Stilbeno-phenylpropanoids from Gnetum montanum Markgr.

Four new stilbeno-phenylpropanoids, gnetumonins A−C (1−3) and (−)-gnetucleistol F (4), together with two known compounds, gnetupendin A and (+)-gnetofuran A, were isolated from the caulis of Gnetum montanum Markgr. (Gnetaceae). The structures of those new compounds were established by extensive analysis of MS, 1D and 2D NMR spectroscopic data. The relative configurations of 1−3 were elucidated by means of the analysis of shielded effect correlating their key ¹H NMR shift changes.     

Three new compounds isolated from the bulbs of Fritillaria pallidiflora Schrenk and their anti-inflammatory activity

Three new compounds, 17β-cevanin-6-oxo-5α,20β-diol yibeinine (1), 2-(tetrahydro-5-(2-hydroxyphenyl)-2H-pyran-3-yl) phenol (2), 1,3-O-diferuloyl-2-methoxypropane diol (3), as well as four known compounds (4–7), have been isolated from the ethanol extract of dried bulbs of Fritillaria pallidiflora Schrenk. All structures were determined based on their spectroscopic data (1D and 2D NMR (including ¹H NMR, ¹³C NMR, ¹H-¹H COSY, HMBC, HSQC, HSQC-TOCSY, and NOESY experiments), and MS). Biological evaluation showed that compounds 1–4 inhibited the production of nitric oxide (NO) in LPS-stimulated RAW 264.7 cells with IC₅₀ values of 18.0, 38.7, 29.5, and 47.1 μM, respectively. These results indicated that compound 1 has potential anti-inflammatory activity.     

Two new antimicrobial steroids and other constituents from the whole plant of Ludwigia abyssinica

The genus Ludwigia belongs to the Onagraceae family and it encompasses seventy-five species of aquatic plants. The chemistry of this genus is scarcely investigated, although some studies have demonstrated the potential of Ludwigia leptocarpa to produce important bioactive compounds. Herein, we describe the phytochemical investigation of Ludwigia abyssinica A. Rich. Two new steroids named 3β-formyloxy-5α,6α-dihydroxysitostane (Ludwigiaformyl A, 1) and 3β,6α-diformyloxy-5α-hydroxysitostane (Ludwigiaformyl B, 2), along with six known compounds, 3β-formyloxysitost-5-en (3), 5α,6β-dihydroxysitosterol (4), maslinic acid (5), oleanolic acid (6) and a mixture of two iridoids: linearin (7) and 1-epilinearin (8) were obtained from whole plant of L. abyssinica. The structures of the isolated compounds were established by extensive analysis of their spectroscopic and spectrometric data, which included HR-TOF-ESIMS, ¹D NMR (¹H, ¹³C) and ²D NMR (¹H–¹H COSY, HSQC, HMBC and ROESY) and by comparison with data reported in the literature. The antimicrobial activities of extracts, fractions, and new compounds (1) and (2) were evaluated using broth microdilution method against fungi and bacteria strains. The MeOH extract and the ethyl acetate fraction displayed different degrees of antibacterial and antifungal activities (MIC = 32 – 512 µg/mL; MMC = 64 – 512 µg/mL) whereas compounds 1 and 2 showed moderate antimicrobial activities against Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Shigella flexneri and Cryptococcus neoformans (MIC = 8 – 32 µg/mL; MMC = 8 – 64 µg/mL).     

Anthraquinones and other constituents from the roots of Eremomastax speciosa (Hochst.) Cufod

The chemical investigation of the roots of Eremomastax speciosa (Hochst.) Cufod (Acanthaceae). led to the isolation of thirteen compounds including five anthraquinones 1,8-dihydroxy-3-methylanthraquinone (1), 1,8-dihydroxy-3-methoxy-6-methylanthraquinone (2), emodin (3), aloe emodin (4) and 8-O-D-glucopyranosideemodin (5); one phenylethanoid glucoside acteoside (6); one benzophenone 2,6-dimethoxybenzophenone (7); two pentacyclic triterpenoids lupeol (8) and betulinic acid (9); three phytosterols stigmasterol (10), β-sitosterol (11), and β-sitosterol-3-O-β-D-glucopyranoside (12) and one fatty acid hexadecanoid acid (13). All these compounds are firstly reported from the roots of E. speciosa. Emodin and acteoside were modified chemically through allylation reaction to afford 3-O-allylated emodin (3a) and a new perallylated acteoside derivative (6a), respectively. The structure of the isolated compounds as well as those of the allylated derivatives were established by means of spectroscopic methods: NMR analysis (¹H and ¹³C NMR, ¹H–¹H–COSY, HSQC and HMBC), high-resolution mass spectrometry (HR-ESI-MS) and by comparison with previously reported data. All those compounds were tested for their cytotoxic activity against the human cervix carcinoma KB-3-1 cells and their antioxidant activity, the allylated acteoside derivative and 2,6-dimethoxybenzophenone showed weak cytotoxicity while acteoside showed a good antioxidant activity. In addition, the chemotaxonomic significance of the isolated compound is discussed.     

