Identification of coumarins from the fruit of Citrus hystrix DC as inhibitors of nitric oxide generation in mouse macrophage RAW 264.7 cells

Three known coumarins have been isolated from Citrus hystrix DC as inhibitors of both lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma)-induced nitric oxide (NO) generation in RAW 264.7 cells. The inhibitory activity of bergamottin (IC(50) = 14 microM) was comparable to that of N-(iminoethyl)-L-ornithine (L-NIO) (IC(50) = 7. 9 microM), whereas oxypeucedanin and 5-[(6',7'-dihydroxy-3', 7'-dimethyl-2-octenyl)oxy]psoralen, structurally different from bergamottin only in their side-chain moieties, were notably less active. Using 21 coumarins, we structurally classified various types of coumarins into groups A-C: (A) bearing an isoprenyl (IP) or a geranyl (GR) group, highly active; (B) bearing an IP group cyclized to a coumarin ring, moderately active; (C) bearing an IP group modified with hydroxyl group(s) and/or having other functional groups except for the IP, completely inactive. Cellular uptake studies suggested that coumarins in group C are inactive because of poor permeability to the cell membrane.     

Novel nitric oxide and superoxide generation inhibitors, persenone A and B, from avocado fruit

One known, (2R)-(12Z,15Z)-2-hydroxy-4-oxoheneicosa-12,15-dien+ ++-1-yl acetate (1), and two novel compounds, persenone A (2) and B (3), have been isolated from avocado fruit (Persea americana P. Mill), as inhibitors of superoxide (O(2)(-)) and nitric oxide (NO) generation in cell culture systems. They showed marked inhibitory activities toward NO generation induced by lipopolysaccharide in combination with interferon-gamma in mouse macrophage RAW 264.7 cells. Their inhibitory potencies of NO generation (1, IC(50) = 3.6; 2, IC(50) = 1.2; and 3, IC(50) = 3.5 microM) were comparable to or higher than that of a natural NO generation inhibitor, docosahexaenoic acid (DHA; IC(50) = 4.3 microM). Furthermore, compounds 1-3 and DHA markedly suppressed tumor promoter 12-O-tetradecanoylphorbol-13-acetate-induced O(2)(-) generation in differentiated human promyelocytic HL-60 cells (1, IC(50) = 33.7; 2, IC(50) = 1.4; 3, IC(50) = 1.8; and DHA, IC(50) = 10.3 microM). It is notable that they were found to be suppressors of both NO- and O(2)(-)-generating biochemical pathways but not to be radical scavengers. The results indicate that these compounds are unique antioxidants, preferentially suppressing radical generation, and thus may be promising as effective chemopreventive agent candidates in inflammation-associated carcinogenesis.     

Quality and elemental content of citrus fruit from exposed and internal canopy positions 1

Quality and elemental content of fruit from internal tree canopies were compared with those from external canopy positions in 4 citrus varieties: ‘Kinnow’ mandarin; ‘Redblush’ grapefruit; ‘Valencia’ orange; and ‘Lisbon’ lemon. Fruit weight, total juice per fruit, peel fresh and dry weight, and rind thickness of fruit from internal canopies of all 4 varieties were significantly higher compared with external fruit. Mandarin, grapefruit, and orange fruit from external canopies had higher soluble solids and specific gravity. Fruit from internal canopies of all varieties had generally higher peel concentrations (% dry weight) of N, P and K due to a dilution effect, while the opposite condition existed in mandarin when these elements were expressed on a percent fresh weight basis. Peel Mg and S from external fruit were higher in all varieties, expressed as percentages of either dry weight or fresh weight. Nitrogen content of mandarin and orange juice and Ca content of grapefruit and lemon juice from external fruit were significantly higher compared to those from internal canopy fruit. Elimination of fruit quality and mineral variations as a result of canopy positions is recommended by the means of cultural practices.     

