Sesquiterpenoids from the Rhizomes of Homalomena occulta

Structure revision and absolute configuration of 5,7-diepi-2α-hydroxyoplopanone and anti-osteoporotic activities of sesquiterpenoids from the rhizomes of Homalomena pendula

Five sesquiterpenoids including 2α-hydroxyoplopanone (1), oplopanone (2), 1β,4β,6α-trihydroxy-eudesmane (3), 1β,4β,7α-trihydroxy-eudesmane (4) and bullatantriol (5) were isolated from Homalomena pendula. The structure of the previously reported compound, 5,7-diepi-2α-hydroxyoplopanone (1a), has been revised to 1 by the spectroscopic evidences (1D-/2D-NMR, IR, UV and HRESIMS) and by comparison between experimental and theoretical NMR data using DP4+ protocol. Furthermore, the absolute configuration of 1 was unambiguously assigned by ECD experiments. Compounds 2 and 4 displayed a potent ability to stimulate osteogenic differentiation of MC3T3-E1 cells at 4 µg/mL (by 123.74% and 131.07%, respectively) and 20 µg/mL (by 112.45% and 126.41%, respectively) whilst 3 and 5 did not show any activities. At 20 µg/mL, 4 and 5 significantly promoted the mineralization of MC3T3-E1 cells with values of 112.95% and 116.37%, respectively, whereas 2 and 3 were inactive. The results indicated that 4 could be an excellent component for anti-osteoporosis studies from the rhizomes of H. pendula.

Homalolides C-D, two new sesquiterpenoids from the rhizomes of Homalomena pendula

Two new sesquiterpenoids, homalolides C - D (1‒2), were co-isolated from the rhizomes of Homalomena pendula (Blume) Bakh.f collected in Vietnam with five known ones, aromadendrane-4α,10α-diol (3), bullatantriol (4), 1β,4β,6α-trihydroxy-eudesmane (5), 1β,4β,6β-trihydroxyeudesmane (6), and 1β,4β,7α-trihydroxy-eudesmane (7). The structures and relative configuration of new compounds were elucidated by 1 D-/2D-NMR, IR, UV and HRESIMS analyses, and by comparisons to the reported data in the literature. Homalolide C presented an unprecedented skeleton with the 4/8 bicyclic system. All isolates did not exhibit appreciable inhibitory effects on LPS-induced NO production in the RAW 264.7 macrophage cell line and on the growth of human lung cancer cell line (SK-LU-1).

Two new dinor-eudesmane sesquiterpenoids from the roots of Chloranthus multistachys

Two new dinor-eudesmane sesquiterpenoids, named multistalin A (1), and multistalin B (2), together with three sesquiterpene glycosides (3-5), and a norlabdane-type diterpene (6) were isolated from the root extract of Chloranthus multistachys Pei. Their structures were elucidated on the basis of spectroscopic analysis including 1D, 2D NMR techniques and HR-ESI-MS. In addition, the cytotoxicity activities of the isolated compounds against selected cancer cells (Hela and A-549) were evaluated by MTT assay.

Unprecedented 4, 9-seco-oplopanane and seven drimane sesquiterpenoids from the Chinese Liverwort Lejeunea flava (Sw.) Nees

An unprecedented 4, 9- seco -oplopanane ( 1 ), two undescribed drimane epimers ( 2 and 3 ), and five known drimane sesquiterpenoids ( 4 - 8 ) were isolated from the Chinese liverwort Lejeunea flava (Sw.) Nees. The structures of the new sesquiterpenoids were determined using nuclear magnetic resonance spectroscopy, electronic circular dichroism calculations, and single-crystal X-ray diffraction measurements. The inhibitory capacity of the new compounds against nitric oxide production in lipopolysaccharide-induced RAW 264.7 murine macrophages, along with the cytotoxicity of the new compounds against A549 and HepG-2 human cancer cell lines, were discussed.

Sesquiterpenoids from the rhizomes of Homalomena pendula and their anti-inflammatory activities

Sixteen sesquiterpenoids including two new ones, homalolides A - B (1‒2), were firstly isolated from the methanolic extract of the rhizomes of Homalomena pendula collected in Vietnam. The structures and relative stereochemistry of new compounds were elucidated by 1D-/2D-NMR, IR, UV and HRESIMS analyses. The GCMS experiment demonstrated that homalolide A (1) is an artifact due to the methylation during methanolic extraction process. All isolates (1‒16) were tested for their inhibitory activities against lipopolysaccharide-induced nitric oxide production in the RAW 264.7 macrophage cell line. Compounds 1, 3, 6‒8, 10‒12 displayed moderate inhibitory effect on NO production with IC₅₀ values ranging from 35.41 to 64.06 μM.

