A new liquid chromatography–mass spectrometry-based strategy to integrate chemistry, morphology, and evolution of eggplant (Solanum) species

SmuMYB113 is the determinant of fruit color in pepino (Solanum muricatum)

Pepino (Solanum muricatum) is an herbaceous crop phylogenetically related to tomato and potato. Pepino fruit vary in color, size and shape, and are eaten fresh. In this study, we use pepino as a fruit model to understand the transcriptional regulatory mechanisms controlling fruit quality. To identify the key genes involved in anthocyanin biosynthesis in pepino, two genotypes were studied that contrasted in foliar and fruit pigmentation. Anthocyanin profiles were analyzed, as well as the expression of genes that encode enzymes for anthocyanin biosynthesis and transcriptional regulators using both RNA-seq and quantitative PCR. The differential expression of the transcription factor genes R2R3 MYB SmuMYB113 and R3MYB SmuATV suggested their association with purple skin and foliage phenotype. Functional analysis of these genes in both tobacco and pepino showed that SmuMYB113 activates anthocyanins, while SmuATV suppresses anthocyanin accumulation. However, despite elevated expression in all tissues, SmuMYB113 does not significantly elevate flesh pigmentation, suggesting a strong repressive background in fruit flesh tissue. These results will aid understanding of the differential regulation controlling fruit quality aspects between skin and flesh in other fruiting species.

Antinociceptive and anti-inflammatory potential, and chemical characterization of the dichloromethane fraction of Solanum lycocarpum (Solanaceae) ripe fruits by LC-DAD-MS

ETHNOPHARMACOLOGICAL RELEVANCE

Solanum lycocarpum A. St. Hil. (Solanaceae) is a species from the Brazilian Cerrado, exhibiting several medicinal properties, being used by the population in the treatment of ulcers, bronchitis, asthma and hepatitis, which involve inflammatory processes.

AIM OF THIS STUDY

This study aimed to chemically characterize the dichloromethane fraction (DCM), as well as verify its antinociceptive, anti-inflammatory and antioxidant potential.

MATERIALS AND METHODS

The DCM fraction was obtained by partitioning the ethanol extract. The chemical constituents of the DCM fraction were characterized by LC-DAD-MS. The DPPH and FRAP assays were used to evaluate the antioxidant potential. The carrageenan-induced paw edema model was used to assess the anti-inflammatory effects, and the inflammatory infiltrate was evaluated by qualitative and quantitative histological analyses. The antinociceptive action of the DCM fraction was evaluated by acetic acid-induced abdominal writhing test, formalin-induced nociception and hot-plate test.

RESULTS

Steroidal alkaloids solasonine, solasodine and solamargine, as well as the alkaloid peiminine/imperialine and caffeoylquinic acids, were annotated in DCM fraction by LC-DAD-MS. The DCM fraction showed antioxidative action in the in vitro DPPH and FRAP tests, as well as an anti-inflammatory effect for the three evaluated doses of 30, 100 and 300 mg/kg in the fourth and sixth hours after the administration of carrageenan. The histological analyses evidenced considerably reduction in leukocyte migration and the number of polymorphonuclear leukocytes. The study also demonstrated antinociceptive activity for the DCM fraction, which reduced abdominal writhing at three concentrations evaluated, as well as a decrease in paw licking in the formalin-induced nociception test both in the neurogenic phase and the inflammatory phase, with greater effectiveness compared to the anti-inflammatory indomethacin. The DCM fraction also increased the latency time of the animals in the hot plate test 60 min after treatment, although it did not seem to involve the opioidergic system.

CONCLUSION

This work evidenced that the dichloromethane fraction of S. lycocarpum fruit possesses antinociceptive and anti-inflammatory potential, which supports its use in folk medicine for management inflammatory conditions.

Identification and quantification of kukoamine A and kukoamine B as novel μ-opioid receptor agonists in potato and other solanaceous plants

Activation of the µ-opioid receptor (µOR) by food components could lead to reward effects or to the modulation of motor functions in the gastrointestinal tract. In an unbiased search for novel µOR agonists in food, a three-step virtual-screening process selected 22 promising candidates with potential to interact with the µOR. Radioligand binding studies showed that ten of these substances indeed bind to the receptor. Functional assays identified kukoamine A as a full agonist (EC50 = 5.6 µM) and kukoamine B as a partial agonist (EC50 = 8.7 µM) to µOR. After extraction, both kukoamines were analyzed by LC-MS/MS in potato, tomato, pepper, and eggplant. Depending on the potato variety, up to 16 µg of kukoamine A and 157 µg of kukoamine B per gram dry weight could be determined in the whole tuber, mainly concentrated in the potato peel. Cooking did not influence the kukoamine contents.

Solanum dulcamara L. Berries: A Convenient Model System to Study Redox Processes in Relation to Fruit Ripening

The present study provides, for the first time, a physicochemical and biochemical characterization of the redox processes associated with the ripening of Solanum dulcamara L. (bittersweet) berries. Electron Paramagnetic Resonance Spectroscopy (EPRS) and Imaging (EPRI) measurements of reactive oxygen species (ROS) were performed in parallel with the tissue-specific metabolic profiling of major antioxidants and assessment of antioxidant enzymes activity. Fruit transition from the mature green (MG) to ripe red (RR) stage involved changes in the qualitative and quantitative content of antioxidants and the associated cellular oxidation and peroxidation processes. The skin of bittersweet berries, which was the major source of antioxidants, exhibited the highest antioxidant potential against DPPH radicals and nitroxyl spin probe 3CP. The efficient enzymatic antioxidant system played a critical protective role against the deleterious effects of progressive oxidative stress during ripening. Here, we present the EPRI methodology to assess the redox status of fruits and to discriminate between the redox states of different tissues. Interestingly, the intracellular reoxidation of cell-permeable nitroxide probe 3CP was observed for the first time in fruits or any other plant tissue, and its intensity is herein proposed as a reliable indicator of oxidative stress during ripening. The described noninvasive EPRI technique has the potential to have broader application in the study of redox processes associated with the development, senescence, and postharvest storage of fruits, as well as other circumstances in which oxidative stress is implicated.

Evaluation of Antimicrobial and Chemopreventive Properties and Phytochemical Analysis of Solanum nigrum L. Aerial Parts and Root Extracts

This study evaluated in vitro antibacterial, antifungal, anticancer and antioxidant activities of methanolic leaf and root extracts from Solanum nigrum L. and determined its chemical composition. The chemical profile of S. nigrum L. extract was tested using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Disc diffusion and microdilution assays were used for the antibacterial activities. Antifungal activity was measured using the poisoned food technique. In vitro activity on the cell culture model was assessed by MTT assay, viability measurement and by determination of cellular ROS by DCFDA assay. The minimal inhibitory concentrations for extracts from aerial parts ranged from 125 to 500 μg/mL for gram-positive cocci and Pectobacterium strains. The growth inhibition coefficient ranged from 17–56%, depending on the dosage. The antifungal effect of S. nigrum extracts on the tested filamentous fungi depended on the dose. An inhibitory effect of 50–56% on fungi was observed against Alternaria alternata and Chaetomium globosum. The study showed a reduction in cellular vitality of THP1, A549, MCF7 and HeLa cancer lines using both extracts. In addition, there was a decrease in the number of viable cells in cultures incubated with the extract of aerial parts and a reduction in oxygen radicals in the cells. The obtained results indicate the possibility of using S. nigrum extracts from the aerial part as antimicrobial factors. Both extracts show chemopreventive properties by inhibiting the growth of cancer cells and reducing the level of free radicals. Both extracts show chemopreventive properties by inhibiting cancer cell growth and lowering free radical levels. The broad biological activity of the studied extracts can be used in agriculture, veterinary usages and medicine.

