Two novel saponins from Cephalaria davisiana (Dipsacaceae)

Two novel hederagenin type triterpene saponins, namely davisianoside A (1) and davisianoside B (2) together with ten known compounds (3–12) were isolated from the aerial parts of Cephalaria davisiana (Dipsacaceae). One new prosapogenin (1a) was also obtained after the alkaline hydrolysis of compound 1. The chemical structures of all compounds were established mainly by 1D-, 2D-NMR and HR-ESI/MS analysis as well as chemical methods.The antibacterial and antifungal effects of compounds 1–2 were evaluated against Gram-positive, Gram-negative bacteria and unicellular yeast C. albicans by MIC method.     

Chemical constituents from Alnus mandshurica (Callier) Hand.-Mazz. and their chemotaxonomic significance

A new phenol compound, (9S)-9-hydroxy-9-[(2-hydroxyphenyl)methoxy]-nonanoic acid methyl ester (1) was isolated from the stem bark of Alnus mandshurica (Callier) Hand.-Mazz., along with eight known compounds (2–9). The structure of compound 1 was determined by spectral analyses, including HR-ESI-MS, 1D and 2D NMR (COSY, HMQC and HMBC) experiments. All the isolated compounds were reported for first time from A. mandshurica. Furthermore, compounds 3–9 were found in the family Betulaceae for the first time.     

Drechmerin H,a novel 1(2), 2(18)-diseco indole diterpenoid from the fungus Drechmeria sp. as a natural agonist of human pregnane X receptor

A novel 1(2), 2(18)-diseco indole diterpenoid, drechmerin H (1), was isolated from the fermentation broth of Drechmeria sp. together with a new indole diterpenoid, 2′-epi terpendole A (3), and a known analogue, terpendole A (2). Their structures were determined by HRESIMS, 1D and 2D NMR, ECD, and X-ray single crystal diffraction analyses as well as quantum chemical calculation. The abosulte configuration of terpendole A (2) was determined for the first time. Compound 1 displayed the significant agonistic effect on pregnane X receptor (PXR) with EC₅₀ value of 134.91 ± 2.01 nM, and its interaction with PXR was investigated by molecular docking. Meantime, a plausible biosynthetic pathway for compounds 1–3 is also discussed in the present work.     

Furan derivatives from Lannea kerstingii

Two new furan derivatives, lannefuran A (1) and lannefuran B (2) were isolated from the stem bark extract of Lannea kerstingii Engl. & K. Krause together with five known compounds, namely: taraxerol, stigmast-4-en-3-one, monoglyceride of hexacosanoic acid, β-sitosterol and its glucoside. Their structures were determined by means of 1D and 2D NMR, IR, and HR–EI–MS spectra and comparison with the data of known analogues reported in the literature. Lannefuran A (1) exhibited very low antiplasmodial activity against Plasmodium falciparum 3D7.     

Biotransformation of 20(R)-panaxatriol by Aspergillus niger AS 3.739

Microbial transformation of 20(R)-panaxatriol (PT) was performed by using the fungus Aspergillus niger AS 3.739. Six metabolites (1–6) including five new compounds were obtained. The chemical structures of these transformed products were elucidated based on various spectroscopic analyses, including 1D and 2D NMR and HRESI-MS. Metabolites 2–6 are new compounds. Furthermore, metabolites 2, 3, 5, and 6 exhibited significant anti-hepatic fibrosis activity, while 4 showed cytotoxicity against HSC-T6 cells.     

Antibacterial and antioxidant activities of flavonoids from Lannea alata (Engl.) Engl. (Anacardiaceae)

Two new prenylated flavonoids, lanneaflavonol (1) and dihydrolanneaflavonol (2) together with the known compounds myricetin-3-O-α-rhamnopyranoside (myricitrin) (3) and myricetin-3-O-α-arabinofuranoside (betmidin) (4), lupeol (5) and sitosterol (6) were isolated from the roots of Lannea alata. Compounds 1–4 exhibited good antibacterial and radical scavenging activity with the glycosides 3 and 4 showing better antioxidant activity than the aglycones 1 and 2 and myricetin-3-O-α-arabinofuranoside (4) showing the best antimicrobial activity followed by the aglycones 1 and 2. Betmidin (4) with an arabinose moiety at the 3-O-position showed the best antibacterial activity against Gram-positive bacteria, followed by the prenylated dihydroflavonol (2), whilst the prenylated linear flavonol (1) showed limited activity against Gram-negative bacteria. The arabinofuranoside (4) followed by the rhamnopyranoside (3) showed the best antioxidant activity comparable to that of ascorbic acid. The biological activities justify the ethnomedicinal uses of the plant in the management of diseases associated with Gram-positive bacteria, such as being used to treat injuries and wounds.     

