Laboratory studies on the photostability of fumagillin, the active ingredient of Fumidil B1

Abstract

-Fumagillin (as the dicyclohexylammonium salt) has been found to be extremely unstable when solutions in 50% ethanol are exposed to sunlight in small vials, undergoing a series of degradations with half-lives in the range of seconds to minutes. Similar results were obtained with photolyses of Fumidil B in either 50% ethanol or sugar syrup. Decomposition also occurred in fluorescent room light. Exposure of fumagillin to sunlight for three days caused almost complete disappearance of UV absorption of fumagillin and all its immediate photoproducts. The reactions involved in the photolyses are apparently reversible Z:E rearrangements in the unsaturated ester portion of the molecule, and do not involve the pharmacologically active moiety. Samples of fumagillin in syrup, irradiated for 0, 0.5, 5, 30, or 360 minutes were all effective in protecting caged bees from nosema disease. While long exposures to sunlight probably should be avoided, brief exposure causes no obvious loss of activity.fumagillin / stability / photolysis / nosema disease / Apis mellifera

The stability and effectiveness of fumagillin in controlling Nosema ceranae (Microsporidia) infection in honey bees (Apis mellifera) under laboratory and field conditions

“…As a result, the fumagillin peak area decreased considerably and two peaks appear at longer retention times, with another two small peaks observed at shorter times. We believe that these new peaks correspond to neofumagillin diastereoisomers, in accordance with previous observations (Assil and Sporns 1991;Kochansky and Nasr 2004) and mass spectrometry analyses . It is noteworthy that when honey-sugar mixtures are irradiated, photodecomposition products are rarely observed despite the notable decrease of the fumagillin peak.…”

“…The UV-spectrum of Fumidil B® was very similar (between 335 and 355 nm) and in accordance with previous reports (Brackett et al 1988;Assil and Sporns 1991;Kochansky and Nasr 2004), 350 nm was the wavelength selected for a sensitive detection.…”

Evaluation of Fumagilin-B® and other potential alternative chemotherapies against Nosema ceranae-infected honeybees (Apis mellifera) in cage trial assays

“…resulting in the irreversible opening of the spiroepoxide group on the core cyclohexane skeleton of fumagillin. This spiro-epoxide is reportedly responsible for the biological activity of fumagillin, since opening of the epoxide by thermal decomposition leads to the loss of biological activity (Griffith et al 1997(Griffith et al , 1998Kochansky and Nasr 2004).…”

Impact of Nosema (Microsporidia) infection and fumagillin treatment on Lygus lineolaris (Hemiptera: Miridae)

“…One method of treatment shown to effectively control or suppress Nosema infections in European corn borer (Lewis and Lynch, 1970;Lewis et al, 1971), spruce budworm, Choristoneura fumiferana (Wilson, 1974), and various Hymenoptera (Kochansky and Nasr, 2004;Webster, 1994) is adding fumagillin to the diet. In this study fumagillin was effective in reducing infection rates and increasing longevity and total oviposition per female.…”