Alkaloids from the leaves of Isatis indigotica fortune and their chemotaxonomic significance

From the leaves of Isatis indigotica Fortune, one new alkaloid, namely (2E)-N-(2-hydroxyphenyl)-2-(1-hydroxy-3-oxoindolin-2-ylidene) acetamide (1), together with four known ones, such as phaitanthrin D (2), methyl quindoline-11-carboxylate (3), cephalandole B (4) and 2,2-di (3-indolyl)-3-indolone (5) were isolated and identified. The structure of compound 1 was elucidated by means of spectroscopic analysis, including HRESIMS together with 1D and 2D NMR experiments. Compounds 1, 2 and 5 were obtained from this genus for the first time. Chemotaxonomic significance of these compounds is described herein.     

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.     

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.     

Chemical constituents from the pericarps of Zanthoxylum bungeanum and their chemotaxonomic significance

The phytochemical study of the pericarps of Zanthoxylum bungeanum Maxim under the guidance of bioactivity led to the isolation of 18 compounds, including a new isobutylhydroxyamide (1) and 17 known compounds, i.e. six alkylamides (2–7), five coumarins (8–12), one benzene derivative (13), three flavonoids (14–16), and two sterols (17–18). Their structures were elucidated based on extensive spectroscopic methods (HRESIMS, 1D and 2D NMR experiments) and by comparison with literature data. New compound (1) and known compound (2) are cis-trans isomeric isobutylhydroxyamides. Among them, compounds 9, 10, and 12 were isolated for the first time from Z. bungeanum, compound 11 was firstly recovered from the genus Zanthoxylum, and compound 14 was reported for the first time from the Rutaceae family. The chemotaxonomic significance of isolated compounds from Z. bungeanum is discussed.     

Chemical constituents from the root bark of Dictamnus dasycarpus Turcz. (Rutaceae) and their chemotaxonomic significance

This work described the isolation and characterization of seven compounds from Dictamnus dasycarpus Turcz., including one new ester, (2R)-4-(2,2-dimethyl-5-oxotetrahydrofuran-3-yl)-2-hydroxypent-3-anoic acid ethyl ester (1); and six known glycosides (2–7). The structure of compound 1 was elucidated on the basis of extensive spectral analyses, including IR, HR-ESIMS, 1D and 2D NMR (NOESY, HMBC and HSQC). All these compounds were described here for the first time from the genus Dictamnus. Moreover, the results provide further information about the diversity of compounds in the genus Dictamnus.     

New diplosporin and agistatine derivatives produced by the fungal endophyte Xylaria sp. isolated from Vitis labrusca

A Xylaria sp. was isolated as an endophyte from a surface-sterilized Concord grape leaf (Vitis labrusca). Dereplication and LC–MS analysis of the filtrate extracts identified two new structures, compound 1, 13-O-methyl-(5R) diplosporin, and 2 a new agistatine. Additionally, five known compounds 3–7 including an agistatine, coriloxin, (5R)-diplosporin, and two mellein derivatives were also isolated. This is the first report of these structurally-related metabolites isolated from the same fungus, suggesting they share a related biosynthesis. Metabolites were isolated using liquid chromatography-solid phase extraction (LC-SPE) and semi-preparative HPLC. Structures were elucidated on the basis of 1D and 2D NMR analysis, HRMS measurements and X-ray structural analysis for compound 1.     

Phytochemical investigation on the fruiting body of Russula aruea Pers

Phytochemical investigation of ethyl acetate fraction from Russula aruea Pers fruiting body led to the isolation and identification of one new isolactarane sesquiterpene (1) and 11 known compounds, including four sesquiterpenes (2-5), four sterols (6–9), one allitol (10), and two fatty acids (11–12). The structure of compound 1 was elucidated by means of spectroscopic analysis, including 1D and 2D NMR, HR-ESI-MS, and X-Ray experiments. Compounds 1–3 and 5–12 are herein reported for the first time from Russula genus, while compound 4 is firstly described in R. aruea. The sesquiterpenes in R. aruea could serve as chemotaxonomic markers.     

Phenolic compounds isolated from Dioscorea zingiberensis protect against pancreatic acinar cells necrosis induced by sodium taurocholate

One new bibenzyl (1) and one new phenanthrene (2), together with two known bibenzyls (3–4) and four known diarylheptanoids (5–8) were isolated from the rhizomes of Dioscorea zingiberensis. The structures of 1–2 were elucidated by spectroscopic methods including 1D and 2D NMR. Phenols 1–8 were evaluated for their anti-pancreatitic activities on sodium taurocholate (NaT)-induced pancreatic acinars necrosis. Notably, 0.5 mM of compound 6 exhibited comparable inhibitory effect with 5 mM of caffeine. Furthermore, compound 6 prevented the ATP depletion and excessive ROS production which could be also involved in mitochondria-mediated injuries in acute pancreatitis. As a result, compound 6 has been demonstrated to be a potential candidate for mediating mitochondrial dysfunction to prevent pancreatic necrosis. This study is also the first report on the isolation of bibenzyls and diarylheptanoids from this plant.     

