Variation of Saponarin Content in Barley Sprouts (Hordeum vulgare L.) by Natural Light Shielding: Implication of the Importance of Light Intensity

Saponarin is a functional metabolite produced by barley sprouts, and the mass production of saponarin by this crop is attractive for dietary supplement manufacturing. Light is the most important environmental factor determining plant growth, survival, and the production of secondary metabolites including flavonoids. This study was conducted to investigate the importance of light intensity for saponarin production in barley sprouts using a hydroponic growth system. Light intensity was manipulated by using shielding treatments to 100, 80, 70, and 50% natural sunlight (NS), and crop cultivation was performed on a monthly cycle. We found that the growth rate and biomass of barley sprouts did not differ in response to the shield treatments, whereas the saponarin content did. The highest saponarin content (i.e., from 1329 to 1673 mg 100 g-1) was observed in the 100% NS treatment, and it gradually decreased as light intensity also decreased. Statistical analysis revealed a significant polynomial relationship of saponarin content with cumulative PPFD (R2 = 76%), implying that the absolute total amount of light exposure over the growth period has a large effect on saponarin productivity in a hydroponic facility. Taken together, our results showed that shielding conditions, which are often unintentionally created by the design of cultivation facilities, can adversely affect saponarin production in barley sprouts. In addition, it was confirmed through our findings that light conditions with at least 70% NS in the cultivation facility enable the production of an amount corresponding to the saponarin content of the sprouts (>1000 mg 100 g-1) produced in the open field. Further studies are needed to investigate the underlying physiological and molecular mechanisms responsible for the relationship of saponarin content with light quantity and quality in barley sprouts.

Lipids and volatile organic compounds in sesame seeds and their relationships with environmental temperature-induced stress

Sesame seeds contain several lipids and fragrances that offer health benefits. However, no studies have reported a relationship between the lipids or flavor compounds of sesame seeds and environmental factors. In this study, we aimed to identify this relationship by analyzing the contents of lipidic and flavor compounds in fifteen genotypes of sesame seeds grown in two cultivation regions (Jeonju and Miryang) and years (2018 and 2019). Herein, 17 lipids and 62 flavor compounds were detected. Multivariate statistical analyses revealed that the cultivation year had a larger influence on the contents of lipidic and flavor compounds than the cultivation region and genotype. Furthermore, heat stress due to high cultivation temperature in 2018 caused the accumulation of sugar and secondary metabolites, increased flavor-related substances, and inhibited the degradation of fatty acids. Our study is the first to demonstrate the metabolic changes in lipids and flavor components of sesame in response to environmental temperature changes affected by different cultivation years. Therefore, this study provides guidance for the cultivation of commercially advantageous sesame seeds in improving the quality of sesame seeds and their products.

Saponarin, a Di-glycosyl Flavone from Barley (Hordeum vulgare L.): An Effective Compound for Plant Defense and Therapeutic Application

Saponarin (SA) is a major di-C-glycosyl-O-glycosyl flavone, which is predominantly accumulated in the young green leaves of barley (Hordeum vulgare L.), with numerous biological functions in plants, such as protection against environmental stresses. Generally, SA synthesis and its localization in the mesophyll vacuole or leaf epidermis are largely stimulated in response to biotic and abiotic stresses to participate in a plant's defense response. In addition, SA is also credited for its pharmacological properties, such as the regulation of signaling pathways associated with antioxidant and anti-inflammatory responses. In recent years, many researchers have shown the potential of SA to treat oxidative and inflammatory disorders, such as in protection against liver diseases, and reducing blood glucose, along with antiobesity effects. This review aims to highlight natural variations of SA in plants, biosynthesis pathway, and SA's role in response to environmental stress and implications in various therapeutic applications. In addition, we also discuss the challenges and knowledge gaps concerning SA use and commercialization.

Cold Plasma Treatment Increases Bioactive Metabolites in Oat (Avena sativa L.) Sprouts and Enhances In Vitro Osteogenic Activity of their Extracts

Cold plasma treatment has been studied to enhance the germination, growth, and bioactive phytochemical production in crops. Here, we aimed to investigate the effects of cold plasma treatment on the growth, bioactive metabolite production, and protein expression related to the physiological and osteogenic activities of oat sprouts. Oat seeds were soaked for 12 h, and then exposed to plasma for 6 min/day for 3 days after sowing. Plasma exposure did not significantly change the growth of oat sprouts; however, increased the content of bioactive metabolites. A single exposure for 6 min on the first day (T-1) increased the content of free amino acids (39.4%), γ-aminobutyric acid (53%), and avenacoside B (23%) compared to the control. Hexacosanol content was the highest in T-3 (6 min exposure on each day for 3 days), 28% higher than that in the control. Oat sprout extracts induced the phosphorylation of adenosine 5'-monophosphate-activated protein kinase and osteoblast differentiation was enhanced by increasing the alkaline phosphatase (ALP) activity; all these effects were induced by plasma treatment. Avenacoside B content was positively correlated with ALP activity (r = 0.911, p < 0.1). These results suggest that plasma treatment has the potential to improve the value of oat sprouts and that it may be used in food fortification to enhance nutritional value for promoting human health.

Elucidation of phenolic metabolites in wheat seedlings (Triticum aestivum L.) by NMR and HPLC-Q-Orbitrap-MS/MS: Changes in isolated phenolics and antioxidant effects through diverse growth times

The current research was characterized on phenolic metabolite profile including six chemical structures (phenolic acid, luteolin, orientin, apigenin, isoscoparin, and tricin) in wheat seedlings using HPLC-Q-Orbitrap-MS/MS and NMR techniques. Our study was also was the first to demonstrate fluctuations of isolated nine phenolic contents and antioxidant properties in various cultivars of this species with different growth times. The antioxidant abilities differed significantly in the 80 % methanol extracts (600 μg/mL) according to cultivar and growth time, with the highest average activities (DPPH: 82 %; ABTS: 87 %) observed after 7 days. The isolated nine compositions exhibited considerable differences in cultivars and growth times, specifically, isoorientin (6) and isochaftoside (8) were observed the most abundant average contents (99.3; 64.3 mg/100 g), representing approximately 28.3 and 18.3 % (total content: 350.8 mg/100 g). Their total phenolics showed the highest rates (420.8 mg/100 g) at 7 days, followed by 9 → 5 → 12 → 14 days with 374.6 → 366.7 → 350.7 → 241.1 mg/100 g, as the rank orders of antioxidant effects. These findings suggest that wheat seedlings may be a potent source of functional agents.

