Cytotoxic major saponin from tomato fruits

Saponin Esculeoside A and Aglycon Esculeogenin A from Ripe Tomatoes Inhibit Dendritic Cell Function by Attenuation of Toll-like Receptor 4 Signaling

Dendritic cells (DCs) can initiate immune response through the presenting antigens to naïve T lymphocytes. Esculeoside A (EsA), a spirosolane glycoside, is reported as a major component in the ripe fruit of tomato. Little is known about the effect of tomato saponin on mice bone marrow-derived DCs. This study revealed that EsA and its aglycon, esculeogenin A (Esg-A), attenuated the phenotypic and functional maturation of murine DCs stimulated by lipopolysaccharide (LPS). We found that EsA/Esg-A down-regulated the expression of major histocompatibility complex type II molecules and costimulatory molecule CD86 after LPS stimulation. It was also determined that EsA-/Esg-A-treated DCs were poor stimulators of allogeneic T-cell proliferation and exhibited impaired interleukin-12 and TNF-α production. Additionally, EsA/Esg-A was able to inhibit TLR4-related and p-NFκB signaling pathways. This study shows new insights into the immunopharmacology of EsA/Esg-A, and represents a novel approach to controlling DCs for therapeutic application.

A BAHD-type acyltransferase concludes the biosynthetic pathway of non-bitter glycoalkaloids in ripe tomato fruit

Tomato is the highest value fruit and vegetable crop worldwide, yet produces α-tomatine, a renowned toxic and bitter-tasting anti-nutritional steroidal glycoalkaloid (SGA) involved in plant defense. A suite of modifications during tomato fruit maturation and ripening converts α-tomatine to the non-bitter and less toxic Esculeoside A. This important metabolic shift prevents bitterness and toxicity in ripe tomato fruit. While the enzymes catalyzing glycosylation and hydroxylation reactions in the Esculeoside A pathway have been resolved, the proposed acetylating step remains, to date, elusive. Here, we discovered that GAME36 (GLYCOALKALOID METABOLISM36), a BAHD-type acyltransferase catalyzes SGA-acetylation in cultivated and wild tomatoes. This finding completes the elucidation of the core Esculeoside A biosynthetic pathway in ripe tomato, allowing reconstitution of Esculeoside A production in heterologous microbial and plant hosts. The involvement of GAME36 in bitter SGA detoxification pathway points to a key role in the evolution of sweet-tasting tomato as well as in the domestication and breeding of modern cultivated tomato fruit.

Content of Two Major Steroidal Glycoalkaloids in Tomato (Solanum lycopersicum cv. Micro-Tom) Mutant Lines at Different Ripening Stages

Esculeoside A and tomatine are two major steroidal alkaloids in tomato fruit (Solanum lycopersicum) that exhibit anti-inflammatory, anticancer, and anti-hyperlipidemia activities. Tomatine contained in immature tomato fruit is converted to esculeoside A as the fruit matures. To develop new tomato varieties based on the content analysis of functional secondary metabolites, 184 mutant lines were generated from the original cultivar (S. lycopersicum cv. Micro-Tom) by radiation breeding. Ultra-performance liquid chromatography coupled with evaporative light scattering detector was used to identify the mutant lines with good traits by analyzing tomatine and esculeoside A content. Compared with the original cultivar, candidates for highly functional cultivars with high esculeoside A content were identified in the mature fruit of the mutant lines. The mutant lines with low and high tomatine content at an immature stage were selected as edible cultivars due to toxicity reduction and as a source of tomatine with various pharmacological activities, respectively. During the process of ripening from green to red tomatoes, the rate of conversion of tomatine to esculeoside A was high in the green tomatoes with a low tomatine content, whereas green tomatoes with a high tomatine content exhibited a low conversion rate. Using methanol extracts prepared from unripe and ripe fruits of the original cultivar and its mutant lines and two major compounds, we examined their cytotoxicity against FaDu human hypopharynx squamous carcinoma cells. Only tomatine exhibited cytotoxicity with an IC₅₀ value of 5.589 μM, whereas the other samples did not exhibit cytotoxicity. Therefore, radiation breeding represents a useful tool for developing new cultivars with high quality, and metabolite analysis is applicable for the rapid and objective selection of potential mutant lines.