A new flavone glycoside from the leaves of Agastache rugosa (Fisch. & C.A.Mey.) Kuntze

Agastache rugosa (Fisch. & C.A.Mey.) Kuntze has been widely used as a food spice and a remedy for colds in Korea, China and Japan. In this study, one new flavone glycoside (1) along with six flavonoids (2–7), nine phenyl glycosides (8–16) and three megastigmane glycosides (17–19) were isolated from the leaves of A. rugosa. By extensive spectroscopic methods including 1D and 2D NMR, and MS data, the structure of the new compound (1) was elucidated as acacetin 7-O-β-(6″-(E)-crotonylglucopyranoside). From present investigation, compound 1 and 7–19 were isolated for the first time from the genus Agastache and 1, 16, 18 and 19 in the Lamiaceae family.     

Iridoids and lignans from Valeriana officinalis L. and their cytotoxic activities

Two new iridoids (1 and 2), one new lignan (3) together with one known iridoid (4) and twelve known lignans (5－16) were obtained from the roots of Valeriana officinalis L. (V. officinalis). The structures were determined using IR, MS, ¹D and ²D NMR spectroscopy and the absolute configurations of the new structures were deduced by ECD experiments. All of the isolated compounds were assayed for their cytotoxic activities against three tumour cell lines (A549, HCT116 and SW620) and the results showed that compounds 9 and 10 showed cytotoxicities against A549 cells, compounds 9 and 11 showed cytotoxicities against SW620 cells and compound 10 showed cytotoxicities against HCT116 cells.     

Quaternary β-carboline alkaloids from Psychotria prunifolia (Kunth) Steyerm.

Two new quaternary alkaloids, compound 1 and the 14-oxo derivative 2, were isolated along with the known alkaloid strictosamide (3) from the leaves of Psychotria prunifolia (Kunth) Steyerm. (Rubiaceae, Psychotriae). Their structures were elucidated using spectroscopic methods (1D and 2D NMR, IR, and HRMS).     

A new flavonoid from the stem bark of Acer tegmentosum

A new flavonoid, 6-carboxyl-(−)-catechin methyl ester (1) was isolated from the stem bark of Acer tegmentosum, along with six known flavonoids (2–7). The structure of compound 1 was determined by spectral analyses, including HR-ESI-MS, 1D and 2D NMR (COSY, HMQC and HMBC) experiments. From present investigation, compound 7 was isolated for the first time from the Aceraceae family.     

Neolignan and monoterpene glycoside from the seeds of Pharbitis nil

Phytochemical investigation of an EtOH extract of Pharbitis nil seeds (Convolvulaceae) resulted in the isolation and identification of a new neolignan, 7R,8S-threo-dihydroxydehydrodiconiferyl alcohol (1), and a new monoterpene glycoside, (3Z,7S)-7-hydroxy-3,7-dimethyl-3,8-octadienyl-β-d-glucopyranoside (2), together with a known compound, ethyl α-l-arabinofuranoside (3). The chemical structures of these compounds were unambiguously determined using physical data, HR-ESI–MS and spectroscopic evidence, including 1D and 2D NMR experiments. The anti-inflammatory activities of the isolates were evaluated by estimating the inhibition of nitric oxide (NO) production. Compounds 1 and 2 reduced NO levels in lipopolysaccharide (LPS)-stimulated murine microglial BV-2 cells. In addition, compound 2 showed weak cytotoxicity against the HCT-15 cell line with an IC₅₀ value of 28.6 μM.     

Chemical constituents from the stem bark of Acer tegmentosum

A new phenolic glycoside, 4-hydroxyphenylethyl-1-O-β-D-[6′-O-(4-hydroxybenzoyl)]-glucopyranoside (1) was isolated from the stem bark of Acer tegmentosum, along with seven known phenolic compounds (2–8). The structure of compound 1 was determined by spectral analyses, including HR-ESI-MS, 1D and 2D NMR (COSY, HMQC and HMBC) experiments. Compounds 3 and 4 were found in the family Aceraceae for the first time.     

Chemical constituents from Eucalyptus citriodora Hook leaves and their glucose transporter 4 translocation activities

Bioassay-guided phytochemical investigation of the EtOAc fraction from the leaves of a Chinese medicinal herb, Eucalyptus citriodora Hook, resulted in the isolation of a new compound rhodomyrtosone E (1), along with 12 known compounds (2–13). The structure of the new compound was established by 1D and 2D NMR, MS data and X-ray crystallographic analysis. Betulinic acid (2) and corosolic acid (5) increased glucose transporter 4 (GLUT-4) translocation by 2.38 and 1.78-fold, respectively.     