The Potential Neuroprotective Effects of Extracts from Oat Seedlings against Alzheimer's Disease

The physiological or dietary advantages of germinated grains have been the subject of numerous discussions over the past decade. Around 23 million tons of oats are consumed globally, making up a sizeable portion of the global grain market. Oat seedlings contain more protein, beta-glucan, free amino acids, and phenolic compounds than seeds. The progressive neurodegenerative disorder of Alzheimer's is accompanied by worsening memory and cognitive function. A key indicator of this disorder is the unusual buildup of amyloid-beta protein (or Aβ) in human brains. In this context, oat seedling extract (OSE) has been identified as a new therapeutic candidate for AD, due to its antioxidant activity and AD-specific mechanism of action. This study directly investigated how OSE affected AD and its impacts by examining the cognitive function and exploring the inflammatory response mechanism. The dried oat seedlings were grounded finely with a grinder, inserted with 50% fermented ethanol 10 times (w/v), and extracted by stirring for 10 h at 45 °C. After filtering the extract by 0.22 um filter, some of it was used for UHPLC analysis. The results indicated that the treatment with OSE protects against Aβ25-35-induced cytotoxicity in BV2 cells. Tg-5Xfad AD mice had strong deposition of Aβ throughout their brains, while WT mice did not exhibit any such deposition within their brains. A drastic reduction was observed in terms of numbers, as well as the size, of Aβ plaques within Tg-5Xfad AD mice exposed to OSE. This study indicated OSE's neuroprotective impacts against neurodegeneration, synaptic dysfunction, and neuroinflammation induced by amyloid-beta. Our results suggest that OSE acts as a neuroprotective agent to combat AD-specific apoptotic cell death, neuroinflammation, amyloid-beta accumulation, as well as synaptic dysfunction in AD mice's brains. Furthermore, the study indicated that OSE treatment affects JNK/ERK/p38 MAPK signaling, with considerable inhibition in p-JNK, p-p38, and p-ERK levels seen in the brain of OSE-treated Tg-5Xfad AD mice.

Changes in metabolites with harvest times of seedlings of various Korean oat (Avena sativa L.) cultivars and their neuraminidase inhibitory effects

Oats and their seeds, stems, and leaves are approved for use as safe food ingredients. Oat seedlings are environmentally friendly and are becoming increasingly popular as they provide several health benefits. We used the UPLC-CAD to quantitatively analyze isolated compounds (1-11) between 15 cultivars of oat seedlings and their harvest time. Maximum average amount of total contents of isolated compounds was observed after the harvest time of 5 days (4711.3 mg/100 g), while the minimum was observed after the harvest time of 7 days (4184.8 mg/100 g). We demonstrated that all isolated compounds (1-11) showed neuraminidase inhibitory effects, with 6 and 7 being the most active with IC₅₀ values of 3.7 and 20.5 µM, respectively. High content of compounds 6 and 7 was observed (2306.6 mg/100 g) in the Dahan cultivar at 9 days, indicating potential good cultivars with a high content of active compounds and neuraminidase inhibition activity.

Antioxidative Effects of Chrysoeriol via Activation of the Nrf2 Signaling Pathway and Modulation of Mitochondrial Function

Retinal pigment epithelium (RPE) cell dysfunction caused by excessive oxidative damage is partly involved in age-related macular degeneration, which is among the leading causes of visual impairment in elderly people. Here, we investigated the protective role of chrysoeriol against hydrogen peroxide (H₂O₂)-induced oxidative stress in RPE cells. The cellular viability, reactive oxygen species (ROS) generation, and mitochondrial function of retinal ARPE-19 cells were monitored under oxidative stress or pre-treatment with chrysoeriol. The expression levels of mitochondrial-related genes and associated transcription factors were assessed using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Moreover, the protein expression of antioxidant signal molecules was characterized by Western blot analysis. Chrysoeriol significantly increased cell viability, reduced ROS generation, and increased the occurrence of antioxidant molecules in H₂O₂-treated ARPE-19 cells. Additionally, mitochondrial dysfunction caused by H₂O₂-induced oxidative stress was also considerably diminished by chrysoeriol treatment, which reduced the mitochondrial membrane potential (MMP) and upregulated mitochondrial-associated genes and proteins. Chrysoeriol also markedly enhanced key transcription factors (Nrf2) and antioxidant-associated genes (particularly HO-1 and NQO-1). Therefore, our study confirms the protective effect of chrysoeriol against H₂O₂-induced oxidative stress in RPE cells, thus confirming that it may prevent mitochondrial dysfunction by upregulating antioxidant-related molecules.

Identification of anthocyanin compositions in black seed coated Korean adzuki bean (Vigna angularis) by NMR and UPLC-Q-Orbitrap-MS/MS and screening for their antioxidant properties using different solvent systems

The aim of the present research was to investigate the antioxidant properties and anthocyanin profiles in the black seed coated adzuki bean (Vigna angularis, Geomguseul cultivar). The acidic 60% methanol extract (40 μg/mL) contains the highest total phenolic and flavonoid contents (486 ± 3 mg GAE/100 g; 314 ± 10 mg CE/100 g) with potent antioxidant properties (trolox equivalent 1272 ± 26 and 662 ± 24 mg TE/100 g) against ABTS and DPPH radicals compared to other methanol-water ratios (20, 40, 80, and 100%). Ten anthocyanin components were identified in this extract including delphinidin-3,5-O-digalactoside (1), delphinidin-3,5-O-diglucoside (2), delphinidin-3-O-galactoside (3), delphinidin-3-O-glucoside (4), delphinidin-3-O-rutinoside (5), delphinidin-3-O-(p-coumaroyl)glucoside (6), cyanidin-3-O-glucoside (7), petunidin-3-O-galactoside (8), petunidin-3-O-glucoside (9) and petunidin-3-O-(p-coumaroyl)glucoside (10) via NMR spectroscopy and UPLC-Q-Orbitrap-MS/MS analysis. The key anthocyanins 3 and 4 of delphinidin type were isolated by reversed phase C-18 MPLC. Our results indicate that the anthocyanin profiles as well as the high phenolic and flavonoid contents are important factors determining the antioxidant effects of black adzuki bean.

