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Phytochemical investigation of the methanol extracts of the twigs of Manniophyton fulvum has led to the isolation and characterization of three new pentacyclic triterpenoids, designated as 3α,28-dihydroxyfriedelan-1-one (1), manniotaraxerol A (3) and manniotaraxerol B (4), along with fourteen known compounds, 3α-hydroxy-1-oxofriedelane (2), betulinic acid (5), friedelin (S1), taraxerol (S2), a mixture of stigmasterol (S3) and β-sitosterol (S4), herranone (S5), docosanoic acid (S6), ursolic acid (S7), nasutin B (S8), bergenin (S9), stigmasterol-3-O-β- d- glucopyranoside (S10), 1,2-di-O-palmitoyl-3-O-(6-sulfo-α- d -quinovopyranosyl)glycerol (S11), and aridanin (S12). The structures of all compounds were determined by comprehensive spectroscopic analyses (1D and 2D NMR, EI and ESI-MS). 3α,28-Dihydroxyfriedelan-1-one (1), 3α-hydroxy-1-oxofriedelane (2), manniotaraxerol A (3), manniotaraxerol B (4), and betulinic acid (5) were evaluated against HeLa (human cervix adenocarcinoma) cancer cells. Manniotaraxerol A (3) showed weak in vitro cytotoxicity with a cell viability value of 49.3%. Betulinic acid (5) also showed significant cytotoxicity against HeLa cell with a cell viability value of 4.0%; the other compounds were inactive in this test.

Phytochemical investigation of the stem bark of Diospyros longiflora yielded longiflorol (1), a new bergenin α-d-apioside, together with bergenin (2) and five known compounds: lupeol (S1), betulin (S2), betulinic acid (S3), stigmasterol (S4) and stigmasterol glucoside (S5). Their structures were determined by one-dimensional (1D) and 2D nuclear magnetic resonance experiments along with electrospray ionization high-resolution mass spectrometry and extended density-functional theory calculations of chiroptical properties. Longiflorol (1) and bergenin (2) were evaluated for their DPPH (2,2-diphenyl-1-picrylhydrazyl) antioxidant activity, with the crude extract for comparison and ascorbic acid as standard. The results showed that the extract and 2 had good antioxidant activity, whereas 1 showed only moderate activity at high concentration (>2 mg mL−1).

Three new alkaloids, janetinine (1a), pleiokomenine A (2), and huncaniterine B (3a), and 13 known compounds, pleiomutinine (3b), huncaniterine A (3c), 1-carbomethoxy-β-carboline (4), evoxanthine (5), deformyltalbotine acid lactone (6), pleiocarpamine (7), N4-methyl-10-hydroxygeissoschizol (8), spegatrine (9), neosarpagine (10), aspidofractinine (11), N1-methylkopsinin (12), pleiocarpine (13), and N1-methylkopsinin- N4-oxide (14), were isolated from the stem bark of Pleiocarpa pycnantha. Janetinine (1a) is a carbazole alkaloid; in pleiokomenine A (2), two aspidofractinine-type alkaloids are bridged by a methylene unit in an unprecedented way, and huncaniterine B (3a) is a pleiocarpamine-aspidofractinine-type dimer. The structures and relative configurations of these compounds were elucidated on the basis of NMR and MS analyses. Their absolute configurations were defined by means of experimental and calculated ECD data, and additionally, the structures of 5 and 13 were determined by single crystal X-ray diffraction. Compounds 1a, 2, 3b, 4, 6, 9, and 12 displayed cancer chemopreventive properties through either quinone reductase induction ( CD = 30.7, 30.2, 29.9, 43.5, and 36.7 μM for 1a, 4, 6, 9, and 12, respectively) and/or NF-κB inhibition with IC50 values of 13.1, 8.4, 9.4, and 8.8 μM for 2, 3b, 6, and 12, respectively.

Many secondary metabolites derived from Rumex extracts exhibited potent activities against a panel of phytopathogens including those of Phytophthora spp. Phytochemical investigation of Rumex abyssinicus has led to the isolation of nine compounds, including one phenolic acid (1), five anthraquinones (2–6) and three flavanols (7–9). Compounds 1, 4, 6–9 are reported here from R. abyssinicus for the first time. The isolated compounds were evaluated for their inhibitory activity against zoospores of the oomycete phytopathogen Phytophthora capsici. Physcion (3) displayed strongest motility inhibitory activity with a MIC value of 15 μg mL− 1, and showed lytic activities against zoospores at 500 μg mL− 1.