Fruit quality and mineral nutrient from exposed verses internal canopy positions of four scitrus varieties

>Quality and mineral content of fruit from internal tree canopies were compared with those from external canopy positions in 4 citrus varities: ‘Kinnow’ mandarin; ‘Redblush’ grapefruit; ‘Valencia’ orange; and ‘Lisbon’ lemon. Fruit weight, total juice per fruit, peel fresh and dry weight, and rind thickness of fruit from internal canopies of all 4 varieties were significantly higher compared with external fruit. Mandarin, grapefruit, and orange fruit from external canopies had higher soluble solids and specific gravity. Fruit from internal canopies of all varieties had generally higher peel concentrations (% dry weight) of N, P and K due to a dilution effect, while the opposite condition existed in mandarin when these elements were expressed on a percent fresh weight basis. Peel Mg and S from external fruit were higher in all varieties, expressed as percentages of either dry weight or fresh weight. Nitrogen content of mandarin and orange juice and Ca content of grapefruit and lemon juice from external fruit were significantly higher compared to those from internal canopy fruit. Elimination of fruit quality and mineral variations as a result of canopy positions is recommended by the means of cultural practices.     

Study of the polyphenolic composition and antioxidant activity of new sherry vinegar-derived products by maceration with fruits

Several experiments of maceration of a sherry wine vinegar with different fruits (orange, lemon, strawberry, grapefruit, and lime) have been carried out. After optimization (only peel, no heating and seven days as maximum time of maceration), parameters such as polyphenolic content, superoxide anion scavenging ability (related to antioxidant activity) and ascorbic acid content were determined in sherry wine vinegars macerated with two amounts of peel and for two maceration times (3 and 7 days). The analysis of variance pointed to a clear relationship (p<0.01) between type of fruit and amount of peel and polyphenolic content. The factor "time" was practically not significant for any polyphenol. Sherry wine vinegars macerated with different fruits exhibited higher superoxide anion scavenger ability, with the maximum values found for the vinegar macerated with lemon peel. The correlation analysis showed that the superoxide anion scavenger ability of the vinegars macerated, and thus their antioxidant activity, was highly correlated (p<0.01) with several polyphenols, especially with naringin, hesperidin, neohesperidin and gentisic acid and not with the ascorbic acid content.     

Comparative analyses of bioactive Mammea coumarins from seven parts of Mammea americana by HPLC-PDA with LC-MS

Mammea americana L. is tropical plant in the Clusiaceae family that bears edible fruit. Mammea coumarins are isoprenylated derivatives of the lactones of the 2-hydroxy-Z-cinnamic acids that are bioactive and have limited distribution in three Clusiaceae genera. Qualitative and quantitative analyses were performed to determine the distribution of mammea coumarins in the seed nucleus, seed coat, fruit flesh, fruit skin, leaf, stem, and root of M. americana using high-performance liquid chromatography-photodiode array detector (HPLC-PDA) and liquid chromatography-mass spectrometry (LC-MS). Ten major mammea coumarins, mammea E/BD (1), mammea E/BC (2), mammea E/BA (3), mammea E/BB (4), mammea B/BA hydroxycyclo F (5), mammea B/BD (6), mammea B/BC (7), mammea B/BA (8), mammea B/BB (9), and mammea B/BA cyclo F (10), were isolated and identified from the seed nucleus of M. americana and employed as standards. The HPLC-PDA method was validated with respect to sensitivity, linearity, recovery, accuracy, and precision. The total content (w/w %) of the 10 major mammea coumarins in M. americana was determined to be highest in the root (0.75%), followed by the leaf (0.64%), seed nucleus (0.48%), fruit skin (0.11%), stem (0.08%), seed coat (0.02%), and fruit flesh (<0.01%). The leaf and seed nucleus are rich and sustainable natural sources of mammea coumarins. Additionally, the described HPLC-PDA and LC-MS methods are sensitive and accurate and can be applied to the analysis of mammea coumarins in other samples.     