Changes in Beneficial C-glycosylflavones and Policosanol Content in Wheat and Barley Sprouts Subjected to Differential LED Light Conditions

The spectral quality and intensity of light, photoperiodism, and other environmental factors have profound impacts on the metabolic composition of light-dependent higher plants. Hence, we investigate the effects of fluorescent light (96 μmol m-2s-1) and white (100 μmol m-2s-1), blue (100 μmol m-2s-1), and red (93 μmol m-2s-1) light-emitting diode (LED) light irradiation on the C-glycosylflavone and policosanol contents in young seedlings of wheat and barley. Ultra-high-performance liquid chromatography (UHPLC) analyses of C-glycosylflavone contents in barley reveal that the saponarin content is significantly enhanced under blue LED light irradiation. Under similar conditions, isoorientin and isoschaftoside contents are improved in wheat seedlings. The contents of these C-glycosylflavones differed along with the light quality and growth period. The highest accumulation was observed in sprouts after three days under blue LED light irradiation. GC/MS analyses of policosanol contents showed that 1-hexacosanol (C26:o-OH) in barley and 1-octacosanol (C28:o-OH) in wheat seedlings were reduced under LED light irradiation, compared to seedlings under fluorescent light conditions. Nonetheless, the policosanol contents gradually improved with the extension of growth times and treatments, irrespective of the light quality. Additionally, a positive correlation was observed between the expression pattern of biosynthesis-related genes and the respective metabolite content in barley. This study demonstrates that blue LED light irradiation is useful in maximizing the C-glycosylflavone content in barley and wheat sprouts.

Two new secondary metabolites isolated from Avena sativa L. (Oat) seedlings and their effects on osteoblast differentiation

Seedlings of natural crops are valuable sources of pharmacologically active phytochemicals. In this study, we aimed to identify new active secondary metabolites in Avena sativa L. (oat) seedlings. Two new compounds, avenafuranol (1) and diosgenoside (2), along with eight known compounds (3-10) were isolated from the A. sativa L. seedlings. Their chemical structures were elucidated via 1D and 2D NMR spectroscopy, high-resolution ESIMS, IR spectroscopy, optical rotation analysis, and comparisons with the reported literature. The effect of each isolated compound on alkaline phosphatase (ALP) activity for osteoblast differentiation induced by bone morphogenetic protein-2 (BMP-2) was investigated using the C2C12 immortal mouse myoblast cell line. Compounds 1, 4, 6, 8, and 9 induced dose-dependent increases in ALP expression relative to ALP expression in cells treated with only BMP-2, and no cytotoxicity was observed. These results suggest that A. sativa L. seedlings are a natural source of compounds that may be useful for preventing bone disorders.

Discrimination of Adzuki Bean (Vigna angularis) Geographical Origin by Targeted and Non-Targeted Metabolite Profiling with Gas Chromatography Time-of-Flight Mass Spectrometry

As international food trade increases, consumers are becoming increasingly interested in food safety and authenticity, which are linked to geographical origin. Adzuki beans (Vigna angularis) are cultivated worldwide, but there are no tools for accurately discriminating their geographical origin. Thus, our study aims to develop a method for discriminating the geographical origin of adzuki beans through targeted and non-targeted metabolite profiling with gas chromatography time-of-flight mass spectrometry combined with multivariate analysis. Orthogonal partial least squares discriminant analysis showed clear discrimination between adzuki beans cultivated in Korea and China. Non-targeted metabolite profiling showed better separation than targeted profiling. Furthermore, citric acid and malic acid were the most notable metabolites for discriminating adzuki beans cultivated in Korea and China. The geographical discrimination method combining non-targeted metabolite profiling and pareto-scaling showed excellent predictability (Q2 = 0.812). Therefore, it is a suitable prediction tool for the discrimination of geographical origin and is expected to be applicable to the geographical authentication of adzuki beans.

Biofunctional soyasaponin Bb in peanut (Arachis hypogaea L.) sprouts enhances bone morphogenetic protein-2-dependent osteogenic differentiation via activation of runt-related transcription factor 2 in C2C12 cells

Improvement of bone formation is necessary for successful treatment of the bone defects associated with osteoporosis. In this study, we sought to elucidate the osteogenic activity of peanut sprouts and their bioactive components. We found that peanut sprout water extract (PSWE) enhanced bone morphogenetic protein‐2‐mediated osteoblast differentiation in a dose‐dependent manner by stimulating expression of runt‐related transcription factor 2 (Runx2) via activation of AKT/MAP kinases. We identified a major component of PSWE, soyasaponin Bb, as the bioactive compound responsible for improvement of anabolic activity. Soyasaponin Bb from PSWE enhanced expression of the osteogenic transcription factor Runx2 and alkaline phosphatase. The soyasaponin Bb content depended on sprouting time of peanut, and the anabolic action of PSWE was dependent on soyasaponin Bb content. Thus, PSWE and soyasaponin Bb have the potential to protect against bone disorders, including osteoporosis.

Characterization of Soybean Germinated Embryo Extract as an Estrogen Receptor Subtype-Selective and Tissue-Specific Modulator

Phytoestrogens possess beneficial effects in the management of menopausal symptoms with few side effects. Soybeans are major natural sources of isoflavones, with high estrogen receptor (ER)-β selectivity. The objective of this study therefore was to develop a solvent-mediated extraction method for soybean germinated embryos (SGEs) and to investigate the biological activities of the extract. Ethanolic extraction yielded the SGE extract (SGEE), which had a unique composition of biologically active aglycones and soyasaponins. SGEE showed a proliferative effect in MCF7 cells and ERβ-selective transcriptional activities in human embryonic kidney cells. In addition, oral administration of SGEE to ovariectomized rats resulted in the induction of ERβ and estrogen-responsive genes in the uterus and a decrease in tail skin temperature and uterus weight. Our data suggest that germination and ethanolic extraction are effective measures for producing isoflavone-rich food supplements, which may be useful as alternative menopausal hormone therapy.

Comparison of nutritional components (isoflavone, protein, oil, and fatty acid) and antioxidant properties at the growth stage of different parts of soybean [Glycine max (L.) Merrill]

This is the first study to investigate antioxidant capacities of isoflavones prepared using microwave-assisted hydrolysis method from different parts (seeds, leaves, leafstalks, pods, stems and roots) of soybean at growth stages. In addition, the fluctuations in the isoflavone, protein, fatty acid, and oil contents in R6-R8 (R6: beginning; R7: beginning maturity; R8: full maturity) seeds were confirmed. The R7 seeds exhibited the most predominant contents of isoflavones (1218.1±7.3 μg/g) in the following order: daidzein (48%)>genistein (35%)>glycitein (17%). The second highest isoflavone content was found in the leaves (1052.1±10.4 μg/g), followed by R8 seeds>roots>R6 seeds>leafstalks> pods; the stems exhibited the lowest isoflavone content (57.2±1.7 μg/g). Interestingly, daidzein showed the highest individual isoflavone content with remarkable variations (57.2-766.8 μg/g), representing 46-100% of the total isoflavone content. R8 exhibited higher protein, fatty acid, and oil contents than R6 or R7. Moreover, the antioxidant capacities against two radicals in different parts of soybean plant showed considerable differences depending upon the isoflavone content. Our results suggested that soybean leaves and seeds might be useful materials for functional foods.

