Prenyleudesmanes, rare natural diterpenoids 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.

Rare noreudesmane sesquiterpenoids from the fruits of Dysoxylum densiflorum

Seven rare noreudesmane sesquiterpenoids (dysoxydenones M-S, 1-7), including three 11,12,13-trinoreudesmanes, three 13-noreudesmanes and one spirovetivane-type sesquiterpenoid, along with two known analogues were isolated from the fruits of Dysoxylum densiflorum. The planar structures were elucidated by a combination of 1D, 2D NMR and HRESIMS analyses. Their absolute configurations were determined by combination of single-crystal X-ray diffraction, CD exciton chirality method and ECD calculation. All compounds were screened for anti-inflammatory activity on LPS-induced RAW 264.7 cells and IL-1β inhibitory activity.

Dysoticans F–H: three unprecedented dimeric cadinanes from Dysoxylum parasiticum (Osbeck) Kosterm. stem bark†

An asymmetrical true-dimeric cadinane via ketonic bridge [C-15/C-3′], dysotican F (1), two symmetrical pseudo-cadinane dimers through an O-ether linkage [C-3/C-3′], dysoticans G (2) and H (3), as well as three known sesquiterpenoids 4–6 were obtained from the stem bark of Dysoxylum parasiticum (Osbeck) Kosterm. (Meliaceae). Their structures were determined by spectroscopic and quantum chemical calculations of ¹³C NMR shifts using a GIAO method and electronic circular dichroism (ECD) using a TDDFT method. A possible biogenetic pathway for 1–3 beginning from the known compounds (i–ii) was proposed. Cytotoxic evaluation showed that 2 as a new lead compound is the most potent against the MCF-7 and HeLa cell lines with IC₅₀ values of 12.07 ± 0.17 μM and 9.29 ± 0.33 μM, while 1 has moderate inhibition with IC₅₀ values of 31.59 ± 0.34 μM and 27.93 ± 0.25 μM. Furthermore, 3 is a selective inhibitor against the HeLa cell growth with an IC₅₀ value of 39.72 ± 0.18 μM. A brief structure–activity relationship analysis of all isolated compounds 1–6 was also provided, including comparison with the coexisting molecules in the previous report.

Dysoxylum parasiticum's stem bark produces an asymmetrical and two symmetrical dimers (1–3), dysoticans F–H, with a novel cadinene dimer skeleton.

Sesquiterpenoids and sesquiterpenoid dimers from the stem bark of Dysoxylum parasiticum (osbeck) kosterm

Two undescribed sesquiterpenoids, namely dysoticans A and B, and three undescribed sesquiterpenoid dimers, namely dysoticans C-E, together with six analogs, were isolated from the stem bark of Dysoxylum parasiticum (Osbeck) Kosterm. (Meliaceae), growing in West Java, Indonesia. Their structures were elucidated based on extensive spectroscopic analysis and theoretical simulations of ECD spectra and ¹³C NMR shifts. Dysoticans A and B possessed undescribed cadinanes with minor modifications, while C and D featured unprecedented pseudo-sesquiterpenoid dimers through O-ether linkages of cadinanes and guaianes, respectively. Dysotican E was also characterized as the true-sesquiterpenoid dimer featuring eudesmane-germacrene hybrid framework from the Meliaceae family. Furthermore, A-C and E showed moderate activities against the human breast cancer MCF-7 and cervical cancer HeLa cell lines with IC₅₀ values ranging from 22.15 to 45.14 μM. D selectively exhibited significant cytotoxicity against the HeLa cell line with an IC₅₀ value of 13.00 ± 0.13 μM.

Spirovetivane- and Eudesmane-Type Sesquiterpenoids Isolated from the Culture Media of Two Cyanobacterial Strains

As part of a study examining polar metabolites produced by cyanobacterial strains, we examined media extracts of a Calothrix sp. (strain R-3-1) and a Scytonema sp. (strain U-3-3). The cell mass of each was separated from the media, and HP20 resin was added for adsorption of secreted metabolites, a relatively unexplored area of cyanobacterial chemistry. HPLC-UV-LCMS-guided isolation led to the discovery of seven sesquiterpenoid compounds with five new, one known, and one previously isolated as the methyl ester. Through a complement of 1D and 2D NMR spectroscopic techniques, the planar structures and relative configurations of the seven compounds were elucidated. Spironostoic acid (1), 11,12-didehydrospironostoic acid (2), and 12-hydroxy-2-oxo-11-epi-hinesol (4) are spirovetivane-type compounds from R-3-1, while stigolone (5), 11R,12-dihydroxystigolone (6), and 11S,12-dihydroxystigolone (7) are three eudesmane-type compounds from U-3-3. Circular dichroism was utilized to decipher the absolute configurations of new compounds 1, 2, 4, 5, 6, and 7. Due to the structural variety observed among the spirovetivane- and eudesmane-type compounds in the literature and often a lack of clarity in how determinations were made, computational spectra and model compounds were used to support the interpretation of ECD and NMR spectra. A straightforward process to determine the configuration of these systems is presented.

Three new diterpenes from Dysoxylum lukii and their NO production inhibitory activity

Three new diterpenes were isolated from the stems of Dysoxylum lukii Merr and characterized on the basis of spectral data. Neoclerod-13Z-ene-3α, 4β, 15-triol (3) exhibited the inhibition of lipopolysaccharide-induced nitric oxide production in RAW264.7 macrophages with an IC₅₀ value of 25.49 μM.[Formula: see text].

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.

Prenyleudesmanes and A Hexanorlanostane from the Roots of Lonicera macranthoides

Three previously undescribed compounds, two prenyleudesmanes (1 and 2), and one hexanorlanostane (3), were isolated from the roots of Lonicera macranthoides. Their structures were established based on 1D and 2D nuclear magnetic resonance (NMR) spectra and high-resolution electrospray ionization mass spectral (HR-ESI-MS) data. The absolute configurations of 1 and 3 were determined by X-ray diffraction. To the best of our knowledge, this is the first time that the absolute configuration of a prenyleudesmane with a trans-decalin system and a hexanorlanostane have been unambiguously confirmed by single-crystal X-ray diffraction with Cu Kα radiation. Thecompounds were tested for their antiproliferative activity on the cancer cell lines (HepG2 and HeLa). The compounds 1–3 exhibited moderate inhibitory effects against two human cancer cell lines.

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.

Dysosesquiflorins A and B, sesquiterpenoids from Dysoxylum densiflorum

Two new aromadendrane sesquiterpenoids, dysosesquiflorins A and B (1 and 2), were isolated from Dysoxylum densiflorum bark, and their structures were elucidated on the basis of NMR spectroscopic data. These dysosesquiflorins showed in vitro cytotoxic activity against several cancer cell lines.

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.