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.     

Platachromone A–D: Cytotoxic 2-styrylchromones from the bark of Platanus × acerifolia (Aiton) Willd.

Four novel 2-styrylchromones, 4′,5,7-trihydroxy-6-isopentene-2-styrylchromone (1), 4′,5,7-trihydroxy-8-isopentene-2-styrylchromone (2), 4′,5,7-trihydroxy-6-(2-hydroxy-3-methylbut-3-enyl)-2-styrylchromone (3) and 4′,5,7-trihydroxy-8-(2-hydroxy-3-methylbut-3-enyl)-2-styrylchromone (4), were isolated from shed bark of Platanus × acerifolia (Aiton) Willd., as well as four known compounds, 4′,5,7-trihydroxy-2-styrylchromone (5), scutellarein (6), 4′,5,7-trihydroxy-6-prenylflavone (7), and 4′,5,7-trihydroxy-8-prenylflavone (8). The structures of compounds 1–4 were established by direct interpretation of their spectral data, mainly high resolution electrospray ionization mass spectrometry (HR-ESI-MS), 1D and 2D NMR (¹H–¹H COSY, HSQC and HMBC). The cytotoxicity of the compounds 1–8 was evaluated in four human carcinoma cell lines, including HepG2, SMMC-7721, MDA-MB-231, and KB. Compounds 1–4 exhibited significantly cytotoxic activity toward HepG2 and KB cells, with IC₅₀ values ranging from 3.0 to 9.7 μM.     

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.     

New purine alkaloids from the Red Sea marine tunicate Symplegma rubra

Investigation of the Red Sea marine tunicate Symplegma rubra Monniot, 1972 gave three new purine alkaloids namely 6-methoxy-7,9-dimethyl-8-oxoguanine (1), 6-methoxy-9-methyl-8-oxoguanine (2), and 2-methoxy-7-methyl-8-oxoadenine (4) together with seven known compounds: 6-methoxy-7-methyl-8-oxoguanine (3), 9-methyl-8-oxoadenine (5), 7-methyl-8-oxoadenine (6), 8-oxoadenine (7), 3-methylxanthine (8), inosine (9), and homarine (pyridinium-2-carboxylic acid-1-methyl) (10). Compound 6 was reported here for the first time from a natural source. The structure determination of the compounds was accomplished by extensive interpretation of their spectroscopic data including 1D (¹H and ¹³C) and 2D (¹H–¹H COSY, HSQC, and HMBC) NMR and high-resolution mass spectral data. The isolated compounds were evaluated for their protein kinase inhibitory activity against different kinases (CDK5, CK1, DyrK1A, and GSK3) at 10 μg/mL. The compounds showed moderate activity against these kinases.     

Phenolic acid glycosides from Parmentiera cereifera Seem. (Candle tree)

Two new phenolic acid glycosides, parmentins A (1) and B (2) were isolated from the methanolic extract of the leaves and stems of candle tree (Parmentiera cereifera Seem). These compounds were accompanied by a mixture of β-sitosterol and stigmasterol (3), β-sitosterol glucoside (4), isovanillic acid (5), vanillic acid (6), and p-hydroxybenzoic acid (7). The structures of the isolated compounds were determined on the basis of physical and spectroscopic analyses, including 1D and 2D NMR (¹H, ¹³C, COSY, HSQC and HMBC) and mass spectrometry (HR-ESI-MS).     

Phytochemical and chemotaxonomic study on Piper pleiocarpum Chang ex Tseng

The phytochemical study of Piper pleiocarpum Chang ex Tseng led to the isolation of eighteen compounds (1–18), including ten lignanoids, galbelgin (1), (+) sesamin (2), denudatin A (3), hancinone (4), (7S,8S, 3′R)-Δ^8'-3,3′,4-trimethoxy-3′,6′-dihydro-6′-oxo-7.0.4′,8.3′-lignan[(2S,3S,3aR)-2-(3,4-dimethoxyphenyl)-3,3a-dihydro-3a-methoxy-3-methyl-5-(2-propenyl)-6(2H))-benzofuranone] (5), (−)-(7R,8R)-machilin D (6), (1R,2R)-2-[2-methoxy-4-((E)-prop-1-enyl)phenoxy]-1-(3,4-dimethoxyphenyl)propyl acetate (7), piperbonin A (8), machilin D (9), 4-methoxymachilin D (10), one amide alkaloid, Δ^α,β-dihydropiperine (11), six polyoxygenated cyclohexenes, ent-curcuminol F (12), uvaribonol E (13), ellipeiopsol A (14), 1S,2R,3R,4S-1-ethoxy-2-[(benzoyloxy)methyl]cyclohex-5-ene-2,3,4-triol, 3-acetate (15), (+)-crotepoxide (16), (+)-senediol (17), and one benzoate derivative, 2-acetoxybenzyl benzoate (18). Their structures were established by spectroscopic data and by comparison with the literature. All the compounds were firstly isolated from P. pleiocarpum, while ten compounds 6–7, 9–10, 12–15, 17–18 were isolated from the genus Piper and the family Piperaceae for the first time. The chemotaxonomic significance of these compounds was also discussed. The isolation of compounds 6–7, 9–10 may be used as chemotaxonomic markers for the genus of Piper.     