Changes occurring in nutritional components (phytochemicals and free amino acid) of raw and sprouted seeds of white and black sesame (Sesamum indicum L.) and screening of their antioxidant activities

The present study is the first to investigate the germination properties regarding phytochemicals, amino acids, total phenolics, and antioxidant capacities of white and black sesame seeds. Nutritional components and antioxidant effects showed considerable differences. Sesamine and sesamolin composition decreased (white: 4.21→1.72, 3.57→1.57 mg/g; black: 2.43→0.58, 1.36→0.45 mg/g) during germination. Moreover, catechin displayed the predominant composition in sprouted seeds with values of 13.50 mg/g (white) and 19.09 (black) mg/g followed by (-)-epicatechin and sinapic acid. Total phenolics increased by approximately 4 times upon germination, i.e., 503.1±27.1→ 2085.0±56.7 (white) and 645.8±31.5→2480.1±49.5 (black), mg GAE/g. Amino acids also remarkably increased in sprouted white (7.04→31.69mg/g) and black (6.55→26.97mg/g) seeds, with individual composition occurring in the following order: asparagine>arginine>tryptophan>leucine>alanine. In particular, arginine and tryptophan exhibited the greatest variations. The antioxidant effects against DPPH radical were stronger in sprouted seeds depending on the phytochemicals. Therefore, sprouted sesame can be utilized as an excellent source for functional foods.

Suppression of Akt-HIF-1α signaling axis by diacetyl atractylodiol inhibits hypoxia-induced angiogenesis

Hypoxia-inducible factor (HIF)-1α is a key regulator associated with tumorigenesis, angiogenesis, and metastasis. HIF-1α regulation under hypoxia has been highlighted as a promising therapeutic target in angiogenesis-related diseases. Here, we demonstrate that diacetyl atractylodiol (DAA) from Atractylodes japonica (A. japonica) is a potent HIF-1α inhibitor that inhibits the Akt signaling pathway. DAA dose-dependently inhibited hypoxia-induced HIF-1α and downregulated Akt signaling without affecting the stability of HIF-1α protein. Furthermore, DAA prevented hypoxia-mediated angiogenesis based on in vitro tube formation and in vivo chorioallantoic membrane (CAM) assays. Therefore, DAA might be useful for treatment of hypoxia-related tumorigenesis, including angiogenesis. [BMB Reports 2016; 49(9): 508-513]

Barley Sprouts Extract Attenuates Alcoholic Fatty Liver Injury in Mice by Reducing Inflammatory Response

It has been reported that barley leaves possess beneficial properties such as antioxidant, hypolipidemic, antidepressant, and antidiabetic. Interestingly, barley sprouts contain a high content of saponarin, which showed both anti-inflammatory and antioxidant activities. In this study, we evaluated the effect of barley sprouts on alcohol-induced liver injury mediated by inflammation and oxidative stress. Raw barley sprouts were extracted, and quantitative and qualitative analyses of its components were performed. The mice were fed a liquid alcohol diet with or without barley sprouts for four weeks. Lipopolysaccharide (LPS)-stimulated RAW 264.7 cells were used to study the effect of barley sprouts on inflammation. Alcohol intake for four weeks caused liver injury, evidenced by an increase in serum alanine aminotransferase and aspartate aminotransferase activities and tumor necrosis factor (TNF)-α levels. The accumulation of lipid in the liver was also significantly induced, whereas the glutathione (GSH) level was reduced. Moreover, the inflammation-related gene expression was dramatically increased. All these alcohol-induced changes were effectively prevented by barley sprouts treatment. In particular, pretreatment with barley sprouts significantly blocked inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 expression in LPS-stimulated RAW 264.7. This study suggests that the protective effect of barley sprouts against alcohol-induced liver injury is potentially attributable to its inhibition of the inflammatory response induced by alcohol.

Mangosenone F, A Furanoxanthone from Garciana mangostana, Induces Reactive Oxygen Species-Mediated Apoptosis in Lung Cancer Cells and Decreases Xenograft Tumor Growth

Mangosenone F (MSF), a natural xanthone, was isolated form Carcinia mangotana, and a few studies have reported its glycosidase inhibitor effect. In this study we investigated the anti lung cancer effect of MSF both in vitro and in vivo. MSF inhibited cancer cell cytotoxicity and induced and induced apoptosis via reactive oxygen species (ROS) generation in NCI-H460. MSF treatment also showed in pronounced release of apoptogenic cytochrome c from the mitochondria to the cytosol, downregulation of Bcl-2 and Bcl-xL, and upregulation of Bax, suggesting that caspase-mediated pathways were involved in MSF-induced apoptosis. ROS activation of the mitogen-activated protein kinase signaling pathway was shown to play a predominant role in the apoptosis mechanism of MSF. Compared with cisplatin treatment, MSF treatment showed significantly increased inhibition of the growth of NCI-H460 cells xenografted in nude mice. Together, these results indicate the potential of MSF as a candidate natural anticancer drug by promoting ROS production.

Saponarin from barley sprouts inhibits NF-κB and MAPK on LPS-induced RAW 264.7 cells

Saponarin (SA), a natural flavonoid, is known for its antioxidant and hepatoprotective activities. SA is the predominant compound (1142.7 ± 0.9 mg per 100 g) in barley sprouts, constituting 72% of the total polyphenol content. We investigated, for the first time, the effects of SA from barley sprouts on cellular anti-inflammatory responses. In lipopolysaccharide (LPS)-induced RAW 264.7 macrophages, SA suppressed the activation of NF-κB, as evidenced by the inhibition of NF-κB DNA binding, nuclear translocation, IκBα phosphorylation, and reporter gene expression, and it downregulated the expression of the pro-inflammatory mediator IL-6. Furthermore, SA reduced the transcription of NF-κB target molecules COX2 and FLIP inhibited the phosphorylation of mitogen-activated protein kinases ERK and p38. These results suggest that SA isolated from barley sprouts exerts anti-inflammatory effects in LPS-induced RAW 264.7 macrophages via inhibition of NF-κB, ERK and p38 signaling. Thus, SA may be a promising natural anti-inflammatory agent.