A new triterpenic diester from the aerial parts of Chrysanthemum macrocarpum

A new triterpenic diester, 3,21-dipalmitoyloxy-16β,21α-dihydroxy-β-amyrine (1), along with two natural cyclitols, conduritol C (2) and viburnitol (3), four known triterpenes (4–7), and seven known flavonoids (8–14) were isolated from the aerial parts of Chrysanthemum macrocarpum. Their structures were established on the basis of extensive 1D and 2D NMR (¹H, ¹³C, COSY, HMBC, HSQC, and ROESY) and ESIMS studies. The chloroform fraction, taraxasterol (4) and β-sitosterol (7) were investigated for their antibacterial activity against Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumoniae. The chloroform fraction and taraxasterol (4) showed a weak antibacterial activity and were evaluated for their cytotoxic activity against human colon cancer HT-29 cells and human prostate carcinoma PC3 cells. The results indicated that both the chloroform fraction and taraxasterol (4) inhibited cell proliferation of both PC3 and HT-29 cells.     

Furanocoumarins from the twigs of Ficus chlamydocarpa (Moraceae)

Two furanocoumarin derivatives, 3-methoxypsoralen (1) and 3,5-dimethoxypsoralen (2), along with nine known compounds, friedelinol (3), 3-oxo-11β-hydroxyoleanan-12-ene (4), lupeol (5), taraxer-3-one (6), a mixture of β-sitosterone (7a) and stigmast-4,22-dien-3-one (7b), ergosterol (8), 9,19-cyclolanost-3-one-24,25-diol (9), oleanan-12-ene-3,11-dione (10), and β-sitosterol 3-O-β-D-glucopyranoside (11) were isolated from the twigs of Ficus chlamydocarpa. Their structures were established by NMR spectroscopic analyses and HRESIMS. The structure of 1 was further confirmed from its single crystal X-ray diffraction. The crude extract, fractions and some isolated compounds were assessed for their preliminary antibacterial activity and cytotoxicity. One of the fractions (FB-B3) exhibited inhibition against the bacterial strain Pseudomonas agarici and induced a remarkable cytotoxic activity toward the human cervix carcinoma cell line KB-3-1 (IC₅₀ 0.166 mg/mL), and compounds 1, 6, and 7 showed moderate antibacterial activity against Bacillus subtilis and Micrococcus luteus.     

A new cycloartane-type triterpene and a new eicosanoic acid ester from fruits of Paullinia pinnata L.

A phytochemical study of the MeOH-soluble portion from the CH₂Cl₂/MeOH extract of the fruits of Paullinia pinnata resulted in the isolation of a new triterpenoid, cyclopinnatol (1), and a new eicosanoic acid ester, paulliniester (2), together with five known compounds including cycloart-22(E)-ene-3β,25-diol (3), cycloartenol (4), β-sitosterol (5), betulonic acid (6) and oleanonic acid (7). The structures of the new compounds were elucidated by spectroscopic analyses (NMR and MS) and comparisons with published data. Cyclopinnatol (1) and the MeOH-soluble portion exhibited significant and weak antibacterial activities against Staphylococcus aureus, with MICs of 32 and 50 μg/mL, respectively.     

Microbiological transformation of diosgenin by resting cells of filamentous fungus,Cunninghamella echinulata CGMCC 3.2716

Microbial transformation of the steroidal sapogenin diosgenin (1) by resting cells of the filamentous fungus, Cunninghamella echinulata CGMCC 3.2716 was studied. Four metabolites were isolated and unambiguously characterized as (25R)-spirost-5-ene-3β,7β-diol-11-one (2), (25R)-spirost-5-ene-3β,7β-diol (3), (25R)-spirost-5-ene-3β,7β,11α-triol (4), and (25R)-spirost-5-ene-3β,7β,12β-triol (5), by various spectroscopic methods (¹H, ¹³C NMR, DEPT, ¹H–¹H COSY, HMBC, HSQC and NOESY). Compound 2 is a new metabolite. The NMR data and full assignment for the known metabolites (25R)-spirost-5-ene-3β,7β-diol (3) and (25R)-spirost-5-ene-3β,7β,11α-triol (4) are described here for the first time. The biotransformation characteristics observed included were C-7β, C-11α and C-12β hydroxylations. Compounds 1–5 exhibited no significant cytotoxic activity to human glioma cell line U87.     

