Determination of Cotton as a Larval Feeding Source for Lepidopteran Moths Using a Derivative from Cotton Metabolites as a Marker by LC-MS/MS Method.

Determination of the feeding history of polyphagous insect pests, such as noctuid moths (Lepidoptera: Noctuidae), is a critical element in developing population and resistance management strategies for such pests. To identify reliable markers for larval host plant determination and to develop simple extraction and detection methods, a metabolomics approach was implemented after acid hydrolysis of adult moth samples. We identified a derivative from cotton metabolites as a marker in adult moths that were fed cotton tissues as a larval diet, and we propose that the marker is tricycloheliocide H4 based on NMR and mass fragmentation analysis. Using this derivative from cotton metabolites as a marker, a targeted LC-MS/MS method reliably identified cotton as a larval diet in extracts of three noctuid moth species: Helicoverpa zea (cotton bollworm), Chloridea (Heliothis) virescens (tobacco budworm) and Chrysodeixis includens (soybean looper). We are using similar approaches to identify markers for other host plants including soybean.

Ealamines A-H, a Series of Naphthylisoquinolines with the Rare 7,8'-Coupling Site, from the Congolese Liana Ancistrocladus ealaensis, Targeting Pancreatic Cancer Cells.

From the twigs and leaves of the Central African liana Ancistrocladus ealaensis (Ancistrocladaceae), a series of ten 7,8'-coupled naphthylisoquinoline alkaloids were isolated, comprising eight new compounds, named ealamines A-H (4a, 4b, 5-10), and two known ones, 6-O-demethylancistrobrevine A (11) and yaoundamine A (12), which had previously been found in related African Ancistrocladus species. Only one of the new compounds within this series, ealamine H (10), is a typical Ancistrocladaceae-type alkaloid, with 3S-configuration at C-3 and an oxygen function at C-6, whereas seven of the new alkaloids are the first 7,8'-linked "hybrid-type" naphthylisoquinoline alkaloids, i.e., 3R-configured and 6-oxygenated in the tetrahydroisoquinoline part. The discovery of such a broad series of 7,8'-coupled naphthyltetrahydroisoquinolines is unprecedented, because representatives of this subclass of alkaloids are normally found in Nature quite rarely. The stereostructures of the new ealamines were assigned by HRESIMS, 1D and 2D NMR, oxidative degradation, and experimental and quantum-chemical ECD investigations, and-in the case of ealamine A (4a)-also confirmed by X-ray diffraction analysis. Ealamines A-D exhibited distinct-and specific-antiplasmodial activities, and they displayed pronounced preferential cytotoxic effects toward PANC-1 human pancreatic cancer cells in nutrient-deprived medium, without causing toxicity under normal, nutrient-rich conditions, with ealamine C (5) as the most potent agent.

An Unusually Broad Series of Seven Cyclombandakamines, Bridged Dimeric Naphthylisoquinoline Alkaloids from the Congolese Liana Ancistrocladus ealaensis.

A series of seven unusual dimeric naphthylisoquinoline alkaloids was isolated from the leaves of the tropical liana Ancistrocladus ealaensis J. Léonard, named cyclombandakamine A (1), 1-epi-cyclombandakamine A (2), and cyclombandakamines A3-7 (3-7). These alkaloids have a chemically thrilling structural array consisting of a twisted dihydrofuran-cyclohexenone-isochromene system. The 1'″-epimer of 4, cyclombandakamine A1 (8), had previously been discovered in an unidentified Ancistrocladus species related to A. ealaensis. Both lianas produce the potential parent precursor, mbandakamine A (9), but only A. ealaensis synthesizes the corresponding cyclized form, along with a broad series of slightly modified analogs. The challenging isolation required, besides multi-dimensional chromatography, the use of a pentafluorophenyl stationary phase. Featuring up to six stereocenters and two types of chiral axes, their structures were elucidated by means of 1D and 2D NMR, HRESIMS, in combination with oxidative chemical degradation experiments as well as chiroptical (electronic circular dichroism spectroscopy) and quantum chemical calculations. Compared to the 'open-chain' parent compound 9, these dimers displayed rather moderate antiplasmodial activities.

Mbandakamine-Type Naphthylisoquinoline Dimers and Related Alkaloids from the Central African Liana Ancistrocladus ealaensis with Antiparasitic and Antileukemic Activities.

