The development of delayed bitterness in citrus products is a major problem to citrus producers and juice processors worldwide. A rapid and sensitive liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) method has been developed to quantify the recognized precursors of limonoid derived delayed bitterness, limonoate and nomilinoate A-ring lactones, in a wide variety of cit...

Enzymatic ring-opening copolymerization of lactones was carried out by using Pseudomonas f luorescens lipase in bulk. In the copolymerizaton of r-caprolactone (E-CL) and b-valerolactone at 60°C for 10 days a copolymer with molecular weight of 3.7 x 103 was obtained and its structure was found to be of random structure having both units from 13C NMR anlaysis. Effects of the feed ratio, the react...

In a straightforward and fast protocol, a mixture of 1,3-dimethylimidazolium fluoride ([DMIM]F) and 1-butylimidazolium tetrafluoroborate ([Hbim]BF₄) efficiently catalyzed the reaction of epoxides with ketene silyl acetals (KSA) to give various γ-lactones under metal-free conditions. Diverse kinds of the desired γ-lactones were directly prepared with high regioselectivities and yields in a simpl...

The extraction of yacon [Smallanthus sonchifolius (Poepp. and Endl.) H. Robinson; Asteraceae] leaves and chromatographic separation yielded two new antibacterial melampolide-type sesquiterpene lactones, 8beta-tigloyloxymelampolid-14-oic acid methyl ester and 8beta-methacryloyloxymelampolid-14-oic acid methyl ester, as well as the four known melampolides, sonchifolin, uvedalin, enhydrin and fluc...

Polycondensation in batch is the classical way to produce polyesters. However, this method requires harsh conditions reach high conversions and drive equilibrium of reaction forward. In order controlled polymers a greener way, we worked on enzymatic ring opening polymerization (e-ROP) lactones using CALB lipase immobilized porous beads (Novozym® 435) as catalyst 3-phenyl-1-propanol (PP) initiat...

Lactones are important intermediates in organic synthesis, and they are employed as monomers and used e.g. as fragrances. Smaller cycles, such as ε-caprolactone, are polymerised to polyesters for medical applications taking advantage of their biodegradability. These small cycles are readily accessible on industrial scales by Baeyer–Villiger oxidation of cyclohexanone. Amongst large-ring lactone...

A number of bacteria, including some significant pathogens, utilize N-acylhomoserine lactones (AHLs) as quorum sensing signals. There is considerable interest in the therapeutic potential of disrupting quorum sensing. Recently, a number of bacteria have been identified which are capable of enzymic inactivation of AHLs. These enzymes show considerable promise as 'quenchers' of quorum sensing. Ho...

The aerial parts of Inula verbascifolia afforded two new guaianolide-type sesquiterpene lactones. Their structures were determined by spectroscopic methods (IR, MS, 1H NMR, 13C NMR, DEPT, 1H-1H COSY, HMQC, and HMBC).