A new dimeric ent-kaurane diterpene, mannic acid (1), and 19 known compounds were isolated from the methanol extract of the stems, roots and leaves of Diospyros mannii Hiern (Ebenaceae). Their structures were established by NMR and MS data. This is the first report of asperglaucide from the family Ebenaceae, while mannic acid (1) and xylopic acid (2) are the first ent-kaurane diterpenes isolated from this family. Their chemotaxonomic value is discussed.

A new highly oxidized tetranortriterpenoid, named mayombensin (1), was isolated from the twigs of Guarea mayombensis together with five known compounds and, further, two ceramides, 3,4-dimethyl-secotirucalla-4(28),7,24-trien-3,21-dioic acid (3), the glucosides of stigmasterol and β-sitosterol, and the respective aglyca. The structure of 1 was elucidated by detailed NMR analysis and confirmed as a novel azadirachtin homologue.

In the 1H NMR-guided fractionation of extracts from the edible mushroom Lactarius deliciosus, two new azulene-type sesquiterpenoids, 7-isopropenyl-4-methyl-azulene-1-carboxylic acid (1) and 15-hydroxy-3,6-dihydrolactarazulene (2), together with seven known compounds were characterized. Their structures were determined on basis of spectroscopic evidence, as well as by comparing with literature data. Amongst the known metabolites, the 13C NMR assignment of 15-hydroxy-6,7-dihydrolactarazulene (3) is reported here for the first time. Moreover, 7-acetyl-4-methylazulene-1-carbaldehyde (5) displayed a moderate antibacterial activity against Staphylococcus aureus. Graphical Abstract *Digital image of L. deliciosus. Retrieved March 17, 2017 from https://upload.wikimedia.org/wikipedia/commons/e/e3/Lactarius_deliciosus_1_(1).jpg . Electronic supplementary material The online version of this article (doi:10.1007/s13659-017-0130-1) contains supplementary material, which is available to authorized users.

Three new bioactive metabolites, 1,6-dihydroxy- 2-methyl-heptan-4-one (1), 4-hydroxy-1-(2-methyl-oxiranyl)- pentan-2-one (2), and 2-(2-hydroxy-propyl)-4-methylfuran- 3-carboxylic acid amide (3) were isolated from the terrestrial Streptomyces sp. isolate ANK245, along with the new microbial constituent p-vinylanisol (4a) and the known metabolites p-vinyl-phenol (4b) and phenethyl alcohol. Analysis of the nonpolar part of the extract by gas chromatography/mass spectrometry (GC-MS) provided further evidence for tetradecanoic acid, 9-octadecenoic acid, hexadecanoic acid, 2-methoxy-4-vinylphenol (4c), 4-hydroxy-3-methoxy-benzaldehyde, o-hydroxybiphenyl, and 1,5,9-trimethyl-4,8,13-cyclotetradecatrien-1,3-diol (5). Structures 1–3 of the new compounds were elucidated by nuclear magnetic resonance (NMR) and NMR spectroscopy, but mass spectrometry (MS) techniques and their absolute configuration were determined by density functional theory (DFT) calculations and Mosher derivatisation. Their antimicrobial and cytotoxic activities were evaluated in comparison with the crude bacterial extract.

A new cycloartane triterpenoid named conocarpol (1) was isolated from the stem bark of Diospyros conocarpa, together with the known compounds aridanin (2), lupeol (3), betulin (4), betulinic acid (5), stigmasterol (6), and stigmasterol 3-O-β-d-glucopyranoside (7). Their structures were established on the basis of 1D and 2D NMR spectroscopy as well as mass spectrometry. Aridanin (2) is reported for the first time in the family Ebenaceae, and conocarpol (1) represents the first cycloartane triterpene within this family.

Two bisindoline alkaloids, contortarine A, 16-epi-pleiomutinine and a reaction product of pleiomutinine, namely N4-chloromethyl-pleiomutinine, were isolated from the roots of Tabernaemontana contorta Stapf. together with five known compounds: pleiomutinine, 1-carbomethoxy-β-carboline, strictosidine lactam, pleiocarpamine, and pleiocarpine. The structures and relative configuration of these alkaloids were determined by extensive 1D and 2D NMR, and MS measurements. The absolute configuration of these compounds was determined by comparison of experimental and calculated ECD spectra. Among the isolated compounds, contortarine A, 1-carbomethoxy-β-carboline and strictosidine lactam presented cancer chemopreventive properties through either quinone reductase (QR) induction with CD values of 16.0 ± 2.5, 30.2 ± 6.1 and 23.1 ± 4.6 μM, respectively, while pleiomutinine and 16-epi-pleiomutinine displayed the inhibition of TNF-α induced NF-κB activity with IC50 at 11.7 ± 2.6 and 3.4 ± 1.1 μM, respectively.

