Chemical constituents from Aphanamixis grandifolia

Sesquiterpenoids from Meliaceae Family and Their Biological Activities

Sesquiterpenoids, an important class of natural products possessing three isoprene-derived units, are widely distributed across plants and have a variety of biological activities. All sesquiterpenoids are derived from farnesyl pyrophosphate (FPP), a biosynthesis precursor that can form various carbon skeletons. In order to provide a reference for further research and development of these compounds, this review focused on the increasing number of isolated and volatile sesquiterpenoids found to be produced by plants of the Meliaceae family between 1968 and 2023. The related articles were collected from SciFinder, Google Scholar, and PubMed. According to a literature review, several studies were started for more than 55 years on the plant's stem barks, twigs, leaves, flowers, seeds, and pericarps, where approximately 413 sesquiterpenoid compounds from several groups such as eudesmane, aromadendrane, cadinane, guaiane, bisabolane, furanoeremophilane, humulene, germacrane, and oppositane-type were isolated and identified with some minor products. Additionally, the hypothetical route of sesquiterpenoids biosynthesis from this family was identified, and eudesmane-type was reported to be 27% of the total compounds. The antimicrobial, antidiabetic, antioxidant, antiplasmodial, antiviral, and cytotoxic activities of the isolated compounds and major volatile sesquiterpenoids constituent on essential oil were also evaluated. The result showed the fundamental of using the sesquiterpenoid compounds from the Meliaceae family in traditional medicine and the discovery of new drugs.

Antifungal Activity of an Endophytic Fungus Aspergillus versicolor DYSJ3 from Aphanamixis grandifolia Blume against Colletotrichum musae

An endophytic fungus strain DYSJ3 was isolated from a stem of Aphanamixis grandifolia Blume, which was identified as Aspergillus versicolor based on the morphological characteristics, internal transcribed spacer (ITS) and calmodulin gene sequences analyses. A. versicolor DYSJ3 exhibited strong antagonistic activity against Colletotrichum musae, C. gloeosporioides and Fusarium oxysporum f. sp. cubense with the inhibition rates of 61.9, 51.2 and 55.3% respectively. The antifungal metabolites mainly existed in the mycelium of A. versicolor DYSJ3, and its mycelial crude extract (CE) had broad-spectrum antifungal activities against plant pathogenic fungi. The CE had a good thermal stability, and the inhibition rate of 100 µg/mL CE against C. musae was above 70.0% after disposing at 120 °C for 1 h. Five secondary metabolites were isolated from the CE and identified as averufanin, ergosterol peroxide, versicolorin B, averythrin and sterigmatocystin. Activity evaluation showed versicolorin B exhibited inhibitory effects on the mycelial growth and conidial germination of C. musae, and sterigmatocystin had a weak inhibitory effect on the mycelial growth of C. musae.

Stigmastane-type steroid saponins from the leaves of Vernonia amygdalina Del

Vernoramyosides A-F (1-6), six new Δ^7,9(11) stigmastane-type steroid saponins, along with four known analogues (7-10) were isolated from the leaves of Vernonia amygdalina Delile (Compositae). Their structures were determined by the combination of NMR, ECD and HR-ESI-MS data. These compounds all possessed highly oxidized side chain and a γ-lactam or α,β-unsaturated five-membered lactone ring. All isolates were screened for their activities in reversing resistance in MCF/DOX cells.

Density Functional Theory (DFT)-Aided Structure Elucidation of Linear Diterpenes from the Irish Brown Seaweed Bifurcaria bifurcata

Brown alga Bifurcaria bifurcata is an extraordinarily rich source of linear (acylic) diterpenes with enormous structural diversity. As part of our interest into secondary metabolites of the Irish seaweeds, here we report four new acyclic diterpenes (1-4) and seven known terpenoids (5-11) from the CHCl3 extract of B. bifurcata. The planar structures of the new metabolites were elucidated by means of 1D and 2D NMR, HRMS, and FT-IR spectroscopy. Since linear diterpenes are highly flexible compounds, the assignment of their stereochemistry by conventional methods, e.g., NOESY NMR, is difficult. Therefore, we employed extensive quantum-mechanical prediction of NMR chemical shifts and optical rotation analyses to identify the relative and absolute configurations of the new compounds 1-4. Several compounds moderately inhibited the human breast cancer cell line (MDA-MB-231) with IC50 values ranging from 10.0 to 33.5 μg/mL. This study not only demonstrates the vast capacity of the Irish B. bifurcata to produce highly oxygenated linear diterpenoids, but also highlights the potential of new methodologies for assignment of their stereogenic centers.