A revision of the "spiny solanums" of Tropical Asia (Solanum, the Leptostemonum Clade, Solanaceae)

The Leptostemonum Clade, or the "spiny solanums", is the most species-rich monophyletic clade of the large cosmopolitan genus Solanum (Solanaceae) and represents almost half the species diversity of the genus. Species diversity in the clade is highest in the Americas, but significant clusters of endemic taxa occur in the Eastern Hemisphere. We present here a taxonomic revision of the 51 species of spiny solanums occurring in tropical Asia (excluding the island of New Guinea, and the lowlands of Nepal and Bhutan). Three species are described as new: Solanumkachinense X.Aubriot & S.Knapp, sp. nov. from northern Myanmar, S.peikuoense S.S.Ying, sp. nov. from Taiwan, and S.sulawesi X.Aubriot & S.Knapp, sp. nov. from northern Sulawesi, Indonesia. Of the spiny solanums occurring in the region, 38 are native and 13 are introduced from the Americas or Africa, either as adventive weeds or as cultivated plants. Phylogenetic resolution amongst these taxa is still a work in progress, so we have chosen to treat these taxa in a geographical context to aid with identification and further taxon discovery. For the native species we provide complete nomenclatural details for all recognised species and their synonyms, complete descriptions, distributions including maps, common names and uses, and preliminary conservation assessments. For the introduced taxa that have been treated in detail elsewhere we provide details of types, synonyms based on tropical Asian material, general distributions, and common names for the region. We provide lecto- or neotypifications for 67 names; 63 for native and 4 for introduced taxa. All taxa are discussed and compared to similar species; keys are provided for all taxa. We illustrate all native species with herbarium and field photographs and introduced species with field photographs only. All specimens examined for this treatment are included in Suppl. materials 1-3 as searchable files.

High-Performance Liquid Chromatography–Mass Spectrometry Analysis of Glycoalkaloids from Underexploited Solanum Species and Their Acetylcholinesterase Inhibition Activity

Solanum glycoalkaloids are gaining increased scientific attention due to their bioactive potential in the defense of plants against pests and pathogens. The comprehensive glycoalkaloid profiling from the leaves, stems, and roots of seven underexploited Solanum species (S. caripense, S. melanocerasum, S. muricatum, S. nigrum, S. quitoense, S. retroflexum, and S. sisymbriifolium) was conducted using high-performance liquid chromatography–time-of-flight mass spectrometry. A total of 51 glycoalkaloids were shared among the studied Solanum species, with concentrations ranging from 7 to 5.63 × 10⁵ ng g⁻¹. Based on the glycoalkaloid composition, plants were separated into two clusters, Cluster 1 (S. melanocerasum, S. nigrum, and S. retroflexum) and Cluster 2 (S. caripense, S. muricatum, S. quitoense, and S. sisymbriifolium). The inhibition activity of glycoalkaloid extracts on acetylcholinesterase showed a half-maximal inhibitory concentration (IC₅₀), ranging from 0.4 (S. nigrum stems) to 344.9 µg mL⁻¹ (S. sisymbriifolium leaves), that was not directly correlated to the total glycoalkaloid contents. This suggests that the composition of glycoalkaloids in the plant extract, rather than the total concentration, is a driver of biological activity. The study provides a framework for the bioprospecting of underexploited Solanum species for exploring bioactive glycoalkaloids and other compounds with potential pesticidal activities for the development of green bioformulation. This is the first comprehensive report on the glycoalkaloid profiles of S. retroflexum.

Scrapped but not neglected: Insights into the composition, molecular modulation and antioxidant capacity of phenols in peel of eggplant (Solanum melongena L.) fruits at different developmental stages

Eggplant fruits are normally harvested and marketed when they reach the commercial maturity, that precedes the physiological ripening when dramatic changes in taste, composition and peel color take place. The biochemical changes in fruit peel across the developmental stages, characterized also by a sizeable decrement of anthocyanins, were studied in four eggplant genotypes differing for fruit pigmentation. HPLC-DAD, HPLC-ESI-MS and NMR analyses identified naringenin chalcone and naringenin 7-O-glucoside as the main phenolic compounds in extracts from the physiological ripe stage, along with compounds tentatively identified as glycosylated naringenin chalcone, naringenin and kaempferol. On average, the levels of anthocyanins, responsible for the peel pigmentation, dropped by 75% during development, while, surprisingly, the level of total phenols showed a slight decrease of 16%, with a final concentration of more than 1000 mg/100g dw. RT-qPCR expression profiling of nine genes coding for enzymes putatively acting at different steps of the involved pathways showed modulation mostly consistent with the observed changes in phenolic composition, with a remarkable decrease in the activity of flavonol reductase and an increase in flavonol synthase during berry development. Antioxidant activity monitored by peroxyl scavenging was similar at all developmental stages while Fremy's analysis evidenced a slight decrement at full physiological ripening. These results are valuable to address the improvement of eggplant commercial fruit quality and the valorization of unmarketable physiological ripe fruits, especially for the newly accumulation of the health-promoting compounds chalcones and flavanones.

Quality Assessment of Wild and Cultivated Green Tea from Different Regions of China

Natural products have always enjoyed great popularity among consumers. Wild tea is an interesting alternative to tea from intensive plantations. The term "wild tea" is applied to many different varieties of tea, the most desirable and valued of which are native or indigenous tea plants. Special pro-health properties of wild tea are attributed to the natural conditions in which it grows. However, there are no complex studies that describe quality and health indicators of wild tea. The aim of this research was to evaluate the quality of wild and cultivated green tea from different regions of China: Wuzhishan, Baisha, Kunlushan, and Pu'Er. The assessment was carried out by verifying the concentration of selected chemical components in tea and relating it to the health risks they may pose, as well as to the nutritional requirements of adults. Wild tea was characterized by higher micronutrient concentration. The analyzed teas can constitute a valuable source of Mn in the diet. A higher concentration of nitrates and oxalates in cultivated tea can be associated with fertilizer use. The analyzed cultivated tea was a better source of antioxidants with a higher concentration of caffeine. There were no indications of health risks for wild or cultivated teas.

Potential Use of Vacuum Impregnation and High-Pressure Homogenization to Obtain Functional Products from Lulo Fruit (Solanum quitoense Lam.)

Lulo (Solanum quitoense Lam.) is a Colombian fruit that is mostly used in the preparation of homemade juice as well as natural remedy for hypertension. The aim of this study was to determine physicochemical and antioxidant properties (antioxidant capacity, total phenols, flavonoids and spermidine content, and polyphenolic compounds profile by liquid chromatography-mass spectrometry (LC-MS)) of the lulo fruit and its juice. Additionally, vacuum impregnation (VI) properties of the fruit and the effect of high homogenization pressure (50, 100, and 150 MPa) on the juice properties were studied. The results revealed a good availability and impregnation capacity of the pores in fruits with similar maturity index. The main differences observed between the juice and fruit derive from removing solids and bioactive components in the filtering operation. However, the effect of high-pressure homogenization (HPH) on particle size and bioactive compounds increases the antiradical capacity of the juice and the diversity in polyphenolics when increasing the homogenization pressure.

Solanum steroidal glycoalkaloids: structural diversity, biological activities, and biosynthesis

Chemical structures of typical Solanum steroidal glycoalkaloids from eggplant, tomato, and potato.