Eight compounds were isolated from the stem bark of Antrocaryon klaineanum, and their structures determined by chemical and spectroscopic methods. Among these compounds, the ergostane-type antrocarine E (1a) is a new compound, although the structure had already been published by mismatching the spectroscopic data with those of 2. In this paper, we are reporting the valid spectroscopic values for antrocarine E and X-ray diffraction results.

The genus Quassia is a promising source of secondary metabolites with biological potential including antimalarial and cytotoxic activities. Limited data are available on the phytochemistry and pharmacology of Quassia silvestris CheekJongkind, a Cameroonian medicinal plant used to treat various ailments.To carry out the bioassay-guided fractionation and LC-HR-ESI-MS analyses of the leaves extract from Q. silvestris; to purify the active fractions and isolate the major compounds using different chromatographic and spectroscopic methods. The obtained compounds will be evaluated for their biological activity.Following the cytotoxic screening and LC-HR-ESI-MS profiling of fractions obtained from partition of the methanolic extract of Q. silvestris leaves, the CHSixteen squalene-derived metabolites were identified with oxasqualenoid derivatives being the most predominant. Among the isolates, structure elucidation of two new oxasqualenoids quassiols E (1) and F (2), were achieved by NMR (one-dimensional (1D) and two-dimensional (2D)) and MS methods. The newly characterised compounds 1 and 2, together with the known tetraol (3) and 3-oxo-oleanoic acid (16) displayed moderate cytotoxicity.The identification and structural characterisation of highly oxidised squalene derived metabolites from this plant may provide important insight data for further pharmacological investigations. The LC-HR-ESI-MS

Five new alkylbenzoquinone derivatives, ardisiaquinones L–P ( 1–5 ) along with the known ardisiaquinone K were isolated from the MeOH extracts of leaves and stems of Ardisia kivuensis Taton (Myrsinaceae). Ardisiaquinones L, M and N were isolated from the leaves while ardisiaquinones K, O and P were obtained from the stem. Ardisiaquinone O was obtained in mixture with ardisiaquinone N, and P together with K, respectively. Their structures were elucidated on the basis of spectroscopic data. All the compounds showed cytotoxicity against Artemia salina and moderate antimicrobial activity.

A new labdane diterpenoid, 2,18-dihydroxylabda-7,13(E)-dien-15-oic acid (1), together with two known labdane diterpenes (3, 4), a new flavone, 5,7-dihydroxy-3,6,4'-trimethoxy-3'-(4-hydroxy-3-methyl-but-2-enyl)flavone (2) with three known flavones (5-7) were isolated from the aerial parts of Dodonaea viscosa. Their structures were determined by extensive analysis of spectroscopic data (1D and 2D NMR, MS) and by comparison with literature data. The anti-inflammatory activity of five compounds (1-5) was evaluated with a flow cytometry TNF-α secretion assay on human THP-1 cell line.

Two new prenylated anthraquinones, laurenquinone A (1) and B (2) were isolated from the seeds of Vismia laurentii together with four known compounds; xanthone V 1 (3), physcion (4), 3-geranyloxyemodin anthrone (5) and friedelin (6). The structures of the new metabolites were determined with the help of spectroscopic data including extensive 2D-NMR spectroscopy. The known compounds were identified by comparison of their physical and spectroscopic data with those reported in the literature. Compounds 1, 4 and 5 exhibited moderate algicidal activity against Chlorella fusca and 3 showed moderate activity against the gram-positive bacterium Bacillus megaterium.

Two new prenylated anthraquinones, laurenquinone A (1) and B (2) were isolated from the seeds of Vismia laurentii together with four known compounds; xanthone V 1 (3), physcion (4), 3-geranyloxyemodin anthrone (5) and friedelin (6). The structures of the new metabolites were determined with the help of spectroscopic data including extensive 2D-NMR spectroscopy. The known compounds were identified by comparison of their physical and spectroscopic data with those reported in the literature. Compounds 1, 4 and 5 exhibited moderate algicidal activity against Chlorella fusca and 3 showed moderate activity against the gram-positive bacterium Bacillus megaterium.