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).     

New azafluorenones with cytotoxic and carbonic anhydrase inhibitory properties: 2-Aryl-4-(4-hydroxyphenyl)-5H-indeno[1,2-b]pyridin-5-ones

New azafluorenones, 2-aryl-4-(4-hydroxyphenyl)-5H-indeno[1,2-b]pyridin-5-ones, were prepared to evaluate their cytotoxic/anticancer properties, also their inhibitory effects on hCA I and II isoenzymes. Aryl part was changed as [phenyl (H1), 4-methylphenyl (H2), 4-methoxyphenyl (H3), 4-fluorophenyl (H4), 4-bromophenyl (H5), 4-chlorophenyl (H6), 3-hydroxyphenyl (H7), and 4-hydroxyphenyl (H8)]. The structure of the synthesized compounds was characterized by ¹H NMR, ¹³C NMR and HRMS spectra.Cytotoxicity results of the series pointed out that the compounds H6 (PSE: 28.0) and H5 (PSE: 27.3), with the highest potency selectivity expression (PSE) value, can be considered as leader compounds of the study in designing novel anticancer agents. Additionally, all azafluorenones synthesized showed a good inhibition profile towards hCA I and II isoenzymes in the range of 54.14–73.72 nM and 67.28–76.15 nM, respectively.The compounds H5 and H6 can be considered for further designs with their cytotoxic and CA inhibitory profiles.     

Isoprenylated flavonoids from the roots of Sophora tonkinensis

Two new isoprenylated flavanones, tonkinochromanes J (1) and K (2), and a new isoprenylated dihydrochalcone, tonkinochromane L (3), were isolated from the roots of Sophora tonkinensis along with four known compounds (4-7). Their structures were determined by means of spectroscopic analyses, including HRMS, IR, ¹H and ¹³C NMR and 2D experiments (COSY, HSQC, and HMBC), and comparison with known related compounds.     

Phytochemicals from the stem wood of Sorbus lanata (D. Don.) Schauer

Three new phenolic compounds, sorlanin (4-(3-(hydroxymethyl)-5-methoxy-7-phenyl-2,3-dihydrobenzo[b][1,4]dioxin-2-yl)-2-methoxyphenol, 1), sorbanin (2-((3,5-dimethoxy-[1,1′-biphenyl]-4-yl)oxy)-1-(4-hydroxy-3-methoxyphenyl)propane-1,3-diol, 2) and sorbalanin (4-(3-(hydroxymethyl)-5,6-dimethoxy-2,3-dihydrobenzo[b][1,4]dioxino[2,3-g]benzofuran-2-yl)-2-methoxyphenol, 3), together with eight known compounds, polystachyol (4), isolariciresinol (5), dihydrodehydrodiconiferyl alcohol (6), tuberculatin (7), ovafolinin E (8), aucuparin (9), 2′-methoxyaucuparin (10), and tetracosyl-3-(3,4-dihydroxyphenyl)acrylate (11), were isolated from Sorbus lanata. The structures of these phytoconstituents were elucidated through extensive spectroscopic techniques, including UV, IR, 1D and 2D NMR, ESI-MS and HRESI-MS experiments. All the compounds except 9 and 10 were isolated for the first time from the genus Sorbus. The isolated compounds were also tested in DPPH radical scavenging reaction where compounds 6, 7, 10 and 11 showed significant activities with IC₅₀ values of 9.2, 11.7, 23.0 and 33.7 μM, respectively.     

