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Fig. 7. 1H–1H in Iboga-type alkaloids with Indolizidino[8,7-b]Indole scaffold and bisindole alkaloids from Tabernaemontana bufalina Lour

Fig. 7. 1H–1H COSY (red bold) and selected HMBC (blue single arrows) correlations of 4 (up left) and 5 (up right), and key NOESY (blue dashed arrows) correlations of 4. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)

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Fig. S9 in Iboga-type alkaloids with Indolizidino[8,7-b]Indole scaffold and bisindole alkaloids from Tabernaemontana bufalina Lour

Fig. S9. The experimental NMR data of 1 were compared with those calculated of 1a and 1b using the linear correlation coefficients (R2), root mean squared error (RMSE) and DP4 + probability analysis. The calculated 13C NMR data for 1a possessed the highest R2 value (0.9991) and lowest RMSE value (1.6). In addition, DP4 + analysis based on all NMR data also showed 100% probability of 1a, which indicated that 1a (14S*, 16R*, 20S*) was the correct relative configuration of 1. To determine the absolute configuration, two stereoisomers 1a-1 (14S, 16R, 20S) and 1a-2 (14R, 16S, 20R) were used as the model compounds. The calculated ECD spectra of 1a-1 and 1a-2 were obtained

Fig. 5 in Isoquinoline alkaloid dimers with dopamine D1 receptor activities from Menispermum dauricum DC

Fig. 5. Dose-dependent curve of compound 1 inhibiting the RFU signals of dopamine on HEK293-D1 cells.

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Fig. 3 in Isosteroidal alkaloids of Fritillaria taipaiensis and their implication to Alzheimer's disease: Isolation, structural elucidation and biological activity

Fig. 3. Key NOESY () correlations for compounds 1–4 [some hydrogens were removed for a clearer exhibition of their 3D structures].

Fig. 6 in Profiling alkaloids in Aconitum pendulum N. Busch collected from different elevations of Qinghai province using widely targeted metabolomics

Fig. 6. Comparison of the peak areas of various classes of significantly different abundant metabolites among HZX, MYG, ZKW, GLM, YSZ, and GNG. Bars represent the peak areas of the significantly differentially abundant metabolites.

Fig. 3 in Profiling alkaloids in Aconitum pendulum N. Busch collected from different elevations of Qinghai province using widely targeted metabolomics

Fig. 3. Differential metabolite analysis OPLS-DA plots of MYG, ZKW, GLM, YSZ, and GNG compared to HZX.

Fig. 7 in Profiling alkaloids in Aconitum pendulum N. Busch collected from different elevations of Qinghai province using widely targeted metabolomics

Fig. 7. Correlation analysis between the environmental parameters and differentially abundant alkaloids (a), and. between differentially abundant alkaloids and anti-inflammatory activity (b). The red block indicates a positive correlation; the green block indicates a negative correlation; * indicates significant correlation; ** indicates extremely significant correlation.. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)

Fig. 5 in Profiling alkaloids in Aconitum pendulum N. Busch collected from different elevations of Qinghai province using widely targeted metabolomics

Fig. 5. Venn diagram illustrating shared or unique metabolite contents that differed significantly among the different comparison groups.

Fig. 1 in Profiling alkaloids in Aconitum pendulum N. Busch collected from different elevations of Qinghai province using widely targeted metabolomics

Fig. 1. Comparison of the total peak areas of various classes of metabolites among HZX, MYG, ZKW, GLM, YSZ, and GNG samples from different regions. Bars represent the sum of the peak areas for all metabolites belonging to each class.

Fig. 4 in Profiling alkaloids in Aconitum pendulum N. Busch collected from different elevations of Qinghai province using widely targeted metabolomics

Fig. 4. Volcano plots for (a) MYG vs. HZX, (b) ZKW vs. HZX, (c) GLM vs. HZX, (d) YSZ vs. HZX, and (e) GNG vs. HZX. The green dots indicate differential metabolites that were significantly downregulated, red dots indicate differential metabolites that were significantly upregulated, and black dots indicate metabolites that were detected in the samples but were not significant. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)

Fig. 5 in Monoterpene indole alkaloids from Vinca minor L. (Apocynaceae): Identification of new structural scaffold for treatment of Alzheimer's disease

