Discovery of steroidal alkaloid metabolites and their accumulation in pigs after short-term tomato consumption

Studies suggest steroidal alkaloids contribute to the health properties of tomato-rich diets. Untargeted studies have detected tomato steroidal alkaloid metabolites in plasma, tissues, and urine, but concentrations remain unknown. Here we utilize UHPLC-MS/MS to characterize 31 steroidal alkaloid metabolites representing 10 unique masses, and a validated UHPLC-MS method to quantify them in blood plasma. In a two-week parallel-arm study, piglets (n = 20) were fed diets containing 10 % tomato powder or a macronutrient-matched control. Concentrations averaged to 107.7 nmol/L plasma, comprising of phase I (66 %) and phase II (4.5 %) metabolites. Primary phase I metabolites were hydroxylated isomers. MS/MS fragments (m/z 253, 271, 289) in conjunction with analysis of diet profile provided higher confidence when identifying hydroxylated metabolites. These results are the first to report quantitative levels of steroidal alkaloid metabolites in plasma, contributing to an understanding of physiologically relevant concentrations. This data is useful for contextualizing research on the health benefits of tomatoes.

Anti-inflammatory and Antioxidant Effect of Lycoperoside H against the 1,2-Dimethyl Hydrazine (DMH) Induced Colorectal Cancer in Rats

In many developed countries, colorectal cancer is a leading cause of morbidity and mortality and its etiology is familiar to be a grouping of nutritional and environmental factors, less physical activity and hereditary factors. Lycoperoside H (LH) is a steroidal alkaloid saponin commonly found in the tomato and exhibited the various pharmacological effects. The aim of the current study was to scrutinized the anticancer effect of LH against 1,2‑Dimethyl Hydrazine (DMH) induced colorectal cancer (CRC) in rats. Subcutaneous injection of DMH (20 mg/kg) was used for induction the CRC and rats were received the oral administration of LH (10, 20 and 40 mg/kg) for 16 weeks. At the end of the investigation, the tumor incidence, weight, and body weight were calculated. Antioxidant enzymes (phase I and II), inflammatory cytokines, lipids and inflammatory markers were all examined. DMH induced rats exhibited the increased tumor incidence, reduced body weight and LH treatment significantly (p < 0.001) suppressed the tumor incidence, and enhanced the body weight. LH treatment significantly (p < 0.001) boosted the level of SOD, GPx, GSH, CAT and suppressed the MDA level. LH treatment suppressed the level cytochrome b5 (Cyto b5), cytochrome P450 (Cyto P450) and boosted the level of glutathione S‑transferase (GST), uridine diphosphoglucuronyltransferase (UDP‑GT) in the liver and colon tissue. LH also decreased the level of cytokines includes interleukin-6 (IL-6), interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α); inflammatory mediators like Inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), prostaglandin (PGE2) and nuclear factor kappa B (NF-κB) in the hepatic and colon tissue. We can conclude that LH revealed the anticancer effect against the DMH induced CRC via suppression of inflammation and oxidative stress.

Decrease of Hyaluronidase Activity and Suppression of Mouse CD4+ T Lymphocyte Activation by Tomato Juice Saponin Esculeoside B, and Its Sapogenol Esculeogenin B

(1) Background: A naturally occurring glycoside, esculeoside B (EsB), has been identified as a major component in juice or canned tomato. We reported how EsB ameliorated mice experimental atopic dermatitis by a decrease in serum IgE levels. However, the underlying immunologic molecular mechanisms are unknown. (2) Methods: The present study tested the effects of EsB on hyaluronidase activity and CD4+ T lymphocyte activation using concanavalin A (ConA)-blast mouse splenocyte primary culture. (3) Results: We found that EsB and its sapogenol esculeogenin B (Esg-B) decreased hyaluronidase activity by a modified Morgan–Elson method. We demonstrated that EsB/Esg-B dose-dependently suppressed T-lymphoproliferation using CFSE-labeled flow-cytometry and water-soluble tetrazolium (WST) assay. Using ELISA and q-PCR methods, EsB/Esg-B suppressed the cytokine secretion and mRNA expression of Th2-relevant IL-4 and Th1-relevant IFN-γ. Moreover, both EsB/Esg-B showed a reduction in IL-10 secretion, but only Esg-B decreased IL-2 secretion. (4) Conclusions: Our study is the first to demonstrate how EsB/Esg-B inhibit hyaluronidase activity and reduce CD4+ T-lymphocyte activation via a reduction in Th2-lymphocyte activity by modulation of Th2/Th1/Treg subunits differentiation.