Black rice (Oryza sativa L.) extracts induce osteoblast differentiation and protect against bone loss in ovariectomized rats

Osteoporosis, an age associated skeletal disease, exhibits increased adipogenesis at the expense of osteogenesis from common osteoporotic bone marrow cells. In this study, black rice (Oryza sativa L.) extracts (BRE) were identified as osteogenic inducers. BRE stimulated the alkaline phosphatase (ALP) activity in both C3H10T1/2 and primary bone marrow cells. Similarly, BRE increased mRNA expression of ALP and osterix. Oral administration of BRE in OVX rats prevented decreases in bone density and strength. By contrast, BRE inhibited adipocyte differentiation of mesenchymal C3H10T1/2 cells and prevented increases in body weight and fat mass in high fat diet fed obese mice, further suggesting the dual effects of BRE on anti-adipogenesis and pro-osteogenesis. UPLC analysis identified cyanidin-3-O-glucoside and peonidin-3-O-glucoside as main anti-adipogenic effectors but not for pro-osteogenic induction. In mechanism studies, BRE selectively stimulated Wnt-driven luciferase activities. BRE treatment also induced Wnt-specific target genes such as Axin2, WISP2, and Cyclin D1. Taken together, these data suggest that BRE is a potentially useful ingredient to protect against age related osteoporosis and diet induced obesity.

Identification and Evaluation of Flavone-glucosides Isolated from Barley Sprouts and their Inhibitory Activity against Bacterial Neuraminidase

Neuraminidase (NA) is one of the key enzymes responsible for bacterial infection and pathogenesis. This study aimed to gain deeper insights into the inhibitory effects of flavone-glucosides (1–9) isolated from barley sprouts (BS) on neuraminidase activity. The isolated compounds were identified as, lutonarin (1), saponarin (2), isoorientin (3), orientin (4), isovitexin (5), isoscoparin-7- O-[6-sinapoyl]-glucoside (6), isoscoparin-7- O-[6-feruloyl]-glucoside (7), isovitexin-7- O-[6-sinapoyl]-glucoside (8), and isovitexin-7- O-[6-feruloyl]-glucoside (9). Among them, compounds 1–5 exhibited neuraminidase-inhibitory activities in a dose-dependent manner, with IC50 values ranging from 20.1 to 32.7 μM, in a non-competitive inhibition mode according to kinetic studies. Moreover, the individual flavone-glucoside levels differed notably, in particular, lutonarin (1) and saponarin (2) were shown to be present in the greatest amounts, according to UPLC analysis. Consequently, our results suggest that BS may be utilized as an effective NA inhibitor in human health food, additives, and feed.

Identification and evaluation of flavone-glucosides isolated from barley sprouts and their inhibitory activity against bacterial neuraminidase

Neuraminidase (NA) is one of the key enzymes responsible for bacterial infection and pathogenesis. This study aimed to gain deeper insights into the inhibitory effects of flavone-glucosides (1-9) isolated from barley sprouts (BS) on neuraminidase activity. The isolated compounds were identified as, lutonarin (1), saponarin (2), isoorientin (3), orientin (4), isovitexin (5), isoscoparin-7-O-[6-sinapoyl]-glucoside (6), isoscoparin-7-O-[6-feruloyl]-glucoside (7), isovitexin-7-O-[6-sinapoyl]-glucoside (8), and isovitexin-7-O-[6-feruloyl]-glucoside (9). Among them, compounds 1-5 exhibited neuraminidase-inhibitory activities in a dose-dependent manner, with IC50 values ranging from 20.1 to 32.7 μM, in a non-competitive inhibition mode according to kinetic studies. Moreover, the individual flavone-glucoside levels differed notably, in particular, lutonarin (1) and saponarin (2) were shown to be present in the greatest amounts, according to UPLC analysis. Consequently, our results suggest that BS may be utilized as an effective NA inhibitor in human health food, additives, and feed.

Cyanidin 3-O-glucoside reduces Helicobacter pylori VacA-induced cell death of gastric KATO III cells through inhibition of the SecA pathway

Two key virulence factors of Helicobacter pylori are the secreted virulent proteins of vacuolating toxin A (VacA) and cytotoxin associated protein A (CagA) which lead to damages of gastric epithelial cells. We previously identified that the cyanidin 3-O-glucoside (C3G) inhibits the secretion of both VacA and CagA. In the current report, we show that C3G inhibits VacA secretion in a dose-dependent manner by inhibiting secretion system subunit protein A (SecA) synthesis. As SecA is involved in translocation of bacterial proteins, we predicted that inhibition of the SecA pathway by C3G should decrease H. pylori-induced cell death. To test this hypothesis, the human gastric cell line KATO III cells were co-cultured with H. pylori 60190 (VacA(+)/CagA(+)) and C3G. We found that C3G treatment caused a decrease in activation of the pro-apoptotic proteins caspase-3/-8 in H. pylori-infected cells leading to a decrease in cell death. Our data suggest that consumption of foods containing anthocyanin may be beneficial in reducing cell damage due to H. pylori infection.

Effect of the growth stage and cultivar on policosanol profiles of barley sprouts and their adenosine 5'-monophosphate-activated protein kinase activation

Adenosine 5'-monophosphate-activated protein kinase (AMPK) is an intracellular sensor that can regulate glucose levels within the cell. For this reason, it is well-known to be a target for drugs against diabetes and obesity. AMPK was activated significantly by the hexane extract of barley sprouts. This AMPK activation emerges across the growth stages of the sprout, becoming most significant (3 times above the initial stages) 10 days after sprouting. After this time, the activation decreased between 13 and 20 days post-sprouting. Analysis of the hexane extracts by gas chromatography-mass spectrometry showed that the amounts of policosanols (PCs, which are linear, primary aliphatic alcohols with 20-30 carbons) in the plant dramatically increased between 5 days (109.7 mg/100 g) and 10 days (343.7 mg/100 g) post-sprouting and then levels fell back down, reaching 76.4 mg/100 g at 20 days post-sprouting. This trend is consistent with PCs being the active ingredient in the barley plants. We validate this by showing that hexacosanol is an activator of AMPK. The richest cultivar for PCs was found to be the Daejin cultivar. Cultivars had a significant effect on the total PC content (113.2-183.5 mg/100 g) within the plant up to 5 days post-sprouting. However this dependence upon the cultivar was not so apparent at peak stages of PC production (10 days post-sprouting). The most abundant PC in barley sprout, hexacosanol, contributed 62-80% of the total PC content at every stage. These results are valuable to determine the optimal times of harvest to obtain the highest yield of PCs.

