Chemical and biological study of flavonoid-related plant pigment: current findings and beyond.

Flavonoids are polyphenolic plant constituents. Anthocyanins are flavonoid pigments found in higher plants that show a wide variety of colors ranging from red through purple to blue. The blue color of the flowers is mostly attributed to anthocyanins. However, only a few types of anthocyanidin, chromophore of anthocyanin, exist in nature, and the extracted pigments are unstable with the color fading away. Therefore, the wide range and stable nature of colors in flowers have remained a mystery for more than a century. The mechanism underlying anthocyanin-induced flower coloration was studied using an interdisciplinary method involving chemistry and biology. Furthermore, the chemical studies on flavonoid pigments in various edible plants, synthetic and biosynthetic studies on anthocyanins were conducted. The results of these studies have been outlined in this review.

Near-infrared-excitable acetylcholinesterase-activated fluorescent probe for sensitive and anti-interference detection of pesticides in colored food.

The development of a common and anti-interference acetylcholinesterase (AChE) inhibition assay for plant-originated food samples has been of great challenge because of the prevalent and strong signal interferences from natural pigments. Plant pigments normally exhibit non-negligible absorbance in the UV-visible region. As a result, the signals of a typical near-infrared (NIR) fluorescent probe could be disturbed through primary inner filter effect if it is excited by UV-visible light during plant sample analysis. In this work, an NIR-excitable AChE-activated fluorescent probe was biomimetically designed and synthesized. And the NIR-excitation strategy was utilized for the anti-interference detection of organophosphate and carbamate pesticides in colored samples with this probe. Sensitive and rapid response to AChE and pesticides was achieved due to the high affinity of the biomimetic recognition unit in the probe. The limits of detection for four representative pesticides including dichlorvos, carbofuran, chlorpyrifos and methamidophos reached 0.0186 µg/L, 2.20 µg/L, 12.3 µg/L and 13.6 µg/L, respectively. Most importantly, fluorescent response to pesticide contents could be accurately measured in the coexistence of different plant pigments by this probe, and the measured results showed completely irrelevance to the plant pigments and their colors. Taking advantage of such probe, the new developed AChE inhibition assay showed good sensitivity and anti-interference ability in the detection of organophosphate and carbamate pesticides in real samples.

Iron Source and Medium pH Affect Nutrient Uptake and Pigment Content in Petunia hybrida 'Madness Red' Cultured In Vitro.

Deficiency or excess of iron (Fe) and improper medium pH will inhibit the growth and development of plants, reduce the transfer and utilization of energy from the root to the leaf, and affect the utilization efficiency of inorganic nutrients. The most common symptom of Fe deficiency in plants is chlorosis of the young leaves. In this study, the effects of the iron source, in combination with the medium pH, on plant growth and development, plant pigment synthesis, and nutrient uptake in a model plant Petunia hybrida cultured in vitro were investigated. Iron sulfate (FeSO4·7H2O) or iron chelated with ethylenediaminetetraacetic acid (Fe-EDTA) were supplemented to the MNS (a multipurpose nutrient solution) medium at a concentration of 2.78 mg·L-1 Fe, and the treatment without any Fe was used as the control. The pH of the agar-solidified medium was adjusted to either 4.70, 5.70, or 6.70 before autoclaving. The experiment was carried out in an environmentally controlled culture room with a temperature of 24 °C with 100 µmol·m-2·s-1 photosynthetic photon flux density (PPFD) supplied by white light emitting diodes (LEDs) during a photoperiod of 16 h a day, 18 °C for 8 h a day in the dark, and 70% relative humidity. Regardless of the Fe source including the control, the greatest number of leaves was observed at pH 4.70. However, the greatest lengths of the leaf and root were observed in the treatment with Fe-EDTA combined with pH 5.70. The contents of the chlorophyll, carotenoid, and anthocyanin decreased with increasing medium pH, and contents of these plant pigments were positively correlated with the leaf color. The highest soluble protein content and activities of APX and CAT were observed in the Fe-EDTA under pH 5.70. However, the GPX activity was the highest in the control under pH 4.70. In addition, the highest contents of ammonium (NH4+) and nitrate (NO3-) were measured in the FeSO4-4.7 and EDTA-5.7, respectively. More than that, the treatment of Fe-EDTA combined with pH 5.70 (EDTA-5.7) enhanced nutrient absorption, as proven by the highest tissue contents of P, K, Ca, Mg, Fe, and Mn. The genes' ferric reduction oxidase 1 and 8 (PhFRO1 and PhFRO8), iron-regulated transporter 1 (PhIRT1), nitrate transporter 2.5 (PhNRT2.5), and deoxyhypusine synthase (PhDHS) were expressed at the highest levels in this treatment as well. In the treatment of EDTA-5.7, the reduction and transport of chelated iron in P. hybrida leaves were enhanced, which also affected the transport of nitrate and catalyzed chlorophyll level in leaves. In conclusion, when the medium pH was adjusted to 5.70, supplementation of chelated Fe-EDTA was more conducive to promoting the growth and development of, and absorption of mineral nutrients by, the plant and the expression of related genes in the leaves.