Lycoperoside H, a Tomato Seed Saponin, Improves Epidermal Dehydration by Increasing Ceramide in the Stratum Corneum and Steroidal Anti-Inflammatory Effect

Tomatoes are widely consumed, however, studies on tomato seeds are limited. In this study, we isolated 11 compounds including saponins and flavonol glycosides from tomato seeds and evaluated their effects on epidermal hydration. Among the isolated compounds, tomato seed saponins (10 µM) significantly increased the mRNA expression of proteins related to epidermal hydration, including filaggrin, involucrin, and enzymes for ceramide synthesis, by 1.32- to 1.91-fold compared with the control in HaCaT cells. Tomato seed saponins (10 µM) also decreased transepidermal water loss by 7 to 13 g/m²·h in the reconstructed human epidermal keratinization (RHEK) models. Quantitative analysis of the ceramide content in the stratum corneum (SC) revealed that lycoperoside H (1–10 µM) is a promising candidate to stimulate ceramide synthesis via the upregulation of ceramide synthase-3, glucosylceramide synthase, and β-glucocerebrosidase, which led to an increase in the total SC ceramides (approximately 1.5-fold) in concert with ceramide (NP) (approximately 2-fold) in the RHEK models. Evaluation of the anti-inflammatory and anti-allergic effects of lycoperoside H demonstrated that lycoperoside H is suggested to act as a partial agonist of the glucocorticoid receptor and exhibits anti-inflammatory effects (10 mg/kg in animal test). These findings indicate that lycoperoside H can improve epidermal dehydration and suppress inflammation by increasing SC ceramide and steroidal anti-inflammatory activity.

Lycoperoside H, a steroidal alkaloid saponin in tomato seeds, ameliorates atopic dermatitis-like symptoms in IL-33 transgenic mice

Tomato seeds contain steroidal saponins called lycoperosides. However, it currently remains unclear whether lycoperosides exert anti-inflammatory or anti-allergic effects. Therefore, we herein investigated the effects of tomato seed extract (TSE) and lycoperoside H (LH) in Interleukin (IL)-33 transgenic mice. TSE (500 mg/kg) or LH (10 mg/kg) was orally administered once a day for 101 days and then evaluated mouse behavior, skin symptoms, and blood and skin inflammatory cytokines. TSE slightly suppressed scratching behavior, while TSE and LH both increased locomotive activity. LH also significantly suppressed inflammation scores in the limbs, and TSE and LH reduced transepidermal water loss. Epidermal hyperplasia and the accumulation of eosinophils and mast cells were decreased by TSE and LH. Skin Th2/Th1 cytokine ratio and serum IgE concentrations were significantly reduced by TSE and LH. The present results suggest that the oral administration of LH derived from tomato seeds effectively ameliorates the symptoms of atopic dermatitis. PRACTICAL APPLICATIONS: It has been reported that tomato seeds contain steroidal saponins, lycoperosides, though the effects of lycoperosides on anti-inflammatory or anti-allergic have not yet been revealed. In this study, we demonstrated that the oral administration of lycoperoside H derived from tomato seeds suppressed atopic dermatitis symptoms in IL-33 transgenic mice.

Identification of Novel Iso-Esculeoside B from Tomato Fruits and LC-MS/MS-Based Food Screening for Major Dietary Steroidal Alkaloids Focused on Esculeosides

Plants from the Solanaceae family are known to be sources of several nutritionally relevant steroidal glycoalkaloids (SGAs). With the aim of quantitatively investigating the occurrence of the main SGA from tomatoes, eggplants, and potatoes in various food samples and evaluating their relevance in the human diet, a rapid single-step extraction liquid chromatography-tandem mass spectrometry method was developed. Over the course of isolating several commercially unavailable SGAs from tomato products to use them as reference standards, a previously unknown derivative was detected, structurally characterized, and identified as a novel isomer of esculeoside B-1 and B-2. After validation of the method, 36 food items exclusively derived from Solanaceae plants were analyzed for their SGA contents and a specific occurrence of each alkaloid in tomato, eggplant, or potato products was revealed. This is the first study reporting quantitative data on the occurrence of esculeoside A, B-1, B-2, and iso-esculeoside B in tomato products obtained by using appropriate reference compounds rather than applying a semi-quantitative approach based on α-tomatine as a reference. Some of the analyzed tomato products contained the esculeosides in concentrations of >500 mg/kg, clearly indicating their relevance in the human diet and the need of investigating their potential bioactivities in the future.

Mass Spectrometry-Based Analysis of Urinary Biomarkers for Dietary Tomato Intake

SCOPE

In this study, the applicability of several β-carboline, imidazole, and steroidal alkaloids as biomarkers for tomato juice intake is evaluated.

METHODS AND RESULTS

Over the course of a 2-week crossover dietary intervention study, 14 volunteers were given low and high doses of tomato juice after 3 days of avoiding tomato-based products. On the day of consumption and the following days, volunteers provided urine samples that were quantitatively analyzed by high-performance liquid chromatography-tandem mass spectrometry. Herein, glucose-derived β-carboline alkaloids are determined as supporting, yet non-specific dietary biomarkers for tomato juice intake. Several imidazole alkaloids represent further biomarkers, which are shown to specifically indicate consumption of tomato juice for 24 h and partly >24 h. Additionally, steroidal alkaloids derived from esculeogenin B are determined to be specific biomarkers for tomato juice detectable for at least 48 h after consumption. The intake of low and high amounts of tomato juice is significantly distinguishable based on the urinary excretion of all determined biomarkers as well.

