Anti-obesity activity of anthocyanin and carotenoid extracts from color-fleshed sweet potatoes.

The anti-obesity effects of anthocyanin and carotenoid extracts from color-fleshed potatoes were studied with 3T3-L1 cells in vitro and high-fat diet (HFD)-induced obese mice in vivo. Treatment of 3T3-L1 adipocytes with anthocyanin and carotenoid extracts, respectively, after differentiation induction significantly inhibited fat accumulation by 63.1 and 83.5%. Studies of adipogenesis inhibition showed that the anthocyanin extract acts at intermediate stages, whereas the carotenoid extract influences all the stages. The extracts significantly diminished triglyceride (TG) content and peroxisome proliferator-activated receptor gamma (PPARγ) protein expression during adipogenesis of the intermediate stage. Oral administration of anthocyanin and carotenoid extracts, respectively, to HFD-fed mice significantly reduced weight gain and restored TG levels to normal or lower as compared to the HFD-fed group with improvement of a lipid profile, TG to HDL-C ratio. Histological differences in liver tissues revealed that the extracts protected the liver tissue from adipogenesis by HFD fed. This research presents the first direct demonstration that the two pigment extracts from sweet potato exhibit anti-obesity activities. PRACTICAL APPLICATIONS: Anthocyanins and carotenoids are the main pigments of purple- and orange-fleshed sweet potatoes, respectively, which are highly nutritious foods with antidiabetic and antioxidant properties. Obesity is a rapidly growing health problem that increases major risk factors of several serious diseases including cardiovascular diseases, diabetes, and cancer. The results of this research suggest that anthocyanin and carotenoid-rich extracts from color-fleshed sweet potatoes may be useful as supplementary ingredients for the treatment of obesity and related diseases.

A new anti-Helicobacter pylori juglone from Reynoutria japonica.

A 70% ethanol extract from the root portion of Reynoutria japonica afforded one new and three known juglone derivatives, namely, 2-methoxy-6-acetyl-7-methyljuglone (1), 2-ethoxy-6-acetyl-7-methyljuglone (2), 2-methoxy-7-acetonyljuglone (3), and 3-acetyl-7-methoxy-2-methyljuglone (4) together with two phenolics (5 and 6), an anthraquinone (7), a stilbene (8) and a phthalide (9). Their structures were elucidated on the basis of comprehensive spectroscopic studies including IR, MS, and 1H, 13C, 2D NMR spectra. Compound 3 is a new compound in nature, and compounds 4-6 have been isolated for the first time from R. japonica. The isolates were evaluated for their antibacterial activity against three strains (43504, 51, and 26695) of Helicobacter pylori. The four isolated juglone derivatives (1-4) showed potent growth inhibitory activity. Among them, compounds 1-3 exhibited stronger inhibitory activity than those of the positive controls, juglone and metronidazole, for the three strains and that of another reference, clarithromycin, for the 43504 and 51 strains. Specifically, the new juglone compound 3 displayed the most potent antibacterial activity against all three strains, 43504, 51, and 26695, with MIC values of 0.06, 0.06 and 0.13 µM, respectively, and MIC50 values of 0.14, 0.11 and 0.15 µM, respectively.

Effect of Volatile Organic Chemicals in Chrysanthemum indicum Linné on Blood Pressure and Electroencephalogram.

This study identified the volatile organic compounds in the essential oils that are extracted from Chrysanthemum indicum Linné (C. indicum Linné) and investigated the effects of the inhalation of these compounds. We detected a total of 41 volatile organic compounds, including 32 hydrocarbons, four acids, three alcohols, two ketones, and one aldehyde. In a sniffing test, seven types of volatile organic compounds were identified. Furthermore, the volatile organic compounds in C. indicum Linné that were identified were found to be derived from 1,8-cineole and camphor. After inhalation of the essential oils, the subjects' systolic blood pressure and heart rate decreased. This indicates that inhalation of the essential oils extracted from C. indicum Linné provides mental and physical relaxation. We examined the changes in electroencephalogram findings that are observed after C. indicum Linné essential oil inhalation. An increase in theta and alpha waves, which usually appear during relaxation, as well as a decrease in beta and gamma waves, which appear during brain activity such as excessive attention, were noted. These results indicate that C. indicum Linné essential oil inhalation helps to reduce blood pressure and may provide mental and physical relaxation.

