Determination of Myricetin in Medicinal Plants by High-Performance Liquid Chromatography

The concentrations of myricetin in medicinal plants such as Rosa canina L. (rosa hip), Terebinthina chica L. (terebinth), Urtica dioica L. (nettle), and Portuca oleracea L. (purslane) were determined by high-performance liquid chromatography-mass spectrometry (HPLC-MS). The aglycones of myricetin were extracted using methanol–ascorbic acid– hydrochloric acid, methanol–hydrochloric acid, and methanol, separated within 5 min, and individually quantitated in the positive ionization mode using optimized conditions for HPLC-MS. Methanol–ascorbic acid–hydrochloric acid was the optimum extraction solvent. The myricetin concentration in the plants were between 3 and 58 mg kg^?1, with a limit of quantification equal to 0.1 mg L^?1.     

无稳定剂悬浮液进样——火焰原子吸收光谱法测定菠菜中的锌、锰、钾、钙

在无稳定剂条件下直接用蒸馏水制成菠菜样品的悬浮液,用SrCl2和CsCl消除相关干扰,在磁力搅拌下进样,应用标准曲线法在同一溶液中利用空气-乙炔火焰原子吸收光谱法测定Zn、Mn、K、Ca等4种元素含量。结果表明,菠菜中富含Zn、K、Ca及Mn。以无刺种菠菜叶样品为例,详细研究了干扰及其消除的条件,考察了方法的准确度和精密度。试验表明,在选定的条件下,菠菜中各元素间相互不干扰测定。方法的加标回收率在90.5%~101.5%之间,相对标准偏差在0.2%~1.1%之间(n=3),测定结果准确可靠。     

马齿苋茎部提取物对双酚A的降解效应研究

大量研究证明:双酚A(BPA)具有环境雌激素作用,极低剂量摄取就能破坏人体的内分泌系统,已成为一种全球性污染物。文章以2mL蒸馏水比1g马齿苋茎部的比例浸提其活性物质,用于双酚A的生物降解。研究了样品中双酚A的初始浓度、光照、透析等因素对马齿苋茎部提取物降解双酚A的影响。实验结果显示:在连续光照及透析条件下,20mLBPA中加入1mL茎汁降解时获得的效果较好,浓度为5mg/L、10mg/L的双酚A在24h内可完全降解,40mg/L的双酚A降解率达到67%。     

Chlorophyll Fluorescence as an Indicator of Physiological Changes in Cold-Stored Broccoli After Transfer to Room Temperature

Our objective was to determine if chlorophyll fluorescence could be used as an indicator of physiological changes in cold-stored broccoli after transfer to room temperature. Mass loss, respiration, and ammonia content increased when the broccoli were held at 18°C for 72h, whereas the chlorophyll fluorescence measurements (Fv/Fm, T½ and Fmd) decreased. Broccoli color began to change after 24h, as hue decreased rapidly and chroma increased. Fv/Fm decreased markedly only after the first 24h when the color changes began, whereas T½ and Fmd decreased continuously as the broccoli aged. Both T½ and Fmd correlated negatively with mass loss and respiration.     

Effects of shade nettings,sowing time and storage on baby spinach flavonoids

Flavonoids are important in plant interactions with the environment and may have positive effects on human health. Effects of light quality and quantity on flavonoid concentration were studied in baby spinach (Spinacia oleracea L.) cultivated under three types of shade netting differing in transmittance of UV‐B and PAR, at two times during the season. Leaves harvested at two growth stages for each sowing were subjected to different post‐harvest storage conditions. Shade nettings had a relatively small effect on flavonoid concentration in baby spinach. The largest effect was found when radiation was most intense. The nettings then decreased total flavonoid concentration by 15–24% at the normal commercial growth stage at harvest. Radiation and plant growth both affected flavonoid concentration, in opposite or similar directions depending on time of season. This variation was reflected in the statistical analysis, showing significant interactions among the factors. There were large differences (up to 100%) in flavonoid concentration between the different times of the season, in shaded as well as unshaded spinach. Flavonoid concentration and composition changed during storage, but no consistent difference was found between the shaded and unshaded leaves. In most cases, total flavonoid concentration increased significantly during the first 6 days of storage. In conclusion, the use of shade netting is acceptable for production of baby spinach as regards flavonoid concentration and composition. Copyright © 2007 Society of Chemical Industry     