Identification and similarity analysis of aroma substances in main types of Fenghuang Dancong tea

Fenghuang Dancong tea covers the oolong tea category and is widely acknowledged for its unique floral and honey flavor. In order to characterize the volatile components in nine different aroma types of Fenghuang Dancong tea, the Headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC- MS) were employed. In addition, the similarity analysis and cluster analysis (CA) were performed to compare the aroma characteristics and establish the correlation between the nine types of teas. The principal component analysis (PCA) and orthogonal partial least squares discrimination analysis (OPLS-DA) method were employed to determine the volatile components with a high contribution to the overall aroma of each type of tea. The results presented a total of 122 volatile aroma components including 24 kinds of alcohol, 23 kinds of esters, 15 kinds of olefins, 12 kinds of aldehydes, 12 kinds of ketones, 13 kinds of alkanes and 23 kinds of other components from the nine types of Fenghuang Dancong tea. Of these volatile aroma components, 22 types were common with linalool, dehydrolinalool, linalool oxide I, linalool oxide II, etc. The similarity of the nine types of Fenghuang Dancong tea was found between 46.79% and 95.94%. The CA indicated that the nine types of Fenghuang Dancong tea could be clustered into four categories when the ordinate distance reached to 10. The PCA demonstrated that decane, octadecane, 2,2,4,6,6-pentamethylheptane, dehydrolinalool, geraniol and nerol were the important aroma components to Fenghuang Dancong Tea. OPLS-DA proved that 2,2,4,6,6-pentamethylheptane, dehydrolinalool, phenylacetaldehyde, nerolidol, linalool oxide I and hexanal were the key differential compounds between the various types of tea samples. This study provides a theoretical basis for characterizing the volatile aroma components in the main types of Fenghuang Dancong tea as well as the similarity and correlation between various types of Fenghuang Dancong tea.

Chemical composition, antioxidant, anti-inflammatory and antinociceptive activities of the ethanol extract of ripe fruits of Solanum lycocarpum St. Hil. (Solanaceae)

ETHNOPHARMACOLOGICAL RELEVANCE

Solanum lycocarpum St. Hil. (Solanaceae) is widely distributed in the Brazilian Cerrado and is used in folk medicine for treatment of inflammatory disorders, such as asthma and hepatitis, as weel as antirheumatic.

AIM OF THE STUDY

The aims of this study were to evaluate the antioxidant, anti-inflammatory and antinociceptive activities of the ethanol extract (EE) obtained from the ripe fruits of S. lycocarpum and to identify its chemical constituents.

MATERIALS AND METHODS

The extract was obtained by percolation with ethanol. This extract was analyzed by liquid chromatography coupled to a diode array detector and mass spectrometer (LC-DAD-MS) for identify its chemical constituents. The antioxidant activity was determined by the reaction with 1,1-diphenyl-2-picrylhydrazyl radical (DPPH). In vivo anti-inflammatory potential was assessed using carrageenan-induced paw edema model, while qualitative and quantitative histological analyses evaluated of the inflammatory infiltrate at different times and treatments. The antinociceptive effect of the EE was evaluated by acetic acid-induced abdominal writhing test, formalin-induced nociception and hot-plate test.

RESULTS

The main compounds identified in EE were steroidal glycoalkaloids (such as robeneoside B or hydroxysolasonine isomers and solanandaine isomers), the aglycone alkaloids peiminine and solasodine, di- and tri-O-caffeoylquinic acid derivatives, O-coumaroyl caffeoylquinic acid derivatives, N1,N10-bis-(dihydrocaffeoyl)spermidine, di-O-hexoside, and hexonic acid. In addition, the EE showed significant antioxidant activity. Intraperitoneal (i.p.) treatment with EE (300 mg/kg) exhibited anti-inflammatory activity. Qualitative and quantitative histological analyses showed that EE significantly reduced the cell infiltrate in acute inflammation. The EE, in all doses evaluated, significantly reduced the abdominal contortions in mice. Besides, reduced licking time was found in both phases in the formalin test after treatment with EE (100 and 300 mg/kg). In addition, the opioid receptor antagonist naloxone reversed the antinociceptive activity of morphine in the both phases the test, but it did not reverse the antinociceptive activity of the EE. The EE (300 mg/kg) also caused an increase in the latency to response in the hot-plate test.

CONCLUSION

The ripe fruits of S. lycocarpum exhibit antioxidant, anti-inflammatory, and antinociceptive activities, attributed mainly to the presence of alkaloids, such as solasodine and peiminine, as well as caffeoylquinic acids in their chemical composition. These results contribute to use of S. lycocarpum ripe fruits for the treatment of inflammatory and painful process.

Phenolic Profile of Herbal Infusion and Polyphenol-Rich Extract from Leaves of the Medicinal Plant Antirhea borbonica: Toxicity Assay Determination in Zebrafish Embryos and Larvae

Antirhea borbonica (A. borbonica) is an endemic plant from the Mascarene archipelago in the Indian Ocean commonly used in traditional medicine for its health benefits. This study aims (1) at exploring polyphenols profiles from two types of extracts—aqueous (herbal infusion) and acetonic (polyphenol rich) extracts from A. borbonica leaves—and (2) at evaluating their potential toxicity in vivo for the first time. We first demonstrated that, whatever type of extraction is used, both extracts displayed significant antioxidant properties and acid phenolic and flavonoid contents. By using selective liquid chromatography–tandem mass spectrometry, we performed polyphenol identification and quantification. Among the 19 identified polyphenols, we reported that the main ones were caffeic acid derivatives and quercetin-3-O-rutinoside. Then, we performed a Fish Embryo Acute Toxicity test to assess the toxicity of both extracts following the Organisation for Economic Cooperation and Development (OECD) guidelines. In both zebrafish embryos and larvae, the polyphenols-rich extract obtained by acetonic extraction followed by evaporation and resuspension in water exhibits a higher toxic effect with a median lethal concentration (LC₅₀: 5.6 g/L) compared to the aqueous extract (LC₅₀: 20.3 g/L). Our data also reveal that at non-lethal concentrations of 2.3 and 7.2 g/L for the polyphenol-rich extract and herbal infusion, respectively, morphological malformations such as spinal curvature, pericardial edema, and developmental delay may occur. In conclusion, our study strongly suggests that the evaluation of the toxicity of medicinal plants should be systematically carried out and considered when studying therapeutic effects on living organisms.

Managing Rhizoctonia Damping-Off of Rocket (Eruca sativa) Seedlings by Drench Application of Bioactive Potato Leaf Phytochemical Extracts

Plants produce a huge array of secondary metabolites that play a key role in defense mechanisms against detrimental microorganisms and herbivores, and represent a suitable alternative to synthetic fungicides in sustainable agriculture. In this work, twelve crude hydroethanolic extracts derived from leaves of different potato cultivars were chemically characterized by LC/MS and their antioxidant properties were investigated in vitro. Furthermore, the biological activity against the fungal pathogen Rhizoctonia solani was evaluated both in vitro and in vivo. Extracts showed the ability to inhibit R. solani growth in vitro and significantly reduced damping-off incidence in in vivo experiments. Furthermore, R. solani mycelia exposed to the extracts showed an altered morphology (low translucency, irregular silhouette, and cytoplasmatic content coagulation) compared to the untreated control in light microscopy examination. Principal component analysis conducted on identified chemical compounds highlighted significant metabolic variations across the different extracts. In particular, those that inhibited most of the growth of the pathogen were found to be enriched in α-chaconine or α-solanine content, indicating that their biological activity is affected by the abundance of these metabolites. These results clearly indicated that plant-derived compounds represent a suitable alternative to chemicals and could lead to the development of new formulates for sustainable control of plant diseases.