Ecdysteroids from the flowers of Aerva javanica

Four new ecdysteroids (1–4), along with three known steroids, β-ecdysone (5), 5-β-2-deoxyintegristerone A (6) and 24-epi-makisterone A (7) (Fig. 1), were isolated from the methanolic extract of the flowers of Aerva javanica by using normal and reverse phase chromatography. The structures of the new compounds (1–4) were determined due to 1D (¹H and ¹³C), 2D NMR (HSQC, HMBC, COSY, NOESY) techniques and high resolution mass spectrometry (HREIMS). The known compounds (5–7) were characterized based on the 1D NMR spectroscopy and mass spectrometry and by comparison with the literature values. All isolates were evaluated for their inhibitory activities against enzymes acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and lipoxygenase (LOX).     

Steroidal saponins and homoisoflavanone from the aerial parts of Sansevieria cylindrica Bojer ex Hook.

Phytochemical study on the methanolic extract of Sansevieria cylindrica aerial parts lead to the isolation, characterization and structure elucidation of a new steroidal saponin, 1β-hydroxy-kryptogenin-1-O-α-l-rhamnopyranosyl-(1 → 2)-α-l-arabinopyranoside (1), a new homoisoflavanone, (3S)-3,7-dihydroxy-8-methoxy-3-(3′,4′-methylenedioxybenzyl) chroman-4-one (2) and the known saponin alliospiroside A (3). To the best of our knowledge, the genin 1β-hydroxy-kryptogenin is reported here for the first time. The structures of the new compounds were determined by UV, IR, EIMS, HRESIMS together with 1D (¹H and ¹³C) and 2D (HSQC and HMBC) NMR spectral analysis. The isolated compounds 1–3 were tested for their radical scavenging activity (DPPH). Compound 2 exhibited activity compared to that of ascorbic acid as a standard. The cytotoxicity of the isolated compounds and the standard doxorubicin was tested against the three human tumor cell lines HT116, MCF-7 and PC-3. The results showed that the isolated compounds were inactive.     

Terpenoids and other constituents from Euphorbia bupleuroides

The phytochemical investigation of the roots of Euphorbia bupleuroides Desf. (Euphorbiaceae) yielded three new compounds named 4,20-dideoxy(4α)phorbol-12-benzoate-13-isobutyrate (1), 25-hydroperoxycycloart-3β-ol (2), and 3β,7β-dihydroxy-4α,14α-dimethyl-8β,9β-epoxy-5α-ergosta-24(28)-ene (3), together with 17 known compounds 4–20. Their structures were established from analysis of 1D (¹H, ¹³C and DEPT) and 2D NMR (COSY, HSQC, HMBC and NOESY) data, and of mass spectrometry (HRESIMS), and by comparison with literature data.     

Five new iridoïd dimers from the fruits of Canthium subcordatum DC (syn. Psydrax subcordata DC)

Five new iridoid dimers, canthiumosides 1–5 (1–4 and 5a), together with nine known compounds, shanzhigenin methyl ester (6), 1-epishanzhigenin methyl ester (6′), linearin (7), 1-epilinearin (7′), mussaenoside (8), shanzhiside methyl ester (9), 3′,4′,7-trihydroxyflavone (10), betulinic acid (11), and oleanolic acid (12) were isolated from the fruits of Canthium subcordatum DC (Syn. Psydrax subcordata (DC) Bridson). The structures of these compounds were established by interpretation of their spectral data, mainly HR-TOFESIMS, 1D NMR (¹H, ¹³C and DEPT) and 2D NMR (¹H–¹H COSY, HSQC, HMBC, and NOESY), and by comparison with the literature.     