Ripe Tomato Saponin Esculeoside A and Sapogenol Esculeogenin A Suppress CD4+ T Lymphocyte Activation by Modulation of Th2/Th1/Treg Differentiation

We report that esculeoside A (EsA), a glycoside and a major component in ripe tomato fruit, ameliorated experimental dermatitis in mice. However, the underlying immunologic molecular mechanisms are unknown. The present study examined its underlying immune nutrition mechanism using concanavalin A (ConA)-blast mouse splenocyte primary culture. We found that EsA and its sapogenol esculeogenin A (Esg-A) concentration-dependently suppressed T-lymphoproliferation using CFSE-labeled flow-cytometry and water-soluble tetrazolium (WST) assay. Using ELISA and q-PCR methods, EsA/Esg-A showed profound decreases in T helper 2 (Th2)-relevant interleukin-4 (IL-4) secretion and mRNA expression, and GATA3 expression. Moreover, EsA/Esg-A suppressed CD4+ T-lymphocyte activation by decreasing IL-2 secretion and mRNA expression and CD25+ cell proportion. Further, EsA/Esg-A alleviated Treg suppressive activity by reducing IL-10 secretion, Foxp3 mRNA expression, and cell numbers. We suggest the immune nutrition function by tomato component, and highlight that EsA/Esg-A are capable of reducing CD4+ T-lymphocyte activation via a reduction in Th2-lymphocyte activity by modulation of Th2/Th1/Treg subunit 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.

Tomato as Potential Source of Natural Additives for Meat Industry. A Review

Tomato industry produces huge amounts of by-products that represent an environmental and economic problem. However, these by-products contain multiple bioactive compounds, which would make them a renewable source for obtaining natural antioxidants and colourants (carotenoids). This is in line with the preferences of the current consumer who demands more natural and healthy products. However, the lipophilic character of carotenoids means that their extraction must be carried out using toxic organic solvents. To overcome environmental and health problems of organic solvents, the application of supercritical fluid extraction (SFE) for the extraction of lipophilic compounds such as lycopene was used successfully, achieving yields similar to those obtained with conventional techniques. Nonetheless, the extraction conditions must be carefully selected, to obtain high yields and at the same time maintain a high antioxidant capacity. On the other hand, the use of tomato and tomato extracts as natural additives in meat products are reduced in comparison with other natural antioxidant/colourant extracts. However, different researches conclude that the use of tomato improved nutritional quality, reduced lipid oxidation and increased stability during the shelf-life period of meat products, while retaining or increasing sensory properties and overall acceptability, which converts tomato by-products into a promising source of natural additives.

Phytoestrogens, phytosteroids and saponins in vegetables: Biosynthesis, functions, health effects and practical applications

Phytoestrogens are non-steroidal secondary metabolites with similarities in structure and biological activities with human estrogens divided into various classes of compounds, including lignans, isoflavones, ellagitannins, coumestans and stilbenes. Similarly, phytosteroids are steroidal compounds of plant origin which have estrogenic effects and can act as agonists, antagonists, or have a mixed agonistic/antagonistic activity to animal steroid receptors. On the other hand, saponins are widely distributed plant glucosides divided into triterpenoid and steroidal saponins that contribute to plant defense mechanism against herbivores. They present a great variation from a structural point of view, including compounds from different classes. In this chapter, the main vegetable sources of these compounds will be presented, while details regarding their biosynthesis and plant functions will be also discussed. Moreover, considering the significant bioactive properties that these compounds exhibit, special focus will be given on their health effects, either beneficial or adverse. The practical applications of these compounds in agriculture and phytomedicine will be also demonstrated, as well as the future prospects for related research.

Competitive Inhibition of Mammalian Hyaluronidase by Tomato Saponin, Esculeoside A

Esculeoside A, a glycoside of spirosolane-type, is identified as a major component in ripe tomato fruits. Our previous study showed that esculeoside A inhibited hyaluronidase activity in vitro and ameliorated experimental dermatitis in vivo. The aim of this present study is to investigate the inhibition mode on mammalian hyaluronidase by esculeoside A. Measured by a modified Morgan-Elson method, the present kinetic analysis of the hydrolysis reaction using hyaluronic acid revealed that no significant difference was observed in velocity maximum Vmax, and Michaelis-Menten constant Km was shown as 0.74 mM in the absence of esculeoside A, was increased as 1.32 and 1.98 mM with 3 and 30 μM of esculeoside A, respectively. Thus suggested that the inhibition mode on hyaluronidase by esculeoside A was competitive. This competitive inhibition on hyaluronidase activity may become valuable in the amelioration of mice experimental dermatitis by esculeoside A.