The Chemistry and Health Benefits of Dietary Phenolamides

Phenolamides, also known as hydroxycinnamic acid amides or phenylamides, have been reported throughout the plant kingdom, while a few of these amine-conjugated hydroxycinnamic acids are unique in foods. The current knowledge of their specific functions in plant development and defense is readily available as is their biosynthesis; however, their functionality in humans is still largely unknown. Of the currently known phenolamides, the most common are avenanthramides, which are unique in oats and similar to the well-known drug Tranilast, which possess anti-inflammatory, antioxidant, anti-itch, and antiatherogenic activities. While recent data have brought to light more information regarding the other known phenolamides, such as hordatines, dimers of agmatine conjugated to hydroxycinnamic acid, and kukoamines, spermine-derived phenolamides, the information is still severely limited, leaving their potential health benefits to speculation. Herein, to highlight the importance of dietary phenolamides to human health, we review and summarize the four major subgroups of phenolamides, including their chemical structures, dietary sources, and reported health benefits. We believe that the studies on phenolamides are still in the infancy stage and additional health benefits of these phenolamides may yet be identified.

Cross-Species Comparison of Fruit-Metabolomics to Elucidate Metabolic Regulation of Fruit Polyphenolics Among Solanaceous Crops

Many solanaceous crops are an important part of the human daily diet. Fruit polyphenolics are plant specialized metabolites that are recognized for their human health benefits and their defensive role against plant abiotic and biotic stressors. Flavonoids and chlorogenates are the major polyphenolic compounds found in solanaceous fruits that vary in quantity, physiological function, and structural diversity among and within plant species. Despite their biological significance, the elucidation of metabolic shifts of polyphenols during fruit ripening in different fruit tissues, has not yet been well-characterized in solanaceous crops, especially at a cross-species and cross-cultivar level. Here, we performed a cross-species comparison of fruit-metabolomics to elucidate the metabolic regulation of fruit polyphenolics from three representative crops of Solanaceae (tomato, eggplant, and pepper), and a cross-cultivar comparison among different pepper cultivars (Capsicum annuum cv.) using liquid chromatography-mass spectrometry (LC-MS). We observed a metabolic trade-off between hydroxycinnamates and flavonoids in pungent pepper and anthocyanin-type pepper cultivars and identified metabolic signatures of fruit polyphenolics in each species from each different tissue-type and fruit ripening stage. Our results provide additional information for metabolomics-assisted crop improvement of solanaceous fruits towards their improved nutritive properties and enhanced stress tolerance.

From Folk Taxonomy to Species Confirmation of Acorus (Acoraceae): Evidences Based on Phylogenetic and Metabolomic Analyses

Plants in Acorus have been used as herbal medicine by various linguistic groups for thousands of years. Arguments of taxonomy of Acorus among scientists resulted in confusions and misuses of Acorus plants. The present study used different methods to investigate the classification of the genus, based on folk taxonomy. The relationships among Acorus species were revealed through phylogenetic analyses by constructing the Maximum Likelihood and Bayesian phylogenetic analyses based on sequences of two chloroplast regions (trnL-trnF and rbcL). All samples named with two so-called synonyms, Acorus macrospadiceus (Yamam.) F. N. Wei and Y. K. Li and Acorus tatarinowii Schott collected from different habitats, were clustered into separate groups, which revealed that they represented two independent species. Multivariate statistical analysis of metabolites from different Acorus populations were carried out based on UPLC-QTOF-MS data. Three independent analysis, principal component analysis, heat-map analysis, and hierarchical cluster analysis, showed that A. macrospadiceus and A. tatarinowii are different from two recognized species in the genus, A. calamus L. and A. gramineus Aiton. The results of phylogenetics and chemotaxonomy, together with morphological and ecological evidences, were consistent with traditional knowledge of local people related to Acorus taxa, which proved the significance of parataxonomy. Multiple evidences including morphological, ecological, folk taxonomic, phylogenetic, and chemical taxonomic results suggested that there are four species in the genus Acorus.

Characterization of steroid 5α-reductase involved in α-tomatine biosynthesis in tomatoes

α-tomatine and dehydrotomatine are steroidal glycoalkaloids (SGAs) that accumulate in the mature green fruits, leaves, and flowers of tomatoes (Solanum lycopersicum) and function as defensive compounds against pathogens and predators. The aglycones of α-tomatine and dehydrotomatine are tomatidine and dehydrotomatidine (5,6-dehydrogenated tomatidine), and tomatidine is derived from dehydrotomatidine via four reaction steps: C3 oxidation, isomerization, C5α reduction, and C3 reduction. Our previous studies (Lee et al. 2019) revealed that Sl3βHSD is involved in the three reactions except for C5α reduction, and in the present study, we aimed to elucidate the gene responsible for the C5α reduction step in the conversion of dehydrotomatidine to tomatidine. We characterized the two genes, SlS5αR1 and SlS5αR2, which show high homology with DET2, a brassinosteroid 5α reductase of Arabidopsis thaliana. The expression pattern of SlS5αR2 is similar to those of SGA biosynthetic genes, while SlS5αR1 is ubiquitously expressed, suggesting the involvement of SlS5αR2 in SGA biosynthesis. Biochemical analysis of the recombinant proteins revealed that both of SlS5αR1 and SlS5αR2 catalyze the reduction of tomatid-4-en-3-one at C5α to yield tomatid-3-one. Then, SlS5αR1- or SlS5αR2-knockout hairy roots were constructed using CRISPR/Cas9 mediated genome editing. In the SlS5αR2-knockout hairy roots, the α-tomatine level was significantly decreased and dehydrotomatine was accumulated. On the other hand, no change in the amount of α-tomatine was observed in the SlS5αR1-knockout hairy root. These results indicate that SlS5αR2 is responsible for the C5α reduction in α-tomatine biosynthesis and that SlS5αR1 does not significantly contribute to α-tomatine biosynthesis.

Phytotoxicity and cytogenotoxicity of hydroalcoholic extracts from Solanum muricatum Ait. and Solanum betaceum Cav. (Solanaceae) in the plant model Lactuca sativa

Plants are rich in biologically active compounds. They can be explored for the production of bioherbicides. In this context, the present work aimed to evaluate the allelopathic effect of hydroalcoholic extracts from two Solanaceae species: Solanum muricatum Ait. and Solanum betaceum Cav. For this end, we conducted phytochemical screening and biological assays, determining the effects of the extracts on germination, early development, cell cycle, and DNA fragmentation in plantlets and meristematic cells of the plant model Lactuca sativa L. (lettuce). The percentage of seeds germinated under effect of S. muricatum extract did not differ from the control, but plantlet growth was reduced at the highest concentrations. For S. betaceum extract, dose dependence was observed for both germination and plantlet development, with the highest concentrations inhibiting germination. The growth curves revealed the concentrations of 2.06 and 1.93 g/L for S. muricatum and S. betaceum extracts, respectively, as those reducing 50% of root growth (RG). At these concentrations, both extracts presented mitodepressive effect, besides inducing significant increase in the frequency of condensed nuclei, associated to DNA fragmentation and cytoplasmic shrinkage. The frequency of chromosome alterations was not significant. We further discuss the mechanisms of action related to the chemical composition of the extracts, which presented organic acids, reducing sugars, proteins, amino acids, and tannins, besides catechins and flavonoids, only found in the extract of S. betaceum.

A novel hydroxycinnamoyl transferase for synthesis of hydroxycinnamoyl spermine conjugates in plants

BACKGROUND

Hydroxycinnamoyl-spermine conjugates (HCSpm) are a class of hydroxycinnamic acid amides (HCAAs), which not only are instrumental in plant development and stress response, but also benefit human health. However, HCSpm are not commonly produced in plants, and the mechanism of their biosynthesis remains unclear. In previous investigations of phenolics in Solanum fruits related to eggplant (Solanum melongena L.), we discovered that Solanum richardii, an African wild relative of eggplant, was rich in HCSpms in fruits.

