Dysosesquiflorins A and B, sesquiterpenoids from Dysoxylum densiflorum

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.

Structure elucidation of a new bicoumarin derivative from the leaves of Dysoxylum parasiticum (Osbeck) Kosterm

A new bicoumarin derivative, bidysoxyletine (1), was isolated from the leaves of Dysoxylum parasiticum (Osbeck) Kosterm. The structure of 1 was elucidated by analysis of NMR, UV, IR, HR-ESITOFMS, and DDFT approach using the B3LYP exchange-correlation function for ¹³ C NMR and UV spectroscopic data. The results indicated that the structure of 1 possessed a dibenzonapthyrone skeleton.

Bidysoxyphenols A-C, dimeric sesquiterpene phenols from the leaves of Dysoxylum parasiticum (Osbeck) Kosterm

Three new sesquiterpene phenol dimers, bidysoxyphenols A-C (2-4), along with two known compounds, namely sesquiterpene phenol (1) and ionone derivatives (5), were isolated from the leaves of Dysoxylum parasiticum (Osbeck) Kosterm. The structures of these new compounds, including their absolute configurations, were elucidated by nuclear magnetic resonance spectroscopy, ultraviolet spectroscopy, infrared spectroscopy, high-resolution electrospray ionization time-of-flight mass spectrometry, and electronic circular dichroism. Compounds 1 and 2 showed cytotoxicity against human promyelocytic leukemia cells, with IC₅₀ values of 18.25 ± 1.52 and 39.04 ± 3.12 μM, respectively.

Walsogynes H-O from Walsura chrysogyne

Eight new limonoids, walsogynes H–O (1–8) were isolated from the barks of Walsura chrysogyne, and their structures were determined on the basis of the 1D and 2D NMR data. Walsogynes H–M (1–6) and O (8) were concluded to be 11,12-seco limonoids with a dodecahydro-1H-naphtho[1,8-bc:3,4-c′]difuran skeleton, and walsogyne N (7) to be 11,12-seco limonoid sharing a unique dodecahydronaphtho[1,8-bc:5,4-b′c′]difuran skeleton. Walsogynes H–O (1–8) exhibited potent antimalarial activity against Plasmodium falciparum 3D7 strain with IC₅₀ value of 2.5, 2.6, 1.6, 2.5, 1.5, 2.6, 2.1, and 1.1 µM, respectively.

Antibacterial and antifungal two phenolic sesquiterpenes from Dysoxylum densiflorum

A new phenolic sesquiterpene, dysoxyphenol (1), and the known sesquiterpene, 7R,10S-2-hydroxycalamenene (2), were isolated from the acetone extract of Dysoxylum densiflorum seeds. The structures of these compounds were determined based on physical, Nuclear Magnetic Resonance, and mass spectral data. Both compounds were evaluated for their antibacterial and antifungal properties against seven pathogenic bacteria and two wood-rotting fungi, respectively. The results showed that both compounds have significant antibacterial properties only against Bacillus subtilis (Minimum Inhibitory Concentration 28 μM), while in the antifungal evaluation compound 1 was found to be more active than compound 2. Therefore, compound 1 has promising antifungal properties that can be developed further for finding new antifungal agents.

Bisleuconothines B-D, Modified Eburnane-Aspidosperma Bisindole Alkaloids from Leuconotis griffithii

Three new bisindole alkaloids, bisleuconothines B-D (1-3), were isolated from the bark of Leuconotis griffithii. Their structures were elucidated by 1D and 2D NMR spectroscopy and DFT calculations. Bisleuconothine B (1) is the first monoterpene indole alkaloid dimer featuring bridges between both C-16-C-10' and C-2-O-C-9'. All compounds were deemed noncytotoxic (IC₅₀ > 10 μM) when tested against A549 human lung adenocarcinoma cells.

Cycloartane Triterpenoids with Anti-melanin Deposition Activity

Bioactivity guided separation of the extract of Malaysian Garcinia sp. resulted in the isolation of 23-acetoxy-mangiferonic acid (1) and the absolute configuration of C-23 was elucidated to be R by the advanced Mosher's method. The anti-melanin deposition activity of 1 was caused by the down regulation of tyrosinase gene expression.

Polyisoprenylated Acylphloroglucinols from Garcinia nervosa

Two new polyisoprenylated acylphloroglucinols, 7- epi-isoxanthochymol and 7- epi-cycloxanthochymol (1 – 2), were isolated from the barks of Garcinia nervosa together with their 7-epimers isoxanthochymol (3) and cycloxanthochymol (4). Their structures were determined on the basis of NMR spectroscopic data. The cytotoxic activity of the isolated compounds against HL-60, MCF-7 (human breast adenocarcinoma), A549 (human lung adenocarcinoma) and HepG2 (human hepatocellular carcinoma) cells were evaluated, and all compounds showed cytotoxic activity against all cell lines.

Reinereins A and B, new onocerane triterpenoids from Reinwardtiodendron cinereum

Bioactivity guided separation of Reinwardtiodendron cinereum barks methanol extract led to the isolation of two new onocerane triterpenoids, reinereins A and B (1 and 2), together with three known onocerane triterpenoids. Their structures were elucidated on the basis of NMR spectroscopic data. In vitro cytotoxic activities of the isolated compounds against several type of cancer cells were evaluated.

Three Tetracyclic Triterpenoic Acids from Dysoxylum densiflorum and Their Antibacterial Activities

This paper reports the chemical isolation and antibacterial properties of terpenoid components of Dysoxylum densiflorum. Three new tetracyclic triterpenoic acids, densiflorinic acids A-C (1-3), were isolated from the acetone extract of the plant's leaves. The structures of the three compounds were determined mainly by extensive analysis of 1-D and 2-D NMR spectroscopic data. On antibacterial evaluation, the highest activity was shown by compound 1 against Bacillus subtilis with an IC50 of 26.5 μM.

Discovery of aromadendrane anologues from the marine-derived fungus Scedosporium dehoogii F41-4 by NMR-guided isolation

Six new aromadendrane sesquiterpenoids and two known analogues, together with a new polyketide were discovered from the marine-derived fungus Scedosporium dehoogii by NMR-guided isolation. The biosynthetic pathways of sesquiterpenoids were proposed.