Anti-hyaluronidase Activity in Vitro and Amelioration of Mouse Experimental Dermatitis by Tomato Saponin, Esculeoside A

The increasing incidence of atopic dermatitis during recent decades has prompted the development of safe and effective agents for prevention of atopic diseases. Esculeoside A, a glycoside of spirosolane type, is identified as a major component in ripe tomato fruits. The present study investigated the effects of esculeoside A and its aglycon esculeogenin A on hyaluronidase activity in vitro and antiallergy in experimental dermatitis mice. Esculeogenin A/esculeoside A (esculeogenin A equivalent) with an IC50 of about 2 μM/9 μM dose-dependently inhibited hyaluronidase activity measured by a modified Morgan-Elson method. Oral treatment with esculeoside A 10 mg/kg of experimental dermatitis mice for 4 weeks significantly decreased the skin clinical score to 2.5 without any detectable side effects compared with 6.75 of the control. The scratching frequency of esculeoside A 100 mg/kg application was decreased significantly as 107.5 times compared with 296.67 times of the control. Thus, the present study showed that esculeoside A/esculeogenin A significantly blocks hyaluronidase activity in vitro and that esculeoside A ameliorates mouse experimental dermatitis.

The bitter side of the nightshades: Genomics drives discovery in Solanaceae steroidal alkaloid metabolism

Steroidal alkaloids (SAs) and their glycosylated forms (SGAs) are toxic compounds largely produced by members of the Solanaceae and Liliaceae plant families. This class of specialized metabolites serves as a chemical barrier against a broad range of pest and pathogens. In humans and animals, SAs are considered anti-nutritional factors because they affect the digestion and absorption of nutrients from food and might even cause poisoning. In spite of the first report on SAs nearly 200 years ago, much of the molecular basis of their biosynthesis and regulation remains unknown. Aspects concerning chemical structures and biological activities of SAs have been reviewed extensively elsewhere; therefore, in this review the latest insights to the elucidation of the SAs biosynthetic pathway are highlighted. Recently, co-expression analysis combined with metabolic profiling revealed metabolic gene clusters in tomato and potato that contain core genes required for production of the prominent SGAs in these two species. Elaborating the knowledge regarding the SAs biosynthetic pathway, the subcellular transport of these molecules, as well as the identification of regulatory and signaling factors associated with SA metabolism will likely advance understanding of chemical defense mechanisms in Solanaceae and Liliaceae plants. It will also provide the means to develop, through classical breeding or genetic engineering, crops with modified levels of anti-nutritional SAs.

A new hemiterpene glycoside from the ripe tomatoes

A new hemiterpene glycoside (1) was isolated from ripe tomatoes (the fruit of Lycopersicon esculentum, Solanaceae) along with eight known compounds. The chemical structure of 1 was determined to be 2-methylbutan-1-ol β-d-glucopyranosyl-(1 → 6)-β-d-glucopyranoside, based on spectroscopic data as well as chemical evidence. In addition, the radical-scavenging activities of the isolated compounds on the free radical of 1,1-diphenyl-2-picrylhydrazyl were examined. Among the tested compounds, tryptophan, 4-O-β-d-glucopyranosyl caffeic acid and dihydro-p-coumaryl alcohol γ-O-β-d-glucopyranoside demonstrated 42.0%, 50.1% and 76.0% scavenging activities, respectively, at a concentration of 0.5 mM.

Bioactivities of glycoalkaloids and their aglycones from Solanum species

Potatoes, tomatoes, and aubergines are all species of the Solanum genus and contain a vast array of secondary metabolites including calystegine alkaloids, phenolic compounds, lectins, and glycoalkaloids. Glycoalkaloids have been the subject of many literature papers, occur widely in the human diet, and are known to induce toxicity. Therefore, from a food safety perspective further information is required regarding their analysis, toxicity, and bioavailability. This is especially important in crop cultivars derived from wild species to prevent glycoalkaloid-induced toxicity. A comprehensive review of the bioactivity of glycoalkaloids and their aglycones of the Solanum species, particularly focused on comparison of their bioactivities including their anticancer, anticholesterol, antimicrobial, anti-inflammatory, antinociceptive, and antipyretic effects, toxicity, and synergism of action of the principal Solanum glycoalkaloids, correlated to differences of their individual molecular structures is presented.