RESULTS

The putative spermine hydroxycinnamoyl transferase (HT) SpmHT was isolated from S. richardii and eggplant. SrSpmHT expression was high in flowers and fruit, and was associated with HCSpm accumulation in S. richardii; however, SpmHT was hardly detected in eggplant cultivars and other wild relatives. Recombinant SpmHT exclusively selected spermine as the acyl acceptor substrate, while showing donor substrate preference in the following order: caffeoyl-CoA, feruloyl-CoA, and p-coumaroyl-CoA. Molecular docking revealed that substrate binding pockets of SpmHT could properly accommodate spermine but not the shorter, more common spermidine.

CONCLUSION

SrSpmHT is a novel spermine hydroxycinnamoyl transferase that uses Spm exclusively as the acyl acceptor substrate to produce HCSpms. Our findings shed light on the HCSpm biosynthetic pathway that may allow an increase of health beneficial metabolites in Solanum crops via methods such as introgression or engineering HCAA metabolism.

Identification of a 3β-Hydroxysteroid Dehydrogenase/ 3-Ketosteroid Reductase Involved in α-Tomatine Biosynthesis in Tomato

α-Tomatine and dehydrotomatine are major steroidal glycoalkaloids (SGAs) that accumulate in the mature green fruits, leaves and flowers of tomato (Solanum lycopersicum), and function as defensive compounds against bacteria, fungi, insects and animals. The aglycone of dehydrotomatine is dehydrotomatidine (5,6-dehydrogenated tomatidine, having the Δ5,6 double bond; the dehydro-type). The aglycone of α-tomatine is tomatidine (having a single bond between C5 and C6; the dihydro-type), which is believed to be derived from dehydrotomatidine via four reaction steps: C3 oxidation, isomerization, C5 reduction and C3 reduction; however, these conversion processes remain uncharacterized. In the present study, we demonstrate that a short-chain alcohol dehydrogenase/reductase designated Sl3βHSD is involved in the conversion of dehydrotomatidine to tomatidine in tomato. Sl3βHSD1 expression was observed to be high in the flowers, leaves and mature green fruits of tomato, in which high amounts of α-tomatine are accumulated. Biochemical analysis of the recombinant Sl3βHSD1 protein revealed that Sl3βHSD1 catalyzes the C3 oxidation of dehydrotomatidine to form tomatid-4-en-3-one and also catalyzes the NADH-dependent C3 reduction of a 3-ketosteroid (tomatid-3-one) to form tomatidine. Furthermore, during co-incubation of Sl3βHSD1 with SlS5αR1 (steroid 5α-reductase) the four reaction steps converting dehydrotomatidine to tomatidine were completed. Sl3βHSD1-silenced transgenic tomato plants accumulated dehydrotomatine, with corresponding decreases in α-tomatine content. Furthermore, the constitutive expression of Sl3βHSD1 in potato hairy roots resulted in the conversion of potato SGAs to the dihydro-type SGAs. These results demonstrate that Sl3βHSD1 is a key enzyme involved in the conversion processes from dehydrotomatidine to tomatidine in α-tomatine biosynthesis.

The chemical composition of a cold-pressed milk thistle seed flour extract, and its potential health beneficial properties

Cold-pressed milk thistle seed flour was extracted with 50% acetone and evaluated for its phytochemical composition, and gut microbiota modulating, free radical scavenging, anti-inflammatory and anti-proliferative capacities. UHPLC-MS analysis detected fifteen compounds in the milk thistle seed flour extract with silychristin as the primary component followed by silybin B and isosilybins A & B. The milk thistle seed flour extract enhanced the total bacteria number and altered the abundance of a specific bacterial phylum or genus under the experimental conditions. The extract had RDSC, ORAC, HOSC, and ABTS˙+ scavenging capacities of 49, 634, 10 420 and 116 μmol Trolox equivalents (TE) per g flour, respectively. In addition, the milk thistle seed flour extract suppressed LPS induced IL-1β mRNA expression in the cultured J774A.1 mouse macrophages and the proliferation of LNCaP prostate cancer cells. The results suggest milk thistle seed flour's potential health benefits in functional foods.

A Complete Survey of Glycoalkaloids Using LC-FTICR-MS and IRMPD in a Commercial Variety and a Local Landrace of Eggplant (Solanum melongena L.) and their Anticholinesterase and Antioxidant Activities

Eggplant contains glycoalkaloids (GAs), a class of nitrogen-containing secondary metabolites of great structural variety that may have both adverse and beneficial biological effects. In this study, we performed a complete survey of GAs and their malonylated form, in two genotypes of eggplants: A commercial cultivated type, Mirabella (Mir), with purple peel and bitter taste and a local landrace, named Melanzana Bianca di Senise (Sen), characterized by white peel with purple strip and a typical sweet aroma. Besides the analysis of their morphological traits, nineteen glycoalkaloids were tentatively identified in eggplant berry extracts based upon LC-ESI-FTICR-MS analysis using retention times, elution orders, high-resolution mass spectra, as well as high-resolution fragmentation by IRMPD. The relative signal intensities (i.e., ion counts) of the GAs identified in Mir and Sen pulp extracts showed as solamargine, and its isomers are the most abundant. In addition, anticholinesterase and antioxidant activities of the extracts were evaluated. Pulp tissue was found to be more active in inhibiting acetylcholinesterase enzyme than peel showing an inhibitory effect higher than 20% for Mir pulp. The identification of new malonylated GAs in eggplant is proposed.

Phytochemical Characterization of Five Edible Purple-Reddish Vegetables: Anthocyanins, Flavonoids, and Phenolic Acid Derivatives

Vegetables comprise a significant portion of our daily diet with their high content in nutrients including fiber, vitamins, minerals, as well as phenolic compounds. Vegetable consumption has been shown to be positively associated with the prevention of several degenerative diseases thanks to their bioactive compounds. Accordingly, five selected vegetables, namely, red chicory, red onion, eggplant, purple sweet potato, and black carrot were thoroughly assessed for their phenolic content in this study. For this purpose, the total phenolic and flavonoid content of these five vegetables and their antioxidant activities that are based on three common methods ABTS radical cation decolorization assay (ABTS), Cupric Ion Reducing Antioxidant Capacity (CUPRAC), and DPPH scavenging activity assay were determined. Additionally, HPLC-PDA/Electrospray ionization coupled with mass spectrometry (HPLC-PDA/-ESI⁺-MS)-based identification and quantification of the members belonging to polyphenols present in each vegetable were determined. Statistical correlations between antioxidant activities and the specific type of phenolic compounds, such as anthocyanins, flavonoids, anthocyanins, and phenolic acids were further elucidated. Phenolic acids (chlorogenic and syringic acids) were found to be the most abundant compounds that are present in all samples. Among the anthocyanins, cyaniding derivatives were present in all vegetables. In terms of their antioxidant activities, the analyzed vegetables were ranked as red chicory > purple sweet potato > black carrot > eggplant > red onion, in descending order. Superior antioxidant activities exhibited by red chicory and purple sweet potato were attributed to the high content of phenolic compounds, especially flavonols (quercetin-3,4-O-diglucoside) in red chicory and anthocyanins (peonidin-3-caffeoyl p-hydroxybenzoylsophoroside-5-glucoside) in purple sweet potato.

