment analyses of the differential metabolites revealed that flavonoid biosynthesis, amino acids biosynthesis, and phenylpropanoid biosynthesis were the main differently regulated pathways. In addition to the tissue-specific accumulation of metabolites, we noticed a cooperative relationship between leaves, fresh carpels, and developing seeds in terms of metabolites transfer. Delphinidin-3-O-(6"-O-p-coumaroyl)glucoside and most of the flavonols were up-regulated in the purple flowers indicating they might be responsible for the purple coloration.

CONCLUSION

This study revealed that the metabolic processes in the sesame tissues are differently regulated. It offers valuable resources for investigating gene-metabolites interactions in sesame tissues and examining metabolic transports during seed development in sesame. Furthermore, our findings provide crucial knowledge that will facilitate sesame biomass valorization.

Verbascoside Protects Pancreatic β-Cells against ER-Stress

Substantial epidemiological evidence indicates that a diet rich in polyphenols protects against developing type 2 diabetes. The phenylethanoid glycoside verbascoside/acteoside, a widespread polyphenolic plant compound, has several biological properties including strong antioxidant, anti-inflammatory and neuroprotective activities. The aim of this research was to test the possible effects of verbascoside on pancreatic β-cells, a target never tested before. Mouse and human β-cells were incubated with verbascoside (0.8-16 µM) for up to five days and a combination of biochemical and imaging techniques were used to assess the β-cell survival and function under normal or endoplasmic reticulum (ER)-stress inducing conditions. We found a dose-dependent protective effect of verbascoside against oxidative stress in clonal and human β-cells. Mechanistic studies revealed that the polyphenol protects β-cells against ER-stress mediated dysfunctions, modulating the activation of the protein kinase RNA-like endoplasmic reticulum kinase (PERK) branch of the unfolded protein response and promoting mitochondrial dynamics. As a result, increased viability, mitochondrial function and insulin content were detected in these cells. These studies provide the evidence that verbascoside boosts the ability of β-cells to cope with ER-stress, an important contributor of β-cell dysfunction and failure in diabetic conditions and support the therapeutic potential of verbascoside in diabetes.