Untargeted analysis of sesquiterpene pyridine alkaloids from the dried roots of Tripterygium wilfordii using high-performance liquid chromatography/electrospray ionization tandem mass spectrometry.

RATIONALE: Sesquiterpene pyridine alkaloids are a large group of highly oxygenated sesquiterpenoids that have attracted attention in the fields of medicine because of their significant biological activities. METHODS: Reference compounds including 14 sesquiterpene pyridine alkaloids and one dihydroagarofuran ester were analyzed by collision-induced dissociation tandem mass spectrometry (CID-MS/MS). A high-performance liquid chromatography/electrospray ionization (HPLC/ESI)-MS/MS method at two collision energies was adopted to investigate the botanical extracts of Tripterygium wilfordii. RESULTS: For 15 reference compounds, in the high mass range, the product ions were formed by the loss of side chains or H2 O. In the low mass range, the high-abundance product ions at m/z 206, 204, or 194 were the characteristic ions of the pyridine moiety. The characteristic product ion at m/z 310 was formed through an ion-neutral complex intermediate. Fifty-four sesquiterpenoid derivatives, including 50 sesquiterpene pyridine alkaloids, were identified or tentatively characterized in botanical extracts of T. wilfordii based on their elemental constituents, characteristic fragmentation patterns, and the major product ion profiles of the reference compounds ascertained with HPLC/ESI-MS/MS at two collision energies. It seems that isocratic energy was appropriate for the untargeted analysis of compounds with molecular weights exceeding 800 Da, whereas a linear gradient energy vs molecular weight was suitable for those compounds with molecular weights below 800 Da. CONCLUSIONS: The HPLC/ESI-MS/MS method, combining characteristic fragmentation patterns and the profiles of the product ions generated at different collision energies, is an effective technique for characterizing untargeted compounds.

Antioxidant compounds from ethanol extracts of bamboo (Neosinocalamus affinis) leaves.

Activity-guided fractionation of Neosinocalamus affinis leaves led to obtain two new flavonoids, 4'-O-((7″R,8″S)-8″-guaiacylglyceryl)-pleioside B (9) and apigenin 6-C-ß-d-fucopyranosyl-7-O-ß-d-glucopyranoside (10) along with eight known compounds. Their structures were elucidated on the basis of spectroscopic data (UV, IR, NMR, and MS). Among these 10 compounds, farobin A (4) and isoorientin (7) showed significant antioxidant activity evaluated by 1,1-diphenyl-2-picrylhydrazyl, 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid), superoxide anion and nitric oxide (NO) radical-scavenging assays.

Integrative Analysis of Elicitor-Induced Camptothecin Biosynthesis in Camptotheca acuminata Plantlets Through a Combined Omics Approach.

Treatments with abiotic elicitors can efficiently induce the accumulation of specialized metabolites in plants. We used a combined omics approach to analyze the elicitation effects of MeJa, AgNO3, and PEG on camptothecin (CPT) biosynthesis in Camptotheca acuminata plantlets. Untargeted analyses revealed that treatments with MeJa, AgNO3, and PEG significantly inhibited the photosynthetic pathway and promoted carbon metabolism and secondary metabolic pathways. The CPT levels increased by 78.6, 73.3, and 50.0% in the MeJa, AgNO3, and PEG treatment groups, respectively. Using C. acuminata plantlets after elicitation treatment, we mined and characterized 15 new alkaloids, 25 known CPT analogs and precursors, 9 iridoid biosynthetic precursors, and 15 tryptamine biosynthetic precursors based on their MS/MS fragmentation spectra. Using 32 characterized genes involved in CPT biosynthesis as bait, we mined 12 prioritized CYP450 genes from the 416 CYP450 candidates that had been identified based on co-expression analysis, conserved domain analysis, and their elicitation-associated upregulation patterns. This study provides a comprehensive perspective on CPT biosynthesis in C. acuminata plantlets after abiotic elicitation. The findings enable us to elucidate the previously unexplored CYP450-mediated oxidation steps for CPT biosynthesis.

Possible clues for camptothecin biosynthesis from the metabolites in camptothecin-producing plants.