Estrogenic activity of constituents from the rhizomes of Rheum undulatum Linné

Stilbenes have been reported to be phytoestrogen compounds owing to its structural similarity to the estrogenic agent diethylstilbestrol. To find new stilbene-derivative phytoestrogens, isolation of stilbene-rich R. undulatum was performed and led to identify six new compounds (1–5 and 28), one newly determined absolute configurations compound (27) together with 21 previously reported compounds (6–26). The structures of compounds were determined on the basis of extensive spectroscopic methods including 1D and 2D NMR and CD spectra data. All the isolated compounds were tested for their estrogenic activities in HepG2 cells transiently transfected with ERα, ERβ and ERE-reporter plasmid. Among them, stilbene-derivatives, piceatannol 3′-O-β-d-xylopyranoside (12), cis-rhaponticin (16) and rhapontigenin 3′-O-β-d-glucopyranoside (17), showed the more potent binding affinity for estrogen receptors than 17β-estrodiol.     

New Labdane diterpenes as intestinal α-glucosidase inhibitor from antihyperglycemic extract of Hedychium spicatum (Ham. Ex Smith) rhizomes

Phytochemical investigation of antihyperglycemic extract of rhizomes of Hedychium spicatum led to the isolation of two new labdane type diterpenes 2, 3 along with seven known compounds (1, 4–9). Their structures were established on the basis of NMR (1D and 2D) and mass spectroscopic analysis. The new compound 2 displayed strong intestinal α-glucosidase inhibitory activity. Other compounds also displayed varying degree of intestinal α-glucosidase inhibitory potential.     

Isoflavones from the roots and stems of Nicotiana Tabacum and their anti-tobacco mosaic virus activities

Two new isoflavones, 7-hydroxy-6,3′,4′,5′-tetramethoxy-isoflavone (1) and 6-hydroxy-7,3′,4′,5′-tetramethoxy-isoflavone (2), together with seven known isoflavones were isolated from the roots and stems of Nicotiana tabacum. Their structures were determined by means of HRESIMS, extensive 1D and 2D NMR spectroscopic studies and chemical evidences. The anti-tobacco mosaic virus (anti-TMV) activities of the isoflavones were also evaluated. The results reveal that compound 9 shows high anti-TMV activity, compound 2 shows moderate anti-TMV activity, and compounds 1, 3–8 show weak anti-TMV activities.     

Chemical constituents from Lonicera japonica flower buds and their anti-hepatoma and anti-HBV activities

Three new naturally occurring monoterpenoids, japopenoid A (1), japopenoid B (23) japopenoid C (24), and one new caffeoylquinic acid derivative (28), together with thirty-one known compounds (2–22, 25–27, 29–35), were isolated and identified from the flower buds of Lonicera japonica Thunb. Their structures were determined by extensive 1D and 2D NMR spectroscopic methods, high-resolution mass spectrometry, and the absolute configurations of 1, 23, 24 were determined by comparison of their electronic circular dichroism (ECD) spectrum with literature and theoretical calculation. Structurally, compound 1 is a monoterpenoid featured with an unusual tricyclic skeleton. All compounds (1–35) were evaluated for their cytotoxicities against human liver cancer cell lines (HepG 2 and SMMC-7721). Compound 12 exhibited the most potent activity with IC₅₀ values of 26.54 ± 1.95 and 8.72 ± 1.57 μg/ml against HepG 2 and SMMC-7721, and the IC₅₀ values of compound 13 were 26.54 ± 1.95 and 12.35 ± 1.43 μg/ml, respectively. Western blot results further proved that compound 13 induces hepatoma cell apoptosis via the intrinsic apoptosis pathway. In addition, most terpenoids showed inhibitory activity against HBsAg and HBeAg secretion, and HBV DNA replication. In particular, 25 μg/mlof compound 11 inhibits HBsAg and HBeAg secretion, and HBV DNA replication by 39.39 ± 5.25, 15.64 ± 1.25, and 16.13 ± 4.10% compared to the control (p < 0.05). These results indicated that L. japonica flower buds could be served as functional food for anti-hepatoma and anti-HBV activities.     

Spicachlorantins A and B,new dimeric sesquiterpenes from the roots of Chloranthus spicatus

Two new lindenane sesquiterpene dimers, spicachlorantins A and B (1 and 2), were isolated from the roots of Chloranthus spicatus along with a known related compound, chloramultilide A (3). Their structures and the absolute stereostructures were established by 1D and 2D NMR as well as by CD spectroscopic analyses.