Apple and pear peel and pulp and their influence on plasma lipids and antioxidant potentials in rats fed cholesterol-containing diets

The aim of this study was to assess the bioactive compounds of apple and pear peel and pulp in vitro and their influence on plasma lipids and antioxidant potentials in vivo. The antioxidant potentials measured by 1,1-diphenyl-2-picrylhydrazyl (DPPH), beta-carotene bleaching (beta-carotene), and nitric oxide inhibition radical scavenging (NO) tests in apple peel and pulp were significantly higher than in pear peel and pulp, respectively. The ethanol extract of apple peels showed the strongest inhibition of lipid peroxidation as a function of its concentration and was comparable to the antioxidant activity of butylated hydroxyanisole. The pear pulp extract had the weakest antioxidant ability, whereas other extracts such as apple pulp and pear peel were nearly equal. The antioxidant activities comprised contributions from polyphenols, phenolic acids, and flavonoids and correlated well with polyphenols and flavonoids. The correlation coefficients between polyphenols and antioxidant activities by DPPH, beta-carotene, and NO were as follows: 0.9207, 0.9350, and 0.9453. Contrarily, the correlation coefficient between the content of dietary fiber and the antioxidant activities test was low. The content of all studied indices in apple and pear peel was significantly higher than in peeled fruits (p < 0.05). Diets supplemented with fruit peels exercised a significantly higher positive influence on plasma lipid levels and on plasma antioxidant capacity of rats than diets with fruit pulps.     

Involvement of limonene hydroperoxides formed after oil gland injury in the induction of defense response against Penicillium digitatum in lemon fruit

The effects of wounding oil glands of lemon [Citrus limon (L.) Burm.] fruit were investigated. Young mature-green lemons demonstrated significantly lower decay incidence than older yellow fruit when their oil glands were punctured in the presence of postharvest wound pathogen Penicillium digitatum Sacc. Contact with the released gland content on the green lemon surface reduced the viability of P. digitatum spores approximately twice. Wounding caused rapid production of limonene hydroperoxides that persisted for only a few minutes. The magnitude depended on the physiological maturity of the fruit; mature-green fruit produced much higher levels than did yellow lemons. Furthermore, wounding of the oil glands or injection of limonene hydroperoxides into the lemon peel elicited the production of the citrus fruit phytoalexins, scoparone and scopoletin, to levels known to be effective in reducing decay caused by P. digitatum. The mature-green fruit produced about twice as much of these phytoalexins as the older yellow fruit. This induced defensive elicitation of phytoalexin production, as well as the direct effects of these antifungal compounds, markedly inhibited the pathogen in mature-green fruits but was ineffective in older yellow ones.     

