Isopimarane-type diterpenoids from Callicarpa macrophylla vahl

Three new isopimarane-type diterpenoids, named callicapene M1 (1), callicapene M2 (2), and callicapene M3 (3), together with four known isopimarane-type diterpenoids (4, 5, 6, 7), were isolated from the Callicarpa macrophylla Vahl. Their structures were elucidated by spectroscopic techniques (IR, UV, MS, 1D, 2D NMR). The isolated compounds 6 and 7 exhibited potent inhibitory activity with inhibition rates of 40.23–46.78% on NO production in LPS-activated RAW 264.7 macrophage cells by using MTT assays.     

Three new flavonol glycosides from Nervilia fordii

Three new flavonol glycosides, nervilifordizins A–C (1–3), were isolated from the whole plant of Nervilia fordii. Their structures were elucidated as rhamnazin 3-O-β-d-xylopyranosyl-(1→4)-β-d-glucopyranoside (1), rhamnazin 3-O-β-d-glucopyranosyl-(1→4)-β-d-glucopyranoside (2) and rhamnazin 3-O-β-d-xylopyranosyl-(1→4)-β-d-glucopyranoside-4′-O-β-d-glucopyranoside (3) on the basis of extensive spectroscopic analysis, including HSQC, HMBC, ¹H–¹H COSY, and chemical evidences.     

Chemical constituents from Silene schimperiana Boiss. belonging to caryophyllaceae and their chemotaxonomic significance

Phytochemical investigation of Silene schimperiana Boiss. ethanolic extract led to the isolation of fifteen compounds (1–15). The isolated compounds were identified by their NMR, MS spectral data analyses and comparing with published data as: vanillic acid (1), ferulic acid (2), caffeic acid (3), ethyl ferulate (4), apigenin (5), hesperetin (6), diosmetin (7), luteolin (8), kaempferol (9), quercetin (10), ecdysterone (11), hesperedin (12), diosmin (13), kaempferol-3-O-rutinoside (14) and rutin (15). The lack of chemical and biological investigations on this plant encouraged us to carry out the above-mentioned work.     

New flavonoids from the fruits of Cornus mas,Cornaceae

One new β-hydroxychalcone, 4-acetoxy-5,2′,4′,6′,β-pentahydroxy-3-methoxychalcone (1), one new flavanone, 7,3′-dihydroxy-5,4′-dimethoxyflavanone (2) and seven known compounds, 2R, 3R-trans-aromadendrin (3), naringenin-7-O-methylether (4), myricetin (5), quercetin-3-O-rutinoside (6), ursolic acid (7), gallic acid (8) and d-glucose (9) were isolated from the methanolic fruit extract of Cornus mas L. (=Cornus mascula L.), Cornaceae. The structures of the new compounds were elucidated on the basis of extensive spectroscopic methods, including 2D NMR experiments and of known compounds by comparison of physical and spectral data with literature.     

Antibacterial constituents from Leucosceptrum canum

Four new long-chain compounds, leucoperoxyterpene (1), leucoester (2), leucoic acid (3), and leucoenoic acid (4) has been isolated from aerial parts of the medicinal plant Leucosceptrum canum together with fifteen known compounds. Compound 1 was found to be a member of the rare class of peroxy open chain natural products. The structures of all compounds were assigned by means of modern spectroscopic techniques. All compounds were tested for their antibacterial activities against Bacillus subtilis, Escherichia coli, Micrococcus luteus, Pseudomonas agarici, Streptococcus minor, and Streptococcus ferus, in which, compounds 1, and 10–15 exhibited potent to moderate activities.     