Five new alkaloids from Aconitum apetalum (Ranunculaceae)

Twenty-one alkaloids, including five new ones, acoapetaldines A–E (1–5), were isolated from the whole plants of Aconitum apetalum. Among them, 1 is an aconitine-type diterpenoid alkaloid, 2 and 3 are aporphine alkaloids and 4 and 5 are napelline-type diterpenoid alkaloids. The structures of the new alkaloids were elucidated by spectroscopic data analysis and that of acoapetaldine D (4) was confirmed by single crystal X-ray crystallography. Acoapetaldine A (1) and aconorine (12) exhibited moderate anti-tobacco mosaic virus (anti-TMV) activity, while corydine (15) displayed moderate antimicrobial activity against Pseudomonas aeruginosa.     

Ulmosides A and B: Flavonoid 6-C-glycosides from Ulmus wallichiana,stimulating osteoblast differentiation assessed by alkaline phosphatase

Chemical investigation of Ulmus wallichiana stem bark resulted in isolation and identification of three new compounds (2S,3S)-(+)-3′,4′,5,7-tetrahydroxydihydroflavonol-6-C-β-d-glucopyranoside (1), (2S,3S)-(+)-4′,5,7-trihydroxydihydroflavonol-6-C-β-d-glucopyranoside (3) and 3-C-β-d-glucopyranoside-2,4,6-trihydroxymethylbenzoate (8), together with five known flavonoid-6-C-glucosides (2, 4–7). Their structures were elucidated using 1D and 2D NMR spectroscopic analysis. The absolute stereochemistry in compounds 1 and 3 were established with the help of CD data analysis and comparison with the literature data analysis. All the isolated compounds (1–8) were assessed for promoting the osteoblast differentiation using primary culture of rat osteoblast as an in vitro system. Compounds 1–3 and 5 significantly increased osteoblast differentiation as assessed by alkaline phosphatase activity.     

Three new koninginins from Trichoderma neokongii 8722

Three new fungal metabolites, named koninginins I (1), J (2) and K (3) together with four known koninginins A (4), B (5), D (6) and E (7), were isolated from solid fermentation products of Trichoderma neokongii 8722. Three new structures were elucidated by extensive spectroscopic methods, including 1D NMR and 2D NMR, and HR-ESI–MS experiments.     

Synthesis,structure elucidation and in vitro anticancer activities of novel derivatives of diethyl (2E)-2-[(2E)-(1-arylimidazolidin-2-ylidene)hydrazono]succinate and ethyl (4-oxo-8-aryl-4,6,7,8-tetrahydroimidazo[2,1-c][1,2,4]triazin-3-yl)acetate

The worked out and optimized synthesis routes and remarkable antitumour activities in vitro of novel polynitrogenated derivatives of diethyl (2E)-2-[(2E)-(1-arylimidazolidin-2-ylidene)hydrazono]succinate (7–10) and ethyl (4-oxo-8-aryl-4,6,7,8-tetrahydroimidazo[2,1-c][1,2,4]triazin-3-yl)acetate (11–16) are presented. Small molecules based on the privileged 7,8-dihydroimidazo[2,1-c][1,2,4]triazin-4(6H)-one scaffold (11–16) were obtained with fairly modest to good overall yields by very facile addition reactions of the nucleophilic centred 1-aryl-2-hydrazonoimidazolidine hydroiodides to diethyl acetylenedicarboxylate (DEAD) in the presence of triethylamine (TEA) and a subsequent cyclocondensation of the putative intermediate chain hydrazones. Heterobicyclic products 12 and 14–16 could also be prepared in high overall yields by an effective intramolecular cyclocondensation of the isolated stable and antiproliferative active heterocyclic hydrazones, namely, diethyl (2E)-2-[(2E)-(1-arylimidazolidin-2-ylidene)hydrazono]succinates (7–10), performed in refluxing DMF. These intermediates are the first products to be formed in the result of an addition of the nucleophilic reactants, namely, 1-aryl-2-hydrazonoimidazolidines of the 1–6 type, bearing the basic nitrogen atom of the hydrazono moiety (N–NH₂), to the carbon–carbon triple bond of the highly electrophilic alkyne, that is, DEAD. Molecular structures of the synthesized compounds (7–16) in the DMSO-d₆ solutions were verified by ¹H NMR and ¹³C NMR spectral data. These were finally confirmed based on the advanced 2D HMBC and HMQC NMR experiments, which were performed for the two representatives (8 and 11) of the two synthesized sets of the bioactive substances. Among the majority of antiproliferative active molecules, the disclosed herein ethyl [4-oxo-8-(3-chlorophenyl)-4,6,7,8-tetrahydroimidazo[2,1-c][1,2,4]triazin-3-yl]acetate (14) is proposed as a promising lead structure for the design of novel highly selective antitumour agents because of the distinctly marked lower cytotoxicity towards the primary cell line of normal HSF cells and several-fold higher against cancer cells used. A double fluorochrome mix-staining was performed in order to find out about the possible mode of action by which this novel small heterobicycle reveals remarkable antiproliferative effects in vitro. Taking into account the obtained double staining results, this small molecule was identified as capable of inducing significantly higher levels of necrotic cells in human cancer cell lines (T47D and HeLa) than in normal HSF cells. Furthermore, its cytotoxicity against cells was found to be connected to the predominant induction of necrosis over apoptosis.     