Comparative Studies of Antioxidant Activities and Nutritional Constituents of Persimmon Juice (Diospyros kaki L. cv. Gapjubaekmok)

The objectives of this research were to evaluate antioxidant activities and nutritional components, including phenolic acid, catechin, organic acid, sugar, and amino acid, of persimmon juice from persimmons grown in different regions around Korea. Persimmon (Diospyros kaki) exhibits potent antioxidant effects in DPPH, ABTS, reducing power, and FRAP methods of analysis. The levels of nutritional constituents showed significant differences among all the samples. In particular, tartaric acid, glucose, gallic acid, epicatechin gallate and aspartic acid were observed to be the predominant component for each of their general chemical groups, with total average contents of 1876.51 mg/kg, 62.69 g/kg, 12.73 mg/kg, 208.99 mg/kg, and 31.84 mg/100 g, respectively. Interestingly, persimmons from the Hadong region presented the highest sugar (130.60 g/kg), phenolic acid (42.27 mg/kg), and catechin (527.97 mg/kg) contents in comparison with other regional samples. Moreover, this location exhibited the greatest antioxidant activity with highest total phenolic (298.01 mg GAE/kg) and flavonoid (32.11 mg/kg RE) contents. Our results suggest that strong antioxidant activities of persimmons correlate with high phenolic acid and catechin contents, particularly gallic acid and epicatechin gallate. Additionally, these two compounds may be key factors when considering the useful ingredients of persimmon.

Structural and quantitative analysis of antioxidant and low-density lipoprotein-antioxidant flavonoids from the grains of sugary rice

Grains of sugary rice were extracted with 80% aqueous methanol, and the concentrated extracts were successively partitioned using ethyl acetate, n-butanol, and water. From the n-butanol fractions, four flavonoid glycosides were isolated through repeated silica gel, octadecyl silica gel, and Sephadex LH-20 column chromatographies. Based on the nuclear magnetic resonance, mass spectrometry, and infrared spectroscopic data, the chemical structures of the compounds were determined to be taxifolin-7-O-β-d-glucopyranoside (1), hyperin (2), isoquercitrin (3), and quercetin gentiobioside (4). These compounds were isolated from the grains of sugary rice for the first time. All isolated compounds were tested for antioxidant activity and low-density lipoprotein (LDL)-antioxidative activity using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and LDL assays. Compound 1 exhibited a strong scavenging effect on DPPH, with a 50% inhibition concentration (IC(50)) value of 8.1 μM, and also inhibited LDL oxidation with an IC(50) value of 40.0±20 μM. A simple and efficient high-performance liquid chromatography/diode array detection method for the simultaneous determination of the four bioactive flavonoids (1-4) has been developed and applied to their content determination in the sugary rice. The grains were extracted by 80% methanol, and the contents of 1, 2, 3, and 4 were determined to be 1.12±0.045, 0.65±0.011, 0.68±0.032, and 0.89±0.021 mg/g, respectively.

Inhibitory effects of anthocyanins on secretion of Helicobacter pylori CagA and VacA toxins

Anthocyanins have been studied as potential antimicrobial agents against Helicobacter pylori. We investigated whether the biosynthesis and secretion of cytotoxin-associated protein A (CagA) and vacuolating cytotoxin A (VacA) could be suppressed by anthocyanin treatment in vitro. H. pylori reference strain 60190 (CagA(+)/VacA(+)) was used in this study to investigate the inhibitory effects of anthocyanins; cyanidin 3-O-glucoside (C3G), peonidin 3-O-glucoside (Peo3G), pelargonidin 3-O-glucoside (Pel3G), and malvidin 3-O-glucoside (M3G) on expression and secretion of H. pylori toxins. Anthocyanins were added to bacterial cultures and Western blotting was used to determine secretion of CagA and VacA. Among them, we found that C3G inhibited secretion of CagA and VacA resulting in intracellular accumulation of CagA and VacA. C3G had no effect on cagA and vacA expression but suppressed secA transcription. As SecA is involved in translocation of bacterial proteins, the down-regulation of secA expression by C3G offers a mechanistic explanation for the inhibition of toxin secretion. To our knowledge, this is the first report suggesting that C3G inhibits secretion of the H. pylori toxins CagA and VacA via suppression of secA transcription.

Pterocarpan profiles for soybean leaves at different growth stages and investigation of their glycosidase inhibitions

Soybean leaves are eaten as seasonal edible greens in Korea. Analysis of the ethyl acetate extract of these leaves showed that it exhibited potent and selective neuraminidase inhibition, which began at the R3 stage and peaked at R7. Ten pterocarpans, including the new 6a-hydroxypterocarpan 10, were isolated from soybean leaves and their inhibition activities tested against a range of glycosidases. The relationship between structure and enzyme inhibition was investigated: 6a-hydroxypterocarpans exhibited much higher inhibition against neuraminidase (IC(50) = 2.4-89.4 μM) than α-glucosidase (IC(50) = 90.4- >100 μM). Glyceollin VII (7) displayed 40-fold greater activity (IC(50) = 2.4 μM) against neuraminidase than α-glucosidase (IC(50) = 90.4 μM). On the other hand, coumestanes (1-3) were good α-glucosidase inhibitors (IC(50) = 6.0-42.6 μM). In kinetic analysis, the most potent neuraminidase inhibitors (5-10) were noncompetitive. HPLC analysis indicated that most pterocarpan synthesis began from the R3 stage, and a rapid change of pterocarpan concentrations was observed between the R4 and R7 stages.

Radiosensitization by celastrol is mediated by modification of antioxidant thiol molecules

The radiosensitizing effects of naturally occurring triterpenes were investigated in human lung cancer cells. Several quinone methide-containing triterpenes (QMTs) enhanced the cytotoxic effect of ionizing radiation (IR) and of these QMTs, celastrol (CE) had the greatest enhancing effect on IR-induced cell death in vitro. Additionally, the quinone methide moiety of CE was shown to be essential for CE-mediated radiosensitization; in contrast, dihydrocelastrol (DHCE), does not contain this moiety. Reactive oxygen species (ROS) production by IR was augmented in combination with CE, which was responsible for CE-mediated radiosensitization. CE induced the thiol reactivity and inhibited the activities of antioxidant molecules, such as thioredoxin reductase and glutathione. In vivo, nude mouse xenografting data also revealed that tumor growth delay was greater in mice treated with CE plus IR, compared with those treated with CE or IR alone. When DHCE, instead of CE, was combined with IR, tumor growth delay was similar to that in IR alone-treated mice. These results demonstrate that CE synergistically enhances the effects of IR and suggest the novel anticancer therapeutic use of CE in combination with radiation therapy.