Bioactive constituents of Helianthus tuberosus (Jerusalem artichoke)

In a cytotoxicity-guided study using the MCF-7 human breast cancer cell line, nine known compounds, ent-17-oxokaur-15(16)-en-19-oic acid (1), ent-17-hydroxykaur-15(16)-en-19-oic acid (2), ent-15β-hydroxykaur-16(17)-en-19-oic acid methyl ester (3), ent-15-nor-14-oxolabda-8(17),12E-dien-18-oic acid (4), 4,15-isoatriplicolide angelate (5), 4,15-isoatriplicolide methylacrylate (6), (+)-pinoresinol (7), (?)-loliolide (8), and vanillin (9) were isolated from the chloroform-soluble subfraction of a methanol extract of the whole plant of Helianthus tuberosus collected in Ohio, USA. This is the first time that diterpenes have been isolated and identified from this economically important plant. The bioactivities of all isolates were evaluated using the MCF-7 human breast cancer cell line as well as a soybean isoflavonoid defense activation bioassay. The results showed that two germacrane-type sesquiterpene lactones, 5 and 6, are cytotoxic agents. While compounds 2, 3, 5 and 6 blocked isoflavone accumulation in the soybean, the norisoprenoid (?)-loliolide (8) was somewhat stimulatory of these defense metabolites.     

Chemical constituents from the fruits of Rhus typhina L. and their chemotaxonomic significance

This work describes the isolation and characterization of twenty-nine compounds from the fruits of Rhus typhina L., including eleven flavonoids (1–11), eleven phenols (12–22), two pentacyclic triterpenes (23–24), two organic acids (25–26), one lumichrome (27), one courmarin (28) and one pyrimidine (29) on the basis of their spectroscopic data. Compounds apigenin (1), daidzein (4), orobol (5), 3′, 5, 5′, 7-tetrahydroxyflavanone (6), naringenin (7), butein (8), (-)-catechin (9), quercetin-3-O-α-L-(3″-O-galloyl)-rhamnoside (11), 2-hydroxybenzoic acid (13), 4-hydroxybenzaldehyde (14), vanillin (15), methyl 3,4-dihydroxybenzoate (16), 3,5-dihydroxybenzamide (18), tyrosol (19), caffeic acid (20), 3-(2,4,6-trihydroxyphenyl)-1-(4-hydroxyphenyl)-propan-1-one (21), phlorizin (22), friedelin (23), oleanolic acid (24), 4,4-dimethyl-heptanedioic acid (25), anthranilic acid (26), lumichrome (27), scoparone (28) and uracil (29) have not been recorded before in this plant. This is the first report on the occurrence of compounds 4–7, 9, 11, 13–14, 16, 18–21, 25–29 from the genus Rhus. Moreover, the chemotaxonomic significance of these isolated compounds was also summarized.     

Phytochemical study on the leaves of Wollemia nobilis

In this work, a phytochemical study performed on the leaves of the rare species, Wollemia nobilis W.G. Jones, K.D. Hill & J.M. Allen, is reported. By means of classical column chromatography and NMR Spectroscopy and Mass Spectrometry, nine compounds were evidenced. These were: pheophorbide a (1), isocupressic acid (2), acetyl-isocupressic acid (3), sandaracopimaric acid (4), agathic acid (5), 7–4′-4‴-tri-O-methyl-agathisflavone (6), 7–4′-7″-4‴-tetra-O-methyl-agathisflavone (7), caffeic acid (8) and shikimic acid (9). Compared to our previous phytochemical analysis on the male cones, some further compounds were identified i.e. compounds 1, 5, 6, 7 and 8. This confirmed the previous chemotaxonomic considerations of the species but also added new ones which were discussed within the text. In addition, a possible different accumulation of secondary metabolites in the tissues and organs of this plant was even noticed.     

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.     

Phenolic compounds and ecdysteroids of Diplazium esculentum (Retz.) Sw. (Athyriaceae) from Japan and their chemotaxonomic significance

Four phenolic compounds, (2R)-3-(4′-hydroxyphenyl) lactic acid, trans-cinnamic acid (2), protocatechuic acid (3) and rutin (4), and three ecdysteroids, amarasterone A1 (5), makisterone C (6) and ponastrone A (7) were isolated and identified from the young fronds of Diplazium esculentum (Retz.) Sw. (Athyriaceae). The structures of these compounds were elucidated on the basis of NMR spectral data and comparison with literature values. Compounds 1, 2 and 5–7 were isolated for the first time from title plant. Their structure elucidation and chemotaxonomic significance are explained in detail.     

