Apricot (Prunus armeniaca L.) fruit quality attributes and phytochemicals under different crop load

Three apricot (Prunus armeniaca L.) cultivars were subjected to different degrees of fruit thinning during pit hardening. At harvest fruit quality characteristics were assessed, along with phytochemicals’ concentration, such as carbohydrates, phenolic compounds and organic acids. Antioxidant capacity of the pulp was estimated by diphenyl picryl hydrazyl and ferric reducing antioxidant power assays. Thinning improved fruit weight in two of the three cultivars with a subsequent decrease in fruit firmness, without significant effect on total soluble solid content and titratable acidity. The skin color was not influenced by thinning, but carbohydrate concentration and sweetness index increased. Total phenol concentration increased with thinning, without any similar increase of the major individual phenolic compounds detected (neo-chlorogenic acid, chlorogenic acid, rutin, catechin, epicatechin, ferulic acid, p-coumaric acid and caffeic acid). The antioxidant capacity of the pulp was not influenced by thinning. In overall, thinning enhanced the pomological traits of apricot fruits as well as their phytochemical content.     

Experimental complexities in evaluating the allelopathic activities in laboratory bioassays: A case study

Soil is the major player in deciding allelopathic activities. A study was designed to examine experimental complexities in determining the allelopathic behavior of soil amended with water-soluble leachates from Chenopodium murale. Chenopodium murale interferes with the growth and establishment of crop seedlings. The present study examined the role of water-soluble organic substances, if any, in the shoot growth suppression of rice (Oryza sativa L.). Rice seeds were grown on C. murale leaf leachate-amended soil to investigate the phytotoxic effects of C. murale leachates. Any modification of C. murale phytotoxic activities was studied through using abiotic soil, activated charcoal and nitrogen (N) fertilization. Chemical and microbiological analysis of C. murale-amended soil was made to evaluate the role of soil components in C. murale phytotoxicity. Significant inhibition in the shoot growth of rice was observed when abiotic or biotic soil was amended with full-strength leaf leachate (T1) of C. murale compared to unamended soils. The inhibitory effect of T1 is maintained when rice seeds were placed on T1-amended soil after 0, 24 or 48 h; however, the inhibitory effects were eliminated when seeds were placed on amended soil after 72, 96 h or 1 wk of incubating soil with T1. Activated charcoal (1, 2 or 4 g) could not eliminate the inhibitory effects of T1-amended soil to the shoot length of rice. The phytotoxic effects of T1-amended soil to the shoot length of rice, however, were largely eliminated after the addition of N fertilization. Interference of C. murale leaf leachate to rice shoot growth could be due to number of effects that could be misconstrued as allelopathy effects.     

甘薯抗蔓割病的酚类物质代谢的研究

通过对甘薯抗蔓割病品种"金山57"和感病品种"岩薯8-6"接菌处理,研究了甘薯体内酚类物质的代谢规律以及与PAL酶活性的变化关系及其对甘薯抗蔓割病的影响。结果表明,两品种接种蔓割病菌后植株体内总酚、类黄酮、木质素、绿原酸、阿魏酸等含量都有提高,但抗病品种比感病品种酚类物质的积累速度快、保持较高浓度的时间长,从而更有利于抵抗病原菌侵染。同时,接菌后PAL酶活性的提高也与品种抗性呈正相关。     

不同梨果实褐变特异性分析

以黄金梨、大香水、新梨七号为试材,研究了贮藏后梨褐变不同部位酚类物质含量和种类、多酚氧化酶(PPO)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)的活性及可溶性蛋白的关系。结果表明,梨果实中的酚类物质以绿原酸为主,果实褐变与酚类物质含量和多酚氧化酶活性,特别是二者在果实中不同部位的分布特性有关。黄金梨果心与其他部位比较具有较高的酚类物质含量和PPO活性。由果皮至果心CAT活性依次降低,而果皮中POD活性极大地高于其他部位。SOD的活性与褐变的直接关系不明显。     

Identification and quantification of phenolic acids and anthocyanins as antioxidants in bran,embryo and endosperm of white,red and black rice kernels (Oryza sativa L.)