Changes in esculeoside A content in different regions of the tomato fruit during maturation and heat processing

We previously demonstrated that esculeogenin A, a new aglycone of the tomato sapogenol esculeoside A, inhibits both acyl coenzyme A:cholesterol acyl-transferase (ACAT)-1 and -2 and ameliorates the pathogenesis of atherosclerosis in apoE deficient mice. Although we believe that daily intake of esculeoside A from tomato products can play a beneficial role in preventing the pathogenesis of atherosclerosis, the compound is not being used for preventive medicine due to the lack of information on methods for quantitative analysis and the content and stability of the compound in tomato products. In the present study, we report the development of a high-performance liquid chromatography (HPLC) method using an instrument equipped with a refractive index (RI) detector for esculeoside A quantification. We used this method to measure the changes in esculeoside A content during maturation, its distribution in the fruit body, and its stability during the heating process. The contents of esculeoside A in cherry tomatoes and Momotaro tomatoes were 21- and 9-fold, respectively, higher than that of lycopene, which is the most well-known compound in tomatoes. Furthermore, the esculeoside A content in pericarp wall was higher than in the whole tomato fruit and increased in a time-dependent manner during maturation. Although the melting point of purified esculeoside A was 225 °C, the esculeoside A in crude tomato extract decreased in a temperature-dependent manner. Degradation due to the heating process was inhibited under a pH of 9. These results demonstrated that the esculeoside A content differs in the various types of tomatoes, during maturation, and during the heating process used for preservation.

The tomato saponin, esculeoside A

Esculeoside A (2), a spirosolane steroidal glycoside, is a major constituent isolated from Solanum lycopersicum, a commercial strain of mini tomatoes. The content variability of esculeoside A (2) was examined in mini, midi, and Momotaro tomatoes and various processed tomato products. In the green immature tomato fruit, tomatine (1) is oxidized at C-23 and C-27 to produce esculeoside A (2) in the ripe fruit. Further, esculeoside A (2) is partly converted to 3β-hydroxy-5α-pregn-16-en-20-one 3-O-β-lycotetraoside (6), a pregnane glycoside, in the overripe fruit. Esculeogenin A (3), the sapogenol of 2, is easily converted into 3β,16β-dihydroxy-5α-pregn-20-one (17). Metabolic studies showed excretion of androstane derivatives in the urine of human volunteer subjects after tomato consumption. Esculeogenin A (3) inhibited the accumulation of cholesterol esters in macrophages through its effects on acyl-CoA:cholesterol acyl transferase (ACAT). Oral administration of esculeoside A (2) to apoE-deficient mice significantly reduced serum levels of cholesterol, triglycerides, and LDL-cholesterol and ameliorated the severity of atherosclerotic lesions.

Three new aromatic glycosides from the ripe fruit of cherry tomato

Three new aromatic glycosides were isolated from the ripe fruit of cherry tomato [Lycopersicon esculentum var. cerasiforme (Dunal) Alef. (Solanaceae)] along with six known aromatic glycosides and one known steroidal alkaloid glycoside. Their chemical structures were determined on the basis of spectroscopic data as well as chemical evidence.

C22 isomerization in alpha-tomatine-to-esculeoside A conversion during tomato ripening is driven by C27 hydroxylation of triterpenoidal skeleton

Compositional analysis by liquid chromatography/mass spectrometry of triterpenoid glycosides in different tomato cultivars, ripening stages, and parts of fruits showed that alpha-tomatine was generally most abundant in the flesh of the mature green stage, whereas esculeoside A was predominant in that of the red ripe stage. The sum of these glycoalkaloids was more or less constant, suggesting that alpha-tomatine is converted to esculeoside A during ripening. Besides various substitutions, the C22alphaN --> C22betaN isomerization is an important step in this transformation. By quantum chemical calculations it was shown that hydroxylation at C27 of the triterpenoidal skeleton is the driving force behind the isomerization. For the protonated form of the glycoalkaloid (predominant at the pH of tomato tissue), the C22betaN configuration becomes more favorable than that of C22alphaN, through the extra energy provided by the hydrogen bond between the protonated nitrogen and the lone pair of the oxygen of the C27-OH.

