Antiplasmodial phloroglucinol derivatives from Syncarpia glomulifera

Bioassay guided fractionation of a MeOH extract of the stem bark of Syncarpia glomulifera (Myrtaceae) led to the isolation of the two new phloroglucinol derivatives (±)-rhodomyrtosone F (1) and (±)-calliviminone C (2), the three known triterpenes, betulinic acid (3), ursolic acid-3-acetate (4), and ursolic acid (5), and 1-(2,4,6-trihydroxyphenyl)-1-hexanone (6). Compound 1 exhibited strong antiplasmodial activity, while compounds 2–4 were moderately active and 5 and 6 were inactive in this assay. The structures of 1 and 2 were elucidated based on analyses of their mass spectrometric data, 1D and 2D NMR spectra, and comparison with related compounds.     

Polycyclic phloroglucinols as PTP1B inhibitors from Hypericum longistylum: Structures,PTP1B inhibitory activities,and interactions with PTP1B

Protein tyrosine phosphatase 1B (PTP1B) has been regarded as a target for the research and development of new drugs to treat type II diabetes and PTP1B inhibitors are potential lead compounds for this type of new drugs. A phytochemical investigation to obtain new PTP1B inhibitors resulted in the isolation of four new phloroglucinols, longistyliones A–D (1–4) from the aerial parts of Hypericum longistylum. The structures of 1–4 were elucidated on the basis of extensive 1D and 2D NMR spectroscopic data analysis, and the absolute configurations of these compounds were established by comparing their experimental electronic circular dichroism (ECD) spectra with those calculated by the time-dependent density functional theory method. Compounds 1–4 possess a rare polycyclic phloroglucinol skeleton. The following biological evaluation revealed that all of the compounds showed PTP1B inhibitory effects. The further molecular docking studies indicated the strong interactions between these bioactive compounds with the PTP1B protein, which revealed the possible mechanism of PTP1B inhibition of bioactive compounds. All of the results implied that these compounds are potentially useful for the treatment of type II diabetes.     

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.     

Secondary metabolites from the stem bark of Juglans mandshurica

A pair of new dibenz[cd,lm]perylene derivatives, juglanperylenone A (1a) and juglanperylenone B (1b), along with ten known compounds, including four anthraquinones (2–5), two coumarins (6–7) and four triterpenoids (8–11), were isolated from the stem bark of Juglans mandshurica Maxim. Their structures were elucidated on the basis of spectroscopic evidence, including 1D and 2D NMR, HR-TOF-MS, and by comparison with literature data. In addition, the chemotaxonomic significance of the isolates was also discussed in this paper.     

Phloroglucinol diglycosides accompanying hydrolyzable tannins from Kunzea ambigua

Six phloroglucinol diglucosides—kunzeaphlogins A-F (1-6) and a hydrolyzable tannin, kunzeatannin A (7)—were isolated along with 10 known polyphenols from the leaf extract of Kunzea ambigua. Structural elucidation of these compounds was based on spectroscopic analyses and chemical properties.     

Cytotoxic triterpene diglycosides from the sea cucumber Stichopus horrens

Using various chromatographic separation techniques, eight triterpene diglycosides (1–8), including four new compounds namely stichorrenosides A–D (1–4), were isolated from a methanol extract of the Vietnamese sea cucumber S. horrens. Their structures were elucidated based on spectroscopic analyses, including HR ESI MS, 1D and 2D NMR. Their in vitro cytotoxic activity against five human cancer cell lines, Hep-G2 (hepatoma cancer), KB (epidermoid carcinoma), LNCaP (prostate cancer), MCF7 (breast cancer), and SK-Mel2 (melanoma), was evaluated using SRB methods. Stichorrenoside D (4), stichoposide A (5), and 3β-O-[β-d-xylopyranosyl-(1→2)-β-d-xylopyranosyl]-23S-acetoxyholost-7-ene (7) showed strong cytotoxicity on all five tested cancer cell lines, whereas significant effect was observed for stichorrenoside C (3) and stichoposide B (6).     

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.     

Chemical constituents of Gardneria ovata wall

A phytochemical investigation on the aerial parts of Gardneria ovata Wall resulted in the isolation and identification of 14 compounds, including three gardneria glycoalkaloids (1–2 and 6), seven gardneria alkaloids (3–5 and 7–10), and four oxindole alkaloids (11–14). 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 11–14 are the first time reported from of G. ovate, while the compounds 3–4, 6, and 8 are also the characteristic secondary metabolites of the title plant. The chemotaxonomic significance and distribution of these monoterpenoid indole alkaloids in Gardneria genus are discussed.     