(2S)-Prenylflavanones and taraxerane triterpenoids from Mallotus mollissimus

Three prenylflavanones, (2S)-5,7-dihydroxy-4′-methoxy-8-(3″,3″-dimethylallyl)flavanone (3), (2S)-5,4′-dihydroxy-7-methoxy-6-(3″,3″-dimethylallyl)flavanone (6), 8-prenylnaringenin (11), and a new epimeric pair (2″S/2″R)-(2S)-5,7-dihydroxy-4′-methoxy-6-(2″-hydroxy-3″-methylbut-3″-enyl)flavanones (4a/4b) were isolated together with taraxerone, taraxerol, epitaraxerol, β-sitosterol, oleanolic acid, 1-O-docosanoyl glycerol, apigenin, and apigenin 7-O-β-D-glucopyranoside from the MeOH extract of the leaves of Mallotus mollissimus. The structures of the isolated compounds were determined on the basis of 1D/2D NMR and HR-MS spectroscopic data; the 2S configuration of the prenylflavanones 3, 4, and 6 was deduced from CD spectroscopic data. The presence of three taraxerane triterpenoids reinforces the inclusion of M. mollissimus (syn. Croton mollissimus) in Mallotus genus. Among species of Mallotus the occurrence of the (2S)-prenylflavanones 3, 4, and 6 is confined to M. mollissimus.     

Chemical constituents from Ibervillea lindheimeri (A. Gray) Greene

A chemical analysis of Ibervillea lindheimeri (A. Gray) Greene led to the isolation of 23,24-dihydrocucurbitacin F (1), 23,24-dihydrocucurbitacin D (2) and 2-O-β-D-glucopyranosyl 23,24-dihydrocucurbitacin D (3). Their structures were identified by spectroscopic analyses and by comparison of their spectral data with those reported in the literature. In addition, 10 compounds were detected by GC–MS analyses from the hexane extract. To the best of our knowledge, this is the first report examining the chemical composition of I. lindheimeri.     

Chemical constituents from Syringa reticulata (Bl.) Hara

A previously undescribed secoiridoid aglycone, syrinretin (1), together with a reported secoiridoid aglycone (2), three phenylethanoids (3, 4 and 6), phenolic acid (5) and two coumarins (7 and 8) were isolated from the stem bark of Syringa reticulata (Bl.) Hara (Oleaceae). The structures were elucidated from 1D and 2D NMR spectroscopic data by comparison with reported literature values. Compound 1 and compounds 2, 4–6 and 8 were identified in the genus Syringa for the first time. The chemotaxonomic significance of these compounds is also discussed.     

Ceramide,cerebroside and triterpenoid saponin from the bark of aerial roots of Ficus elastica (Moraceae)

Three compounds, ficusamide (1), ficusoside (2) and elasticoside (3), were isolated from the bark of aerial roots of Ficus elastica (Moraceae), together with nine known compounds, including four triterpenes, three steroids and two aliphatic linear alcohols. The chemical structures of the three compounds were established by extensive 1D and 2D NMR spectroscopy, mass spectrometry and by comparison with published data. The growth inhibitory effect of the crude extract and isolated compounds was evaluated against several microorganisms and fungi. The cytotoxicity against human cancer cell lines was also assessed. Ficusamide (1) displayed a moderate in vitro growth inhibitory activity against the human A549 lung cancer cell line and a strong activity against Staphylococcus saprophyticus, while elasticoside (3) showed a potent activity on Enterococcus faecalis.     