Xylarianins A-D from the endophytic fungus Xylaria sp. SYPF 8246 as natural inhibitors of human carboxylesterase 2

Eighteen secondary metabolites were isolated from the fermentation broth of the endophytic fungus Xylaria sp. SYPF 8246, including four new compounds, xylarianins A-D (1–4), three new natural products, 6-methoxycarbonyl-2′-methyl-3,5,4′,6′-tetramethoxy-diphenyl ether (5), 2-chlor-6-methoxycarbonyl-2′-rnethyl-3,5,4′,6′-tetramethoxy-diphenyl ether (6), and 2-chlor-4′-hydroxy-6-methoxy carbonyl-2′-methyl-3,5,6′-trimethoxy-diphenyl ether (7), and eleven known compounds (8–18). Their structural elucidations were conducted by using 1D and 2D NMR, HRESIMS, and Rh₂(OCOCF₃)₄-induced electronic circular dichroism (ECD) spectra analyses. The integrated ¹H and ¹³C NMR data of three new natural products 5–7 were reported for the first time. All the isolated compounds were assayed for their inhibitory activities against human carboxylesterase 2 (hCE 2). Compounds 1, 5–9, and 18 displayed significant inhibitory activities against hCE 2 with IC₅₀ values of 10.43 ± 0.51, 6.69 ± 0.85, 12.36 ± 1.27, 18.25 ± 1.78, 29.78 ± 0.48, 18.86 ± 1.87, and 20.72 ± 1.51 µM, respectively. The interactions between compounds 1 and 5 with hCE 2 were anaylzed by molecular docking.     

Three new monoterpene glucosides and one new sorbitol ester identified from Sibiraea angustata with hypolipidemic activities in HepG2 cells

Three new monoterpene glycosides, sibiraglycoside L (1), M (2), N (3) and one new sorbitol ester, resibirate (4), together with four known compounds including caffeic acid glucitol ester (5), sibiscolacton C (6), geraniol-1-O-[α-l-rhamnopyranosyl-(1 → 6)-1-β-d-glucopyranoside] (7), and sibiraglycoside K (8), respectively, were isolated from an aqueous extract of the aerial portion of Sibiraea angustata. Their structures were elucidated on the basis of extensive spectroscopic data analysis (including ¹³CNMR,¹HNMR, HSQC, HMBC,¹H-¹H COSY, ROESY, HRESIMS, MS and CD experiments) and comparison to previously reported data. In addition, a preliminary evaluation of the hypolipidemic activities of these compounds is presented, some compounds showed moderate hypolipidemic activities in HepG2 cells.     

Phytochemical and chemotaxonomic study of Pulsatilla cernua (Thunb.) Bercht. ex J. Presl

Twenty-two compounds were isolated from the 70% EtOH–H₂O extract of Pulsatilla cernua (Thunb.) Bercht. ex J. Presl roots, and their structures were determined based on ¹H NMR, ¹³C NMR and MS spectroscopic data, including (+)-pinoresinol (1), matairesinol (2), 4-ethoxycinnamic acid (3), p-hydroxy ethyl cinnamate (4), 3-(4′-methoxyphenyl)-2(E)-propenoic acid (5), methyl 4-hydroxycinnamate (6), radicol (7), cryptomeridiol (8), fraxinellone (9), diolmycin B2 (10), hederagonic acid (11), hederagenin (12), oleanolic acid (13), 3-O-α-L-arabinopyranosyl-oleanolic acid (14), hederagenin 3-O-α-L-arabinopyranoside (15), 3-O-[α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranosyl] oleanolic acid (16), hederasaponin B (17), kizutasaponin K₁₂ (18), patrinia saponin H3 (19), hederacholichiside F (20), cernuoside A (21) and cernuoside B (22). Eight compounds (3–10) were isolated and identified from the genus Pulsatilla for the first time.     

Alkenylresorcinols and cytotoxic activity of the constituents isolated from Labisia pumila

Phytochemical investigation on the leaves of Labisia pumila (Myrsinaceae), an important medicinal herb in Malaysia, has led to the isolation of 1-O-methyl-6-acetoxy-5-(pentadec-10Z-enyl)resorcinol (1), labisiaquinone A (2) and labisiaquinone B (3). Along with these, 16 known compounds including 1-O-methyl-6-acetoxy-5-pentadecylresorcinol (4), 5-(pentadec-10Z-enyl)resorcinol (5), 5-(pentadecyl)resorcinol (6), (−)-loliolide (7), stigmasterol (8), 4-hydroxyphenylethylamine (9), 3,4,5-trihydroxybenzoic acid (10), 3,4-dihydroxybenzoic acid (11), (+)-catechin (12), (−)-epicatechin (13), kaempferol-3-O-α-rhamnopyranosyl-7-O-β-glycopyranoside (14), kaempferol-4′-O-β-glycopyranoside (15), quercetin-3-O-α-rhamnopyranoside (16), kaempferol-3-O-α-rhamnopyranoside (17), (9Z,12Z)-octadeca-9,12-dienoic acid (18) and stigmasterol-3-O-β-glycopyranoside (19) were also isolated. The structures of these compounds were established on the basis of 1D and 2D NMR spectroscopy techniques (¹H, ¹³C, COSY, HSQC, NOESY and HMBC experiments), mass spectrometry and chemical derivatization. Among the constituents tested 1 and 4 exhibited strongest cytotoxic activity against the PC3, HCT116 and MCF-7 cell lines (IC₅₀ values ⩽10 μM), and they showed selectivity towards the first two-cell lines relative to the last one.     