New class of acetylcholinesterase inhibitors from the stem bark of Knema laurina and their structural insights

Bioassay-guided extraction of the stem bark of Knema laurina showed the acetylcholinesterase (AChE) inhibitory activity of DCM and hexane fractions. Further repeated column chromatography of hexane and DCM fractions resulted in the isolation and purification of five alkenyl phenol and salicylic acid derivatives. New compounds, (+)-2-hydroxy-6-(10′-hydroxypentadec-8′(E)-enyl)benzoic acid (1) and 3-pentadec-10′(Z)-enylphenol (2), along with known 3-heptadec-10′(Z)-enylphenol (3), 2-hydroxy-6-(pentadec-10′(Z)-enyl)benzoic acid (4), and 2-hydroxy-6-(10′(Z)-heptadecenyl)benzoic acid (5) were isolated from the stem bark of this plant. Compounds (1-5) were tested for their acetylcholinesterase inhibitory activity. The structures of these compounds were elucidated by the 1D and 2D NMR spectroscopy, mass spectrometry and chemical derivatizations. Compound 5 showed strong acetylcholinesterase inhibitory activity with IC₅₀ of 0.573 ± 0.0260 μM. Docking studies of compound 5 indicated that the phenolic compound with an elongated side chain could possibly penetrate deep into the active site of the enzyme and arrange itself through π-π interaction, H-bonding, and hydrophobic contacts with some critical residues along the complex geometry of the active gorge.     

Sesquiterpene lactones and other secondary metabolites from Crepis commutata (Spreng.) Greuter – Asteraceae

Sesquiterpene lactones, especially guaianolides, are widespread in the genus Crepis L. We have undertaken the chemical investigation of Crepis commutata (Spreng.) Greuter, an edible plant in Crete. From the non-polar extract of the aerial flowering parts of C. commutata five sesquiterpene lactones: 8-epi-grosheimin (1), 8-epi-isoamberboin (2), 8-epi-isolipidiol (3), 3-acetyl-8-epi-isolipidiol (4), integrifolin 3-O-β-D-glucopyranoside (5), two flavonoids: luteolin (6), luteolin 7-O-β-D-glucuronide (7), and three phenolic acids: p-anisic acid (8), p-hydroxyphenylacetic acid (9) and E-caffeic acid (10) were isolated. The structures of the isolated compounds were elucidated by high-field NMR spectroscopy.     

Phytochemical and chemotaxonomic studies on the stems and leaves of Schisandra chinensis (Turcz.) Baill

A comprehensive phytochemical investigation of the stems and leaves of Schisandra chinensis (Turcz.) Baill. resulted in isolation of seventeen compounds, including five lignans: meso-dihydroguaiaretic acid (1), licarin-A (2), pregomisin (3), gomisin A (4), acutissimanide (5), three phenylpropanoids: 2-[4-(3-hydroxypropyl)-2-methoxyphenoxy]-propane-1,3-diol (6), 2-methoxy-4-(2-propenyl) phenyl β-D-glucopyranoside (7), erigeside 2 (8), six sesquiterpenoids: 7′-hydroxy-abscisic acid (9), burmannic acid (10), (3S,5R,6R,7E)-3,5,6-trihydroxy-7-megastigmen-9-one (11), 3-Cyclohexene-1,2-diol, 4-(3-hydroxybutyl)- 3, 5, 5-trimethyl- (12), (−)-loliolide (13), (3Z,5R,8R,11R)-Caryophyll-3-ene-5,8,15-triol (14), one monoterpenoid: (6R,3Z)-6,7-dihydroxy-3,7-dimethyl-2-octenoic acid (15) and two other compounds: methyl shikimate (16), 4-Hydroxydodec-2-enedioic acid (17). Their chemical structures were confirmed through NMR, HRESIMS and comparison with the data in the literature. This is the first report of compounds 5, 6, 8–15, 17 from the family Schisandraceae and compounds 2, 16 from the genus Schisandra. Furthermore, we performed a chemotaxonomic study of the separated compounds.     