Bioactive butylphthalide derivatives from Ligusticum chuanxiong

Seven new butylphthalide derivatives, ligusticumolide A-G (1–7), together with two known butylphthalide derivatives (8–9) were isolated from an ethanol extract of Ligusticum chuanxiong Hort. The structures of these derivatives were elucidated from analysis of 1D/2D NMR, UV, IR and HRESIMS data. The absolute configurations of these derivatives were determined by electronic circular dichroism (ECD) calculations and Mosher′s method. Ligusticumolide A (1) and ligusticumolide B (2) are enantiomers that were obtained by chiral separation. Ligusticumolide C (3) and ligusticumolide D (4) are diastereomers. All of the compounds were evaluated for their hepatoprotective activity against N-acetyl-p-aminophenol-induced HepG2 cell injury. Compounds 4, 5, and 7–9 showed more significant hepatoprotective activity than that of the positive control drug (bicyclol) at a concentration of 10 μM (p < 0.01).     

New derivatives from the aerial parts of Boerhaavia diffusa L. (Nyctaginaceae)

Boerhaavia diffusa L. is used in the traditional medicine of several Asian countries. The isolation and identification of five new compounds, together with 11 known compounds, from the ethyl acetate extract of the aerial part of B. diffusa grown Vietnam is reported. The structure of the new compounds was established by 1D and 2D NMR spectroscopy, and high resolution ESI-MS analysis. New compounds are two rotenoids: 9,11-dihydroxy-6,10-dimethoxy[1]benzopyrano[3,4-b][1]benzopyran-12(6H)-one (boeravinone P, 3) and 3-[2-(β-d-glucopyranosyloxy)-3-hydroxyphenyl]-5-hydroxy-2-hydroxymethyl-7-methoxy-6-methyl-4H-1-benzopyran-4-one (boeravinone Q, 9), an atropisomeric mixture of two rotenoid glycosides (3′,5-dihydroxy-2-hydroxymethyl-7-methoxy-6-methylisoflavone 2′-O-β-d-glucopyranoside, 11), a sesquiterpene lactone (4,10-dihydroxy-8-methoxyguai-7(11)-en-8,12-olide, 5) and a new phenylpropanoid glycoside (boerhaavic acid, 15).     

Caffeoylquinic acid derivatives from the roots of Arctium lappa L. (burdock) and their structure–activity relationships (SARs) of free radical scavenging activities

Eight caffeoylquinic acid (CQA) derivatives have been identified from the roots of Arctium lappa L. (burdock), including three new derivatives (1–3) together with five known derivatives (4–8). Their chemical structures were determined by 1D and 2D NMR as well as HR-TOF-MS data. The free radical scavenging activities of each compound were determined experimentally and found to be significant, especially the tri-CQA (8) and di-CQAs (6–7). Besides, our data showed that the number of caffeoyl groups in the caffeoyl derivatives played a crucial role for these physiological functions.     

Chemical constituents of Stenotaenia macrocarpa Freyn & Sint. (Apiaceae)

Phytochemical investigation of Stenotaenia macrocarpa Freyn & Sint. (Apiaceae) led to the isolation of ten known compounds: eight flavonoids (1–8) and two furanocoumarins (9–10). The chemical structures of the compounds were elucidated based on 1D and 2D NMR and MS spectra, as well as comparison with the relevant literature data. To the best of our knowledge, this is the first detailed phytochemical study about Stenotaenia macrocarpa and the first report on the isolation of all the compounds from the genus Stenotaenia, and manghaslin (2) and its methoxylated derivative typhaneoside (3) from Apiaceae. The chemotaxonomic significance of isolates was also discussed.     

Two new germacranolides from Elephantopus tomentosus

The bioassay-guided chemical investigation of the whole plant of Elephantopus tomentosus led to the isolation of two new germacranolides, tomenphantopin C (1) and tomenphantopin D (2), together with four known compounds (3–6). Their structures were determined by spectroscopic techniques (UV, IR, MS, 1D and 2D NMR). All compounds were evaluated for cytotoxic and antibacterial activities.     

Chemical constituents of Pteris wallichiana J.Agardh (Pteridaceae)

Chemical investigation on the whole plants of Pteris wallichiana J. Agardh led to the isolation and identification of a new pterosin glycoside, ptemuloside A (1), along with other seventeen known compounds (2–18) (Fig. 1). The structure of compound 1 was elucidated by means of spectroscopic techniques, including HRESIMS, and 1D and 2D NMR experiments. Compounds 2, 3, and 5–17 are first time reported from the title plant. The pterosins in P. wallichiana could serve as its chemotaxonomic markers.