Whole rice grain comprising endosperm, embryo (or germ), and bran has potential beneficial health effects in addition to provision of nutrients. The distribution of phenolic acids and anthocyanins in endosperm, embryo, and bran of white, red, and black rice grains was investigated in this study. The total phenolic content (TPC) was highest in the bran, averaging 7.35 mg GAE/g and contributing 60%, 86% and 84% of phenolics in white, red and black rice. The average TPC of the embryo and endosperm were 2.79 and 0.11 mg GAE/g accounting for 17% and 23%, 4% and 10% and 7% and 9% in white, red and black rice, respectively. The antioxidant capacity determined using DPPH and ORAC displayed a trend similar to TPC. Free/conjugated phenolic acids in white, red and black rice bran accounted for 41%, 65% and 85% of total acids. Bound phenolic acids in rice bran accounted for 90% of total acids in whole grain. Cis-p-coumaric was detected in bound form in bran while cis-sinapic acid was detected in the free/conjugated form in embryo and bran. Cyanidin-3-O-glucoside and peonidin-3-O-glucoside were identified mainly in black rice bran as the total anthocyanins. Cyanindin-3-O-rutinoside was also detected in black rice bran.     

苹果果皮酚类物质对光强变化的适应性研究

 以套袋3个月的富士苹果为试材,研究光强变化对果皮酚类物质的影响。结果表明,未套袋果实果皮的UV吸收物、芦丁、花青苷含量明显高于套袋果实的,而绿原酸含量降低。套袋果实除袋后,果皮绿原酸、UV吸收物、花青苷、芦丁呈现上升趋势;摘袋后用水杨酸(SA)浸蘸处理提高了果皮SA、槲皮素含量。     

Can Sphagnum leachate chemistry explain differences in anaerobic decomposition in peatlands?

Peatlands are important ecosystems in the global carbon cycle, serving as both the largest terrestrial soil carbon pool and a significant source of the greenhouse gas methane (CH₄). In Sphagnum moss-dominated wetlands, anaerobic decomposition, and in particular the production of CH₄, is highly variable and controlling factors are poorly understood. The main objective of this study was to determine if leachates of Sphagnum can explain differences in anaerobic decomposition and CH₄ production from three Sphagnum-dominated peatlands.Soils from each peatland were incubated anaerobically for 40 days with Sphagnum-derived organic matter (S-DOM) extracted using distilled water at 25 or 60 °C in a fully-crossed experimental design. S-DOM extracted at 25 °C had a minimal effect on decomposition, but S-DOM extracted at 60 °C increased CO₂ production in all soils. The magnitude of the increased CO₂ production in response to S-DOM depended on the source site of the S-DOM. The response of CH₄ production to additions of S-DOM extracted at 60 °C was more complex. Soils from one peatland produced no CH₄ during the incubation, regardless of S-DOM source. The same S-DOM additions led to an increase in CH₄ production in a second soil, but a decrease in CH₄ production in the third soil. Stable isotopic evidence suggests that these patterns were driven by the selective inhibition or stimulation of acetoclastic methanogenesis. Taken together, these data suggest S-DOM alone does not explain differences in anaerobic decomposition in peatlands, but may play a role in regulating CO₂ and CH₄ production.     

Constituents of Craspedolobium schochii

Nine phenolic compounds, including a new one, were isolated from 70% acetone extract of Craspedolobium schochii. The new compound was identified as 3-(3,4-dimethoxy-2-hydroxyphenyl)-7-hydroxy-coumarin (1) on the basis of spectroscopic evidence.     

Constitutive phenolics of Harpephyllum caffrum (Anacardiaceae) and their biological effects on human keratinocytes

Assessment of the UV protecting potential of an aqueous methanol leaf extract of Harpephyllum caffrum proved that it possesses a distinct radical scavenging effect and inhibits the production of the proinflammatory cytokine IL-6 by human keratinocytes (HaCaT cells) following UV radiation. Phytochemical investigation of this extract led to isolation and structural determination of the hitherto unknown phenolics, kaempferol 3-O-(2″-sulphatogalactopyranoside), its quercetin analogue and 3-methoxyellagic acid 4-O-galactopyranoside in addition to 18 known phenolic compounds. The structures were determined by spectroscopic and conventional methods of analysis. Flavonoid sulphatoglycosides which have been rarely found in nature were major phenolic constituents of this plant, and this is the first report of the isolation of any of them from Anacardiaceae. The extract was found to diminish UV phototoxic reaction of keratinocytes. However, the isolated kaempferol sulphatogalactopyranoside did not interact with UVB triggered IL-6 production of HaCaT keratinocytes.     

Constituents from Lonicera japonica

Five caffeoylquinic acids and esters (1-5), including a new compound, 3,5-dicaffeoylquinic acid butyl ester (5), were isolated from the flowers and buds of Lonicera japonica and their structures were determined by NMR spectral analysis.