不同钾氮配比对荔枝果实矿质元素含量及其耐贮性的影响

【目的】在广东省惠州市荔枝主产区,于2009 2012年连续3年研究不同钾氮养分比例对荔枝果实矿质元素含量的影响及其与耐贮性的关系,以期为荔枝高产优质高效栽培与耐贮增值的科学施肥技术提供理论依据。【方法】在大田栽培条件下,以1995年嫁接苗种植的国内主栽品种妃子笑为试材,设钾氮不同施用比例(K2O/N分别为0.6、0.8、1.0、1.2和1.4)5个处理,分别用K0.6N、K0.8N、K1.0N、K1.2N、K1.4N表示。在荔枝收获期测定果实矿质元素含量,并进行室温(25±1°C)自然贮藏试验,每2d采样测定相关贮藏指标。【结果】1)随着K2O/N比的提高,荔枝外果皮钾(K)、硼(B)含量呈下降趋势,内果皮K含量呈先下降后增加,果肉K、内外果皮和果肉钙(Ca)、内果皮B含量均呈现先增加后下降,果核Ca含量呈现逐渐增加的趋势。2)随着K2O/N比的提高,内外果皮K/Ca、Mg/Ca、(Mg+K)/Ca、K/B比均呈先下降后增加,外果皮Ca/B比呈增加的趋势。3)内果皮K含量与果实好果率呈极显著负相关,外果皮Ca、内果皮B含量与果实好果率呈显著或极显著正相关。内、外果皮K含量与果皮细胞膜透性呈显著正相关,外果皮Ca含量与果皮细胞膜透性呈显著负相关。内、外果皮K含量与多酚氧化酶(PPO)、过氧化物酶(POD)活性呈显著正相关,而内、外果皮Ca含量则与两种酶活性呈显著负相关。4)内、外果皮K/Ca、Mg/Ca、(Mg+K)/Ca和K/B比与果实好果率呈显著或极显著负相关,与果皮细胞膜透性、PPO和POD活性均呈显著或极显著正相关,而Ca/B比则完全相反。【结论】荔枝生产中合理调控钾、氮养分施用比例(K2O/N),不仅可以提高内、外果皮的Ca/B比值,还有利于降低内、外果皮K/Ca、Mg/Ca、(Mg+K)/Ca和K/B的比值,对提高果实耐贮性具有重要作用。本试验条件和施肥方法下,K2O/N的施用比例以1.2∶1时能最大限度地满足优良耐贮性能适宜的养分含量及比例。     

Investigation of heat treating conditions for enhancing the anti-inflammatory activity of citrus fruit (Citrus reticulata) peels

In traditional Chinese medicine, dried citrus fruit peels are widely used as remedies to alleviate coughs and reduce phlegm in the respiratory tract. Induction of inducible nitric oxide synthase (iNOS) in inflammatory cells and increased airway production of nitric oxide (NO) are well recognized as key events in inflammation-related respiratory tract diseases. Despite the fact that the enhancing effect of heat treatment on the antioxidant activity of citrus fruit peels has been well documented, the impact of heat treatment on citrus peel beneficial activities regarding anti-inflammation is unclear. To address this issue, we determined the anti-inflammatory activities of heat-treated citrus peel extracts by measuring their inhibitory effect upon NO production by lipopolysaccharide-activated RAW 264.7 macrophages. Results showed that the anti-inflammatory activity of citrus peel was significantly elevated after 100 degrees C heat treatment in a time-dependent fashion during a period from 0 to 120 min. Inhibition of iNOS gene expression was the major NO-suppressing mechanism of the citrus peel extract. Additionally, the anti-inflammatory activity of citrus peel extract highly correlated with the content of nobiletin and tangeretin. Conclusively, proper and reasonable heat treatment helped to release nobiletin and tangeretin, which were responsible for the increased anti-inflammatory activity of heat-treated citrus peels.     

Phenylalanine ammonia-lyase as related to ethylene in the development of chilling symptoms during cold storage of citrus fruits.

Low-temperature, nonfreezing, storage induces pitting and necrosis in the flavedo tissue of chilling susceptible citrus fruits. In this study the role of ethylene and phenylalanine ammonia-lyase (PAL; EC 4.3.1.5) in the cold-induced citrus peel damage has been investigated. It has been shown that increasing PAL activity by applying ethylene at a nonchilling temperature did not cause fruit damage or reduce the incidence of this peel disorder when fruits were subsequently held at a chilling temperature (2 degrees C). The cold-induced peel damage was enhanced by applying inhibitors of PAL activity and ethylene synthesis and action. These results indicate that the induction of PAL and ethylene during fruit cold storage, but not before, plays a role in reducing the development of chilling symptoms. The cold-induced PAL activity was reduced by inhibitors of ethylene production, but inhibitors of ethylene action exerted little effect on the activation of this enzyme. Therefore, the activation of PAL may be dependent on ethylene but also an independent cold signal apparently related to the cold-induced peel damage.     