Cytotoxic protobassic acid glycosides from Planchonella obovata leaf

Four triterpenoid glycosides, possessing protobassic acid as common aglycon, together with 16 known compounds were isolated from the leaves of Planchonella obovata. They are 6β-hydroxy-conyzasaponin G (2), 3‴-O-de-β-d-apiofuranosylisoarganin F (3), isoarganin F (4), and 6β-hydroxy-conyzasaponin N (5). The structures of these glycosides were elucidated based on spectroscopic analysis, in particular using 1D TOCSY to confirm the ¹H NMR assignment of each sugar residue. The absolute configuration of each monosaccharide in the glycon part was determined by GC-FID. Compound 5, Mi-saponin A (8), and ursolic acid (10) showed moderate inhibitory activities against HL-60 leukemia cell line with the IC₅₀ values of 16.88, 15.50, and 12.68 μM, respectively.     

Chemical constituents from Tribulus terrestris and screening of their antioxidant activity

Two oligosaccharides (1, 2) and a stereoisomer of di-p-coumaroylquinic acid (3) were isolated from the aerial parts of Tribulus terrestris along with five known compounds (4–8). The structures of the compounds were established as O-β-d-fructofuranosyl-(2 → 6)-α-d-glucopyranosyl-(1 → 6)-β-d-fructofuranosyl-(2 → 6)-β-d-fructofuranosyl-(2 → 1)-α-d-glucopyranosyl-(6 → 2)-β-d-fructofuranoside (1), O-α-d-glucopyranosyl-(1 → 4)-α-d-glucopyranosyl-(1 → 4)-α-d-glucopyranosyl-(1 → 2)-β-d-fructofuranoside (2), 4,5-di-p-cis-coumaroylquinic acid (3) by different spectroscopic methods including 1D NMR (¹H, ¹³C and DEPT) and 2D NMR (COSY, TOCSY, HMQC and HMBC) experiments as well as ESI-MS analysis. This is the first report for the complete NMR spectral data of the known 4,5-di-p-trans-coumaroylquinic acid (4).The antioxidant activity represented as DPPH free radical scavenging activity was investigated revealing that the di-p-coumaroylquinic acid derivatives possess potent antioxidant activity so considered the major constituents contributing to the antioxidant effect of the plant.     

Vernoguinamide: A new ceramide and other compounds from the root of Vernonia guineensis Benth. and their chemophenetic significance

The chemical investigation of the roots of Vernonia guineensis Benth. (Asteraceae) resulted in the isolation of a new ceramide, named vernoguinamide (1), together with fifteen known compounds, including three anthraquinones, physion (2), erythroglaucin (3) and emodin (4), three triterpenoids, hop-17(21)-en-3β-yl acetate (5), lupeol (6) and betulinic acid (7), six steroids, vernoguinoside A (8), vernoguinoside (9), β-sitosterol 3-O-β-D-glucoside (10), stigmasterol 3-O-β-D-glucoside (11), stigmasterol (12) and β-sitosterol (13) and three fatty acid derivatives, tetracosanoic acid (14), tricosanic acid (15) and arachidic acid glycerol ester (16). The structure of the new compound as well as those of the known compounds were established by spectrometric analysis including HRESI-MS, 1D and 2D-NMR and by comparison with the previously reported data. Among these compounds, the anthraquinones 2–4 and the triterpene 5 were isolated for the first time from Vernonia genus and compounds 6, 7 and 14–16 were extracted for the first time from the species. The isolated compounds were tested for their antibacterial activity and 3, 8 and 9 were the most active compounds against the tested bacteria. Furthermore, the chemophenetic relationships of the isolated compounds and their significance were also discussed.     

α-Glucosidase inhibitory constituents from Chrozophora plicata

Five new secondary metabolites have been isolated from Chrozophora plicata including an acacetin derivative (1), three pyrrole alkaloids plicatanins A–C (2–4, resp.) and the bilactone plicatanone (5). Together with these compounds, the known compounds, β-sitosterol (6), methyl p-coumarate (7), 4-hydroxyphenylacetic acid (8), succinic acid (9), speranberculatine A (10), β-sitosterol-3-O-β-d-glucopyranoside (11) and apigenin-5-O-β-d-glucopyranoside (12) have also been isolated. The structures of isolates 1–12 were established by 1D (¹H, ¹³C) and 2D NMR (HMQC, HMBC, COSY) spectroscopy and mass spectrometry (EIMS, HREIMS, FABMS, HRFABMS). The structure of plicatanin A (3) was further confirmed through single crystal X-ray technique. Compounds 1–12 were evaluated for their inhibitory activity against the enzyme yeast α-glucosidase. The compound 4 was found to be most potent with IC₅₀ value 27.8 μM.     

