Abstract-Male coconut rhinoceros beetles, Orycres rhinoceros (L.), produce three sex-specific compounds, ethyl 4-methyloctanoate, ethyl 4-methylheptanoate, and 4-methyloctanoic acid, the first of which is an aggregation pheromone. Synthesis of these compounds involving conjugate addition of organocuprates to ethyl acrylate is reported. In field trapping experiments, (4S)-ethyl 4-methyloctanoate and the racemic mixture were equally attractive and 10 times more effective in attracting beetles than ethyl chrysanthemumate, a previously recommended attractant. Ethyl 4-methylheptanoate was as attractive as ethyl chrysanthemumate and more attractive than 4-methyloctanoic acid, but further studies are required before it can be classed as an aggregation pherornone. Compared to ethyl 4-methyloctanoate alone, combinations of the three male-produced compounds did not increase attraction, whereas addition of freshly rotting oil palm fruit bunches to pheromone-baited traps sjgnificantly enhanced attraction. With increasing dose, captures of O. rhinocerós'increased, but doses of 6, 9, and 18 mg/day were competitive with 30 mg/day lures. Newly designed vane traps were more effective in capturing beetles than were barrier or pitfall traps. Results of this study indicate that there is potential for using ethyl 4-methyloctanoate in operational programs to control O. rhinoceros in oil palm plantations.
Objective-Outcomes from the Women's Health Initiative have demonstrated adverse effects associated with hormone therapy (HT), and have prioritized the need to develop new alternative treatments for the management of menopause and osteoporosis. To this end, we have been investigating natural herbal medicines used by Costa Rican women to manage menopausal symptoms.Design-Seventeen plant species were collected and extracted in Costa Rica. To establish possible mechanisms of action, and determine their potential future use for menopause or osteoporosis, the estrogenic activities of the herbal extracts were investigated in an estrogen reporter gene ERβ-CALUX® assay in U2-OS cells, and in reporter and endogenous gene assays in MCF-7 cells.Results-Six of the plant extracts bound to the estrogen receptors. Four of the six extracts stimulated reporter gene expression in the ERβ-CALUX® assay. All six extracts modulated expression of endogenous genes in MCF-7 cells, with four extracts acting as estrogen agonists and two extracts, Pimenta dioica and Smilax domingensis, acting as partial agonist/antagonists by enhancing E2-stimulated pS2 mRNA expression, but reducing E2-stimulated PR and PTGES mRNA expression. Both P. dioica and S. domingensis induced a 2ERE-luciferase reporter gene in transient transfected MCF-7 cells, which was inhibited by the ER antagonist ICI 182780.Conclusions-This work presents a plausible mechanism of action for many of the herbal medicines used by Costa Rican women to treat menopausal symptoms. However, it further suggests that studies of safety and efficacy are needed before these herbs should be used as alternative therapies to HT.
Abstract-Coupled gas chromatographic-electroantennographic detection (GC-EAD) analyses and coupled GC-mass spectrometry (MS) of volatiles produced by male and female West Indian sugarcane weevils (W1SW), Metamasius hemipterus sericeus (Oliv.), revealed eight male specific, EAD-aclive compounds: 3-pentanol (1), 2-methyl-4-heptanol (2), 2-methyl-4-octanol (3), *To whom correspondence should be addressed. 'Current address: Department of Chemistry, University of Costa Rica, 2060 San Pedro, San Jose, Costa Rica. 4-methyl-5-nonanol (4), and the corresponding ketones. In field experiments in Florida, alcohols 1-4 in combination with sugarcane were most attractive, whereas addition of the ketones or replacement of alcohols with ketones significantly reduced attraction. In Costa Rica field experiments testing alcohols 1-4 singly and in all binary, ternary, and quaternary combinations revealed 4 in combination with 2 was the major aggregation pheromone, equally attracting male and female WISW. Stereoisomeric 4 and (45,5S)-4, the only isomer produced by WISW, were equally attractive. Addition of 4S-, 4R-or (±)-2 to (4S,5S)-4 significantly enhanced attraction. Sugarcane stalks in combination with 2 plus 4 (ratio of 1:8) were highly synergistic, whereas EAD-active sugarcane volatiles ethyl acetate, ethyl propionate, or ethyl butyrate only moderately increased attractiveness of the pheromone lure.
Small trunk pieces of a freshly felled 10-year-old oil palm,Elaeis quineensis (Jacq.), were placed in a modified Nalgene desiccator, and volatiles captured for six days on Porapak Q. Gas chromatographic (GC) analysis of Porapak-Q-trapped volatiles with both flame ionization (FID) and electroantennographic detection (EAD) using male or femaleR. phoenicis antennae revealed several EAD-active compounds. They were identified as: ethyl acetate, ethyl propionate, isobutyl propionate, ethyl butyrate, and ethyl isobutyrate. In field experiments in the La Me Research Station, Côte d'Ivoire, ethyl propionate (50 mg/24 hr) but not all esters combined (50 mg/24 hr each) significantly increased capture ofR. phoenicis in pheromone-baited (3 mg/24 hr) traps. One kilogram of 1- to 3-day-old palm tissue was significantly more effective than ethyl propionate in enhancing pheromone attraction. Superior attraction of palm tissue may be attributed to additional as yet unknown semiochemicals. Alternatively, release rates and/or ratios of synthetic volatiles differed from those of palm tissue at peak attraction.
5-Methyl-4-octanol is the major aggregation pheromone of the palmetto weevil,Rhynchophorus cruentatus (F.). The pheromone (cruentol) was identified by coupled gas chromatographic-electroantennographic (GC-EAD) analysis of male-produced volatiles, coupled GC-mass spectrometry (MS) in electron impact and chemical ionization mode, and coupled GC-high resolution MS. In laboratory and field assays, a diastereomeric mixture of synthetic cruentol greatly enhanced attraction of weevils to cabbage palmetto,Sabal palmetto (Walter), stem tissue, indicating that cruentol and host volatiles are synergistically attractive. An attractive lure in combination with efficient traps should facilitate development of semiochemical-based management forR. cruentatus.
This paper presents several organic molecules that have been labeled as acids but do not contain a carboxylic acid functional group. The rationale for the nomenclature and appropriate explanations for the apparent acidity are discussed. For each molecule, the structure is shown and the most acidic proton is highlighted. Various chemical principles such as pK a, tautomerization, aromaticity, conformation, resonance, and induction are explored.
The structures of two derivatives of 2‐hydroxy‐1,4‐naphthoquinone (lawsone) are examined using the density functional theory (DFT) hybrid functional B3LYP. Using the optimized structure of lawsone acetate, the reactivity of acyl transfer is described. Also, the nucleophilicity of the conjugate base of lawsone is predicted using the conceptual descriptors related to softness within the DFT framework. Copyright © 2008 John Wiley & Sons, Ltd.
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