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.     

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.     

Flavonoids from the leaves and twigs of Knema elegans

Knema elegans, a tropical evergreen plant, belongs to Myristicaceae family. Phytochemical investigation on the leaves and twigs of K. elegans led to the isolation and identification of two new flavonoids knemavones A and B (1 and 2), along with fifteen known analogues (3–17). These compounds belong to four subtypes of flavonoids, including chalcones, flavanes, flavones, and isoflavones. The structures of 1 and 2 were elucidated by means of spectroscopic techniques, including HRESIMS, 1D, and 2D NMR experiments. Compounds 3–17 are isolated from the title plant for the first time. Moreover, the new chalcones 1 and 2 could serve as chemotaxonomic markers of K. elegans.     

Chemical constituents of Melodinus hemsleyanus diels

Phytochemical investigation on the aerial parts of Melodinus hemsleyanus diels (Jahrb, Syst, 1995) led to the isolation and identification of 27 compounds, including fifteen aspidosperma-type alkaloids (1–15), four quinoline-type alkaloids (16–19), three quebrachamine-type alkaloids (20–22), and five eburna-type alkaloids (23–27). The structure of compound 1 was elucidated by means of spectroscopic analysis, including HRESIMS, and 1D and 2D NMR experiments. Compounds 1–2, 6, 10, 12, 13, 15, 16 and 20–27 are herein reported for the first time from the studied plant, while the compounds 1–2 and 21 have not previously been recorded in the genus Melodinus. The aspidosperma-type monoterpenoid indole alkaloids in M. hemsleyanus could serve as chemotaxonomic markers.     

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 aerial parts of Thymelaea lythroides

Chemical investigation of the EtOAc extract of the medicinal plant Thymelaea lythroides yielded eight secondary metabolites, including bassiatin (1), daphenone (2), daphnelone (3), daphnoretin (4), δ-sesamin (5), wikstromol (6), trans-tiliroside (7), and rutarensin (8). The structures of the isolated compounds were determined on the basis of 1D and 2D NMR spectroscopy as well as mass spectrometry. Compounds 1–8 were reported from T. lythroides for the first time and the chemotaxonomic significance of these compounds is summarized.     

Polyoxygenated seco-cyclohexenes and other constituents from Uvaria valderramensis

Phytochemical study on the Philippine endemic Annonaceae plant Uvaria valderramensis afforded a new highly oxygenated seco-cyclohexene derivative, valderepoxide (1), along with the six known compounds uvamalols D (2) and G (3), grandiuvarone (4), 2′-hydroxy-3′,4′,6′-trimethoxychalcone (5), valderramenol B (6) and benzoic acid. The structure of 1 was determined through extensive spectroscopic analyses including 1D, 2D NMR and HRESIMS. Its relative stereochemistry was established using 2D-NOESY. This is the first report on the isolation of polyoxygenated compounds 1–3 and chalcone 5 from U. valderramensis.     

Oxytrofalcatins A–F,N-benzoylindole analogues from the roots of Oxytropis falcata (Leguminosae)

Indole alkaloids, oxytrofalcatins A–F (1–6), together with five other known alkaloids (7–11), were isolated from the roots of Oxytropis falcata. Their structures were elucidated by comprehensive spectroscopic analyses, including using 1D and 2D NMR spectroscopy and mass spectrometry. This is the first report of N-benzoylindoles from a natural source. Compounds 1–6 lacked significant cytotoxicity against SGC-7901 and HL-60 tumor cell lines.     

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.     

New spermidine alkaloids from Capparis spinosa roots

Three new spermidine alkaloids capparispine (1), capparispine 26-O-β-d-glucoside (2) and cadabicine 26-O-β-d-glucoside hydrochloride (3) were isolated from the roots of Capparis spinosa. Their structures were established on the basis of spectroscopic analysis, including 1D and 2D NMR experiments (¹H–¹H COSY, HSQC, HMBC).     

Cytotoxic cycloartanes from the fruits of Caloncoba glauca

Two new cycloartane-type triterpenoids, glaucartanoic acids A (1) and B (2), together with five known compounds were isolated from the fruits of Caloncoba glauca. Their structures were elucidated by spectroscopic methods including extensive 1D and 2D NMR techniques, by chemical evidence and by comparison with literature data. The new compounds were evaluated for their in vitro cytotoxicity against five human cancer cell lines.     

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.