Drying temperature affects rice seed vigor via gibberellin, abscisic acid, and antioxidant enzyme metabolism / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Seed vigor is a key factor affecting seed quality. The mechanical drying process exerts a significant influence on rice seed vigor. The initial moisture content (IMC) and drying temperature are considered the main factors affecting rice seed vigor through mechanical drying. This study aimed to determine the optimum drying temperature for rice seeds according to the IMC, and elucidate the mechanisms mediating the effects of drying temperature and IMC on seed vigor. Rice seeds with three different IMCs (20%, 25%, and 30%) were dried to the target moisture content (14%) at four different drying temperatures. The results showed that the drying temperature and IMC had significant effects on the drying performance and vigor of the rice seeds. The upper limits of drying temperature for rice seeds with 20%, 25%, and 30% IMCs were 45, 42, and 38 °C, respectively. The drying rate and seed temperature increased significantly with increasing drying temperature. The drying temperature, drying rate, and seed temperature showed extremely significant negative correlations with germination energy (GE), germination rate, germination index (GI), and vigor index (VI). A high IMC and drying temperature probably induced a massive accumulation of hydrogen peroxide (H2O2) and superoxide anions in the seeds, enhanced superoxide dismutase (SOD) and catalase (CAT) activity, and increased the abscisic acid (ABA) content. In the early stage of seed germination, the IMC and drying temperature regulated seed germination through the metabolism of H2O2, gibberellin acid (GA), ABA, and α-amylase. These results indicate that the metabolism of reactive oxygen species (ROS), antioxidant enzymes, GA, ABA, and α-amylase might be involved in the mediation of the effects of drying temperature on seed vigor. The results of this study provide a theoretical basis and technical guidance for the mechanical drying of rice seeds.

Air-drying temperature changes the content of the phenolic acids and flavonols in white mulberry (Morus alba L.) leaves / Temperatura de secagem ao ar altera o teor de ácidos fenólicos e flavonóis em folhas de amoreira branca (Morus alba L.)

ABSTRACT: The white mulberry leaves are typically available on the market in dried or encapsulated form. It was assumed in the study that appropriate drying of leaves of the white mulberry is significant for obtaining intermediate products with high content of compounds having anti-oxidative activity. The purpose of the study was to determine the influence of the temperature of mulberry leaves air drying on the content of phenolic acids and flavonols. It has been determined that the content of these compounds in the leaves depended on the drying temperature. Drying at 60 °C favored release of phenolic acids and flavonols from complexes and/or formation of new compounds. Their total content was 22% higher than in leaves dried at 30 °C. Drying at 90 °C reduced the phenolic acid and flavonol content by 24%. The most favorable drying temperature was 60 °C.

RESUMO: As folhas da amoreira branca estão normalmente disponíveis no mercado em forma seca ou encapsulada. Assumiu-se no estudo que a secagem adequada das folhas da amora branca é importante para a obtenção de produtos intermediários com alto teor de compostos com atividade antioxidante. O objetivo do estudo foi determinar a influência da temperatura de secagem de ar de folhas de amoreira sobre o teor de ácidos fenólicos e flavonóis. Foi determinado que o conteúdo destes compostos nas folhas dependia da temperatura de secagem. Secagem a 60 °C favoreceu a liberação de ácidos fenólicos e flavonóis a partir de complexos e / ou formação de novos compostos. Seu teor total foi 22% superior ao das folhas secas a 30 °C. A secagem a 90 °C reduziu o teor de ácido fenólico e flavonol em 24%. A temperatura de secagem mais favorável foi de 60 °C.

Effects of drying temperature, growing area and plucking time on two saponins from leaves of Hedera helix / 中成药

AIM To investigate the effects of drying temperature,growing area and plucking time on hederacoside C,α-hederin from leaves of Hedera helix L..METHODS Three batches of H.helix leaves plucked in different time from two growing areas were dried in a vacuum oven to the constant weight at 60 ℃,70 ℃,80 ℃,90 ℃ and 105 ℃,respectively.Two saponins in the processed leaves were determined by HPLC.The powders of the processed H.helix leaves of different batches were mixed with proper ratios,which were determined by least squares optimization method with constraints.RESULTS The content of hederacoside C in the processed H.helix leaves of the three batches increased while that of α-hederin decreased with increasing temperature.The relative error between measured value and desired contents of hederacoside C and α-hederin in the mixed H.helix leaves was less than 5.5％.CONCLUSION The effects of three factors on the content of two saponins in the H.helix leaves are in the order of drying temperature,growing area and plucking time.Mixing processed H.helix leaves of different quality statues reasonably can control the contents of two saponins in a certain range.

Atividade antioxidante das folhas de espinheira-santa - Maytenus ilicifolia Mart. ex Reiss., secas em diferentes temperaturas / Antioxidant activity of "espinheira-santa" - Maytenus ilicifolia Mart. ex Reiss., leaves dried in different temperatures

Maytenus ilicifolia Mart. ex Reiss, a espinheira-santa verdadeira, é largamente utilizada para tratamento de gastrites e úlceras estomacais. O seu valor terapêutico é atribuído principalmente aos polifenóis (flavonóides e taninos) e triterpenos. Os polifenóis são bastante estudados e estão relacionados à atividade antioxidante exercida pela planta. Existem vários métodos para avaliar a atividade antioxidante, a qual pode ser medida a capacidade antioxidante total utilizando o método de formação do complexo fosfomolibdênio e a atividade antioxidante em relação à redução de um radical, utilizando-se o DPPH (2,2-difenil-1-picrilhidrazila). A atividade antioxidante das folhas de espinheira-santa seca em diferentes temperaturas foi avaliada, visando verificar a possível influência das temperaturas de secagens e seu poder antioxidante. Foram utilizadas cinco temperaturas (40, 50, 60, 70 e 80 ºC) e uma temperatura de secagem de rotina, de um produtor/beneficiador de plantas medicinais. As menores temperaturas apresentaram as maiores atividades antioxidantes.

Maytenus ilicifolia Mart. ex Reiss, the true "espinheira-santa" is widely used for treating gastritis and stomach ulcers. Its therapeutic values are due mainly polyphenols (flavonoids and tannins) and triterpens. Polyphenols are largely studied and they are related to the antioxidant activity of the plants. There are several methods for evaluating the antioxidant activity, which can measured the total antioxidant capacity through the formation of a phosphomolybdenum complex and the antioxidant activity related to the reduction of one radical, using the DPPH (2,2-diphenyl-1-picrylhydrazyl). The antioxidant activity of "espinheira-santa" dried leaves in different temperatures was measured in order to evaluated the possible influence of drying temperatures under its antioxidant power. Five temperatures used were (40, 50, 60, 70 and 80 ºC) and a drying routine of medicinal plants as well. Lower temperatures showed the highest antioxidant activities.