Inhibitory effect of trans-tiliroside on very low-density lipoprotein secretion in HepG2 cells and mouse liver.

An acylated flavonol glycoside, trans-tiliroside (1), is found in certain parts of different herbs, including the seeds of Rosa canina (Rosaceae). Previous studies on compound 1 have focused on triglyceride (TG) metabolism, including its anti-obesity and intracellular TG reduction effects. In the present study, the effects of compound 1 on cholesterol (CHO) metabolism were investigated using human hepatocellular carcinoma-derived HepG2 cells and mice. Compound 1 decreased CHO secretion in HepG2 cells, which was enhanced by mevalonate in a concentration-dependent manner and decreased the secretion of apoprotein B (apoB)-100, a marker of very low-density lipoprotein (VLDL). Compound 1 also inhibited the activity of microsomal triglyceride transfer proteins, which mediate VLDL formation from cholesterol and triglycerides in the liver. In vivo, compound 1 inhibited the accumulation of Triton WR-1339-induced TG in the blood of fasted mice and maintained low levels of apoB-100. These results suggest that compound 1 inhibits the secretion of CHO as VLDL from the liver and has the potential for use for the prevention of dyslipidemia.

A Gedunin-Type Limonoid, 7-Deacetoxy-7-Oxogedunin, from Andiroba (Carapa guianensis Aublet) Reduced Intracellular Triglyceride Content and Enhanced Autophagy in HepG2 Cells.

The seed oil of Carapa guianensis Aublet (Andiroba) has been used in folk medicine for its insect-repelling, anti-inflammatory, and anti-malarial activities. This study aimed to examine the triglyceride (TG) reducing effects of C. guianensis-derived limonoids or other commercially available limonoids in human hepatoblastoma HepG2 cells and evaluate the expression of lipid metabolism or autophagy-related proteins by treatment with 7-deacetoxy-7-oxogedunin (DAOG; 1), a principal limonoid of C. guianensis. The gedunin-type limonoids, such as DAOG (% of control at 20 µM: 70.9 ± 0.9%), gedunin (2, 74.0 ± 1.1%), epoxyazadiradione (4, 73.4 ± 2.0%), 17ß-hydroxyazadiradione (5, 79.9 ± 0.6%), 7-deacetoxy-7α-hydroxygedunin (6, 61.0 ± 1.2%), andirolide H (7, 87.4 ± 2.2%), and 6α-hydroxygedunin (8, 84.5 ± 1.1%), were observed to reduce the TG content at lower concentrations than berberine chloride (BBR, a positive control, 84.1 ± 0.3% at 30 µM) in HepG2 cells pretreated with high glucose and oleic acid. Andirobin-, obacunol-, nimbin-, and salannin-type limonoids showed no effect on the intracellular TG content in HepG2 cells. The TG-reducing effect of DAOG was attenuated by the concomitant use of compound C (dorsomorphin), an AMPK inhibitor. Further investigation on the detailed mechanism of action of DAOG at non-cytotoxic concentrations revealed that the expressions of autophagy-related proteins, LC3 and p62, were upregulated by treatment with DAOG. These findings suggested that gedunin-type limonoids from Andiroba could ameliorate fatty liver, and that the action of DAOG in particular is mediated by autophagy.

Ursane-type triterpene oligoglycosides with anti-hepatosteatosis and anti-hyperlipidemic activity from the leaves of Ilex paraguariensis A. St.-Hil.

The methanol extract from the leaves of Ilex paraguariensis A. St.-Hil. (Aquifoliaceae), popularly known as mate, maté, or yerba maté, inhibits the intracellular triglyceride accumulation in HepG2 cells and suppresses the plasma triglyceride elevation in olive oil-treated mice. Three new triterpene saponins, termed mateosides I (1), II (2), and III (3), were isolated from the extract along with 29 known compounds. The structures of 1-3 were elucidated based on chemical and spectroscopic evidence. Among the isolates, principal saponin constituents, 2 and matesaponins 1 (7) and 2 (9), potently inhibited the triglyceride accumulation in HepG2 cells simultaneously treated with oleic acid and high glucose. In vivo assay of the methanol extract of I. paraguariensis revealed that 7 and 9 showed anti-hyperlipidemic activities in olive oil-treated mice. These results suggested that the saponin constituents of I. paraguariensis could be valuable bioactive marker for the anti-obesogenic activity.

Glucose Tolerance-Improving Activity of Helichrysoside in Mice and Its Structural Requirements for Promoting Glucose and Lipid Metabolism.

