Desflavasides A-D: Four new tetrasaccharide pregnane glycosides from Desmidorchis flava

Four new pregnane glycosides named desflavasides A-D (1–4) were isolated from the sap of Desmidorchis flava (N.E.Br) Meve & Liede. The structures of all new compounds were elucidated based on 1D and 2D NMR spectroscopic techniques coupled with mass spectromentry (ESIMS and HRESIMS).     

Melanogenesis inhibitory pregnane glycosides from Cynanchum atratum

Bioassay-guided fractionation of the methanolic extract from the roots of Cynanchum atratum has resulted in the isolation of three new pregnane glycosides (1–3) along with four known compounds (4–7). Their structures were identified by analysis of the spectroscopic data including extensive 2D NMR. All of the isolates were evaluated for their potential to inhibit the melanin production in α-melanocyte stimulating hormone (α-MSH)-activated B16 melanoma cells. Of these, compounds 4–7 dose-dependently inhibited the melanin production with the IC₅₀ values ranging from 4?μM to 33?μM.     

6-Methoxyflavonols from the aerial parts of Tetragonia tetragonoides (Pall.) Kuntze and their anti-inflammatory activity

Dried aerial parts of Tetragonia tetragonoides were extracted with 70% EtOH, and the evaporated residue was successively separated into EtOAc, n-BuOH, and H₂O fractions. As a result of repeated SiO₂, ODS, and Sephadex LH-20 column chromatography, four new 6-methoxyflavonol glycosides (2–4, 8) along with four known ones (1, 5–7) were isolated. Several spectroscopic data led to determination of chemical structures for four new 6-methoxyflavonol glycosides (2–4, 8) and four known ones, 6-methoxykaempferol 3-O-β-d-glucopyranosyl-(1 → 2)-β-d-glucopyranosyl-7-O-(6‴′-(E)-caffeoyl)-β-d-glucopyranoside (1), 6-methoxyquercetin (5), 6-methoxykaempferol (6), and 6-methoxykaempferol 7-O-β-d-glucopyranoside (7). Methoxyflavonol glycosides 2–8 also have never been reported from T. tetragonoides in this study. 6-Methoxyflavonols 5 and 6 showed high radical scavenging potential in DPPH and ABTS test. Also, all compounds showed significant anti-inflammatory activities such as reduction of NO and PGE₂ formation and suppression of TNF-α, IL-6, IL-1β, iNOS, and COX-2 expression in LPS-stimulated RAW 264.7 macrophages. In general, the aglycones exhibited higher activity than the glycosides. In addition, quantitative analysis of 6-methoxyflavonols in the T. tetragonoides aerial parts extract was conducted through HPLC.     

Flavonoid glycosides from the aerial parts of Curcuma comosa

Four new flavonoid glycosides, curcucomosides A–D (1–4), three known flavonoid glycosides, 5–7, and four known diarylheptanoids, 8–11, were isolated from the ethanol extract of the aerial parts of Curcuma comosa. The structures of the new compounds were established as rhamnazin 3-O-α-l-arabinopyranoside (1), rhamnocitrin 3-O-α-l-arabinopyranoside (2), rhamnazin 3-O-α-l-rhamnopyranosyl-(1→2)-O-α-l-arabinopyranoside (3), and rhamnocitrin 3-O-α-l-rhamnopyranosyl-(1→2)-O-α-l-arabinopyranoside (4) by spectroscopic analysis and chemical reactions whereas those of the known compounds were identified by spectral comparison with those of the reported values.     

Iridoids from the flowers of Gardenia jasminoides Ellis and their chemotaxonomic significance

Phytochemical investigation of the flowers of Gardenia jasminoides Ellis (Rubiaceae Gardenia) resulted in the isolation and identification of four iridoid aglycones (1–4) and eleven iridoid glycosides (5–15). This is the first report of the occurrence of these compounds in the genus Gardenia: garjasmine (1), dunnisin (2), α-gardiol (3), β-gardiol (4), diffusoside A (6), diffusoside B (7), genameside C (13), and deacetylasperulosidic acid (14). The chemotaxonomic significance and biosynthetic pathways of these iridoid aglycones (1–4) and iridoid glycosides (5–15) are summarized. Iridoid aglycones and iridoid glycosides are considered as important chemotaxonomic markers in Rubiaceae and this work indicates that the iridoid aglycones (1–4) have a limited distribution in the Rubiaceae.     

Oleanane glycosides from the roots of Alhagi maurorum

Three new oleanane-type triterpene glycosides (1–3), along with four known compounds (4–7) glycosides, were isolated from the roots of Alhagi maurorum. Their structures were elucidated by 1D and 2D-NMR experiments as well as ESI-MS analysis. The antiproliferative activity of the isolated compounds was evaluated against a small panel of cancer cell lines including human breast cancer (MCF-7), human lung adenocarcinoma (A549), human prostate cancer (PC-3) and human leukemia (U937) cell lines. None of the tested compounds, in a range of concentrations between 1 and 50 μM, caused a significant reduction of the cell number.     

