Enantioselective Degradation of (2RS,3RS)‐Paclobutrazol in Peach and Mandarin Under Field Conditions

Abstract

In this study we investigated the enantioselective degradation of (2RS,3RS)-paclobutrazol in peach and mandarin fruits under field conditions after foliar treatment at 500 mg active ingredient/L using a Lux Cellulose-1 chiral column on a reverse-phase liquid chromatography-tandem mass spectrometry system. Degradations of paclobutrazol in both fruits followed first-order kinetics, with half-lives of about 9 days. Initial deposits were 1.63 mg/kg on peach and 1.99 mg/kg on mandarin; terminal concentrations were lower than 0.05 mg/kg, which was acceptable in most cases. As anticipated, paclobutrazol levels in peels of mature mandarin were about 6.3 times higher than in pulp, indicating the potential risk of peel consumption. We also observed that paclobutrazol degradation in mature mandarin was relatively slow, indicating it might not be efficient enough to hold mandarin fruits on trees for lowering paclobutrazol concentrations. Significant enantioselectivity was observed: the (2R,3R)-enantiomer was preferentially degraded in mandarin (whole fruit, peels, and pulp) but enriched in peach. Because of its more rapid degradation in mandarin and the lower levels observed in pulp compared with peels, potential endocrine-related side effects due to the (2R,3R)-enantiomer pose less of a risk in mandarin than in peach.

Enantioselective Degradation of (2RS, 3RS)‐Paclobutrazol in Rat Liver Microsomes

“…The enantiomeric fractions (EF) were defined as E(+)/(E(+)+E(–)) for enantiomers with a known elution order, where E(+), E(–) are peak areas of respective enantiomers with their signs of optical rotation. The order of elution of paclobutrazol enantiomers was confirmed to be (+)(2 R , 3 R )‐paclobutrazol and (–)(2 S , 3 S )‐paclobutrazol based on published data . Therefore, in this article the EF of paclobutrazol was calculated from the equation EF = [2 R , 3 R ] / ([2 R , 3 R ] + [2 S , 3 S ]) and is graphed in Figure B.…”

“…This study also indicated the enzymatic stereoselective behavior of paclobutrazol enantiomers in organisms and other environmental matrices. 8,13,17 As a consequence, our investigation may provide reference data for the safe and efficient use of the chiral plant growth regulator paclobutrazol.…”

“…The order of elution of paclobutrazol enantiomers was confirmed to be (+)(2R, 3R)-paclobutrazol and (-)(2S, 3S)-paclobutrazol based on published data. 17,20 Therefore, in this article the EF of paclobutrazol was calculated from the equation EF = [2R, 3R] / ([2R, 3R] + [2S, 3S]) and is graphed in Figure 3B.…”

Enantiomeric effect of paclobutrazol on the microorganism composition during wine fermentation

“…The reasons for this might be the use of yeast as a starter. In addition, compared with A0d, the relative abundance of Aureobasidium in AN7d and AP7d was significantly lower ( P <.05, Q < 0.05), indicated that the fermentation system of wine was not suitable for the growth of Aureobasidium , and previous study illustrated that Aureobasidium is an important saprophytic yeast, and usually found in various habitats . In the fermentation system with no yeast added, Schwanniomyces and Cladosporium were the dominant fungi at the beginning of fermentation (B0d), and after 7 days of fermentation, the abundance of Pichia was increased and became the main fungi (BN7d and BP7d).…”

The different dissipation behavior of chiral pesticide paclobutrazol in the brine during Chinese cabbage pickling process

“…(2R, 3R)-Paclobutrazol was preferentially degraded in mandarin but enriched in peach. 18 Fermentation food is a traditional food worldwide through thousands of years under the action of microorganisms. 19,20 Different foods have been fermented in daily life such as vegetable, bean, fruit, dairy, and fish.…”