Acyclic diterpene and norsesquiterpene from the seed of Aphanamixis polystachya

Aphanamoxene A-D (1-4), three new acyclic diterpene derivatives and one new acyclic norsesquiterpene were isolated from the seed of Aphanamixis polystachya. Their structures were elucidated on the basis of extensive spectroscopic methods, including 1D and 2D NMR and HRESIMS. And the absolute configuration of 1 was achieved by Mosher method. These acyclic terpenoids (1-4) showed obvious nitric oxide production inhibitory activity on lipopolysaccharide-Induced RAW264.7 macrophages with IC₅₀ values of 17.6 ± 1.4, 9.8 ± 0.7, 16.6 ± 1.2, and 14.2 ± 0.9 μM, respectively.

Two novel nornemoralisin-type diterpenoids from Aphanamixis polystachya (Wall.) R. Parker

Two novel heptanornemoralisin-type diterpenoids nornemoralisins A (1) and B (2), together with two known compounds nemoralisin (3) and nemoralisin A (4), were isolated from the stem bark and leaves of Aphanamixis polystachya (Wall.) R. Parker. Their structures were established through comprehensive analyses of NMR spectroscopic data and high resolution mass spectrometric (HR-ESI-MS) data. The absolute configurations of carbon stereocenters were elucidated by circular dichroism (CD) analyses. The four compounds were tested for their potential cytotoxic effects against ACHN, HeLa, SMMC-7721, and MCF-7 cell lines. Nornemoralisins A (1) and B (2) exhibited significant cytotoxicity on ACHN with an IC₅₀ value of 13.9 ± 0.8 and 10.3 ± 0.4 μM, respectively, and other compounds failed to reveal obvious cytotoxicity on the tested cell lines, compared to positive control vinblastine (IC₅₀, 28.0 ± 0.9 μM).

High-throughput metabolomics for evaluating the efficacy and discovering the metabolic mechanism of Luozhen capsules from the excessive liver-fire syndrome of hypertension

Essential hypertension (EH) is a chronic disease characterized by a variety of causes of elevated systemic arterial pressure, which often causes functional or organic damage to important organs such as the heart, brain, and kidney. Hypertension of excessive liver-fire syndrome is a type of classification for young people with essential hypertension. The disease is slower in its onset and its symptoms are more ambiguous, and thus its pathogenesis is complicated and still unclear. In this study, aconite, dried ginger and cinnamon extracts were combined with l-NAME to establish a model of excessive liver-fire hypertension. Blood pressure (systolic blood pressure), ANGII, NE and 5-HT were used as evaluation indicators to establish the model. Urinary metabolomics based on ultra-high performance liquid chromatography coupled with quadruple time-of-flight mass spectrometry was used to characterize the metabolic changes and potential biomarkers in modeled rats. Compared to the treatment group, 32 potential biomarkers were initially identified in the model using multivariate statistical analysis involving 11 metabolic pathways. After oral administration of Luozhen capsules, eight biomarkers that can be adjusted in high, medium and low doses of Luozhen capsules in urine were preliminarily determined, mainly involving two metabolic pathways of amino acid metabolism and lipid metabolism. In conclusion, this study explored the metabolomic changes in rats with hypertension of liver-fire hyperactivity syndrome and the post-dose metabolomics, determined the relevant biomarker groups, and clarified the metabonomic connotation of Luozhen capsules in the treatment of liver-fire excessive type hypertension.

Essential hypertension (EH) is a chronic disease characterized by a variety of causes of elevated systemic arterial pressure, which often causes functional or organic damage to important organs such as the heart, brain, and kidney.

Anti-inflammatory diterpene dimers from the root barks of Aphanamixis grandifolia

A total of 14 new diterpene dimers, aphanamenes C-P ()1-14, with four known homologous compounds were isolated from the root barks of Aphanamixis grandifolia Bl. The structures of these compounds were elucidated by spectroscopic analyses, and their absolute configurations were determined using the CD exciton chirality method. In addition, all the compounds exhibited significant inhibition of lipopolysaccharide-induced nitric oxide production in RAW264.7 macrophages, with IC50 values between 7.75 and 38.23 μM.

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.

Assignment of absolute configurations of highly flexible linear diterpenes from the brown alga Bifurcaria bifurcata by VCD spectroscopy

Correct assignment of the stereogenic centers of highly flexible linear diterpenes (LDs) is challenging. Herein we report the first application of VCD spectroscopy for the absolute configuration determination of LDs of algal origin and provide experimental and computational procedures, such as a fragmentation approach, which will facilitate the use of VCD spectroscopy for configuration assignments of LDs.

Diterpenoids of terrestrial origin

This review covers the isolation and chemistry of diterpenoids from terrestrial as opposed to marine sources and includes, labdanes, clerodanes, pimaranes, abietanes, kauranes, gibberellins, cembranes and their cyclization products. The literature from January to December, 2014 is reviewed.