Limonoids from the roots of Trichilia sinensis and their cytotoxicities

Research progress of meliaceous limonoids from 2011 to 2021

Covering: July 2010 to December 2021Limonoids, a kind of natural tetranortriterpenoids with diverse skeletons and valuable insecticidal and medicinal bioactivities, are the characteristic metabolites of most plants of the Meliaceae family. The chemistry and bioactivities of meliaceous limonoids are a continuing hot area of natural products research; to date, about 2700 meliaceous limonoids have been identified. In particular, more than 1600, including thirty kinds of novel rearranged skeletons, have been isolated and identified in the past decade due to their wide distribution and abundant content in Meliaceae plants and active biosynthetic pathways. In addition to the discovery of new structures, many positive medicinal bioactivities of meliaceous limonoids have been investigated, and extensive achievements regarding the chemical and biological synthesis have been made. This review summarizes the recent research progress in the discovery of new structures, medicinal and agricultural bioactivities, and chem/biosynthesis of limonoids from the plants of the Meliaceae family during the past decade, with an emphasis on the discovery of limonoids with novel skeletons, the medicinal bioactivities and mechanisms, and chemical synthesis. The structures, origins, and bioactivities of other new limonoids were provided as ESI. Studies published from July 2010 to December 2021 are reviewed, and 482 references are cited.

Khayalactone- and phragmalin-type limonoids with PTP1B inhibitory activity from Trichilia sinensis Bentv

An investigation on the extract from the plant Trichilia sinensis Bentv. led to the isolation of 13 new limonoids (1-13), in which two were of khayalactone skeleton and 11 were phragmalin-type limonoids, and eight known phragmalin-type limonoids (14-21). Their structures were elucidated by using spectroscopic techniques and HRESIMS experiment. Compounds 6 and 17 displayed potent protein tyrosine phosphatase 1B inhibitory activity with IC₅₀ values of 1.2 ± 0.1 and 8.1 ± 0.5 μM, respectively.

MS diagnostic model and rapid distinguishing of bioactive limonoids in fruits of Melia toosendan using solid-phase extraction coupled with LC-MS/MS

INTRODUCTION

Melia toosendan Sieb. et Zucc. has been used as a Chinese folk medicine for roundworm treatment since ancient times. Many diverse limonoids have been isolated from Meliaceae plants, but it remains difficult to isolate and identify other limonoids because of their small natural concentrations.

OBJECTIVE

This study was performed to overcome the difficulties associated with fast and accurate identification of limonoids and establish a reliable and sensitive method for the analysis of minor limonoids in M. toosendan fruits.

METHODS

An efficient strategy for enrichment, detection, and identification of minor limonoids from M. toosendan fruits using solid-phase extraction with high-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (SPE-HPLC-Q-TOF-MS/MS) was developed herein.

RESULTS

Characteristic fragmentations and fragmentation ions containing trichilin-, nimbin-, and vilasinin-class limonoid skeletons were initially studied, and characteristic diagnostic ions involved retro Diels-Alder (RDA) reactions or homolytic cleavages, which were used to identify minor limonoids. In total, 13 limonoids, including four new ones, were identified.

CONCLUSION

This is the first report on the analysis of M. toosendan fruits to identify limonoids. This novel analysis method may stimulate further research regarding the identification of limonoids in other plant species.

Highly oxygenous trichilin-type limonoids from Trichilia sinensis

Six new trichilin-type limonoids (1-6) with C-19/29 lactol or acetal bridge and a new ring intact limonoid (7) were isolated from the desiccative ripe fruits of Trichilia sinensis. Their structures were determined by extensive spectroscopic methods including ¹H NMR, ¹³C NMR, HSQC, HMBC, ROESY experiments as well as HRESI-MS data. All isolated compounds were evaluated for toxicities against human pulmonary carcinoma A549 and Hela cell lines by sulforhodamine B (SRB) method. Compound 7 showed weak inhibitory activity in Hela cell line at 40 μmol·L^-1.