Metabolic Profiling of Different Parts of Acer truncatum from the Mongolian Plateau Using UPLC-QTOF-MS with Comparative Bioactivity Assays

Acer truncatum is an important ornamental, edible, and medicinal plant resource in China. Previous phytochemical research has focused on the leaf (AL) due to its long history as a tea for health. Other parts such as the branch (ABr), bark (ABa), fruit (AF), and root (AR) have drawn little attention regarding their metabolites and bioactivities. The strategy of an in-house chemical library combined with Progenesis QI informatics platform was applied to characterize the metabolites. A total of 98 compounds were characterized or tentatively identified, including 63 compounds reported from this species for the first time. Principal component analysis showed the close clustering of ABr, ABa, and AR, indicating that they share similar chemical components, while AL and AF clustered more distantly. By multiple orthogonal partial least-squares discriminant analyses (OPLS-DA), 52 compounds were identified as potential marker compounds differentiating these different plant parts. The variable influence on projection score from OPLS-DA revealed that catechin, procyanidins B2 or B3, and procyanidins C1 or C2 are the significant metabolites in ABa extracts, which likely contribute to its antioxidant and cytotoxic activities.

A efficient method to identify cardioprotective components of Astragali Radix using a combination of molecularly imprinted polymers-based knockout extract and activity evaluation

Although herb medicines have become the major source for new drug discovery, many of them are largely under-explored due to the purity-activity relationship. Efficient identification of bioactive compounds in conventional stepwise separation and isolation has not yet been elucidated. Therefore, we proposed a new separation strategy for holism understanding of herb pharmacology using molecularly imprinted polymers (MIPs). Astragali Radix (AR), important in traditional Chinese medicine, was chosen in this study for multicomponent knockout followed by bioactivity evaluation. We prepared calycosin molecularly imprinted polymers (calycosin-MIPs) which could selectively recognize flavonoid aglycons in AR. The molecular selectivity of calycosin-MIPs as a critical parameter was evaluated using the template and other high content compounds in AR. Based on it, using the calycosin-MIPs material via solid-phase extraction procedures was applied for the knockout of flavonoid aglycons in AR. Finally, hypoxia/reoxygenation model in H9c2 cells was used to evaluate the activity of the AR extract before and after knockout. The results showed that calycosin-MIPs as recognition materials for flavonoid aglycons in AR are applied in one-step separation with high selectivity and tunability. The subextract in the absence of flavonoid aglycons has been demonstrated to clarify the cardio-protective components of AR. In conclusion, this proof-of-principle study is the first one showing that molecular imprinting technology coupled with a bioassay can be used to explore the bioactive variability from the perspective of multicomponent separation of herbal medicine.

Rapid differentiation of Chinese hop varieties (Humulus lupulus) using volatile fingerprinting by HS-SPME-GC-MS combined with multivariate statistical analysis

BACKGROUND

Hops impart flavor to beer, with the volatile components characterizing the various hop varieties and qualities. Fingerprinting, especially flavor fingerprinting, is often used to identify 'flavor products' because inconsistencies in the description of flavor may lead to an incorrect definition of beer quality. Compared to flavor fingerprinting, volatile fingerprinting is simpler and easier.

RESULTS

We performed volatile fingerprinting using head space-solid phase micro-extraction gas chromatography-mass spectrometry combined with similarity analysis and principal component analysis (PCA) for evaluating and distinguishing between three major Chinese hops. Eighty-four volatiles were identified, which were classified into seven categories. Volatile fingerprinting based on similarity analysis did not yield any obvious result. By contrast, hop varieties and qualities were identified using volatile fingerprinting based on PCA. The potential variables explained the variance in the three hop varieties. In addition, the dendrogram and principal component score plot described the differences and classifications of hops.

CONCLUSION

Volatile fingerprinting plus multivariate statistical analysis can rapidly differentiate between the different varieties and qualities of the three major Chinese hops. Furthermore, this method can be used as a reference in other fields. © 2018 Society of Chemical Industry.

γ-Pyrone compounds: flavonoids and maltol glucoside derivatives from Herniaria glabra L. collected in the Ternopil region of the Ukraine

The phytochemical investigation of the whole plant extracts of Herniaria glabra L. (Caryophyllaceae) led to the identification and isolation of four known flavonoids, one known and three undescribed maltol derivatives, and benzyl β-gentiobioside. The structures were established by extensive 1D and 2D NMR spectroscopic analyses, as well as HRESIMS data. For the first time in Herniaria genus, as well as in Caryophylaceae family the presence of apiorutin {quercetin 3-O-[(D-apio-β-d-furanosyl-(1 → 2)-O-[-α-l-rhamnopyranosyl-(1 → 6)]-β-d-glucopyranoside]} and licoagroside B {maltol 3-O-[6-O-(3-hydroxy-3-methylglutaroyl)]-β-d-glucopyranoside} were revealed. Additionally, antioxidant actions of apiorutin, rutin, narcissin (isorhamentin 3-O-β-d-rutinoside) and licoagroside B were assessed in human blood plasma, exposed to the peroxynitrite-induced oxidative stress in vitro. The isolates partly reduced oxidative (oxidation of thiol groups) and nitrative (tyrosine nitration) damage to blood plasma proteins, decreased plasma lipid peroxidation as well as enhanced the non-enzymatic antioxidant capacity of blood plasma. No cytotoxicity of the examined substances towards peripheral blood mononuclear cells was found.

Comprehensive metabolite profiling of Solanum tuberosum L. (potato) leaves by HPLC-ESI-QTOF-MS

The objective of this work was to study the non-targeted metabolite profiling of potato leaves using high performance liquid chromatography coupled to quadrupole-time of flight mass spectrometry (HPLC-ESI-QTOF-MS). The mass accuracy, true isotopic pattern in both MS and MS/MS spectra provided by QTOF-MS made possible the tentative identification of 109 compounds present in potato leaves, including organic acids, amino acids and derivatives, phenolic acids, flavonoids, iridoids, oxylipins and other polar and semi-polar compounds. Among them, 32 compounds have been found for the first time in potato leaf and in the Solanaceae family. Quinic acid and its derivatives represented more than 45% of the bioactive compounds quantified in the extract. Derivatives of hydroxybenzoic acid and gentisic acid were also founded at considerable concentrations. This study shed light on the composition of potato leaf extract and will serve as a base for further research into activities of the various compounds found in this matrix which has demonstrated a potential use as functional ingredients.

Short-chain dehydrogenase/reductase governs steroidal specialized metabolites structural diversity and toxicity in the genus Solanum

Thousands of specialized, steroidal metabolites are found in a wide spectrum of plants. These include the steroidal glycoalkaloids (SGAs), produced primarily by most species of the genus Solanum, and metabolites belonging to the steroidal saponins class that are widespread throughout the plant kingdom. SGAs play a protective role in plants and have potent activity in mammals, including antinutritional effects in humans. The presence or absence of the double bond at the C-5,6 position (unsaturated and saturated, respectively) creates vast structural diversity within this metabolite class and determines the degree of SGA toxicity. For many years, the elimination of the double bond from unsaturated SGAs was presumed to occur through a single hydrogenation step. In contrast to this prior assumption, here, we show that the tomato GLYCOALKALOID METABOLISM25 (GAME25), a short-chain dehydrogenase/reductase, catalyzes the first of three prospective reactions required to reduce the C-5,6 double bond in dehydrotomatidine to form tomatidine. The recombinant GAME25 enzyme displayed 3β-hydroxysteroid dehydrogenase/Δ^5,4 isomerase activity not only on diverse steroidal alkaloid aglycone substrates but also on steroidal saponin aglycones. Notably, GAME25 down-regulation rerouted the entire tomato SGA repertoire toward the dehydro-SGAs branch rather than forming the typically abundant saturated α-tomatine derivatives. Overexpressing the tomato GAME25 in the tomato plant resulted in significant accumulation of α-tomatine in ripe fruit, while heterologous expression in cultivated eggplant generated saturated SGAs and atypical saturated steroidal saponin glycosides. This study demonstrates how a single scaffold modification of steroidal metabolites in plants results in extensive structural diversity and modulation of product toxicity.

