Squash leaf glandular trichome volatiles: Identification and influence on behavior of female pickleworm moth [Diaphania nitidalis (Stoll.)] (Lepidoptera: Pyralidae)

Fourteen volatile compounds occurring in leaf trichomes of yellow squash (Cucurbita pepo L. cv. Early Prolific Straightneck) were identified. These compounds accounted for 83.5% of the volatile matrix. Ubiquitous constituents of the epidermis (myristic, palmitic, and stearic acids,n-tricosane, andn-pentacosane) accounted for 73.7%; these compounds were not bioassayed. The volatileso-,m-, andp-xylene, toluene, 2-heptanone, (R)-(+)- and (S)-(–)-limonene, and germacrene D were tested for their influence on attraction and oviposition by the pickleworm moth (Diaphania nitidalis Stoll.). No single compound, except germacrene D, was attractive. (R)-(+)-Limonene and 2-heptanone were weakly repellent. Mixtures of the highly volatile fractions were as attractive as volatiles emanating from whole, intact leaves. Oviposition levels on treated artificial sites corresponded with levels of visitation. Oviposition was significantly stimulated by whole-leaf volatiles, and (S)-(–)-limonene caused a slight but significant reduction.Mention of a trade name or proprietary product does not constitute a warranty or guarantee by the U.S. Department of Agriculture, nor does it imply exclusion of other products that may also be suitable.     

Identification of a volatile attractant forDiabrotica andAcalymma spp. from blossoms ofCucurbita maxima duchesne

Fractionation of headspace volatiles fromCucurbita maxima blossoms by high-performance liquid chromatography resulted in the isolation of a single component which was highly active in an electroantennogram bioassay onDiabrotica undecimpunctata howardi antennae. This compound was identified as indole by gas chromatography-mass spectrometry. Field-trapping bioassays were conducted which indicated that indole is a potent attractant of the western corn rootworm,D. virgifera virgifera, and the striped cucumber beetle,Acalymma vittatum. The southern corn rootworm,D. u. howardi, did not respond, despite its strong EAG response. The sex ratio ofD. v. virgifera found in indole-baited traps varied seasonally. Males were trapped in abundance in late July and later September, 1983, while females were more abundant August and early September. The effectiveness of indole as aD. v. virgifera attractant also varied seasonally. A prolonged period of depressed trap catches occurred in early August 1983, during the silking and tasseling period of the corn in the field where trapping was carried out.Coleoptera: Chrysomelidae.     

南瓜中游离叶黄素的制备及抗氧化活性

为了探究南瓜提取物中叶黄素酯的皂化工艺条件和其体外抗氧化能力,在单因素试验基础上,以皂化液浓度、皂化温度和皂化时间为响应因子,采用Box-Behnken中心组合实验原理进行三因素三水平设计,优化南瓜叶黄素的皂化工艺;利用高效液相色谱（HPLC）和质谱（MS）分析检测皂化产物;经硅胶柱色谱分离得到纯化的南瓜叶黄素;采用分光光度法,通过比较DPPH·和·OH的清除能力评价南瓜中游离叶黄素的体外抗氧化活性。结果表明,南瓜提取物中叶黄素酯的最佳皂化工艺条件为皂化液质量浓度33 g/dL,温度33 ℃,时间5.5 h。在最优工艺条件下,南瓜提取物中游离叶黄素得率为0.4175%,与预测值相近,说明该优化工艺稳定可行。高效液相色谱（HPLC）和质谱（MS）分析检测表明皂化产物为叶黄素。硅胶柱色谱纯化后,游离叶黄素的纯度可提高到91.39%。南瓜中游离叶黄素清除DPPH·和·OH的半抑制质量浓度IC₅₀分别为0.021 4 mg/mL和0.038 3 mg/mL,抗氧化活性较高,可作为一种良好的天然抗氧化剂。     

Stability of pumpkin seed oil

In Austria pumpkins are grown primarily for the production of pumpkin seeds that can be used for eating or the production of salad oil. Pumpkin seed oil is dark green and its fatty acid composition consists typically of linoleic acid and oleic acid as the dominant fatty acids. The saturated fatty acids palmitic and stearic acid occur at lower levels. The samples for this study were taken from a breeding program that intends to increase the seed and oil productivity. 15 samples with different contents of linoleic acid (40—57%) and vitamin E (100—600 μg/g) were selected. The stability of the oil was measured in a Rancimat that oxidizes the oil at 120 �C and measures the induction time that is needed for the oxidation. The correlation analysis showed that only the ratio of linoleic acid to oleic acid had a significant influence on the oxidative stability of the oil. Vitamin E did not show any correlation. When α‐tocopherol was added to the oil a strong pro‐oxidative effect was observed.     

西葫芦多酚氧化酶酶学特性研究

以邻苯二酚为底物,采用分光光度法对西葫芦多酚氧化酶(PPO)的酶学特性及不同抑制剂对多酚氧化酶活性的影响进行研究。结果表明,西葫芦多酚氧化酶最适pH为6.6,最适温度为35℃,90℃处理5min可使该酶失活。多酚氧化酶催化的酶促褐变反应动力学符合米氏方程,动力学参数为Km=0.0417mol/L,Vmax=208.33U。四种抑制剂对PPO的抑制效果由强到弱依次为:亚硫酸氢钠>L-半胱氨酸>抗坏血酸>柠檬酸。     

苦味西葫芦果实木脂素类成分研究

采用色谱技术对苦味西葫芦果实的抗炎活性部位的化学成分进行分离,应用1HNMR、13CNMR确定化合物的结构.从正丁醇萃取部位分离得到4个木脂素化合物:Larisiresinol 4'-O-β-D-glucopyranoside(Ⅰ)、( )-5'-Methoxyisolarisiresinol 3α-O-β-D-glucopyranoside(Ⅱ)、Lyoniside(Ⅲ)、Isolariciresinol-9-O-β-D-xylopyranoside(Ⅳ).化合物Ⅰ、Ⅱ、Ⅲ和Ⅳ均为首次从南瓜属植物中分离得到.     

Cucurbitacins fromCucurbita texana: Evidence for the role of isocucurbitacins

In addition to cucurbitacins E andI, cucurbitacins D,1, 3-epi-isocucurbitacin D,2, and B,3, were isolated from the fruits ofCucurbita texana and structurally identified by UV, IR,¹H NMR,¹³C NMR, and MS, and 2-O--glucopyranosylcucurbitacin I was identified. These compounds have not been reported previously as constituents of this species. The isolation of 3-epi-isocucurbitacin D2 together with normal cucurbitacins suggests that isocucurbitacins occur naturally. Evidence is also discussed that isocucurbitacins are biosynthesized one step ahead of normal cucurbitacin.     

Production technology and characteristics of Styrian pumpkin seed oil

Cucurbita pepo subsp. pepo var. Styriaca, the so‐called Styrian oil pumpkin, is a phylogenetically young member of the Cucurbita spp. A single mutation occurred only in the 19^th century and led to dark green seeds with stunted outer hulls. This mutation facilitated the production of Styrian pumpkin seed oil that became a regional specialty oil in the south‐eastern part of Europe during the last few decades. We describe in this article the production and economic value of this edible specialty oil as well as the most important parameters relevant for its quality. Furthermore, we report on its molecular composition including fatty acids, vitamins, phytosterols, minerals, polyphenols, and those compounds that are responsible for its color, taste and flavor. Finally, information is provided on potential contaminants of Styrian pumpkin seed oil as well as its putative beneficial health effects.