从马齿苋中提取叶蛋白工艺的研究

采用酸法及加热法，分析了从马齿苋中提取叶蛋白的工艺条件。结果表明：从马齿苋中提取叶蛋白工艺的最佳条件：加热时间为9min，加热温度为75℃，盐酸调pH值为3，液料比为4；该工艺提取叶蛋白的提取率为0.95％，叶蛋白的沉淀率为20.02％。     

正交实验法优化马齿苋中α-亚麻酸的提取工艺参数研究

为优化马齿苋中α-亚麻酸提取工艺,在单因素实验的基础上,采用正交实验,以反相高效液相色谱法测定提取液中α-亚麻酸的提取得率,研究马齿苋中α-亚麻酸提取的工艺参数,探讨超声波功率、料液比、提取时间等因子的交互作用及其最佳水平。研究表明,各因素对α-亚麻酸提取得率的影响次序为提取时间>超声波功率>料液比;马齿苋中α-亚麻酸的最佳提取条件为:超声波功率330W,料液比1∶20,提取时间4h,提取溶剂正己烷,提取温度60℃,物料大小200目。在上述条件下测得马齿苋中α-亚麻酸的提取得率为24.302mg/100g。     

Simultaneous evaluation of intact glucosinolates and phenolic compounds by UPLC-DAD-MS/MS in Brassica oleracea L. var. botrytis

A method for the simultaneous determination of intact glucosinolates and main phenolic compounds (flavonoids and sinapic acid derivatives) in Brassica oleracea L. var. botrytis was proposed. A simplified sample extraction procedure and a UPLC separation were carried out to reduce the total time of analysis. B. oleracea samples were added with internal standards (glucotropaeolin and rutin), and extracted with boiling methanol. Crude extracts were evaporated under nitrogen, redissolved in mobile phase and analysed by UPLC with double detection (ESI⁻-MRM for glucosinolates and flavonoids, and DAD for main sinapic acid derivatives). The proposed method allowed a satisfactory quantification of main native sinapic acid derivatives, flavonoids and glucosinolates with a reduced time of analysis.     

Basis for the new challenges of growing broccoli for health in hydroponics

BACKGROUND: Variations in the contents of phytochemicals with biological activity in broccoli could originate as a result of genetic and environmental factors. An understanding of the effects of growth conditions on the bioactive compounds in broccoli is essential for improving its quality and nutritive value. Using salinity (40 mmol L^?1 NaCl), and foliar sprayed compounds (methionine, tryptophan and chitosan) as different stress conditions, broccoli developed in soilless culture in the greenhouse was analysed for biologically active phytochemicals (glucosinolates, caffeoyl‐quinic, ferulic and sinapic derivatives and vitamin C). RESULTS: The application of elicitors during head formation could be beneficial for the enrichment in phytochemicals in broccoli. Management practices for increasing a given phytochemical (e.g., glucoraphanin or glucobrassicin) may be related to a decreased level of natural antioxidants (hydroxycinnamic acids). Growing broccoli hydroponically in the greenhouse in winter (Mediterranean climate) needs the supporting treatment of abiotic stress during development (i.e., NaCl, elicitors). CONCLUSION: The use of hydroponic growth conditions for broccoli and the application of stress factors (elicitors) at head induction and during development may serve the purpose of enhancing its nutritional quality to deliver a health‐promoting food. Copyright © 2008 Society of Chemical Industry     

不同单色LED对低温贮藏西兰花的保鲜作用

为改善西兰花的采后贮藏品质,以期为蔬菜保鲜的实际应用提供新思路。本文研究了低温下不同波长的单色发光二极管(lighting-emitting diode,LED)对西兰花品质的保鲜作用。本研究采用了红光(642 nm)、黄光(591 nm)、绿光(519 nm)、蓝光(464nm)、紫光(435nm)不同波长的单色LED照射西兰花,光照时间24h/d,并从感官、理化、营养和微生物指标综合评价分析不同单色LED对西兰花不同贮藏时期品质的影响。结果表明:不同单色LED光照能延缓西兰花在贮藏过程中营养品质的下降。贮藏12 d后,绿光LED(519 nm)能够最大程度地保持西兰花的感官品质,抑制亮度L*的增加,延缓叶绿素、还原糖及可溶性固形物的降解,同时能够有效地抑制微生物的增长速度,延缓色相角度H值的降低、保持维生素C的含量。因此,绿光LED照射对于西兰花的低温贮藏品质的保持效果最佳,从而延长西兰花的贮藏期。