Free amino acids, biogenic amines, and ammonium profiling in tobacco from different geographical origins using microwave-assisted extraction followed by ultra high performance liquid chromatography

This work describes a rapid, stable, and accurate method for determining the free amino acids, biogenic amines, and ammonium in tobacco. The target analytes were extracted with microwave-assisted extraction and then derivatized with diethyl ethoxymethylenemalonate, followed by ultra high performance liquid chromatography analysis. The experimental design used to optimize the microwave-assisted extraction conditions showed that the optimal extraction time was 10 min with a temperature of 60°C. The stability of aminoenone derivatives was improved by keeping the pH near 9.0, and there was no obvious degradation during the 80°C heating and room temperature storage. Under optimal conditions, this method showed good linearity (R2 > 0.999) and sensitivity (limits of detection 0.010-0.081 μg/mL). The extraction recoveries were between 88.4 and 106.5%, while the repeatability and reproducibility ranged from 0.48 to 5.12% and from 1.56 to 6.52%, respectively. The newly developed method was employed to analyze the tobacco from different geographical origins. Principal component analysis showed that four geographical origins of tobacco could be clearly distinguished and that each had their characteristic components. The proposed method also showed great potential for further investigations on nitrogen metabolism in plants.

Multipathway Integrated Adjustment Mechanism of Glycyrrhiza Triterpenes Curing Gastric Ulcer in Rats

Background:

Gastric ulcer is a common chronic disease in human digestive system, which is difficult to cure, easy to relapse, and endangers human health seriously. Compared with western medicine, traditional Chinese medicine has a unique advantage in improving the general situation, stablizing medical condition, and with little side effects. Glycyrrhiza known as “king of all the medicine”, has a range of pharmacological activities and is commonly used in a variety of proprietary Chinese medicines and formulations.

Objective:

On the basis of explicit antiulcer effect of Glycyrrhiza triterpenes, the molecular mechanisms of its therapeutic effect on acetic acid induced gastric ulcer in rats were explored.

Materials and Methods:

Acetic acid induced gastric ulcer model in rats was established to evaluate the curing effect of G. triterpenes and all of the rats were randomised into six groups: Control group, model group, omeprazole group (0.8 mg/mL), triterpenes high dose group (378.0 mg/mL), triterpenes middle dose group (126.0 mg/mL), and triterpenes low dose group (42.0 mg/mL). All rats in groups were orally administered the active group solution 1.5 mL once daily (model and control groups with saline) for 7 days. HPLC-TOF-MS analysis method was performed to obtain the plasma metabolites spectrums of control group, model group, triterpenes high, middle and low dose groups.

Results:

A total of 11 differential endogenous metabolites related to the therapeutic effect of G. triterpenes were identified, including tryptophan, phingosine-1-phosphate, pantothenic acid, and so on, among which tryptophan and phingosine-1-phosphate are related with the calcium signaling pathway and arachidonic acid (AA) metabolism. At the same time, in order to verify the above results, quantitative real time polymerase chain reaction were performed to evaluate the expression of H⁺-K⁺-ATPase alpha mRNA and phospholipase a 2 mRNA in relational signaling pathways. Combined with statistical analysis of plasma metabolic spectrum and gene expression in tissue, it is suggested that G. triterpenes has antiulcer effect on gastric ulcer in rats.

Conclusion:

G. triterpenes has a certain regulating effect on the metabolism of tryptophan, AA, sphingosine, and other endogenous metabolites, and we speculated that the antiulcer potential of G. triterpenes can be primarily attributed to its inhibiting gastric acid secretion, reducing the release of inflammatory mediators, and protecting gastric mucosa effects to prevent the further development of gastric ulcer.

SUMMARY

G. triterpenes can obviously relieve the symptoms of gastric ulcer, especially the low dose group.

G. triterpenes can effectively regulate the amount of small molecule metablism in gastric ulcer rats in vivo, including tryptophan, phingosine-1-phosphate, etc.

G. triterpenes resisting gastric ulcer is probably by regulating arachidonic acid metabolism, sphingosine metabolism, etc.

Down-regulation of H+-K+-ATPase alpha subunit mRNA and up-regulation of PLA₂ mRNA in gastric tissue of dose group validated the possible mechanisms of G. triterpenes for the treatment of gastric ulcer

Abbreviations used: HP: Helicobacter pylori, ECL: enterochromaffinlike, TCM: Traditional Chinese medicine; HPLC: High Performance Liquid Chromatography, HPLC/MS: High Performance Liquid chromatography Mass Spectrometry, HPLC-TOF-MS: High Performance Liquid Chromatography and Tof Mass Spectrometry, SD: Sprague Dawley, PCDL: Personal Compound Database and Library, MPP: Mass Profiler Professiona; PCA: principal component analysis, RT-PCR: real time polymerase chain reaction, PGE 2: Prostaglandin E2, COX1: cyclooxygenase 1 S1P: Sphingosine-1-phosphate, AA: Arachidonic acid, 5-HT: 5- hydroxytryptamine.

Comprehensive MS and Solid-State NMR Metabolomic Profiling Reveals Molecular Variations in Native Periderms from Four Solanum tuberosum Potato Cultivars

The potato (Solanum tuberosum L.) ranks third in worldwide consumption among food crops. Whereas disposal of potato peels poses significant challenges for the food industry, secondary metabolites in these tissues are also bioactive and essential to crop development. The diverse primary and secondary metabolites reported in whole tubers and wound-healing tissues prompted a comprehensive profiling study of native periderms from four cultivars with distinctive skin morphologies and commercial food uses. Polar and nonpolar soluble metabolites were extracted concurrently, analyzed chromatographically, and characterized with mass spectrometry; the corresponding solid interfacial polymeric residue was examined by solid-state ¹³C NMR. In total, 112 secondary metabolites were found in the phellem tissues; multivariate analysis identified 10 polar and 30 nonpolar potential biomarkers that distinguish a single cultivar among Norkotah Russet, Atlantic, Chipeta, and Yukon Gold cultivars which have contrasting russeting features. Compositional trends are interpreted in the context of periderm protective function.

Chemical and functional characterization of seed, pulp and skin powder from chilto (Solanum betaceum), an Argentine native fruit. Phenolic fractions affect key enzymes involved in metabolic syndrome and oxidative stress

The aim of this work was to assess the nutritional and functional components of powder obtained by lyophilization of whole fruits, seeds, pulp and skin from chilto (Solanum betaceum Cav) cultivated in the ecoregion of Yungas, Argentina. The powders have low carbohydrate and sodium content and are a source of vitamin C, carotenoid, phenolics, potassium and fiber. The HPLC-ESI-MS/MS analysis of the fractions enriched in phenolics allowed the identification of 12 caffeic acid derivatives and related phenolics, 10 rosmarinic acid derivatives and 7 flavonoids. The polyphenols enriched extracts before and after simulated gastroduodenal digestion inhibited enzymes associated with metabolic syndrome, including α-glucosidase, amylase and lipase and exhibited antioxidant activity by different mechanisms. None of the analyzed fruit powders showed acute toxicity or genotoxicity. The powders from the three parts of S. betaceum fruit may be a potential functional food and the polyphenol enriched extract of seed and skin may have nutraceutical properties.

Fragmentation study of major spirosolane-type glycoalkaloids by collision-induced dissociation linear ion trap and infrared multiphoton dissociation Fourier transform ion cyclotron resonance mass spectrometry

RATIONALE

Glycoalkaloids play a key role in the plant protection system against phytopathogens including fungi, viruses, bacteria, insects and worms. They can be toxic to humans if consumed in high concentrations causing gastrointestinal disturbances.