An acylated flavonol glycoside, helichrysoside, at a dose of 10 mg/kg/day per os for 14 days, improved the glucose tolerance in mice without affecting the food intake, visceral fat weight, liver weight, and other plasma parameters. In this study, using hepatoblastoma-derived HepG2 cells, helichrysoside, trans-tiliroside, and kaempferol 3-O-ß-D-glucopyranoside enhanced glucose consumption from the medium, but their aglycones and p-coumaric acid did not show this activity. In addition, several acylated flavonol glycosides were synthesized to clarify the structural requirements for lipid metabolism using HepG2 cells. The results showed that helichrysoside and related analogs significantly inhibited triglyceride (TG) accumulation in these cells. The inhibition by helichrysoside was more potent than that by other acylated flavonol glycosides, related flavonol glycosides, and organic acids. As for the TG metabolism-promoting activity in high glucose-pretreated HepG2 cells, helichrysoside, related analogs, and their aglycones were found to significantly reduce the TG contents in HepG2 cells. However, the desacyl flavonol glycosides and organic acids derived from the acyl groups did not exhibit an inhibitory impact on the TG contents in HepG2 cells. These results suggest that the existence of the acyl moiety at the 6'' position in the D-glucopyranosyl part is essential for glucose and lipid metabolism-promoting activities.

Collagen Synthesis-Promoting Effects of Andiroba Oil and its Limonoid Constituents in Normal Human Dermal Fibroblasts.

The seed oil of andiroba (Carapa guianensis, Meliaceae) was found to promote collagen synthesis in normal human dermal fibroblasts. To characterize the active constituents of this oil, the collagen synthesis-promoting activities of 10 principal limonoid constituents, gedunin (1), 6α-acetoxygedunin (2), 7-deacetoxy-7-oxogedunin (3), 7-deacetoxy-7α-hydroxygedunin (4), andirolide H (5), 6α-hydroxygedunin (6), methyl angolensate (7), 17ß-hydroxyazadiradione (8), and carapanosides C (9) and R (10), were examined. Among them, 1-4, 6, 7, and 9 were found to significantly promote collagen synthesis without cytotoxicity at the effective concentrations.

Pomegranate-Derived Polyphenols Reduce Reactive Oxygen Species Production via SIRT3-Mediated SOD2 Activation.

Pomegranate-derived polyphenols are expected to prevent life-style related diseases. In this study, we evaluated the ability of 8 pomegranate-derived polyphenols, along with other polyphenols, to augment SIRT3, a mammalian SIR2 homolog localized in mitochondria. We established a system for screening foods/food ingredients that augment the SIRT3 promoter in Caco-2 cells and identified 3 SIRT3-augmenting pomegranate-derived polyphenols (eucalbanin B, pomegraniin A, and eucarpanin T1). Among them, pomegraniin A activated superoxide dismutase 2 (SOD2) through SIRT3-mediated deacetylation, thereby reducing intracellular reactive oxygen species. The other SIRT3-augmenting polyphenols tested also activated SOD2, suggesting antioxidant activity. Our findings clarify the underlying mechanisms involved in the antioxidant activity of pomegraniin A.

Anti-Glycation Effects of Pomegranate (Punica granatum L.) Fruit Extract and Its Components in Vivo and in Vitro.

Accumulation of advanced glycation end products (AGEs) leads to various diseases such as diabetic complications and arteriosclerosis. In this study, we examined the effect of pomegranate fruit extract (PFE) and its constituent polyphenols on AGE formation in vivo and in vitro. PFE, fed with a high-fat and high-sucrose (HFS) diet to KK-A(y) mice, significantly reduced glycation products such as glycoalbumin (22.0 ± 2.4%), hemoglobin A1c (5.84 ± 0.23%), and serum AGEs (8.22 ± 0.17 µg/mL), as compared to a control HFS group (30.6 ± 2.6%, 7.45 ± 0.12%, and 9.55 ± 0.17 µg/mL, respectively, P < 0.05). In antiglycation assays, PFE, punicalin, punicalagin, ellagic acid, and gallic acid suppressed the formation of AGEs from bovine serum albumin and sugars. In this study, we discuss the mechanism of the antiglycation effects of PFE and its components in vivo and in vitro.

Daily intake of rosehip extract decreases abdominal visceral fat in preobese subjects: a randomized, double-blind, placebo-controlled clinical trial.

