Four New Limonoids from Aphanamixis grandifolia

Triterpenoids from the fruits of Aphanamixis polystachya and their inhibitory activities on nitric oxide production

Nineteen triterpenoids, including five previously unknown (four triucallane-type derivatives and one highly oxidized A, B-seco limonoids), together with fourteen known triterpenoids, were isolated from the fruits of Aphanamixis polystachya. Their structures were elucidated by extensive spectroscopic analysis. All isolates were evaluated their anti-inflammatory activities. The result showed that all compounds inhibit LPS-induced nitric oxide production in RAW264.7 macrophages with their IC50 value ranging from 95 to 1332 uM, and compound 6 exhibited obvious anti-inflammatory activity comparable to that of the positive control, with IC50 values of 94.96 uM.

Two new triterpenoids from the fruits of Aphanamixis polystachya

Two new triucallane triterpenoids, polystanin F (1) and polystanin G (2), along with eight known compounds (3-10) were isolated from the fruits of Aphanamixis polystachya. Their structures were established on the basis of extensive spectroscopic analysis. Moreover, eight compounds were evaluated for their in vitro cytotoxicity against three cancer cell lines (liver cancer RT112, colon cancer HCT-116 and breast cancer M231) using the MTT method. Compound 7 showed significant cytotoxic activity against HCT-116 with IC₅₀ 1.27 μM.

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.

Natural product sciences: an integrative approach to the innovations of plant natural products

The study on plant natural products not only helps us understand that their structural diversity is the inevitable result of plant species diversity, but also helps us understand certain rules and unity of the inevitable connection between the two. The diversity and complexity of chemical structures of many natural products are beyond imagination before we elucidated their structures. The question that follows is what is the biological significance of these natural products. Intrigued by the relationship between plant resources, natural products and biological functions, the Hao laboratory has taken an integrative approach that employs tools and knowledge from multi-disciplines, including natural product chemistry, chemical ecology and chemical biology, to unveil the effects of plant natural products on plant resistance to diseases, and environmental acclimations. Collaborating with cell biologists, the research has resulted in discovery of new mechanisms of cellular signaling and lead compounds.

Antimalarial diterpenoid dimers of a new carbon skeleton from Aphanamixis grandifolia

Chemical investigation into the minor constituents of Aphanamixis grandifolia yielded three new diterpenoid dimers, aphadilactones E-G (1-3) featuring a new carbon skeleton. Their structures and absolute configurations were fully established by comprehensive spectroscopic data analysis and ECD calculation. Discovery of another two new dimers (4 and 5) suggested the structure of recently reported aphanamene A to be re-investigated. Compounds 1-5 showed moderate antimalarial activities with low micromolar IC50 values.

Bioactive Limonoid Constituents of Munronia henryi

Fourteen new limonoids, munronins A-N (1-14), and eight known limonoids (15-22) were isolated from the whole plants of Munronia henryi. The structures of the new compounds were elucidated by 2D NMR spectroscopy and mass spectrometry, and the structure of 8 was confirmed by single-crystal X-ray diffraction analysis. Compound 1 represents the first limonoid found with a novel 7-oxabicyclo[2.2.1]heptane moiety produced by incorporating C-11 and C-14 via an oxygen atom. All compounds were evaluated for their anti-tobacco mosaic virus (TMV) activity and in vitro cytotoxicity against the human cancer HL-60, SMMC-7721, A-549, MCF-7, and SW-480 cell lines. Among them, compounds 2, 8, 9, 10, 11, 12, 18, and 20 showed significant anti-TMV activity, with IC50 values in the range 19.6-44.4 μg/mL. Compounds 1 and 18 exhibited cytotoxic effects for all five cancer cell lines, with IC50 values between 0.4 and 4.8 μM.

Triterpenoids

This review covers the isolation and structure determination of triterpenoids reported during 2012 including squalene derivatives, lanostanes, holostanes, cycloartanes, cucurbitanes, dammaranes, euphanes, tirucallanes, tetranortriterpenoids, quassinoids, lupanes, oleananes, friedelanes, ursanes, hopanes, serratanes, isomalabaricanes and saponins; 348 references are cited.

Bioactive terpenoids from the fruits of Aphanamixis grandifolia

From the fruits of the tropical tree Aphanamixis grandifolia, five new evodulone-type limonoids, aphanalides I-M (1-5), one new apo-tirucallane-type triterpenoid, polystanin E (6), and three new chain-like diterpenoids, nemoralisins A-C (7-9), along with 12 known compounds were identified. The absolute configurations were determined by a combination of single-crystal X-ray diffraction studies, Mo2(OAc)4-induced electronic circular dichroism (ECD) data, the Mosher ester method, and calculated ECD data. The cytotoxicities of all the isolates and the insecticidal activities of the limonoids were evaluated.