Simple and sensitive determination of o-phenylphenol in citrus fruits using gas chromatography with atomic emission or mass spectrometric detection

In this work, a simple and sensitive method for the analysis of the pesticide o-phenylphenol (OPP) on citrus fruits was developed. OPP is extracted with dichloromethane by ultrasonication and derivatized with ferrocenecarboxylic acid chloride. Using ferrocene as a label, residues of OPP are determined by gas chromatography with atomic emission detection in the iron selective mode or with mass spectrometric detection. Sample cleanup is simple and rapid and merely involves a removal of excess reagent on an alumina minicolumn. The method detection limit is 2 ng of OPP/g of fruit, and recoveries from lemon samples fortified at levels of 35 and 140 ng/g are 101 and 106%, respectively. The citrus fruits analyzed (oranges, grapefruits, lemons) contained between 60 ng/g and 0.37 microg/g OPP (RSD = 8-13%), and the results were in good agreement with results obtained when OPP was analyzed using an established HPLC-FLD method. Several alcohols could also be identified in the fruit peel.     

Volatile components of peel and leaf oils of lemon and lime species

Peel and leaf oils of 43 taxa of lemons and limes were obtained from fruits and leaves collected from trees submitted to the same pedoclimatic and cultural conditions. Their chemical composition was investigated by capillary GC, GC-MS, and (13)C NMR, and the results were submitted to principal component analysis to check for chemical variability. Three major chemotypes were distinguished for lemon peel oils: limonene; limonene/beta-pinene/gamma-terpinene; and limonene/linalyl acetate/linalool. Two chemotypes were identified for lemon leaf oils: limonene/beta-pinene/geranial/neral and linalool/linalyl acetate/alpha-terpineol. In lime peel oils, four chemotypes were distinguished: limonene; limonene/gamma-terpinene; limonene/beta-pinene/gamma-terpinene; and limonene/gamma-terpinene/beta-pinene/oxygenated products. Four others were identified for lime leaf oils: beta-pinene/limonene; limonene/geranial/neral; limonene/linalool/citronellal; and limonene/sabinene/citronellal/linalool. These results were interpreted using principal component analysis.     

不同机械伤处理对香蕉果皮活性氧代谢的影响

为探究不同机械伤处理对香蕉果皮活性氧代谢的影响，该研究以"桂蕉6号"为材料，采用划伤、穿刺、坠落3种不同机械伤处理，以未处理组为对照，测定贮藏过程中香蕉果皮活性氧代谢的变化，并进行相关性分析和主成分分析。结果表明，3种不同机械损伤处理均加速了香蕉果实硬度和叶绿素含量的下降；引起O2-产生速率和H2O2含量的积累，其中划伤处理组的O2-产生速率在贮藏第8 天为对照组的2.0倍，H2O2含量为对照组的2.5倍，这可能与机械伤处理抑制了果皮组织中过氧化物酶、超氧化物歧化酶、过氧化氢酶及抗坏血酸过氧化物酶活性有关；同时，3种不同机械损伤处理加速细胞膜脂过氧化的进程，造成香蕉细胞膜透性及丙二醛含量的升高，其中对照、划伤、穿刺和坠落处理组的丙二醛含量在贮藏第8 天分别是贮藏初期的3.3、3.4、5.4和7.5倍。；此外，划伤和穿刺处理均可显著提高香蕉果皮中PPO活性（P <0.01)。相关性聚类热图分析表明，H2O2含量与香蕉果实硬度、叶绿素含量和抗坏血酸过氧化物酶活性呈极显著负相关（P <0.01)，与超氧化物歧化酶活性呈显著负相关（P <0.05)；同时，多酚氧化酶活性与H2O2含量、丙二醛含量和细胞膜透性呈现极显著正相关（P <0.05)。结合主成分分析可知，不同机械伤处理均可加速香蕉果皮活性氧的积累进而导致香蕉果实的衰老腐败，其中划伤处理对香蕉果皮活性氧代谢影响最大，其次是穿刺处理，坠落处理对香蕉果皮活性氧代谢影响最小。该研究阐明了香蕉果实机械伤、活性氧和贮藏品质三者的关系，并为香蕉采后不同机械伤控制提供理论依据。     