Nutritional value and inclusion levels of residual annatto seed meal in diets for Japanese quails / Valor nutricional y niveles de inclusión de harina residual de semilla de achiote en dietas para codorniz Japonesa / Valor nutritivo e níveis de inclusão do farelo residual da semente de urucum em dietas para codornas Japonesas

Abstract Background: Residual annatto seed meal (RASM) is a byproduct after extraction of bixin in the cosmetic industry and may be used in animal diets. Objective: Two experiments were carried out to determine the nutritive value and effect of RASM inclusion levels in the diets of Japanese quails. Methods: For the digestibility experiment, 160 Japanese quails were distributed in a randomized study with two treatments and 10 replicates with eight birds each. The treatments consisted of a reference diet and a test diet containing 75% of the reference diet and 25% of RASM. For the performance assay, 192 Japanese quails were used in a randomized study with six treatments and four replicates with eight birds each. Treatments consisted of a control corn-based diet (Contr1) and another diet based on sorghum + canthaxanthin (Contr2), and four diets based on sorghum with increasing inclusion levels of RASM (0, 3, 6, and 9%). Results: Digestibility of dry matter and crude protein, metabolization coefficient of gross energy, and retention of calcium and phosphorus were 41.05, 43.12, 47.97, 25.49, and 30.35%, respectively. RASM inclusion did not influence bird productivity; however, feed conversion worsened in treatments with 0-6% RASM inclusion relative to that in Contr1. Yolk color increased due to RASM treatment. Conclusion: RASM may be included in sorghum-based diets for quails at 9%, with improvement in yolk color and no negative effects on productivity and egg quality.

Resumen Antecedentes: La harina de la semilla de achiote (RASM) es un subproducto de la extracción de bixina por la industria cosmética y puede ser usada en alimentación animal. Objetivo: Se realizaron dos experimentos para determinar el valor nutritivo y los efectos de la inclusión de RASM en dietas para codorniz. Métodos: Para el experimento de digestibilidad, 160 codornices japonesas fueron distribuidas en un estudio al azar con dos tratamientos y 10 repeticiones con ocho aves cada uno. Los tratamientos consistieron en una dieta referencia y una dieta de prueba, la cual estuvo compuesta por 75% de la dieta referencia y 25% de RASM. Para el ensayo de desempeño, 192 codornices japonesas fueron usadas en un estudio al azar con seis tratamientos y cuatro repeticiones con ocho aves cada uno. Los tratamientos consistieron en una dieta control a base de maíz (Contr1) y otra a base de sorgo + cantaxantina (Contr2) y cuatro dietas a base de sorgo con niveles de inclusión de RASM (0, 3, 6 y 9%). Resultados: Los coeficientes de digestibilidad de materia seca y proteína bruta, el coeficiente de metabolización de la energía bruta y la retención de calcio y fósforo fueron 41,05; 43,12; 47,97; 25,49 y 30,35%, respectivamente. La inclusión de RASM no influyó la productividad de las aves; entretanto la conversión alimenticia empeoró debido a los tratamientos con 0-6% RASM comparado con el tratamiento Contr1. El color de la yema aumentó debido a la RASM. Conclusión: RASM puede ser incluido en dietas a base de sorgo para codornices en un 9%, debido a la mejora en el color de la yema, además de no tener ningún efecto negativo en el desempeño productivo y calidad del huevo.

Resumo Antecedentes: O farelo residual da semente de urucum (RASM) é um subproduto da extração da bixina pela indústria cosmética e pode ser usado na alimentação animal. Objetivo: Dois experimentos foram conduzidos para determinar o valor nutritivo e os efeitos de inclusão do FRSU em dietas para codornas Japonesas. Métodos: Para o experimento de digestibilidade, 160 codornas Japonesas foram distribuídas em um estudo casualizado com dois tratamentos e 10 repetições com oito aves cada. Os tratamentos consistiram em uma dieta referência e uma dieta teste, a qual era composta por 75% da dieta referência e 25% de RASM. Para o ensaio de desempenho, 192 codornas Japonesas foram usadas em estudo ao acaso com seis tratamentos e quatro repetições com oito aves cada. Os tratamentos consistiram em uma dieta controle a base de milho (Contr1) e outra à base de sorgo com cantaxantina (Contr2) e quatro dietas a base de sorgo com níveis de inclusão de RASM (0, 3, 6 e 9%). Resultados: Os coeficientes de digestiblidade de matéria seca e proteína bruta, coeficiente de metabolização da energia bruta e retenção de cálcio e fósforo foram 41,05; 43,12; 47,97; 25,49 e 30,35%, respectivamente. A inclusão do FRSU não influenciou a produtividade das aves; entretanto, a conversão alimentar piorou devido aos tratamentos com 0-6% FRSU comparado com o tratamento Contr1. A cor da gema aumentou devido ao FRSU. Conclusão: RASM pode ser incluido em dietas baseadas em sorgo para codornas em 9%, devido a mehoria na cor da gema e nenhum efeito negativo no desempenho produtivo e qualidade de ovo.

Allium Discoloration: Color Compounds Formed during Pinking of Onion and Leek.

Structures and formation pathways of compounds responsible for pink discoloration of onion and leek were studied. A procedure was developed for the isolation and purification of the color compounds from various model systems and their identification by HPLC-DAD-MS/MS. In total, structures of 15 major color compounds were tentatively determined. It was found that the pigment is a complex mixture of highly conjugated species composed of two N-substituted 3,4-dimethylpyrrole-derived rings linked by either a methine or a propenylidine bridge. These two-ring units are further modified by various C1- and C3-side chains. Experiments with isotope-labeled thiosulfinates revealed that the methine bridge and C1-side chains originate from the methyl group of methiin, whereas the C3 units are derived from the propenyl group of isoalliin.