Altered cross-linking of HSP27 by zerumbone as a novel strategy for overcoming HSP27-mediated radioresistance

PURPOSE

HSP27 or HSP25 negatively regulates apoptosis pathways after radiation or chemotherapeutic agents. Abrogation of HSP27 function may be a candidate target for overcoming radio- and chemoresistance.

METHODS AND MATERIALS

Zerumbone (ZER), a cytotoxic component isolated from Zingiber zerumbet smith. Clonogenic survival assay and flow cytometry after Annexin V staining were performed to determine in vitro sensitization effects of ZER with ionizing radiation. A nude mouse xenografting system was also applied to detect in vivo radiosensitizing effects of ZER.

RESULTS

ZER produced cross-linking of HSP27, which was dependent on inhibition of the monomeric form of HSP27. ZER was directly inserted between the disulfide bond in the HSP27 dimer and modified normal HSP27 dimerization. Pretreatment with ZER before radiation inhibited the binding affinity between HSP27 and apoptotic molecules, such as cytochrome c and PKCδ, and induced sensitization in vitro and in an in vivo xenografted nude mouse system. Structural analogs lacking only the carbonyl group in ZER, such as α-humulene (HUM) and 8-hydroxy-humulen (8-OH-HUM), did not affect normal cross-linking of HSP27 and did not induce radiosensitization.

CONCLUSIONS

We suggest that altered cross-linking of HSP27 by ZER is a good strategy for abolishing HSP27-mediated resistance.

Enhancement of radiation sensitivity in lung cancer cells by celastrol is mediated by inhibition of Hsp90

The radiosensitizing activity of celastrol, a quinone methide triterpene was examined. We found that celastrol treatment of the NCI-H460 lung cancer cell line increased radiation-induced cell killing. The increased radiosensitivity was correlated with decreased levels of Hsp90 clients, such as EGFR, ErbB2 and survivin as well as with increased p53 expression. Celastrol inhibited the ATP-binding activity of Hsp90. Furthermore, celastrol treatment dissociated an Hsp90 client protein, EGFR, and this in turn resulted in degradation of the client protein. These results were not observed with another structurally similar triterpenoid, 6β-acetonyl-22β-hydroxytingenol (TG), suggesting that a specific structural feature of the triterpenoid is required for radiosensitization. Moreover celastrol treatment increased p53 levels by phosphorylating Ser15 and Ser20 residues as well as by inhibiting its proteasomal degradation. Celastrol may be considered an effective radiosensitizer acting as an inhibitor of Hsp90 and a p53 activator. The two activities could be applicable to a broad range of cancer cells with either wild-type or mutant p53 because either activity could be effective for the enhancement of radiation cell killing. Further analysis with other triterpenoids should identify the functional moiety of the structure and additional candidates for effective radiosensitizers, which can be used in combined radiotherapy.

Anti-tumor effects by a synthetic chalcone compound is mediated by c-Myc-mediated reactive oxygen species production

Overexpression of c-Myc represents the most frequently deregulated genetic event in cancer, and therefore c-Myc may represent a good molecular target for cancer therapy. The human lung carcinoma cell line, NCI-H1299, shows resistance to conventional cancer treatments, such as ionizing radiation (IR) and cisplatin, while the lung carcinoma cell line, NCI-H460, is sensitive to treatment with these agents. However, when treated with a chalcone compound [toluenesulfonylamido-chalcone, 4'-(p-toluene sulfonyl amino)-3,4-dihydroxy chalcone (TSHDC)], cell death was dramatically induced in NCI-H1299 cells as compared to NCI-H460 cells. TSHDC-mediated cytotoxicity was not dependent on the status of p53 and p21. However, TSHDC exerted increased c-Myc-dependent reactive oxygen species (ROS) production in NCI-H1299 cells in which c-Myc is overexpressed, while increased ROS production did not occur in A549 or NCI-H460 cells with a low c-Myc level. Several colon and brain cancer cells also showed a correlation between c-Myc expression and TSHDC-mediated increased cell death. Tumor regression by TSHDC was more dramatic in NCI-H1299 cells than NCI-H460 cells, when these cells were grafted to nude mice. However, in the case of IR and cisplatin, NCI-H460 cells were more sensitive than NCI-H1299 cells. From these results, c-Myc-mediated ROS production may be a good target for screening of novel cancer drugs and TSHDC might be a good candidate as a cancer drug, specifically in cancer cells that overexpress c-Myc.

Sialylation of integrin beta1 is involved in radiation-induced adhesion and migration in human colon cancer cells

PURPOSE

Previously, we reported that radiation-induced ST6 Gal I gene expression was responsible for an increase of integrin beta1 sialylation. In this study, we have further investigated the function of radiation-mediated integrin beta1 sialylation in colon cancer cells.

METHODS AND MATERIALS

We performed Western blotting and lectin affinity assay to analyze the expression and level of sialylated integrin beta1. After exposure to ionizing radiation (IR), adhesion and migration of cells were measured by in vitro adhesion and migration assay.

RESULTS

IR increased sialylation of integrin beta1 responsible for its increased protein stability and adhesion and migration of colon cancer cells. However, for cells with an N-glycosylation site mutant of integrin beta1 located on the I-like domain (Mu3), these effects were dramatically inhibited. In addition, integrin beta1-mediated radioresistance was not observed in cells containing this mutant. When sialylation of integrin beta1 was targeted with a sulfonamide chalcone compound, inhibition of radiation-induced sialylation of integrin beta1 and inhibition of radiation-induced adhesion and migration occurred.

CONCLUSION

The increase of integrin beta1 sialylation by ST6 Gal I is critically involved in radiation-mediated adhesion and migration of colon cancer cells. From these findings, integrin beta1 sialylation may be a novel target for overcoming radiation-induced survival, especially radiation-induced adhesion and migration.

Evaluation of anti-pigmentary effect of synthetic sulfonylamino chalcone

The 4'-(p-toluenesulfonylamino)-4-hydroxychalcone (TSAHC), which bears inhibitory chemotypes for both alpha-glucosidase and tyrosinase, was evaluated for tyrosinase activity and depigmenting ability relative to compounds designed to only target tyrosianse activity. TSAHC emerged to be a competitive reversible inhibitor of mushroom tyrosinase. More importantly, it was also able to return the melanin content of alpha-melanocyte stimulated by alpha-MSH to base levels unlike other inhibitors that only targeted tyrosinase. The Western blot for expression levels of proteins involved in melanogenesis showed that TSAHC significantly decreased three main tyrosinase related protein in melanin biosynthesis, tyrosinase, TRP-1 and TRP-2.