Type 1 diabetes alters astrocytic properties related with neurotransmitter supply, causing abnormal neuronal activities.

Glutamine synthetase (GS), an astrocytic protein in the brain, mediates the process by which glutamate (Glu) is transformed into glutamine (Gln) during Glu and gamma-aminobutyric acid (GABA) de novo synthesis. There are many types of neural complications related with those neurotransmitters in type 1 diabetes (T1D) patients, but there is little information about the change GS. Therefore, we examined changes in GS activity and expression, as well as the amount of Glu, Gln, and GABA in the brain of a T1D animal model. Using primary culture we found that glucose fluctuation caused glial fibrillary acidic protein (GFAP) and GS changes but constant high glucose level didn׳t. In T1D mouse, GS expression increased in the prefrontal cortex (PFC) and hippocampus (HI), but decreased GS activity was only observed in the HI whereas GFAP expression decreased in both regions. Gln increased in both regions, but Glu and GABA were only increased in the HI of T1D animals where GS activity decreased with higher reactive oxygen/nitrogen species. Collectively, low GS activity may be closely related with high levels of Glu and GABA in the HI of T1D brain, and this would result in abnormal neurotransmissions.

Overexpression of the sweet potato IbOr gene results in the increased accumulation of carotenoid and confers tolerance to environmental stresses in transgenic potato.

In a previous study, we have evidenced that the overexpression of the IbOr gene isolated from sweet potato conferred a tolerance activity against salinity and methyl viologen (MV) treatment in transgenic sweet potato calli along with an enhanced carotenoid content. In this study, to further examine the function of the IbOr gene in heterologous organism, we transformed the IbOr gene into potato under the direction of SWPA2 promoter, a strong inducible promoter upon treatment with various environmental stresses. Consistently with our previous study of sweet potato calli, the level of total carotenoid was elevated up to 2.7-fold (38.1 µg g(-1)DW) compared to the non-transgenic control, Atlantic cultivar. However, the composition of carotenoid was not influenced by the overexpression of the IbOr gene since only pre-existing carotenoids in the non-transgenic control including violaxanthin, lutien and ß-carotene were elevated at a similar level of total carotenoids. In general, the transcript levels for most of carotenogenesis-related genes were elevated in transgenic tuber, whereas they remained at similar levels in transgenic leaf tissues compared to those of non-transgenic controls. The increased levels of carotenoid content in the leaf or tuber tissue of transgenic lines were correlated with the enhanced tolerance activity against salt- or MV-mediated oxidative stresses and DPPH radical-scavenging activity. Our preliminary results suggest that further investigation is required for the development of a crop tolerant to salinity and other environmental stresses through the overexpression of the IbOr gene.

Accumulation of PrLeg, a Perilla legumin protein in potato tuber results in enhanced level of sulphur-containing amino acids.

Potato is the fourth staple food in the world, following rice, wheat, and maize, whereas tubers contain high quality of starch, relatively high amounts of vitamin C and many other important substances. It also contains relatively good quality of protein (about 3 to 6% of the dried weight) and patatin, and 11S globulin is a major storage protein with high level of lysine. However, tuber protein contains relatively low amounts of sulphur-containing amino acids, which may result in low nutritional value. Recently, we cloned a gene encoding PrLeg polypeptide, a seed storage protein from Perilla, which contains relatively higher levels of sulphur-containing amino acids. We transformed PrLeg cDNA into a potato plant to over-express under the direction of the tuber-specific promoter, patatin. Most of the transgenic lines identified through PCR and RT-PCR analyses were able to accumulate high amount of prLeg transcript in their tuber tissue, while very little or no transcript that were detected in their leaf tissues. The level of methionine content was elevated up to three-fold compared to non-transgenic parental line, without any significant changes in other amino acids, suggesting that further research is required to get a deeper insight into their nutritional value.

Antioxidant and antimicrobial activities of ethanol extract from the stem and leaf of Impatiens balsamina L. (Balsaminaceae) at different harvest times.