METHODS

The structural characterization of the major spirosolane glycoalkaloids, solasonine, solamargine, α-tomatine and dehydrotomatine, were investigated by positive electrospray ionization (ESI) coupled with a hybrid linear ion trap (LIT) and Fourier transform ion cyclotron resonance (FTICR) mass spectrometer. Tandem mass spectrometric analysis of spirosolane glycoalkaloids was performed by both collision-induced dissociation (CID) within the LIT and infrared multiphoton dissociation (IRMPD) in conjunction with the FTICR cell.

RESULTS

Several common product ions were observed, generated by losses of the sugar moiety or aglycone fragmentation in the B- or E-ring, that can provide information on the accurate mass of aglycone and the primary sequence and branching of the oligosaccharide chains. Thanks to the multistage CID it was possible to understand the fragmentation pathways and thanks to the high resolution of IRMPD-FTICR the elemental compositions of product ions were obtained.

CONCLUSIONS

Because the investigated tandem mass spectra data were acquired with high mass accuracy, unambiguous interpretation and determination of the chemical compositions for the majority of detected fragment ions were feasible. From these data, generalized fragmentation pathways were proposed, providing guidance for the characterization of unknown glycoalkaloids in plants. Copyright © John Wiley & Sons, Ltd.

Spermidine Derivatives in Lulo (Solanum quitoense Lam.) Fruit: Sensory (Taste) versus Biofunctional (ACE-Inhibition) Properties

The bitterness in lulo (Solanum quitoense Lam.) fruit is increased during processing (juicing or drying). To identify the bitter-active compounds, the ethanolic fruit pulp extract was subjected to RP-18 solid-phase extraction, and then sensory-guided fractionated by HPLC. Two spermidine derivatives, N(1),N(4),N(8)-tris(dihydrocaffeoyl)spermidine and N(1),N(8)-bis(dihydrocaffeoyl)spermidine, were isolated and their structures confirmed by analysis of their HPLC-ESI/MS and (1)H and (13)C NMR data. The N(1),N(4),N(8)-tris(dihydrocaffeoyl)spermidine was synthesized and used as an authentic sample to unequivocally confirm the structure of this compound and to quantitate it in both fresh and dried fruit. In silico analyses demonstrated that spermidine derivatives identified in lulo pulp exhibited a strong ACE-I (angiotensin I-converting enzyme) inhibitory activity. Subsequently, these results were confirmed by in vitro analyses and showed the potential use of lulo fruit pulp as an ingredient of functional foods related to the prevention of blood hypertension.

Oolong tea made from tea plants from different locations in Yunnan and Fujian, China showed similar aroma but different taste characteristics

Consistent aroma characteristics are important for tea products. However, understanding the formation of tea aroma flavor and correspondingly proposing applicable protocols to control tea quality and consistency remain major challenges. Oolong tea is one of the most popular teas with a distinct flavor. Generally, oolong tea is processed with the leaves of tea trees belonging to different subspecies and grown in significantly different regions. In this study, Yunnan and Fujian oolong teas, green tea, black tea, and Pu-erh tea were collected from major tea estates across China. Their sensory evaluation, main water-soluble and volatile compounds were identified and measured. The sensory evaluation, total polysaccharide, caffeine, and catechin content of Yunnan oolong tea was found to be different from that of Fujian oolong tea, a result suggesting that the kinds of tea leaves used in Yunnan and Fujian oolong teas were naturally different. However, according to their aroma compounds, principal component analysis (PCA) and cluster analysis (CA) of the volatile compounds showed that the two types of oolong teas were similar and cannot be clearly distinguished from each other; they are also different from green, black, and Pu-erh teas, a result indicating that the same oolong tea processing technology applied to different tea leaves results in consistent aroma characteristics. The PCA analysis results also indicated that benzylalcohol, indole, safranal, linalool oxides, β-ionone, and hexadecanoic acid methyl ester highly contributed to the distinct aroma of oolong tea compared with the other three types of teas. This study proved that the use of the same processing technology on two kinds of tea leaves resulted in a highly consistent tea aroma.

Chemotaxonomic Studies of Nine Gentianaceae Species from Western China Based on Liquid Chromatography Tandem Mass Spectrometry and Fourier Transform Infrared Spectroscopy

INTRODUCTION

Gentianaceae species which widely occur all over the world are used as folk medicine and raw food material with bitter properties. Although comparative analysis on metabolites in several Gentianaceae species has been reported, metabolic similarities used for chemotaxonomic studies are not yet clear.

OBJECTIVE

To systematically characterise the variations of holistic metabolome and characteristic metabolites (iridoid glycosides and phenols) in nine Gentianaceae species from western China.

METHODOLOGY

Fourier transform infrared (FT-IR) spectroscopy was applied to determine the variations of holistic metabolome. A targeted metabolic profiling using liquid chromatography with tandem mass spectrometry (LC-MS/MS) was established for determination of seven characteristic metabolites and identification of their derivatives. Both FT-IR and LC-MS/MS data were subjected to chemometrics analysis for exploring variations in iridoid glycosides and phenols within these species.

RESULTS

Holistic metabolome in genera Gentiana and Swertia was largely different. Diversity of the biosynthetic pathway of iridoid glycosides was also observed in these species. Principal component analysis (PCA) showed a clear separation according to infrageneric classifications of genus Gentiana. Some secondary metabolites, such as mangiferin, rhodenthoside A-C, isoorientin, isovitexin, amarogentin, and swertianolin would serve as potential chemotaxonomic markers to differentiate Gentianaceae species. Furthermore, the accumulation of the six major metabolites seems to depend on geographical regions in Sect. Monopodiae and Sect. Cruciata.

CONCLUSIONS

The combination of LC-MS/MS and FT-IR would provide some potential evidence on chemotaxonomic studies of Gentianaceae. Copyright © 2016 John Wiley & Sons, Ltd.

Potato wound-healing tissues: A rich source of natural antioxidant molecules with potential for food preservation

The need for safe, effective preservatives is a prominent issue in the food and drug industries, reflecting demand for natural alternatives to synthetic chemicals viewed as harmful to consumers and the environment. Thus, this study determined the identities and scavenging capacities of antioxidant metabolites produced as a response to potato tuber wounding, using activity-guided fractionation of polar extracts from a Yukon Gold cultivar that had previously exhibited exceptionally high radical-scavenging activity. Activity-guided fractionation using the ABTS(+) radical scavenging assay and LC-MS with TOF-MS for compositional analysis of the most potent antioxidant fractions yielded identification of nine constituents: coumaroylputrescine; feruloylquinic acid; isoferuloylputrescine; ferulic acid; 22,25-dimethoxy-3-[[2,3,4-tri-O-methyl-6-O-(2,3,4,6-tetra-O-methyl-β-d-glucopyranosyl)-β-d-glucopyranosyl]oxy]-(3β)-lanost-9(11)-en-24-one; 4-(2Z)-2-decen-1-yl-5-[1-(4-hydroxyphenyl)decyl]-1,2-benzenediol; 8-[(2E)-3,7-dimethyl-2,6-octadien-1-yl]-5-hydroxy-2,8-dimethyl-6-(3-methyl-2-buten-1-yl)-2H-1-benzopyran-4,7(3H,8H)-dione; 3-[(2-O-β-d-glucopyranosyl-β-d-glucopyranosyl)oxy]-20-[(6-O-β-d-xylopyranosyl-β-d-glucopyranosyl)oxy]-dammar-24-en-19-al; (3β)-28-oxo-28-(phenylmethoxy)oleanan-3-yl 2-O-β-d-galactopyranosyl-3-O-(phenylmethyl)-, butyl ester β-d-glucopyranosiduronic acid. A positive correlation was observed between the scavenging activities and the polarities of the active fractions. The antioxidant capacities of the fractions were also characterised by monitoring the activity throughout a 45-minute assay period.