Involvement of ethylene in the accumulation of esculeoside A during fruit ripening of tomato (Solanum lycopersicum)

The composition of glycoalkaloids in tomato fruit changes with ripening. However, it has not been clarified whether the accumulation of glycoalkaloids is controlled by the ripening-inducing phytohormone, ethylene. Here, we report the effect of ethylene on the accumulation of tomato fruit glycoalkaloids. We investigated the effect of exogenously applied ethylene. In response to ethylene treatment, the content of alpha-tomatine decreased, whereas the content of esculeoside A increased. Next, we analyzed the fruits of ripening mutants, rin, nor, and Nr. In fruits of these mutant lines, the level of accumulation of esculeoside A decreased, whereas alpha-tomatine accumulated to higher levels than in wild-type fruit. These results demonstrated that the esculeoside A accumulation was associated with production and perception of ethylene. Additionally, the accumulation profiles of the intermediate metabolites of esculeoside A biosynthesis in ripening mutant fruits suggest that a glycosylation step in the putative pathway from alpha-tomatine to esculeoside A depends on ethylene.

Esculeogenin A, a new tomato sapogenol, ameliorates hyperlipidemia and atherosclerosis in ApoE-deficient mice by inhibiting ACAT

OBJECTIVE

We recently identified esculeoside A, a new spirosolane-type glycoside, with a content in tomatoes that is 4-fold higher than that of lycopene. In the present study, we examined the effects of esculeoside A and esculeogenin A, a new aglycon of esculeoside A, on foam cell formation in vitro and atherogenesis in apoE-deficient mice.

METHODS AND RESULTS

Esculeogenin A significantly inhibited the accumulation of cholesterol ester (CE) induced by acetylated low density lipoprotein (acetyl-LDL) in human monocyte-derived macrophages (HMDM) in a dose-dependent manner without inhibiting triglyceride accumulation, however, it did not inhibit the association of acetyl-LDL to the cells. Esculeogenin A also inhibited CE formation in Chinese hamster ovary cells overexpressing acyl-coenzymeA (CoA): cholesterol acyl-transferase (ACAT)-1 or ACAT-2, suggesting that esculeogenin A suppresses the activity of both ACAT-1 and ACAT-2. Furthermore, esculeogenin A prevented the expression of ACAT-1 protein, whereas that of SR-A and SR-BI was not suppressed. Oral administration of esculeoside A to apoE-deficient mice significantly reduced the levels of serum cholesterol, triglycerides, LDL-cholesterol, and the areas of atherosclerotic lesions without any detectable side effects.

CONCLUSIONS

Our study provides the first evidence that purified esculeogenin A significantly suppresses the activity of ACAT protein and leads to reduction of atherogenesis.

Distinction of Absolute Configuration at C-22 of C-23-Hydroxyspirostane and C-23-Hydroxyspirosolane Glycosides

It has been revealed that the absolute configurations at C-22 of 23-hydroxyspirostane and 23-hydroxyspirosolane could be unambiguouly judged by the (1)H- and (13)C-NMR spectroscopies.

A liquid chromatography-mass spectrometry-based metabolome database for tomato

For the description of the metabolome of an organism, the development of common metabolite databases is of utmost importance. Here we present the Metabolome Tomato Database (MoTo DB), a metabolite database dedicated to liquid chromatography-mass spectrometry (LC-MS)- based metabolomics of tomato fruit (Solanum lycopersicum). A reproducible analytical approach consisting of reversed-phase LC coupled to quadrupole time-of-flight MS and photodiode array detection (PDA) was developed for large-scale detection and identification of mainly semipolar metabolites in plants and for the incorporation of the tomato fruit metabolite data into the MoTo DB. Chromatograms were processed using software tools for mass signal extraction and alignment, and intensity-dependent accurate mass calculation. The detected masses were assigned by matching their accurate mass signals with tomato compounds reported in literature and complemented, as much as possible, by PDA and MS/MS information, as well as by using reference compounds. Several novel compounds not previously reported for tomato fruit were identified in this manner and added to the database. The MoTo DB is available at http://appliedbioinformatics.wur.nl and contains all information so far assembled using this LC-PDA-quadrupole time-of-flight MS platform, including retention times, calculated accurate masses, PDA spectra, MS/MS fragments, and literature references. Unbiased metabolic profiling and comparison of peel and flesh tissues from tomato fruits validated the applicability of the MoTo DB, revealing that all flavonoids and alpha-tomatine were specifically present in the peel, while several other alkaloids and some particular phenylpropanoids were mainly present in the flesh tissue.