Four new glycosides from the seeds of Cassia obtusifolia

Four new glycosides, including one anthraquinone glycoside (1), one naphthalene glycoside (2), and two naphthopyrone glycosides (3–4), with 10 known compounds (5–14) were isolated from the seeds of Cassia obtusifolia L. The new structures were determined by spectroscopic analysis and chemical transformations.     

Three new glycosides from the whole plant of Clematis lasiandra Maxim and their cytotoxicity

Phytochemical investigation on the whole plant of Clematis lasiandra Maxim led to the isolation of two new phenolic glycosides (1 and 2), one new lignanoid glycoside (3), together with three known lignanoid glycosides (4–6). The structures of the new compounds were elucidated as 4-O-β-d-galactopyranosyl-ethyl-E-caffeate (1), 4-O-β-d-galactopyranosyl-3-hydroxyl-phenylethene (2) and (8R)-3,3′-dimethoxy-4,4′,9,9′-tetrahydroxy-5′,8-lignan 3′-O-β-d-glucopyranoside (3), on the basis of extensive spectral analysis and chemical evidence. The characteristic of the polymerized C-5′–C-8 type lignanoid aglycone in glycoside 3 was found from genus Clematis for the first time. Compounds 1–6 were evaluated for their cytotoxicity against human tumor cell lines HL-60, Hep-G2 and SGC-7901, the new glycosides 1 and 2 showed significant cytotoxicity against those three tumor cell lines with IC₅₀ in the range from 9.73 to 22.31 μM, while lignanoid glycosides 3–6 showed weak cytotoxicity to those test cell lines with IC₅₀ value more than 52.71 μM.     

Pregnane steroids from the South China Sea gorgonian coral Subergorgia suberosa

Chemical investigation on gorgonian coral Subergorgia suberosa collected from the South China Sea led to the isolation and identification of eight 17-acetyl pregnane steroids (1–8), of which 1, 6 and 7 were obtained for the first time from this species, as well as from the genus Subergorgia. Compounds 1 and 7 are new natural products. Compared with other species in the genus Subergorgia, pregnane steroids with 17-acetyl group (1–8) were only achieved from S. suberosa, suggesting that the 17-acetyl pregnane steroids might be characteristic constituents of S. suberosa, and may be useful as chemotaxonomic markers for the species S. suberosa.     

A new phenylpropanoid glycoside from the bark of Streblus ilicifolius (Vidal) Corner

A new compound, pheglycoside A (1), along with four known aromatic glycosides (2-5) and three known lignan glycosides (6–8) were isolated from Streblus ilicifolius (Vidal) Corner. The structure of compound 1 was determined by spectral analyses, including HRESIMS, 1D, and 2D NMR (COSY, HSQC, and HMBC) experiments. The absolute configuration of compound 1 was determined using the CD spectrum and experiment data. From the present investigation, all these compounds were isolated for the first time from S. ilicifolius. It is interesting that phenylpropanoid glycoside and aromatic glycosides are reported for the first time in the genus Streblus. The chemotaxonomic significance of these compounds was summarized.     

Anti-proliferative and computational studies of two new pregnane glycosides from Desmidorchis flava

Two new pregnane glycosides named desmiflavasides C (1) and D (2) were isolated from the sap of Desmidorchis flava (N.E.Br.) Meve & Liede and have had their structures confirmed from 1D and 2D NMR spectroscopic techniques and mass spectrometry (ESIMS). Further, the effects of desmiflavasides C (1) and D (2) on the proliferation of breast and ovarian cancer cells as well as normal breast epithelial cells in culture were examined. Interestingly, desmiflavasides C (1) and D (2) were able to cause a substantial decline in the viability of cancer cells in a concentration-dependent manner. Moreover, treatment of normal cells with compound 2 resulted in no significant growth inhibition, indicating that its cytotoxicity was selective towards cancer cells. Furthermore, the activity of compound 2 against cancer as well as normal epithelial cells was found to be similar to that of a previously reported pregnane glycoside, nizwaside (3). Molecular docking studies of desmiflavasides C (1) and D (2) and nizwaside (3) were carried out to ascertain if it was possible to predict any important binding orientations required of small molecule drug candidates with suggested protein target molecules for the purposes of being able to predict the affinity and activity to an acceptable degree by such compounds. Desmiflavaside D (2) showed a relatively good binding affinity (−22.4449 kcal/mol) as compared to the other two compounds viz., nizwaside (3) (−20.0319 kcal/mol), and desmiflavaside C (1) (−19.4042 kcal/mol). Docking results of the three pregnane glycosides viz., 1–3 revealed that these ligand molecules can accurately interact with the target protein.     

Chemical constituents of the bulbs of Haemanthus multiflorus

Six new (1–6) and four known (7–10) phenolic glycosides were isolated from the bulbs of Haemanthus multiflorus (Amaryllidaceae). The structures of the new compounds were determined on the basis of spectroscopic analysis and of chromatographic analysis of the hydrolyzed products. Moreover, compound 1 showed moderate cytotoxicity against HL-60 human promyelocytic leukemia cells.     