BACKGROUND: Obesity has become a great problem all over the world. We repeatedly screened to find an effective food to treat obesity and discovered that rosehip extract shows potent anti-obesity effects. Investigations in mice have demonstrated that rosehip extract inhibits body weight gain and decreases visceral fat. Thus, the present study examined the effect of rosehip extract on human body fat in preobese subjects. METHODS: We conducted a 12-week, single-center, double-blind, randomized, placebo-controlled study of 32 subjects who had a body mass index of ≥25 but <30. The subjects were assigned to two random groups, and they received one tablet of placebo or rosehip that contained 100 mg of rosehip extract once each day for 12 weeks with no dietary intervention. Abdominal fat area and body fat percent were measured as primary outcomes. The other outcomes were body weight and body mass index. RESULTS: Abdominal total fat area, abdominal visceral fat area, body weight, and body mass index decreased significantly in the rosehip group at week 12 compared with their baseline levels (P<0.01) after receiving the rosehip tablet intake, and the decreases in these parameters were significantly higher when compared with those in the placebo group. Additionally, body fat percent tended to decrease compared with the placebo group and their baseline level. Moreover, the abdominal subcutaneous fat area was significantly lower in the rosehip group than in the placebo group at week 12 after the initiation of intake (P<0.05). In addition, there were no abnormalities, subjective symptoms, and findings that may indicate clinical problems during the study period. CONCLUSION: These results suggest that rosehip extract may be a good candidate food material for preventing obesity.

Ellagitannin oligomers and a neolignan from pomegranate arils and their inhibitory effects on the formation of advanced glycation end products.

Two new ellagitannin oligomers, pomegraniins A (7, tetramer) and B (8, pentamer), and a new glucose ester of neolignan, pomegralignan (19), together with six known ellagitannins, were isolated from the arils and pericarps of Punica granatum L. (pomegranate). The structures of the new compounds were elucidated based on spectroscopic analyses and chemical evidence. The known ellagitannins included oligomers such as oenothein B (4), eucalbanin B (5), and eucarpanin T1 (6), in addition to the known ellagitannin monomers such as punicalagin (1), punicalin (2), and punicacortein C (3). This paper therefore represents the first report concerning the isolation of ellagitannin oligomers from pomegranate. Examination of the inhibitory activities of the polyphenolic constituents from pomegranate towards the formation of advanced glycation end products (AGEs) revealed that all ellagitannins tested were more potent inhibitors than aminoguanidine, which was used as a positive control, and pomegraniin A (7) showed the most potent effect.

Rosehip Extract Inhibits Lipid Accumulation in White Adipose Tissue by Suppressing the Expression of Peroxisome Proliferator-activated Receptor Gamma.

Recent studies have shown that Rosa canina L. and tiliroside, the principal constituent of its seeds, exhibit anti-obesity and anti-diabetic activities via enhancement of fatty acid oxidation in the liver and skeletal muscle. However, the effects of rosehip, the fruit of this plant, extract (RHE), or tiliroside on lipid accumulation in adipocytes have not been analyzed. We investigated the effects of RHE and tiliroside on lipid accumulation and protein expression of key transcription factors in both in vitro and in vivo models. RHE and tiliroside inhibited lipid accumulation in a dose-dependent manner in 3T3-L1 cells. We also analyzed the inhibitory effect of RHE on white adipose tissue (WAT) in high-fat diet (HFD)-induced obesity mice model. Male C57BL/6J mice were fed HFD or HFD supplemented with 1% RHE (HFDRH) for 8 weeks. The HFDRH-fed group gained less body weight and had less visceral fat than the HFD-fed group. Liver weight was significantly lower in the HFDRH-fed group and total hepatic lipid and triglyceride (TG) content was also reduced. A significant reduction in the expression of peroxisome proliferator-activated receptor gamma (PPARγ) was observed in epididymal fat in the HFDRH-fed group, in comparison with controls, through Western blotting. These results suggest that downregulation of PPARγ expression is involved, at least in part, in the suppressive effect of RHE on lipid accumulation in WAT.

Tiliroside, a glycosidic flavonoid, inhibits carbohydrate digestion and glucose absorption in the gastrointestinal tract.