New 19α-hydroxyursane-type triterpenes from the leaves of Meyna spinosa (= Vangueria spinosa), Rubiaceae

Two new 19α-hydroxyursane-type triterpenes, 2α,3α,19α,24,28-pentahydroxyurs-12-ene (1) and meyanthic acid, 3β-acetoxy-2β,19α,23-trihydroxyurs-12-en-28-oic acid (2) along with one new aliphatic ester, myricyl pentadecanoate (3) and five known compounds, 19α-hydroxyasiatic acid (4), oleanolic acid (5), myricyl alcohol (6), β-sitosterol (7) and its glycoside (8) were isolated from the methanolic leaf extract of Meyna spinosa Roxb. ex Link (= Vangueria spinosa Roxb., Rubiaceae). The structures of the new compounds were elucidated on the basis of extensive spectroscopic (including 2D NMR) analysis and comparison with literature. Except oleanolic acid, isolation of known compounds was reported for the first time from this plant.     

Pentacyclic triterpenoids and other constituents isolated from the leaves of Gambeya lacourtiana and their antibacterial activity

The phytochemical study was done on the leaves of Gambeya lacourtiana. This plant has been used in traditional medicine to treat of different ailments such as uterine heamorrhage, metritis and other vaginal infections. Chromatographic fractionation and purification on the leaves crude extract afforded lupeol acetate (1), lupenone (2), lupeol (3), taraxerol (4) stigmasterol (5), erythrodiol (6), chamaedrydiol (7), methyl pheophorbide-a (8), corosolic acid (9), tormentic acid (10), epicatechin (11) and 22-dihydrospinasterol 3-O-β-D-glucopyranoside (12). The structures of compounds 1–12 were elucidated on the basis of 1D and 2D NMR, mass spectrometric and the spectroscopic data as well as comparison with the literature. Compounds 4, 7–10 and 12 were isolated for the first time from Gambeya genus. Crude extract, fractions and compounds 6–12 were evaluated for their antibacterial activity. Methyl pheophorbide-a (8) demonstrated moderate activity against Salmonella typhi CPC with MIC values of 62.5 μg/mL. The chemophenetic significance of these compounds is also discussed.     

Three terpenoid glycosides of Centipeda minima

From the n-BuOH-soluble extract of the whole plant of Centipeda minima (Asteraceae), the investigation on chemical constituents led to the isolation of three new compounds including 3′-desulphatedatractyloside (1), 15-O-[α-l-rhamnosyl-(1→2)-β-d-glucosyl]grandiflorolic acid (2), and 2α-hydroxylemmonin C (3), along with five known compounds (4–8). Their structures were elucidated on the basis of the NMR spectroscopic analysis.     

Bioactive secondary metabolites from the marine-associated fungus Aspergillus terreus

Three new compounds, including a prenylated tryptophan derivative, luteoride E (1), a butenolide derivative, versicolactone G (2), and a linear aliphatic alcohol, (3E,7E)-4,8-dimethyl-undecane-3,7-diene-1,11-diol (3), together with nine known compounds (4–12), were isolated and identified from a coral-associated fungus Aspergillus terreus. Their structures were elucidated by HRESIMS, one- and two-dimensional NMR analysis, and the absolute configuration of 2 was determined by comparison of its electronic circular dichroism (ECD) spectrum with the literature. Structurally, compound 1 featured an unusual (E)-oxime group, which occurred rarely in natural products. Compounds 1–3 were evaluated for the α-glucosidase inhibitory activity, and compound 2 showed potent inhibitory potency with IC₅₀ value of 104.8 ± 9.5 μM, which was lower than the positive control acarbose (IC₅₀ = 154.7 ± 8.1 µM). Additionally, all the isolated compounds were evaluated for the anti-inflammatory activity against NO production, and compounds 1–3, 5–7, and 10 showed significant inhibitory potency with IC₅₀ values ranging from 5.48 to 29.34 μM.     