高氮和NO2-对中亚热带森林土壤N2O和NO产生的影响

利用15N同位素标记方法,研究在两种水分条件即60%和90% WHC下,添加硝酸盐(NH4NO3, 300mgN kg-1)和亚硝酸盐(NaNO2, 1mgN kg-1)对中亚热带天然森林土壤N2O和NO产生过程及途径的影响。结果表明,在含水量为60% WHC的情况下,高氮输入显著抑制了N2O和NO的产生(p<0.01);但当含水量增为90% WHC后,实验9h内抑制N2O产生,之后转为促进。所有未灭菌处理在添加NO2-后高氮抑制均立即解除并大量产生N2O和NO,与对照成显著差异(p<0.01)。在60% WHC条件下,这种情况维持时间较短(21h),但如果含水量高(90% WHC)这种情况会持续很长时间(2wk以上),说明水分有效性的提高和外源NO2-在高氮抑制解除中起到重要作用。本实验中N2O主要来源于土壤反硝化过程,而且加入未标记NO2-后导致杂合的N2O(14N15NO)分子在实验21h内迅速增加,表明这种森林土壤的反硝化过程可能主要是通过真菌的“共脱氮”来实现,其贡献率可多达80%以上。Spearman等级相关分析表明未灭菌土壤NO的产生速率与N2O产生速率成显著正相关性(p<0.05),土壤含水量越低二者相关性越高。灭菌土壤添加NO2-能比未灭菌土壤产生更多的NO,但却几乎不产生N2O,表明酸性土壤的化学反硝化对NO的贡献要大于N2O。     

Distribution of various peptides in citrus fruits (grapefruit, lemon, and orange)

Tissue- and species-specific peptides of the grapefruit have been investigated by SDS-PAGE and Western blot. Five peptides from the juice and one peptide from the peel were isolated by preparative gel electrophoresis. Polyclonal antibodies were developed against them in mice. It can be established that 82, 63, and 46 kDa peptides occurred exclusively in the samples prepared from the grapefruit and the lemon juice, whereas in the orange juice, only the 82 kDa peptide could be detected. The 31 kDa peptide is characteristic for the peel samples of grapefruit and lemon. The 210 kDa peptide did not show any specificity. A 117 kDa peptide appeared in the juice and peel of grapefruit and in the peel of lemon but not in the orange. From the data of this study, it is supposed that some of the polyclonal antibodies developed against characteristic juice and peel peptides can be used to test commercial grapefruit juice products for adulteration.     

Effect of the rootstock and interstock grafted in lemon tree (Citrus limon (L.) Burm.) on the flavonoid content of lemon juice