SCOPE: Recent studies have reported that tiliroside, a glycosidic flavonoid, possesses anti-diabetic activities. In the present study, we investigated the effects of tiliroside on carbohydrate digestion and absorption in the gastrointestinal tract. METHODS AND RESULTS: This study showed that tiliroside inhibits pancreatic α-amylase (IC50 = 0.28 mM) in vitro. Tiliroside was found as a noncompetitive inhibitor of α-amylase with K(i) values of 84.2 µM. In male ICR mice, the increase in postprandial plasma glucose levels was significantly suppressed in the tiliroside-administered group. Tiliroside treatment also suppressed hyperinsulinemia after starch administration. Tiliroside administration inhibited the increase of plasma glucose levels in an oral glucose tolerance test, but not in an intraperitoneal glucose tolerance test. In human intestinal Caco-2 cells, the addition of tiliroside caused a significant dose-dependent inhibition of glucose uptake. The inhibitory effects of both sodium-dependent glucose transporter 1 (SGLT1) and glucose transporter 2 (GLUT2) inhibitors (phlorizin and phloretin, respectively) on glucose uptake were significantly inhibited in the presence of tiliroside, suggesting that tiliroside inhibited glucose uptake mediated by both SGLT1 and GLUT2. CONCLUSION: These findings indicate that the anti-diabetic effects of tiliroside are at least partially mediated through inhibitory effects on carbohydrate digestion and glucose uptake in the gastrointestinal tract.

Evaluation of risk and benefit in the application of near-infrared spectroscopy to monitor the granule coating process.

The purpose of this article is to study risk and benefit in the application of near-infrared (NIR) spectroscopy to the coating process of granules to monitor the process for determining the coating end point. Cylindrical granules or spherical granules were used as core granules and were coated using a fluidized bed coating apparatus by spraying coating suspension. During the coating run, samples of granules were pulled at regular intervals and amount of talc or lactose, which were the components of the film layer, were estimated by NIR spectroscopy. When the coating layer of granules was thin like the case of the spherical granules, it was possible to monitor and understand the coating process well by an application of NIR spectroscopy, because it was possible to estimate some components in the coating layer simultaneously. However, it was found that as the coating layer became thick like the case of the cylindrical granules, NIR light was scattered by titanium dioxide in the coating layer, and that the increase of the coating layer estimated from NIR spectroscopy showed the misunderstanding saturation. NIR spectroscopy could not be used for the estimation of the granule coating process even if the formulation and amount applied for the coating was same as the spherical granules. When NIR spectroscopy is intended to be used to control granule coating process, it is necessary to check the impacts of the formulation applied for coating, the amount of the coating layer, and the thickness of the coating layer on the estimations.

[Functional saponins in tea flower (flower buds of Camellia sinensis): gastroprotective and hypoglycemic effects of floratheasaponins and qualitative and quantitative analysis using HPLC].

As a part of our characterization studies on the bioactive saponin constituents of tea flowers (Camellia sinensis, flower buds), the methanolic extract and 1-butanol-soluble portion (the saponin fraction) from the flower buds were found to exhibit potent inhibitory effects on ethanol- and indomethacin-induced gastric mucosal lesions in rats and on serum glucose elevation in sucrose-loaded rats. Among the constituents of the 1-butanol-soluble portion, floratheasaponins A, B, and C showed gastroprotective and hypoglycemic activities. Furthermore, we have developed qualitative and quantitative methods using HPLC for the principle saponins, floratheasaponins A-F, in tea flowers, which were previously found to show antiallergic and antiobesity effects. Using those methods, the saponin composition of Indian tea flowers were found to be similar to those of Chinese (Anhui) but not of Japanese tea flowers. On the other hand, it was found that the floratheasaponin contents in tea flowers varied markedly during the blooming period, and they were abundant at half-bloom. Additionally, the contents of caffeine in the tea flowers were examined using HPLC.

Effects of allyl isothiocyanate from horseradish on several experimental gastric lesions in rats.

Allyl isothiocyanate is well known to be a principal pungent constituent of horseradish and an agonist for transient receptor potential (TRP) A1. Ally isothiocyanate markedly inhibited the formation of gastric lesions induced by ethanol (1.5 ml/rat, p.o.), 0.6 M HCl (1.5 ml/rat, p.o.), 1% ammonia (1.5 ml/rat, p.o.), and aspirin (150 mg/kg, p.o.) (ED(50)=1.6, 2.2, 1.7, ca. 6.5 mg/kg, p.o.). It also significantly inhibited the formation of gastric lesions induced by indomethacin (20 mg/kg, p.o.), though the inhibition was ca. 60% at a high dose (40 mg/kg, p.o.). Furthermore, several synthetic isothiocyanate compounds also significantly inhibited ethanol and indomethacin-induced gastric lesions. Whereas, TRPV1 agonists, capsaicin and piperine, inhibited gastric lesions induced by ethanol, 1% ammonia, and aspirin, but had less of an effect on 0.6 M HCl-induced gastric lesions. With regard to mode of action, the protective effects of ally isothiocyanate on ethanol-induced gastric lesions were attenuated by pretreatment with indomethacin, but not with N(G)-nitro-L-arginine methyl ester hydrochloride (L-NAME), or ruthenium red. Pretreatment with indomethacin reduced the protective effects of piperine, and L-NAME reduced the effects of capsaicin and omeprazole. Furthermore, ruthenium red reduced the effects of capsaicin, piperine, and omeprazole. These findings suggest that endogenous prostaglandins play an important role in the protective effect of allyl isothiocyanate in ethanol-induced gastric lesions different from capsaicin, piperine, and omeprazole.