The aim of this study was to investigate the total phenolic content, total flavonoid contents, antioxidant activity and antimicrobial activity of ethanolic extract from stems (S) and leaves (L) of Impatiens balsamina L. (Balsaminaceae), which were harvested in Korea on March 10, 2011 (S1 and L1), May 14, 2011 (S2 and L2), and July 5, 2011 (S3 and L3), respectively. Our results revealed that the total phenolic (79.55-103.94 mg CE/g extract) and flavonoid (57.43-104.28 mg QE/g extract) contents of leaf extract were higher (p < 0.01) than those of stem extract. Leaf extracts (L1, L2, and L3) exhibited stronger (p < 0.01) free radical scavenging activity (66.06, 63.71, and 72.19%, respectively) than that of the positive control. In terms of antimicrobial activity, leaf extracts showed higher inhibitory effects against microorganisms than those of stem extracts (S1, S2, and S3). Among the leaf extracts at different harvest times, L3 showed the greatest antimicrobial activity against both Gram negative and Gram positive strains. From these results, the leaf extract from I. balsamina L. might be a valuable bioactive resource, and would seem to be applicable as a natural antioxidant in food preservation.

The sweet potato ADP-glucose pyrophosphorylase gene (ibAGP1) promoter confers high-level expression of the GUS reporter gene in the potato tuber.

Molecular farming refers to the process of creating bioengineered plants with the capability of producing potentially valuable products, such as drugs, vaccines, and chemicals. We have investigated the potential of the sweet potato ADP-glucose pyrophosphorylase gene (ibAGP1) promoter and its transit peptide (TP) as an expression system for the mass production of foreign proteins in potato. The ibAGP1 promoter and its TP sequence were transformed into potato along with beta-glucuronidase (GUS) as a reporter gene, and GUS activity was subsequently analyzed in the transgenic potato plants. In tuber tissues, GUS activity in transgenic plants carrying only the ibAGP1 promoter (ibAGP1::GUS) increased up to 15.6-fold compared with that of transgenic plants carrying only the CaMV35S promoter (CaMV35S::GUS). GUS activity in transgenic plants was further enhanced by the addition of the sweetpotato TP to the recombinant vector (ibAGP1::TP::GUS), with tuber tissues showing a 26-fold increase in activity compared with that in the CaMV35S::GUS-transgenic lines. In leaf tissues, the levels of GUS activity found in ibAGP1::GUS-transgenic lines were similar to those in CaMV35S::GUS-lines, but they were significantly enhanced in ibAGP1::TP::GUS-lines. GUS activity gradually increased with increasing tuber diameter in ibAGP1::GUS-transgenic plants, reaching a maximum level when the tuber was 35 mm in diameter. In contrast, extremely elevated levels of GUS activity - up to about 10-fold higher than that found in CaMV35S::GUS-lines - were found in ibAGP1::TP::GUS-transgenic lines at a much earlier stage of tuber development (diameter 4 mm), and these higher levels were maintained throughout the entire tuber developmental stage. These results suggest that the sweetpotato ibAGP1 promoter and its TP are a potentially strong foreign gene expression system that can be used for molecular farming in potato plants.

Molecular and biochemical characterizations of dehydroascorbate reductase from sesame (Sesamum indicum L.) hairy root cultures.

Dehydroascorbate reductase (DHAR) is a biotechnologically or physiologically important reducing enzyme in the ascorbate-glutathione recycling reaction for most higher plants. A DHAR cDNA was isolated from sesame (Sesamum indicum L.) hairy roots, and its structure and biochemical properties were characterized to provide some information about its expressional and biochemical profiles in the hairy root cultures. The cDNA contained a catalytic motif CXXS, which may be indicative of a thiol-dependent redox function. A fusion DHAR expressed in an Escherichia coli expression system was purified with four purification steps until a homogeneous single band signal was seen in an acrylamide gel, and its antibody was prepared for Western blot analyses. The biochemical results showed that the purified recombinant DHAR had an optimal pH of around 6.0, which was different from those (pH 7.8-8.2) of other plant species. The temperature optimal for the DHAR activity was in a relatively wide range of 30-60 degrees C. It was proved by a real-time RT-PCR technique that the transcription activity of the DHAR was about 2-5-fold higher during the first 3 week cultures than during the latter 3 week ones. The highest activity of the sesame DHAR was detected in the 4 week cultures of the hairy roots, after which its activity was rapidly decreased to approximately 80%, suggesting that the most active DHAR occurred in this culture period. Western blot analyses confirmed that the presence of DHAR enzyme was identified in both cultures of the fused E. coli and the sesame hairy roots.