Steroidal saponins from the leaves of Cordyline fruticosa (L.) A. Chev. and their cytotoxic and antimicrobial activity

Three new steroidal saponins, spirosta-5,25(27)-diene-1β,3β-diol-1-O-α-l-rhamnopyranosyl-(1→2)-β-d-fucopyranoside (fruticoside H) 1, 5α-spirost-25(27)-ene-1β,3β-diol-1-O-α-l-rhamnopyranosyl-(1→2)-(4-O-sulfo)-β-d-fucopyranoside (fruticoside I) 2, and (22S)-cholest-5-ene-1β,3β,16β,22-tetrol 1-O-β-galactopyranosyl-16-O-α-l-rhamnopyranoside (fruticoside J) 3, together with the known quercetin 3-O-β-d-glucopyranoside, quercetin 3-O-[6-trans-p-coumaroyl]-β-d-glucopyranoside, quercetin 3-rutinoside, apigenin 8-C-β-d-glucopyranoside and farrerol, were isolated from the leaves of Cordyline fruticosa. Their structures were elucidated by spectroscopic techniques (¹H NMR, ¹³C NMR, HSQC, ¹H–¹H COSY, HMBC, TOCSY, NOESY), mass spectrometry (HRESIMS, Tandem MS–MS), chemical methods and by comparison with published data. Compounds 1 and 2 showed moderate cytotoxic activity against MDA-MB 231 human breast adenocarcinoma cell line, HCT 116 human colon carcinoma cell line, and A375 human malignant melanoma cell line, while compound 3 was not active. Compound 2 also showed a moderate antibacterial activity against the Gram-positive Enterococcus faecalis.     

Efficient synthesis and antimicrobial activity of some novel S-β-d-glucosides of 5-aryl-1,2,4-triazole-3-thiones derivatives

A series of 3-S-β-d-glucosides-4-arylideneamino-5-aryl-1,2,4-triazoles were rationally designed and synthesized according to the principle of superposition of bioactive substructures by the combination of 1,2,4-triazole, Schiff base and glucosides. The structures of the target compounds have been characterized by ¹H NMR, ¹³C NMR, IR, MS and HRMS. All the newly synthesized compounds have been evaluated for their antimicrobial activities in vitro against Staphylococcus aureus (ATCC 6538), Escherichia coli (ATCC 8099) as well as Monilia albican (ATCC 10231). The bioactive assay showed that most of the tested compounds displayed variable inhibitory effects on the growth of the Gram-positive bacterial strain (Staphylococcus aureus), Gram-negative bacterial strains (Escherichia coli) and fungal strains (Monilia albican). All the target compounds exhibited better antifungal activity than antibacterial activity. Especially, compounds 6b, 6c, 6f, 6j, 6k and 6l showed excellent activity against fungus Monilia albican with MIC values of 16 μg/mL.     

Chemical constituents from Ficus natalensis hochst (Moraceae) and their chemophenetic significance

Phytochemical investigation of the stem bark of Ficus natalensis afforded eleven compounds including one ceramide (1), two anthraquinones (2, 3), four triterpenes (4–7), two polyols (8, 9) and two steroids (10, 11). The structures of the compounds were determined by spectroscopic analyses including IR, UV, MS, 1D- and 2D- NMR (¹H, ¹³C, ¹H–¹H COSY, HMQC, HMBC and NOESY), as well as by comparison with literature data. The antibacterial activity and the cytotoxicity of the extract, fractions and some isolated compounds (3, 5, 8 and 9) were evaluated. Some fractions and sub-fractions from various column chromatography displayed moderate antibacterial activity with diameter zone of inhibition (DZI) ranging from 7 to 10 mm. None of the compounds tested had activity. In the present study, all the compounds are isolated for the first time from the species F. natalensis. Compounds 2, 4–7, 10 and 11 were previously reported from the genus Ficus. The chemophenetic significance of the isolated compounds is discussed.     

Staphylopeptide A,a new cyclic tetrapeptide from culture broth of Staphylococcus sp.

Re-investigation of the culture broth of the marine bacterium Staphylococcus sp. (no. P-100826-4-6) afforded a new cyclic tetrapeptide namely staphylopeptide A (1), along with five known compounds, cyclo (l-prolyl-l-valine) (2), cyclo (l-prolyl-l-tyrosine), (3), cyclo (l-prolyl-l-alanine) (4), l-phenylalanine (5), and l-tryptophan (6). The structures of the isolated compounds were determined by extensive IR, 1D (¹H and ¹³C) and 2D (¹H-¹H COSY, HSQC, HMBC, and NOESY) NMR and HRFABMS spectral measurements. The antimicrobial activity of the isolated compounds (1–6) was evaluated.