Saponarin Content Research Articles

Effect of Abiotic Signals on the Accumulation of Saponarin in Barley Leaves in Hydroponics Under Artificial Lights.

Functional flavonoid production is a new agenda in the agricultural industry, and young barley leaves (YBL) are one of the highlighted crops due to their health-beneficial flavonoid, saponarin. For the year-round cultivation of a high saponarin content of YBL, abiotic signal effects on the biosynthesis and metabolism in YBL need to be understood clearly. In this research, the effects of reactive oxygen species (ROS)-related abiotic signals, such as light, potassium, and sodium, were investigated on the biosynthetic metabolism in YBL cultivation under artificial lights. A higher quantity of blue-rich white light (6500 K of light temperature) irradiation enhanced ROS levels and the related enzyme activities (APX and CAT), as well as photosynthesis and saponarin amount, while red-rich white light (3000 K of light temperature) increased the photosynthesis only. In addition, 1.0 g L-1 K+ treatment in water slightly reduced ROS levels and increased saponarin accumulation in YBL. These blue-rich light and K+ supplemental conditions relatively increased OGT expression and reduced 4-coumaric acid and isovitexin as saponarin precursors. Furthermore, the relative ratio of lutonarin as an oxidized product of saponarin increased in increments of light quantity. Finally, the abiotic conditions for saponarin production were optimized with the mixture solution treatment of 1.0 g L-1 Na+ and 1.0 g L-1 K+ under 500 PPFD of 6500 K light, and the saponarin amount per leaf was 219.5 μg plant-1; it was comparable amount with that under sunlight condition.

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.

Influence of Different Growth Conditions on Saponarin, Water-Soluble Vitamins, and Mineral Content of Barley Sprouts Cultivated in Chamber System

Barley sprouts contain various secondary metabolites such as polyphenol, policosanol, and γ-aminobutyric acid (GABA). In particular, saponarin, which accounts for about 72% of polyphenols, is well known for antioxidant, anti-inflammatory, and liver function protection effects. Saponarin is greatly affected by environmental conditions such as light, temperature, and moisture. However, there is a lack of studies about the effect of the microclimatic environment on saponarin content in barley sprouts. This study was conducted to evaluate the influence of daily temperature range, light intensity, and light period on saponarin, water-soluble vitamins, and minerals content in barley sprouts. Seeds of Hordeum vulgare L. were sown on a plastic box and cultivated in growth chambers with different conditions by adjusting daily temperature range (DT, 0 → 10°C), light intensity (LI, 120 → 180 µmol m-2 s-1), and light period (LP, day 12 hours → day 18 hours). The plants were harvested when the leaf length reach 15 cm. The fresh weight was not significantly different between each treatment, yet the growth period was highest in barley sprouts cultivated with DT. Saponarin content was higher in DT, LI and LP than control, and highest saponarin content in DT. In contrast, vitamin C content was highest in control and lowest in DT. Similarly, vitamin B1 and B5 content showed the highest in control. Changes in light and temperature elevated saponarin content in barley sprouts, especially daily temperature range showed a dramatic increase. However, the change in daily temperature range affects an increase in growth period and a decrease in vitamin C content. In conclusion, daily temperature range is the predominant environmental factor to produce saponarin-enriched barley sprouts.Different response of saponarin and vitamin C in barley sprouts to change in daily temperature range.

Decisive Climatic Factors for Production of Bioactive Saponarin-Rich Barley Sprouts: A Study of Seasonal Effect

Saponarin content in barley sprouts may vary greatly with environmental conditions, such as climate, leading to difficulty in uniformly producing saponarin-rich barley sprouts in situ farmlands throughout the year. This research was an early attempt to identify the optimal conditions of various climatic factors, such as temperature, light, and humidity according to seasonal change, for maximizing the saponarin content of sprouted barley through the two-year field experiment. As a result, the growth index, as leaf length relative to growth period, of barley sprouts varied greatly with sowing time, and they tended to decrease with an increase in the ambient temperature, such as average daily temperature. In contrast, higher saponarin contents were observed in the sprouts collected in March, April, September, and October than those collected from May to August. We also found significantly positive correlations of saponarin content with daily temperature range and average light period, indicating that they could be decisive climatic factors for the production of barley sprouts with a higher saponarin content. Interestingly, the polynomial relationship between saponarin yield and leaf length showed the highest yield with 2.18 mg plant−1 at 15.9 cm in length, suggesting a best cutting time for the production of saponarin-rich barely sprouts based on the leaf length. Overall, the decisive climatic factors according to seasonal change for saponarin biosynthesis may be considered to be daily temperature differences and light hours.

Correlation of saponarin content with biosynthesis-related gene expression in hulled and hulless barley (Hordeum vulgare L.) cultivars

Correlation of saponarin content with biosynthesis-related gene expression in hulled and hulless barley (<i>Hordeum vulgare</i> L.) cultivars

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.