Fig. 5. The top-scored docking poses of 19 in hBuChE (A, B; PDB ID: 4BDS) and the crystal structure of tacrine bound to hBuChE (C, D). The ligands are displayed in blue (A) and green (C) for 19 and tacrine, respectively; important amino acid residues responsible for ligand anchoring are shown in grey for hBuChE (A, C). Catalytic triad residues are displayed in yellow (A, C). Important interactions are rendered by black dashed lines; distances are measured in angstroms (Å). The rest of the receptor is displayed in light-grey cartoon conformation (A, C). Figures A and C were created with The PyMOL Molecular Graphics System, Version 2.4.1, Schr¨odinger, LLC. 2D figures (B, D) were generated with Maestro 12.3 (Schr¨odinger Release, Schr¨odinger, LLC, New York, NY, 2020). (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)

Fig. 3. Described key 2D in Monoterpene indole alkaloids from Vinca minor L. (Apocynaceae): Identification of new structural scaffold for treatment of Alzheimer's disease

Fig. 3. Described key 2D NMR correlations of revision of previously assigned positions in molecule 17 (COSY interaction – red bond, HMBC interaction – blue arrow). (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)

Fig. 4 in Monoterpene indole alkaloids from Vinca minor L. (Apocynaceae): Identification of new structural scaffold for treatment of Alzheimer's disease

Fig. 4. Steady state competitive type inhibition of hBuChE substrate hydrolysis by active compound 19 at different concentrations. Lineweaver Burk plots of initial velocity at increasing substrate concentrations (2.5–10.0 mM) are presented. Lines were derived from a linear regression of the data points. All measurements were made in triplicate and averaged.

Fig. 2. Indole alkaloids with a in Monoterpene indole alkaloids from Vinca minor L. (Apocynaceae): Identification of new structural scaffold for treatment of Alzheimer's disease

Fig. 2. Indole alkaloids with a quebrachamine framework previously described in the literature employing at least 1H NMR analysis. The difference in the H-3 chemical shift of 3-epimers can be valuable for distinguishing between these diastereomers, which is highlighted. It must be mentioned that the C-3 configuration for all compounds shown was described to the contrary in Kutney's article (Kutney et al., 1975). However, the correct configuration of these alkaloids had already been identified by Kompisˇet al. (1968).

Fig. 6. Overlapped top-scored poses for ligands 19 in Monoterpene indole alkaloids from Vinca minor L. (Apocynaceae): Identification of new structural scaffold for treatment of Alzheimer's disease

Fig. 6. Overlapped top-scored poses for ligands 19 (blue) and crystal structure of tacrine (green) in the active site of hBuChE (PDB ID: 4BDS). Amino acid residues involved in the interactions with ligands are depicted as either grey or yellow (catalytic triad) lines. The rest of the receptor is displayed in light-grey cartoon conformation. The Figure was created with The PyMOL Molecular Graphics System, Version 2.4.1, Schr¨odinger, LLC. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)

Fig. 1 in Establishing the metabolic network of isoquinoline alkaloids from the Macleaya genus

Fig. 1. Diagram of systematic screening of isoquinoline alkaloids by HPLC-Q-TOF-MS combined with a screening method. (a) X, Y, Z, M, and N represent the number of OCH2O, OCH3, OH, glucose, and H groups, respectively. (b) The number of substituent groups connected to the target skeleton is no more than four.

Fig. 4 in Establishing the metabolic network of isoquinoline alkaloids from the Macleaya genus

Fig. 4. Proposed new biosynthesis pathways for protoberberine (97), sanguinarine (144) and chelerythrine (145).

Fig. 2 in Establishing the metabolic network of isoquinoline alkaloids from the Macleaya genus

Fig. 2. Proposed metabolic network of isoquinoline alkaloids in the Macleaya genus. a the solid arrow represents verified biosynthesis pathways; b the dotted arrow represents unverified pathways, c the double arrow represents two or more steps needed for biosynthesis; d MT, GOA, and COA are abbreviation for methyl transferase, glycosyltransferase, and cyclooxygenase, respectively; e the red moieties represent the changed substituent groups, and f the blue moieties represent the 13C -labeled benzene ring. (For 6 interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)

Fig. 5. Proposed fragmentation scheme for 2-aminobenzoyl O in Chemotaxonomic investigation of Apocynaceae for retronecine-type pyrrolizidine alkaloids using HPLC-MS/MS

Fig. 5. Proposed fragmentation scheme for 2-aminobenzoyl O-β-D-apiofuranosyl-(1 → 6)- β-D-glucopyranoside (m/z 432.15 when protonated) in positive ion mode ESI to m/z 300.11, 138.06, and 120.04 fragments.

Fig. 2 in Chemotaxonomic investigation of Apocynaceae for retronecine-type pyrrolizidine alkaloids using HPLC-MS/MS

Fig. 2. Common esterification patterns between necic acids and necine bases observed in retronecine-type PAs.