Tetraspanin TM4SF5 mediates loss of contact inhibition through epithelial-mesenchymal transition in human hepatocarcinoma

The growth of normal cells is arrested when they come in contact with each other, a process known as contact inhibition. Contact inhibition is lost during tumorigenesis, resulting in uncontrolled cell growth. Here, we investigated the role of the tetraspanin transmembrane 4 superfamily member 5 (TM4SF5) in contact inhibition and tumorigenesis. We found that TM4SF5 was overexpressed in human hepatocarcinoma tissue. TM4SF5 expression in clinical samples and in human hepatocellular carcinoma cell lines correlated with enhanced p27Kip1 expression and cytosolic stabilization as well as morphological elongation mediated by RhoA inactivation. These TM4SF5-mediated effects resulted in epithelial-mesenchymal transition (EMT) via loss of E-cadherin expression. The consequence of this was aberrant cell growth, as assessed by S-phase transition in confluent conditions, anchorage-independent growth, and tumor formation in nude mice. The TM4SF5-mediated effects were abolished by suppressing the expression of either TM4SF5 or cytosolic p27Kip1, as well as by reconstituting the expression of E-cadherin. Our observations have revealed a role for TM4SF5 in causing uncontrolled growth of human hepatocarcinoma cells through EMT.

New building block for polyhydroxylated piperidine: total synthesis of 1,6-dideoxynojirimycin

(3R,4S)-3-Hydroxy-4-N-allyl-N-Boc-amino-1-pentene 10, an important precursor for the synthesis of polyhydroxylated piperidines, has been achieved as a single diastereomer without racemization via vinyl Grignard addition to N-Boc-N-allyl aminoaldehyde 9, which was derived from an enantiopure natural amino acid. Having forged a tetrahydropyridine ring scaffold 13 from 10 in 85% yield via RCM using Grubbs II catalyst, we were able to effect its stereodivergent dihydroxylation, via a common epoxide intermediate to yield a range of interesting hydroxylated piperidines, including ent-1,6-dideoxynojirimycin (ent-1,6-dDNJ) 1 (28% overall yield) and 5-amino-1,5,6-trideoxyaltrose 2 (29% over all yield) in excellent dr. To the best of our knowledge, our synthesis of ent-1,6-dDNJ 1 is the most expeditious to date.

Inhibitory effects of Orostachys japonicus extracts on the formation of N-nitrosodimethylamine

In Korea, Orostachys japonicus has been used traditionally as a drug and health food. The aim of this study was to investigate possible inhibitory effects of O. japonicus extracts on the formation of N-nitrosodimethylamines (NDMA). Chloroform extraction was the most effective method for recovering the highest number of phenolic compounds and flavonoids; in these extracts the greatest nitrite-scavenging activity and inhibition of NDMA formation occurred at pH 2.5. The chloroform extract was separated into 10 fractions (J1-J10); fraction J4 inhibited NDMA formation by 90.1 +/- 0.4%. This fraction was then separated into five subfractions (J4-1-J4-5) using a silica gel column. Subfractions J4-2 [(+)-catechin] and J4-4 (3,4-dihdroxybenzoic acid) inhibited NDMA formation by 89.5 +/- 0.9 and 77.6 +/- 0.8%, respectively.

Highly Diastereoselective Epimerization: Stereodivergent Synthesis of α-Hydroxy-β-amino Isopentanoic Acid

The high diastereoselectivity of the base-catalyzed epimerization of oxazolidin-2-ones 7 and 8 is shown to depend on the nature of the N-substituent (R group); when R = Bn, the 4,5-trans-product (4S,5R)-9 is formed, whereas when R = H the 4,5-cis-product (4S,5S)-10 is formed, both with >99:1 dr. The successful hydrolysis of the oxazolidin-2-one group in both cis- and trans-derivatives show this to be a stereodivergent route to enantiopure alpha-hydroxy-beta-amino isopentanoic acids (2R,3S)-1 and (2S,3S)-2.

Sulfonamide chalcone as a new class of alpha-glucosidase inhibitors

Chalcones 1-20, a new class of glycosidase inhibitors, were synthesized, and their glycosidase inhibitory activities were investigated. Non-aminochalcones 1-12 had no inhibitory activity, however, aminochalcones 13-20 had strong glycosidase (alpha-glucosidase, alpha-amylase, and beta-amylase) inhibitory activities. In particular, sulfonamide chalcones 17-20 had more potent alpha-glucosidase inhibitory activity than aminated chalcone 13-16. 4'-(p-Toluenesulfonamide)-3,4-dihydroxy chalcone 20 (IC(50)=0.4microM) was the best inhibitor against alpha-glucosidase, and these sulfonamide chalcones showed non-competitive inhibition.

α-Rhamnosidase inhibitory activities of polyhydroxylated pyrrolidine

We designed and synthesized polyhydroxylated pyrrolidines 1-12 from L-tyrosine, L-phenylalanine, and D-tyrosine through iodine-mediated intramolecular cyclization followed by Woodward-Prevost reaction. The synthetic polyhydroxylated pyrrolidines were identified with structure-based inhibitory activity and selective inhibitory activity against alpha-rhamnosidase. (2S,3S,4R)-deacetyl anisomycin 7 was the best inhibitor among the 12 polyhydroxylated pyrrolidines because it possesses the same stereoconfiguration at C1, C2, C3 as alpha-L-rhamnopyranoside. An investigation into the nature of the inhibition showed that the synthetic pyrrolidines are competitive inhibitors. They also did not have remarkable inhibitory activity against seven glycosidases (alpha-glucosidase, alpha-mannosidase, alpha-amylase, beta-glucosidase, beta-galactosidase, beta-amylase, and invertase).

Stereodivergent Syntheses of Anisomycin Derivatives from d-Tyrosine

[structures: see text] Enantiomerically pure 2-alkyl-3-acetoxy-4-iodopyrrolidines with all groups cis, and all adjacent groups trans (10 and 17), important precursors for the synthesis of pyrrolidinediols, have been prepared from D-tyrosine through regio- and diastereoselective reduction of a vinyl ketone and subsequent iodoamidation controlled by minimization of nonbonding steric interactions. Highly stereodivergent Woodward-Prevost methodology, applied to both iodopyrrolidines, yielded enantiomerically pure (2R,3R,4R)-, (2R,3R,4S)-, and (2R,3S,4R)-deacetylanisomycin (3, 4, and 5), each in excellent de. Incorporation of differential protection of the hydroxyl groups led to a one-pot synthesis of (2R,3R,4R)-anisomycin 2.