CONCLUSIONS

The dietary intake of tomato juice is conclusively traceable based on urinary excretion of multiple β-carboline, imidazole, and steroidal alkaloids, and can be determined for up to 48 h after consumption. Furthermore, different intake doses can clearly be distinguished based on their urinary excretion.

A High-Throughput Extraction and Analysis Method for Steroidal Glycoalkaloids in Tomato

Tomato steroidal glycoalkaloids (tSGAs) are a class of cholesterol-derived metabolites uniquely produced by the tomato clade. These compounds provide protection against biotic stress due to their fungicidal and insecticidal properties. Although commonly reported as being anti-nutritional, both in vitro as well as pre-clinical animal studies have indicated that some tSGAs may have a beneficial impact on human health. However, the paucity of quantitative extraction and analysis methods presents a major obstacle for determining the biological and nutritional functions of tSGAs. To address this problem, we developed and validated the first comprehensive extraction and ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) quantification method for tSGAs. Our extraction method allows for up to 16 samples to be extracted simultaneously in 20 min with 93.0 ± 6.8 and 100.8 ± 13.1% recovery rates for tomatidine and alpha-tomatine, respectively. Our UHPLC-MS/MS method was able to chromatographically separate analytes derived from 18 tSGA peaks representing 9 different tSGA masses, as well as two internal standards, in 13 min. Tomato steroidal glycoalkaloids that did not have available standards were annotated using high resolution mass spectrometry as well as product ion scans that provided fragmentation data. Lastly, we utilized our method to survey a variety of commonly consumed tomato-based products. Total tSGA concentrations ranged from 0.2 to 3.4 mg/serving and represent some of the first reported tSGA concentrations in tomato-based products. Our validation studies indicate that our method is sensitive, robust, and able to be used for a variety of applications where concentrations of biologically relevant tSGAs need to be quantified.

Identification of potential human urinary biomarkers for tomato juice intake by mass spectrometry-based metabolomics

PURPOSE

Dietary biomarkers allow the accurate and objective determination of the dietary intake of humans and can thus be valuable for investigating the relation between consumption of foods and biochemical as well as physiological responses. The objective of this study was the identification of potential urinary biomarkers for consumption of tomato juice.

METHODS

In the course of a dietary intervention study, the human urine metabolome of a study cohort was compared between a tomato-free diet and after intake of tomato juice by application of an LC-HRMS-based metabolomics approach. The data acquisition was achieved using an orbitrap mass spectrometer, followed by multistage data processing and univariate as well as multivariate statistical analysis to identify discriminating features.

RESULTS

Statistical analysis revealed several unique features detectable after tomato juice intake. The most discriminating markers were putatively identified as hydroxylated and sulfonated metabolites of esculeogenin B, aglycone of the steroidal glycoalkaloid esculeoside B recently found in tomato juice. Furthermore, the β-carboline alkaloids tangutorid E and F and glucuronidated derivatives thereof were identified in urine.

CONCLUSIONS

Steroidal glycoalkaloids in tomato juice are cleaved after ingestion, and hydroxylated and sulfonated metabolites of their aglycones might serve as urinary biomarkers for tomato juice intake. Similarly, β-carboline alkaloids and glucuronidated derivatives were identified as potential urinary biomarkers. Both the aglycones of the steroidal alkaloids and the β-carboline alkaloids might exhibit biological activities worth investigating.

Recent advances in steroidal saponins biosynthesis and in vitro production

Steroidal saponins exhibited numerous pharmacological activities due to the modification of their backbone by different cytochrome P450s (P450) and UDP glycosyltransferases (UGTs). Plant-derived steroidal saponins are not sufficient for utilizing them for commercial purpose so in vitro production of saponin by tissue culture, root culture, embryo culture, etc, is necessary for its large-scale production. Saponin glycosides are the important class of plant secondary metabolites, which consists of either steroidal or terpenoidal backbone. Due to the existence of a wide range of medicinal properties, saponin glycosides are pharmacologically very important. This review is focused on important medicinal properties of steroidal saponin, its occurrence, and biosynthesis. In addition to this, some recently identified plants containing steroidal saponins in different parts were summarized. The high throughput transcriptome sequencing approach elaborates our understanding related to the secondary metabolic pathway and its regulation even in the absence of adequate genomic information of non-model plants. The aim of this review is to encapsulate the information related to applications of steroidal saponin and its biosynthetic enzymes specially P450s and UGTs that are involved at later stage modifications of saponin backbone. Lastly, we discussed the in vitro production of steroidal saponin as the plant-based production of saponin is time-consuming and yield a limited amount of saponins. A large amount of plant material has been used to increase the production of steroidal saponin by employing in vitro culture technique, which has received a lot of attention in past two decades and provides a way to conserve medicinal plants as well as to escape them for being endangered.