Globally,
the citrus industry produces various wastes, which contain
a great deal of limonoids. In order for the sustainable development
of the citrus industry, and considering the diverse bioactivities
of limonoids, a series of ester derivatives were constructed by structural
modification of limonin in the B ring. Furthermore, two seven-membered
lactone derivatives of limonin and obacunone with a novel skeleton
in the B ring were obtained by the Baeyer–Villiger oxidation
rearrangement. The steric structures of six key compounds 3a, 3b, 4m, 4n, 6, and 7 were determined by X-ray crystallography. It
demonstrated that the molar ratio of 3a (7α-isomer)
and 3b (7β-isomer) depended on the mixed solvents
in the reduction system. The anti-tobacco mosaic virus (TMV) activities
under three different modes of action for most of the tested compounds
were as the following sequence: inactivation effect > protection
effect
> curative effect. It was noteworthy that compound 4aa displayed the most potent anti-TMV/insect growth inhibitory activities,
which indicated that the introduction of the phenylacryloyloxy group
at the C-7β position of limonin could significantly improve
its agricultural biological activities. This study will pave the way
for future value-added application of citrus industrial wastes and
provide strong evidence for the discovery of sustainable biopesticides
based on limonoids.
:
Cholesterol, a steroid alcohol, was discovered by M.E. Chevreul in 1815. Cholesterol and its derivatives showed
a large variety of biological properties such as anticancer activity, anticardiac activity, anti-inflammatory activity,
antimicrobial activity, anti-psychotic activity, antioxidant activity, drug-loaded activity, etc. In this mini-review, the
advances of structural modification of cholesterol from 2014 to 2020 were summarized. In addition, the bioactivities,
mechanisms of action and structure-activity relationships of cholesterol and its related derivatives were involved.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.