Chemical constituents from the roots of Caragana grandiflora (M. B.) DC. and their chemotaxonomic importance

A comprehensive phytochemical research on roots of Caragana grandiflora, a native plant to Iran, resulted in isolation of ten compounds including four phenolic compounds (2, 4, 5, 8), two fatty alcohols (1, 6), one fatty acid (9), one triterpene (3), one glyceride derivatives (7) and one fatty acid methyl ester (10), from which eight compounds (1, 2, 4–6 and 8–10) were isolated from the genus Caragana and two compounds (5 and 10) from the family Fabaceae, for the first time. All compounds (1–10) were described from Caragana grandiflora for the first time. Chemical structures of the purified compounds were identified through FT-IR, NMR and MSS, and spectral data comparison with literature reported evidences.Our findings provide valuable information in reporting the rare existence of natural fatty acid methyl ester (10) in the Fabaceae family. Moreover, the chemotaxonomic significance of these compounds was discussed.     

Characterization,quantitation, similarity evaluation and combination with Na+,K+-ATPase of cardiac glycosides from Streblus asper

Streblus asper Lour. (Moraceae) is a medicinal plant in Asian countries including India and Thailand, possessing activities of anti-tumor, anti-allergy, anti-parasitic and anti-bacterial. In this paper, characterization, quantitation and similarity evaluation of cardiac glycosides in different parts of S. asper were investigated by HPLC-Q-TOF-MS and chemometric methods. Then, the inhibition of Na⁺,K⁺-ATPase activity by the compounds isolated from S. asper was measured. Meanwhile, enzyme kinetics and molecular docking were determined to exhibit the combination modes between cardiac glycosides and Na⁺,K⁺-ATPase. As a result, twenty peaks of cardiac glycosides were assigned. Strophanthidin-3-O-α-l-rhamnopyranosyl-(1 → 4)-6-deoxy-β-d-allopyranoside (1), glucostrebloside (2), strebloside (4) and mansonin (8) with a significant activity of inhibiting Na⁺,K⁺-ATPase (IC₅₀ 7.55–13.60 μM) were chosen for the determination of enzyme kinetics, exhibiting anticompetitive inhibitory characteristics towards Na⁺,K⁺-ATPase. Compound 4 could reasonably bind to the active sites of Na⁺,K⁺-ATPase, proved by molecular docking. Furthermore, the contents of the major compounds in four different parts of S. asper were extremely different, analyzed by chemometric methods, similarity analysis and principle compounds analysis. All these findings indicated that the contents of major compounds in different parts of S. asper were extremely different with a significant activity of inhibiting Na⁺,K⁺-ATPase, providing a reference for determination of effective part and administered dosage. The combination modes between cardiac glycosides and Na⁺,K⁺-ATPase were also revealed by enzyme kinetics and molecular docking, which provided a basis for further study of pharmacological activity.     

New alkaloids from Tabernaemontana divaricata

A re-investigation of the root bark of Tabernaemontana divaricata resulted in the isolation of 18 compounds, viz. α-amyrin acetate, lupeol acetate, α-amyrin, lupeol, cycloartenol, β-sitosterol, campesterol, benzoic acid, aurantiamide acetate, coronaridine, coronaridine hydroxyindolenine (1), ibogamine, 5-hydroxy-6-oxocoronaridine (6), 5-oxocoronaridine (9), 6-oxocoronaridine (10), (±)-19-hydroxycoronaridine (11), 3-oxocoronaridine (12) and voacamine. The alkaloids 6, 9, 10 and 11 are new compounds, whereas cycloartenol, campesterol, ibogamine, benzoic acid, aurantiamide acetate and coronaridine hydroxyindolenine are reported from this plant for the first time.