Variations of Saponarin Content in Young Barley Leaves Illuminated with Different Light-Emitting Diodes (LEDs)

In this study, the effect of light on the regulation of flavonoid production in young barley leaves (YBLs) was investigated. YBLs following germination were illuminated with different light-emitting diode (LED) lights, i.e. blue, red, far-red light, along with fluorescence and dark conditions as controls, and as the main flavonoid, saponarin content of YBLs was analyzed quantitatively with HPLC. In addition, the antioxidant activities of the crude ethanoic extracts of YBLs were analyzed by several antioxidant assays. The content of saponarin in blue light-illuminated barley leaves is two or three times higher than those in barley leaves with other lighting conditions, i.e. red, far-red, and the content with fluorescence and even dark conditions as controls. However, the levels of saponarin among the leaves illuminated with other lighting systems show no significant difference. And, the antioxidant potentials of the extracts of YBLs demonstrated same tendency shown in saponarin levels. Our results suggested that blue lighting conditions might evoke the photoprotection changes in YBLs, leading elevated level of saponarin, consequently increasing their antioxidant potentials.

Model Examination for the Effect of Treading Stress on Young Green Barley (&amp;lt;i&amp;gt;Hordeum vulgare&amp;lt;/i&amp;gt;)

Treading barley (“Mugifumi” in Japanese) is a barley culturing process that is unique and indispensable in Japan. Generally, roller machines or human feet are used to tread young barley several times (Figure 1). As a model examination, a stainless steel instrument was used for treading barley in this study (Figure 2(a)). Treading damages plants and decreases growth, such as the height and weight of aerial parts, which then recover gradually. In our study, the total amino acid contents increased with the treading stress. The treading stress induced a 1.7-fold increase in aspartic acid contents and an approximately 1.6-fold increase in glutamic acid, proline, cystine, and methionine contents. Isolation and purification suggested that the main components of the methanol-eluted fraction from the young green barley were six known phenolic compounds. Saponarin and lutonarin were the main components. The saponarin content was about 160 mg/g (methanol-soluble fraction) at 10 days after germination. We found that the higher antioxidant activity was due to the increased lutonarin/saponarin ratio from 10% to 24%. Therefore, our results suggest that treading stress is useful for young green barley.

Developmental Changes in Flavonoids and Enzyme Activities of Primary Leaves from Field-Grown Barley

C-glycosylflavone levels, fresh weight, soluble protein, and activities of eight enzymes of phenolic and general metabolism were investigated in primary leaves of field-grown Atlas 68 barley over a 35-day period from juvenility to leaf senescence. Three distinct patterns of metabolic activity were found. Phenylalanine ammonia-lyase and shikimate dehydrogenase levels were highest during the earliest stages of leaf development and decreased progressively as the leaves matured. Catalase, malate dehydrogenase, cytochrome c oxidase, soluble protein, the flavonoids saponarin and lutonarin, and fresh weight showed dramatic increases during the early development of the leaves, reached maximum levels around 15-20 days, and decreased progressively as the leaves senesced. Peroxidase, polyphenol oxidase, and chalcone-flavanone isomerase activities were maximal at 15-20 days, decreased, but exhibited a surge of activity just prior to death of the primary leaves. When 15-day-old leaves were divided into apical, middle and basal sections of equivalent lengths, the basal portion had the highest levels of peroxidase and chalcone-flavanone isomerase while the apical sections had the highest activities of the other enzymes. At the stages of maximum flavonoid accumulation, saponarin levels were about 4 times higher than lutonarin levels. As saponarin content decreases, isovitexin, the 7-O-aglycone of saponarin, was detected. The results are discussed in terms of the balance of biosynthesis and degradation of flavonoids in the primary leaf throughout its development from juvenile to senescent stages under field conditions.

Photocontrol of C-glycosylflavones in barley seedlings

The sole flavonoid of etiolated barley plumules is saponarin, a C-glycosylflavone restricted to the primary leaves. Increased saponarin synthesis is under a typical low-energy phytochrome control in both etiolated plumules and in those grown in white light. Prolonged illumination with white light, or high levels of blue light followed by red light, greatly increases saponarin and initiates the synthesis of lutonarin; this response is characteristic of high-energy photoresponses (HER). Kinetic studies show a typical lag of about 4 hr for phytochrome control of saponarin in etiolated plumules. Surprisingly, during this lag-phase and within 2 min following a red-light (132 Kerg cm −2) treatment, there is a 25 per cent decrease in saponarin recovered from whole plumules. Within 1 hr the light-treated plants yield only about half as much saponarin as do the dark controls. After 1 hr apparent saponarin content increases and by the fourth hour the flavonoid content of the light-treated and dark-control plants is similar. The fate of this “lost” saponarin is not known; it may be in part translocated into other parts of the seedling as the apical 1 cm of the plumule shows a more rapid recovery under these conditions, a part may be complexed into forms not recoverable by our techniques. Mediatory aspects of changes in saponarin localization within the tissues are considered.