Metabolism of Tomato Steroidal Glycosides in Humans

Pregnane glycosides have been isolated in small amounts, along with the major components furostanol and spirostanol glycosides, from Dioscoreaceae, Taccaceae, and Solanaceae, suggesting that pregnane glycosides might be biosynthesized from furostanol and spirostanol glycosides. Recently, commercial natural foods composed of diosgenin have been used for the treatment of diseases such as osteoporosis and premenstrual syndrome in women. It is anticipated that diosgenin would be metabolized into a type of steroidal hormone, for instance progesterone, however, this metabolism has not been confirmed. Therefore, we have examined the metabolites in the urine of subjects who ingested tomatoes, which contain a considerable amount of the steroidal glycoside esculeoside A. The occurrence of steroidal hormones in the metabolites has been recognized. It has been proven that when a steroidal glycoside is administered, it is partly metabolized into a type of steroidal hormone exhibiting various physiological activities.

Steroidal Alkaloid Glycosides, Esculeosides C and D, from the Ripe Fruit of Cherry Tomato

Two new steroidal alkaloid glycosides, esculeosides C and D, have been isolated from the ripe fruit of Cherry tomato [Lycopersicon esculentum var. cerasiforme (DUNAL) ALEF.], along with three known steroidal alkaloid glycosides, esculeoside A, esculeoiside B, and lycoperoside G. Their chemical structures were determined on the basis of spectroscopic data.

Tomato New Sapogenols, Isoesculeogenin A and Esculeogenin B

Two novel sapogenols, isoesculeogenin A (1) and esculeogenin B (2) of steroidal alkaloid glycosides, lycoperoside F and esculeoside B, respectively, isolated from the ripe tomato have been characterized as (5alpha,22R,23R,25S)-3beta,23,27-trihydroxyspirosolane and (5alpha,22S,23R,25S)-22,26-epimino-16beta,23-epoxy-3beta,23,27-trihydroxycholestane, respectively.

A New Tomato Pregnane Glycoside from the Overripe Fruits

A new pregnane glycoside has been isolated from the overripe fruits of Cherry tomato (Mini tomato), Lycopersicon esculentum var. cerasiforme (DUNAL) ALEF. The structure was determined to be 3-O-beta-lycotetraosyl 3beta-hydroxy-5alpha-pregn-16-en-20-one on the basis of spectroscopic analysis. The seasonal variation of the tomato saponin is discussed.

Biological activities and distribution of plant saponins

Plant saponins are widely distributed amongst plants and have a wide range of biological properties. The more recent investigations and findings into their biological activities were summarized. Isolation studies of saponins were examined to determine which are the more commonly studied plant families and in which families saponins have been identified.

[Search for functions of natural oligoglycosides--Solanaceae and Leguminosae origin glycosides]

Our extensive investigation of the isoprenoidal glycosides in Solanaceae and Leguminosae folk medicines to verify their effectiveness, antiherpes and anti-HSV-1 activities, and hepatoprotective action has resulted in the elucidation of their structure-activity relationships. We present the respective optimum models here.

Steroidal alkaloid glycosides from tomato (Lycopersicon esculentum)

Three new steroidal alkaloid glycosides, lycoperosides F-H (1-3), were isolated from tomato fruits (Lycopersicon sculentum) along with lycoperosides A-D, esculeoside A, and rutin. The structures of these glycosides were characterized as the 3-O-beta-lycotetraosides of 23(R)-23-acetoxy-27-hydroxy-27-O-beta-d-glucopyranosyltomatidine (1), (23S,24R)-23-acetoxy-24-O-beta-d-glucopyranosylsoladulcidine-24-ol (2), and 22-isopimpifolidine (3), by means of their spectroscopic data. Also obtained was the new natural product lycoperodine-1 (4).