Chemical constituents from Lagopsis supina (Steph.) Ik.-Gal. ex Knorr

Phytochemical investigation of the whole plants of Lagopsis supina (Steph.) Ik.-Gal. ex Knorr. led to the isolation of 18 compounds (1–18), including ten phenylethanoid glycosides (1–10), one phenylmethanoid glycoside (11), four megastigmane glycosides (12–15), and three monoterpenoid glycosides (16–18). Lagopsides A (1) and B (2) were identified as new phenylethanoid glycosides. This is the first report of compounds 7, 11, 12, 15, and 16 from the Labiatae family, while compounds 4–6, 8–10, 13–14, and 17–18 were isolated from the genus Lagopsis for the first time. The chemotaxonomic significance of these isolated compounds was summarized.     

Ximaosteroids A–D,new steroids from the Hainan soft coral Scleronephthya sp.

One novel uncommon steroid, ximaosteroid A (1), possessing an unusual tetrahydrofuran moiety and three new pregnane steroids, ximaosteroids B–D (2–4), were isolated from the Hainan soft coral Scleronephthya sp. Their structures were elucidated on the basis of detailed spectroscopic (IR, MS, and 2D NMR) analysis and by comparison with those reported in the literature.     

Chemical constituents from the leaves of Ilex urceolatus

Eighteen compounds, including four hemiterpene glycosides (1–4), three triterpenoid saponins (5–7), four triterpenes (8–11), five sterols (12-16) and two monoterpene glucosides (17 and 18), were isolated from the leaves of Ilex urceolatus C. B. Shang, K. S. Tang et D. Q. Du, which was identified as a new species belonging to the genus Ilex. Among them, compounds 14–18 were firstly isolated from the genus Ilex, others were obtained from I. urceolatus for the first time. This work represented the initially phytochemical study on this plant. The isolated compounds have significant chemotaxonomic characteristics with the other species from this genus.     

New phenolic glycosides isolated from Penthorum chinense Pursh

A phytochemical investigation from 80% ethanol extract of Penthorum chinense Pursh (Saxifragaceae) resulted in the isolation of three new phenolic glycosides (1–3), together with three known phenolic glycosides (4–6). The structures of the new compounds were deduced from their comprehensive spectroscopic analysis including IR, HR-EI-MS, ¹H NMR, ¹³C NMR, DEPT, COSY, HMBC and HMQC. And the structures of known compounds 4–6 were identified by comparison of their spectral data with those reported in the literature.     

Bibenzyl and phenolic glycosides from Pterospermum heterophyllum

A new bibenzyl, heterophyllic acid (1), and three new phenolic glycosides, heterophylloside A–C (2–4), along with two known phenolic glycosides oldhamioside (5) and 6′-O-vanilloylisotachioside (6) were isolated from Pterospermum heterophyllum. The structures of these compounds were elucidated on the basis of 1D, 2D NMR, MS spectroscopic analysis, and chemical methods. Their cytotoxic activities against KB and MCF-7 cancer cell lines were evaluated. Compound 2 showed significant cytotoxic activities.     

Two new labdane diterpenoids and one new β-lactam from the aerial parts of Roylea cinerea

Two new labdane diterpenoids cinereanoid C (1), cinereanoid D (2), a new β-lactam, cinerealactam E (3) as well as six known flavonoid glycosides (4–9) were isolated from the aerial parts of Roylea cinerea (Lamiaceae). The structures of (1–9) were all determined by MS, IR and NMR spectroscopy. The structure of cinereanoid D (2) was further proven by single crystal X-ray diffraction. Six known flavonoid glycosides (4–9) were also isolated for the first time from this plant. 2, 5, 6 and 7 were found to significantly inhibit the ATP binding of a tumour growth-promoting heat shock protein, Hsp90.     

Six new compounds from the flowers of Chrysanthemum morifolium and their biological activities

Flower of Chrysanthemum morifolium is widely used in China and Japan as a folk medicine in treatment of many diseases. However, its active compounds remain largely unknown. In the present work, we have isolated, purified and characterized six new compounds (1–6), including two new arylnaphthalene lignans and four new phenolic glycosides, together with eight known compounds (7–14), from the flower of C. morifolium. Their structures and absolute configurations were elucidated in detail using 1D and 2D NMR, UV, IR, ORD, HRESIMS and ECD spectrometric data. In addition, compounds 1–3 possessed the significant neuroprotective activity against hydrogen peroxide-induced neurotoxicity in human neuroblastoma SH-SY5Y cells.     

Structure–activity relationship of lupane-triterpene glycosides from Acanthopanax koreanum on spleen lymphocyte IL-2 and IFN-γ

Phytochemical investigation resulted in the isolation of three new lupane-triterpene glycosides acankoreosides M–O (1, 2 and 8) together with eight known lupane-triterpene glycosides (3–7, 9–11) from the leaves of Acanthopanax koreanum (Araliaceae). Their chemical structures were elucidated by mass, 1D and 2D NMR spectroscopy. The effect of eleven lupane-triterpene glycosides on Con A-induced splenolytic production of IL-2 and IFN-γ were measured as markers of acquired immune responses. Compounds 4, 5, 7, and 11 (5, 25, and 100 μM) significantly increased IFN-γ and IL-2 release in spleen cells.