Triterpene saponins with gastroprotective effects from tea seed (the seeds of Camellia sinensis).

Six new triterpene saponins, theasaponins A(1) (1), A(2) (2), A(3) (3), F(1) (4), F(2) (5), and F(3) (6), were isolated from the saponin fraction of the seeds of Camellia sinensis. The stereostructures of 1-6 were elucidated on the basis of chemical and physicochemical evidence. Theasaponin A(2) (2) showed an inhibitory effect on ethanol-induced gastric mucosal lesions in rats at a dose of 5.0 mg/kg, p.o., and its activity was more potent than that of omeplazole. Structure-activity relationships for theasaponins on ethanol-induced gastroprotective activities may be suggested as follows: (1) the 28-acetyl moiety enhances activity; (2) theasaponins having a 23-aldehyde group exhibit more potent activities than those with a 23-hydroxymethyl group or a 23-methoxycarbonyl group.

Bioactive saponins and glycosides. XXIII. Triterpene saponins with gastroprotective effect from the seeds of Camellia sinensis--theasaponins E3, E4, E5, E6, and E7.

The saponin fraction from the seeds of the tea plant [Camellia sinensis (L.) O. KUNTZE (Theaceae)] was found to exhibit potent protective effects on ethanol- and indomethacin-induced gastric mucosal lesions in rats. Five new triterpene saponins, theasaponins E3 (1), E4 (2), E5 (3), E6 (4), and E7 (5), were isolated together with 11 known saponins from the saponin fraction. The chemical structures of 1-5 were elucidated on the basis of chemical and physicochemical evidence. Among the isolated saponins, theasaponins E1 (6), E2 (7), and E5 (3) and assamsaponin C (10) showed an inhibitory effect on ethanol-induced gastric mucosal lesions at a dose of 5.0 mg/kg, p.o. and their activities were stronger than that of omeplazole. With regard to the structure-activity relationships of theasaponins, the following structural requirements for a protective effect on ethanol-induced gastric lesions were suggested; 1) the 21- and/or 22-acyl groups are essential for the activity, 2) acetylation of the 16-hydroxyl group reduce the activity.

Floratheasaponins A-C, acylated oleanane-type triterpene oligoglycosides with anti-hyperlipidemic activities from flowers of the tea plant (Camellia sinensis).

The methanolic extract and its n-butanol-soluble fraction from the flowers of the tea plant (Camellia sinensis) were found to suppress serum triglyceride elevation in olive oil-treated mice. From the n-butanol-soluble fraction, three new acylated oleanane-type triterpene oligoglycosides, floratheasaponins A-C (1-3), were isolated together with several flavonol glycosides and catechins. The structures of 1-3 were elucidated on the basis of chemical and physicochemical evidence as 21-O-angeloyl-22-O-acetyltheasapogenol B 3-O-[beta-D-galactopyranosyl(1-->2)][beta-D-xylopyranosyl(1-->2)-alpha-L-arabinopyranosyl(1-->3)]-beta-D-glucopyranosiduronic acid, 21,22-di-O-angeloyl-R1-barrigenol 3-O-[beta-D-galactopyranosyl(1-->2)][beta-D-xylopyranosyl(1-->2)-alpha-L-arabinopyranosyl(1-->3)]-beta-D-glucopyranosiduronic acid, and 21-O-angeloyl-22-O-2-methylbutyryl-R1-barrigenol 3-O-[beta-D-galactopyranosyl(1-->2)][beta-D-xylopyranosyl(1-->2)-alpha-L-arabinopyranosyl(1-->3)]-beta-D-glucopyranosiduronic acid, respectively. Floratheasaponins (1-3) showed inhibitory effects on serum triglyceride elevation, with their activities being more potent than those of theasaponins E1 (4) and E2 (5) obtained previously from the seeds of C. sinensis.