Chemical composition and antibacterial activities of essential oils from rhizomes and aerial parts of Homalomena cochinchinensis (Araceae)

In this study, the phytochemical composition and antibacterial activity of the essential oils isolated from the rhizomes and the aerial parts of Homalomena cochinchinensis were analysed for the first time using gas chromatography-mass spectrometry (GC-MS) and disk diffusion method. Consequently, 36 constituents were reported from H. cochinchinensis rhizomes, including linalool (57.4%), terpinen-4-ol (10.6%), α-sabinene (4.2%) as major compounds. Meanwhile, 30 compounds have been identified in the essential oil of the aerial parts of H. cochinchinensis, which myrcene (41.1%), sabinene (8.2%), D-limonene (9.1%) were the main constituents. Furthermore, the antibacterial activity of the essential oil from the rhizomes of the studied species could inhibit the growth of all six tested bacterial strains, including Bacillus cereus, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Salmonella enteritidis and Salmonella typhimurium whereas the essential oil from the aerial parts was proved to be able to inhibit the growth of five bacterial strains except S. enteritidis.

Structurally diverse terpenoids with neuroprotective activities from the resins of Populus euphratica

Five new terpenoids including one new abietane diterpenoid (1), one new aromadendrane diterpenoid (6), two new norsesquiterpenoids (8 and 9), and a new cembrane-derived diterpenoid (12), together with seven known compounds were isolated from Populus euphratica resins. The structures of these new compounds, including their absolute configurations, were characterized by spectroscopic and computational methods. All the compounds except 8 were test for their neuroprotective activities. The result revealed that compounds 1, 7, and 10-12 display neuroprotective activities in glutamate-induced SH-SY5Y cells in a concentration-dependent manner.

Diterpenoid Alkaloids and One Lignan from the Roots of Aconitum pendulum Busch

Diterpenoid alkaloids have neroprotective activity. Herein, three napelline-type diterpenoid alkaloids 1-3, two aconitine-type diterpenoid alkaloids 4-5, and one isoquinline-type alkaloid 6, as well as one lignan glycoside 7, have been isolated from the roots of Aconitum pendulum Busch. Compounds 1 and 7 were new compounds, and their chemical structures were determined on the basis of nuclear magnetic resonance (NMR) spectra and mass spectrometry analysis. A ThT assay revealed that compound 2 showed significant disaggregation potency on the Aβ_1-42 aggregates.

Two New Eudesmane Sesquiterpenoids from the Flowers of Chrysanthemum indicum

The flowers of Chrysanthemum indicum, i.e. Ye-ju-hua recorded in the Chinese Pharmacopoeia, has been widely used in China as an important heat-clearing and detoxifying herb for the treatment of inflammation, headache, and vertigo. A phytochemical investigation of this herb has led to the isolation of two new eudesmane sesquiterpenoids, 7-epi-eudesm-4(15),11(13)-diene-1β,3β-diol (1) and 7-epi-1β-hydroxy-β-eudesmol (2). The molecular structures of these new sesquiterpenoids were established based on the comprehensive spectroscopic analyses, including NMR, MS, and IR, and comparing with the literatures.

Purification, characterization, crystal structure and NO production inhibitory activity of three new sesquiterpenoids from homalomena occulta

Two new isodaucane-type sesquiterpenoids, namely (1R,4S,5S,6R,7S,10R)-isodauc-6,7,10-triol, C₁₅H₂₈O₃, (1), and (1R,4S,5S,6S,7S,10R)-isodauc-6,7,10-triol, (2), and a new eudesmane-type sesquiterpenoid, 1β,4β,5α-trihydroxyeudesmane, (3), were obtained from the rhizomes of homalomena occulta with the aid of column chromatography. Their structures were elucidated based on extensive spectroscopic analyses, including 1D NMR, 2D NMR and HRESIMS. The structure of (1) was confirmed by single-crystal X-ray diffraction and the absolute configuration was assigned with respect to that of the precursor. The single-crystal structure reveals that adjacent molecules of (1) embrace through two groups of intermolecular O-H...O hydrogen bonds to generate a two-dimensional sheet with a 6³-net topology. The three compounds were evaluated for their activity against lipopolysaccharide-induced production of nitrogen oxide (NO) in RAW 264.7 cells, and (1) showed an inhibitory effect on NO production, with IC₅₀ values of 5.7±0.22 µM.