The grafting of the rootstock with the lemon tree is an agronomical technique used to improve production and/or quality of the fruit. The interstock has been used with different fruit trees to modulate the tree size, fruit production and quality, and the aging of the tree. The lemon trees grafted with interstocks increase their longevity, lemon production and quality; interstocks are also used to decrease the thickness of the trunk at the grafting point. This enlarging of the trunk provokes a decrease of the sap flow. In our study, "Verna" lemon trees were grafted with interstock between the rootstock and the lemon tree to follow the flavonoid content of the lemon juice. The lemon juice was obtained from the lemons collected of the grafted lemon trees. Two types of rootstocks were used: Citrus aurantium L. and Citrus macrophylla L. Seven interstocks from five cultivars of orange tree, one cultivar of lime tree, and one cultivar of tangerine tree were used. "Verna" lemon trees were also grafted directly to the rootstock. The rootstock was more important agronomic factor than the interstock on the total flavonoid content of lemon juice. The interstock grafting had only a small influence on the flavonoid content of the lemon juice, and it modulated the individual flavonoid content. Citrus aurantium L. rootstock and "Berna" and "Washington Navel" interstocks were the most appropriate to graft in the lemon tree. This interstock grafting technique does not increase the flavonoid content of the lemon juice. Regarding the individual flavonoids, the 6,8-di-C-glucosyl diosmetin was the most affected flavonoid by the type of rootstock used. The interstock used is able to alter the individual quantitative flavonoid order of eriocitrin, diosmin, and hesperidin. In addition, the HPLC-ESI/MS(n) analyses provided the identification of two new flavonoids in the lemon juice: Quercetin 3-O-rutinoside-7-O-glucoside and chrysoeriol 6,8-di-C-glucoside (stellarin-2). The occurrence of apigenin 6,8-di-C-glucoside (vicenin-2), eriodictyol 7-O-rutinoside, 6,8-di-C-glucosyl diosmetin, hesperetin 7-O-rutinoside, homoeriodictyol 7-O-rutinoside and diosmetin 7-O-rutinoside was also confirmed in lemon juice by this technique.     

沙田柚果实贮藏期水分变化与枯水的关系

沙田柚采后经１０ｄ预贮藏于常温室内,用＾３Ｈ２Ｏ示踪,定期测定果蒂部、果皮,果肉（汁胞）的放射性比活度和果实的失重率,果汁率,组织含水量,呼吸速率及营养物质含量变化,结果表明,沙田柚贮藏期间,果瓣之间,果肉和果皮之间水分是相互流动的,果实枯水时,水分从果肉到果皮的转移速度大于正常果,沙田柚果实枯水的原因可能与果肉营养物质消耗和果皮组织相对再生长同步进行有关。     

钙、硼营养对黄冠梨品质和果面褐斑病发生的影响

为探讨钙、硼营养对黄冠梨品质和褐斑病的影响,于幼果套袋之前进行叶面喷施0.3% H3BO4 (B)、0.5% CaCl2(Ca)、0.3% H3BO4＋0.5% CaCl2 (B＋Ca) 3次,每次间隔7d的试验。结果表明,3种处理均能显著降低果实贮藏前期果皮多酚氧化酶（PPO）活性、提高过氧化物酶（POD）活性和冷藏期间果皮褐斑指数;其中B+Ca处理效果最明显,并显著提高采收时单果重、果皮中Ca含量、Ca/Mg和Ca/K;Ca、B+Ca处理能降低果皮中可溶性酚含量;B处理显著提高果皮和果肉中的硼含量。这说明B+Ca处理能明显改善黄冠梨果实采收品质和贮藏性能。     

Isolation and identification of insecticidal components from Citrus aurantium fruit peel extract

Three active components were identified by bioassay-guided fractionation of bitter orange ( Citrus aurantium L.) fruit peel petroleum ether extract. Silica gel fractionation of the extract yielded a fraction that inflicted up to 96% mortality to adults of the olive fruit fly Bactrocera oleae (Gmelin) three days post-treatment. Subsequent HPLC purification of the active fraction resulted in the isolation of three components, eluted in fractions F 222, F 224, and F 226, that induced adult mortality. Considering the data obtained from UV, FTIR, MS, and (1)H NMR spectra, they were identified as 7-methoxy-8-(3'-methyl-2'-butenyl)-2 H-1-benzopyran-2-one (osthol), 4-methoxy-7 H-furo[3,2- g]benzopyran-7-one (bergapten), and 4-(( E)-3'-methyl-5'-(3',3'-dimethyloxiran-2'-yl)pent-2'-enyloxy)-7 H-furo[3,2- g][1]benzopyran-7-one (6',7'-epoxybergamottin). Our results are in concordance with those reported in the literature and were further verified by direct comparison to authentic components. 6',7'-Epoxybergamottin was toxic when tested individually, while bergapten and osthol were found to act synergistically to 6',7'-epoxybergamottin.