Phragmalin and mexicanolide limonoids with reversal of multidrug resistance from the seeds of Chukrasia tabularis A. Juss

Phragmalin-Type Limonoids from the Fruits of Chukrasia tabularis and Their Anti-Inflammatory Activity

Phytochemical investigation on the fruits of C. tabularis led to the isolation of five new phragmalin-type limonoids (1-5) and four known ones (6-9). The structures of the new compounds 1-5, named chuktabamalins A-E, were elucidated via spectroscopic techniques (HRESIMS, 1D and 2D NMR) and were comparable with the literature data of known compounds. In addition, new compounds were evaluated for in vitro anti-inflammatory activity. Compounds 1, 2, 3 and 5 showed moderate anti-inflammatory activity with IC₅₀ values of 21.72 ± 2.79, 23.29 ± 1.00, 47.08 ± 3.47 and 66.67 ± 2.89 μM, respectively.

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.

Aglatestine A, a Rearranged Limonoid with a 3/6/6 Tricarbocyclic Framework from the Fruits of Aglaia edulis

Aglatestine A (1), an unprecedented 3/6/6 tricarbocyclic limonoid framework along with four biogenic A/D-seco limonoid analogues with rare β-substituents at C-6 (2-5), was discovered from the fruits of Aglaia edulis. The structures of 1-5 along with their absolute configurations were clarified using methods of HRMS(ESI), NMR, electronic circular dichroism, X-ray diffraction crystallography, and quantum chemical calculations. The plausible biogenetic speculation suggested that an electrophilic cyclization between C-1 carbocation from acetolysis and electron-rich C-5 from enolization of C═O of 2 may play a key role. The biological evaluation showed that 5 exhibited anti-inflammatory activity indicated by inhibiting NO release in LPS-activated RAW 264.7 macrophages (IC₅₀: 35.72 ± 1.96 μM).