New metabolites from the alga-derived fungi Penicillium thomii Maire and Penicillium lividum Westling

A new meroterpenoid, austalide H acid ethyl ester (1), 5-(2′,4′-dihydroxy-6′-methylphenyl)-3-methylfuran-2-carboxylic acid (2), 5-(2′-hydroxy-6′-methylphenyl)-3-methylfuran-2-carboxylic acid (3) and 5-((6′-methyl-4′-oxo-3′,4′-dihydro-2H-pyran-2′-yl)methyl)-3-methylfuran-2-carboxylic acid (4), along with six known compounds, austalides H, J, K, and P (5–8), questin (9) and sulochrin (10) were isolated from the lipophilic extract of the alga-derived fungi Penicillium thomii KMM 4645 and Penicillium lividum KMM 4663. The structures of the isolated compounds were determined based on spectroscopic methods. The austalides showed significant inhibitory activity against endo-1,3-β-d-Glucanase from a crystalline stalk of the marine mollusk Pseudocardium sachalinensis.     

New ursane-type triterpenes from the root bark of Calotropis procera

As a part of our continuing interest in identifying anticancer drug leads from natural sources, we have investigated the in vitro growth inhibitory effects of the hexane fraction of the root bark of Calotropis procera (Ait) R. Br. (Asclepiadaceae). This study reports the isolation and structure elucidation of four new ursane-type triterpenes named calotroprocerol A (1), calotroproceryl acetate A (2), calotroprocerone A (3) and calotroproceryl acetate B (4) in addition to five known compounds including pseudo-taraxasterol acetate (5), taraxasterol (6), calotropursenyl acetate B (7), stigmasterol (8) and (E)-octadec-7-enoic acid (9). Their structures were established on the basis of 1D and 2D NMR studies (¹H–¹H COSY, HSQC, and HMBC) and HRMS spectral data. The in vitro growth inhibitory activity of the isolated compounds was evaluated against three human cancer cell lines including the A549 non-small cell lung cancer (NSCLC), the U373 glioblastoma (GBM) and the PC-3 prostate cancer cell lines.     

Anti-inflammatory iridoid glycosides from fruits of Cornus officinalis

Three undescribed iridoid glycosides, cyc(7β-O-6′)-morroniside (1), 6′-methyl succinate-7β-O-methylmorroniside (2), and 7β-O-methyl phenyllactate morroniside (3) were isolated from 50% ethanol extract of Cornus officinalis fruits. The structures of the isolated compounds were determined by HRESIMS, ¹D NMR, ²D NMR, UV and IR spectroscopic methods. Compounds 1-3 exhibited moderate anti-inflammatory activities in vivo in a CuSO₄-induced zebrafish inflammation model (when evaluated at 50 μM).     

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.     

Two new metabolites from Portulaca oleracea and their anti-inflammatory activities

Two new metabolites, identified as 6-phenylbenzofuran-4-ol, named olerabenzofuran (1), and 2-(furan-2-yl)− 6-hydroxy-1 H-inden-1-one, named oleraindenone (2), together with eight furan compounds obtained for the first time, (+)-pinoresinol (3), (-)-syringaresinol (4), (+)-diasyringaresinol (5), (+)-episyringaresinol (6), (2 S)− 1-[2-(furan-2-yl)− 2-oxoethyl]− 5-oxopyrrolidine-2-carboxylic acid (7), methyl (2 S)− 1[2-(furan-2-yl)− 2-oxoethyl]− 5-oxopyrrolidine-2-carboxylate (8), drynaran (9), and 2-furoic acid (10), were isolated from Portulaca oleracea L., and spectroscopic methods, including 1D and ²D NMR and UHPLC-ESI-QTOF/MS spectrometry techniques, were employed to determine their structures. It was suggested that both olerabenzofuran (1) and oleraindenone (2) could significantly inhibit inflammatory factor interleukin-1β (IL-1β) in RAW 264.7 cells induced by LPS.     

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).