Four new dimeric naphthylisoquinoline alkaloids, michellamine A5 (2) and mbandakamines C-E (4-6), were isolated from the Congolese plant Ancistrocladus ealaensis, along with the known dimer mbandakamine A (3). They represent constitutionally unsymmetric dimers, each consisting of two 5,8'-coupled naphthylisoquinoline monomers. While the molecular halves of michellamine A5 (2) are linked via C-6' of both of the naphthalene moieties, i.e., via the least-hindered positions, so that the central biaryl axis is configurationally unstable and not an additional element of chirality, the mbandakamines 3-6 possess three consecutive stereogenic axes. Their monomeric units are linked through an unprecedented 6',1″-coupling in the binaphthalene core, leading to a high steric load, since the central axis is located in one of the peri-positions, neighboring one of the outer axes. In addition, four new 5,8'-coupled monomeric naphthylisoquinolines, viz., ancistroealaines C-F (7-10), were identified, along with four "naphthalene-devoid" tetra- and dihydroisoquinolines, named ealaines A-D (11-14). The new mbandakamines C (4) and D (5) showed pronounced activities against the malaria parasite Plasmodium falciparum, and they were likewise found to display strong cytotoxic activities against human leukemia (CCRF-CEM) and multi-drug-resistant tumor cells (CEM/ADR5000).

Antiplasmodial Ealapasamines A-C,'Mixed' Naphthylisoquinoline Dimers from the Central African Liana Ancistrocladus ealaensis.

Three unusual heterodimeric naphthylisoquinoline alkaloids, named ealapasamines A-C (1-3), were isolated from the leaves of the tropical plant Ancistrocladus ealaensis J. Léonard. These 'mixed', constitutionally unsymmetric dimers are the first stereochemically fully assigned cross-coupling products of a 5,8'- and a 7,8'-coupled naphthylisoquinoline linked via C-6' in both naphthalene portions. So far, only two other West and Central Ancistrocladus species were known to produce dimers with a central 6,6″-axis, yet, in contrast to the ealapasamines, usually consisting of two 5,8'-coupled monomers, like e.g., in michellamine B. The new dimers 1-3 contain six elements of chirality, four stereogenic centers and the two outer axes, while the central biaryl axis is configurationally unstable. The elucidation of the complete stereostructures of the ealapasamines was achieved by the interplay of spectroscopic methods including HRESIMS, 1D and 2D NMR (in particular ROESY measurements), in combination with chemical (oxidative degradation) and chiroptical (electronic circular dichroism) investigations. The ealapasamines A-C display high antiplasmodial activities with excellent half-maximum inhibition concentration values in the low nanomolar range.

Gardenifolins A-H, Scalemic Neolignans from Gardenia ternifolia: Chiral Resolution, Configurational Assignment, and Cytotoxic Activities against the HeLa Cancer Cell Line.

From the tropical plant Gardenia ternifolia Schumach. and Thonn. (Rubiaceae), eight stereoisomeric 2,3-dihydrobenzo[b]furan neolignans, named gardenifolins A-H (1a-d and 2a-d), were isolated and fully structurally characterized. Reversed-phase chromatography of a stem bark extract afforded two peaks, viz. mixtures I and II, each one consisting of two diastereomers and their respective enantiomers. They were resolved and stereochemically analyzed by HPLC on a chiral phase coupled to electronic circular dichroism (ECD) spectroscopy, giving single ECD spectra of all eight stereoisomers. The double-bond geometries (E or Z) of the gardenifolins A-H and their relative configurations (cis or trans) at the stereogenic centers C-7 and C-8 in the dihydrofuran ring system were assigned by 1D and 2D NMR methods, in particular, using NOE difference experiments, whereas the absolute configurations of the isolated enantiomers were established by ECD spectroscopy by applying the reversed helicity rule. The individual pure gardenifolin isomers A-H showed the most different cytotoxic effects against the human cancer HeLa cell line, with 1d and 2a displaying the highest activities, with IC50 values of 21.0 and 32.5 µM, respectively. Morphological experiments indicated that gardenifolin D (1d) induces apoptosis of HeLa cells at 25 µM.

Rational quality assessment procedure for less-investigated herbal medicines: Case of a Congolese antimalarial drug with an analytical report.

Herbal medicines are the most globally used type of medical drugs. Their high cultural acceptability is due to the experienced safety and efficiency over centuries of use. Many of them are still phytochemically less-investigated, and are used without standardization or quality control. Choosing SIROP KILMA, an authorized Congolese antimalarial phytomedicine, as a model case, our study describes an interdisciplinary approach for a rational quality assessment of herbal drugs in general. It combines an authentication step of the herbal remedy prior to any fingerprinting, the isolation of the major constituents, the development and validation of an HPLC-DAD analytical method with internal markers, and the application of the method to several batches of the herbal medicine (here KILMA) thus permitting the establishment of a quantitative fingerprint. From the constitutive plants of KILMA, acteoside, isoacteoside, stachannin A, and pectolinarigenin-7-O-glucoside were isolated, and acteoside was used as the prime marker for the validation of an analytical method. This study contributes to the efforts of the WHO for the establishment of standards enabling the analytical evaluation of herbal materials. Moreover, the paper describes the first phytochemical and analytical report on a marketed Congolese phytomedicine.