The photochemistry of citral

Cookson, R. C.; Hudec, J.; Knight, S.A.; Whitear, B. R. D.

doi:10.1016/0040-4020(63)85014-0

Cited by 47 publications

(18 citation statements)

References 20 publications

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“…Moreover, just moderate ambient temperature (Table ), below the optimal 25 °C for B. bassiana growth (Fargues et al., ), triggers release and possibly biosynthesis of monoterpenes by B. rubrolineata (Figures A, A, and ). The phototoxicity of monoterpenes is enhanced by UV radiation (Cookson et al., ), and high temperature may increase formation of phototoxic products (Barany et al., ), but none was observed in our study. Moreover, germinated conidia exposed to monoterpenes do not elongate (Schwarz, ), and thus cannot penetrate the insects' integument.…”

Section: Discussioncontrasting

confidence: 70%

Do western boxelder bugs sunbathe for sanitation? Inferences from in vitro experiments

Schwarz

Punja

Goettel³

et al. 2012

Entomologia Exp Applicata

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When western boxelder bugs, Boisea rubrolineata (Barber) (Hemiptera: Rhopalidae), form aggregations in warm sunlight, they release from their posterior dorsal abdominal gland an odorous blend of monoterpenes with heretofore unknown biological function. In laboratory analyses and experiments, we show that bugs in warm sunlight, but not in shade, exude and spread copious amounts of monoterpenes onto their cuticle. These monoterpenes do not serve as a pheromone, but rather as a means of sanitation. They inhibit germination of conidia of the fungal pathogen Beauveria bassiana (Bals.‐Criv.) Vuill. (Hypocreales) as well as halt the growth of germinated spores. This prophylactic defense against pathogens appears adaptive for phytophagous insects, like B. rubrolineata, that are prone to infections by microbes thriving on leaf surfaces and in the insects' overwintering microhabitat.

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Section: Discussioncontrasting

confidence: 70%

Do western boxelder bugs sunbathe for sanitation? Inferences from in vitro experiments

Schwarz

Punja

Goettel³

et al. 2012

Entomologia Exp Applicata

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“…On the other hand, efforts have also been put forth to elucidate the mechanisms of the various photoreactions, which also often produce off-flavors (10)(11)(12)(13). The formation of hydroperoxides from (R)-limonene was described in detail by Grosch et al (10).…”

Section: A Different Aging Model For Orange Oil: Deterioration Productsmentioning

confidence: 98%

A Different Aging Model for Orange Oil: Deterioration Products

Ziegler¹,

Brandauer²,

Ziegler³

et al. 1991

Journal of Essential Oil Research

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Publication details, including instructions for authors and subscription information: ABSTRACT: Deterioration products and processes of sweet orange oil (Citrus sinensis L. Osbeck) were investigated on the basis of simulated aging conditions. For these experiments, we employed an aqueous acidic orange oil emulsion which was exposed to UV-light at room temperature for specified periods of time. Subsequent GUMS analysis revealed some relevant changes in the composition of the orange oil. The treatment caused a significant increase in several known compounds, such as carvone, isopulegol, isomers of carveol, the limonene and linalool oxides. On the other hand, other constituents, such as neral, geranial and citronellal, decreased. Moreover, we were also able to identify a number of newly formed secondary constituents. Among these were p-mentha-l&dien-4-01, a-cyclocitral, photocitral A, iso(iso)pulegol, carvonecamphor, menthone, isomenthone, isomers of p-mentha-l( 7),8-dien-2-01 and isopiperitenol.

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“…Carbonyl compounds with a, p-unsaturation are known to undergo a variety of photochemical reactions. Citral exposed to UV light formed photocitral A (2) and photocitral B (3) by an intramolecular [2+2] photocyclization process (Cookson et al, 1963). At elevated temperatures (2 SOOC) additional cycloproducts of citral were formed which were postulated to proceed via a biradical mechanism (Barany ef al., 1978).…”

Section: Citralmentioning

confidence: 99%

Mechanisms of Citral Phototoxicity

Asthana¹,

Larson²,

Marley³

et al. 1992

Photochem & Photobiology

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Citral, a monoterpene aldehyde synthesized by several plant genera, has been reported to exhibit antimicrobial activity. For the first time, we report that critral exhibits UV-A (315-400 nm) light enhanced oxygen-dependent toxicity against a series of Escherichia coli strains differing in DNA repair and catalase proficiency. Those E. coli strains carrying a gene leading to catalase deficiency (katF) are particularly sensitized to inactivation by citral and UV-A treatment when compared to catalase proficient strains (katF+). Consistent with these in vivo observations, citral when treated with UV-A in vitro produces H2O2. When tested against Fusarium oxysporum and F. solani, fungal root pathogens of Citrus, enhanced toxicity by citral in the presence of UV-A was demonstrated, while dark toxicity was negligible. When the plasmid pBR322 was treated with citral in the presence of UV-A, a change in conformation from the covalently closed circular to the open circular and, ultimately, the linear form was observed. The change in plasmid conformation corresponded to a reduction in transforming activity. Holding plasmid DNA which had been treated with UV-A light in the presence of citral at 4 degrees C for 22 h in the dark resulted in continued degradation of the DNA and loss of transforming activity. Holding plasmid DNA treated with UV-A or citral alone under identical conditions had no detectable effect on either plasmid conformation or transforming activity.

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The photochemistry of citral

Cited by 47 publications

References 20 publications

Do western boxelder bugs sunbathe for sanitation? Inferences from in vitro experiments

Do western boxelder bugs sunbathe for sanitation? Inferences from in vitro experiments

A Different Aging Model for Orange Oil: Deterioration Products

Mechanisms of Citral Phototoxicity

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