The plant derived camptothecin (CPT) is a pentacyclic pyrroloquinoline alkaloid with unique antitumor activity. Successive discoveries of new CPT-producing plants occurred in recent years due to market demands. The scattered distribution among angiosperms drew researchers' attention. The aim of this review is to appraise the literature available to date for CPT distribution and the phytochemistry of these CPT-producing plants. Metabolite comparative analyses between the plants were also conducted for tracking of possible clues for CPT biosynthesis. Forty-three plant species in total were reported to possess CPT-producing capability, and one hundred twenty-five alkaloids classified into three major categories are summarized herein. Metabolite comparative analysis between these plants suggests the probability that the formation of the central intermediate for CPT biosynthesis has multiple origins. A more complete biogenetic reasoning for CPT and its structural homolog was delineated based on this fragmentary phytochemical evidence from a chemical point of view. Furthermore, an in-house compound database was constructed for further metabolomic analysis.

(2S,NS)-N-Allyl-N-benzyl-1-hydr-oxy-3-(4-hydroxy-phen-yl)-N-methyl-propan-2-aminium bromide.

The title compound, C(20)H(26)NO(2) (+)·Br(-), is an N-chiral quaternary ammonium salt synthesized from (2S*)-N-benzyl-N-methyl-tyrosine methyl ester. The dihedral angle between the phenyl ring and the benzene ring is 11.61 (19)°. In the crystal structure, the allyl group is disordered over two positions with site occupancy factors of ca 0.8 and 0.2. The bromide anion links to the quaternary ammonium cations via O-H⋯Br hydrogen bonding. An intramolecular O-H⋯Br hydrogen bond is also observed.

Brevianamide J, a new indole alkaloid dimer from fungus Aspergillus versicolor.

Brevianamide J (1), a new indole alkaloid dimer, was isolated together with four new diketopiperazine alkaloids (brevianamide K-N, 2-5) from the solid-state fermented culture of Aspergillus versicolor. Their structures were elucidated on the basis of spectral data. X-ray crystallographic analysis confirmed the structures of 1 and 4.

Chiral decalins: preparation from oleanolic acid and application in the synthesis of (-)-9-epi-ambrox.

A novel and versatile process was developed to prepare the trans-decalins Delta9(11)-3beta-acetoxysclareolide (2) and Delta9(11)-3beta-acetoxy-8-epi-sclareolide (3), respectively, with 4a-methoxycarbonyl-2,7,7-trimethyl-1-oxo-cis-decalin-2-ene (4) and its C-3 hydroxyl derivative 5 from oleanolic acid (3beta-hydroxyolean-12-en-28-oic acid, 1). Three key steps were (a) introduction of the AcO-12 group and the C-9,C-11 double bond at ring C of methyl 3beta-acetoxyolean-12-en-28-oate (8) to afford the diene, methyl 3,12-diacetoxyolean-9(11),12-dien-28-oate (11); (b) photolytic cleavage of the C-8,C-14 bond in the diene to give an acetoxy-substituted triene 14; and (c) oxidative cleavage of the triene or its hydrolyzed alpha,beta-unsaturated ketone product with m-CPBA/TsOH to give the cis- and trans-decalins 2-5. Delata9(11)-3beta-Acetoxysclareolide (2) was stereospecifically reduced to give 3beta-acetoxy-9-epi-sclareolide (23), from which (-)-9-epi-ambrox (7) was synthesized.

Four new glycosides from Pleurospermum franchetianum.

Four new glycosides, pleurofranosides I-IV, together with eight known compounds were isolated from the whole plants of Pleurospermum franchetianum Hemsl. Based on the spectral data and chemical evidence, the structures of pleurofranosides 1, II, III and IV were elucidated to be 16beta, 21beta, 23, 28-tetrahydroxyolean-12-ene-3beta-yl-O-beta-D-glucopyranosyl-(1 --> 2)-beta-D-glucopyranoside, 13beta, 28-epoxy-16beta, 23-dihydroxyolean-11-ene-3beta-yl-O-beta-D-glucopyranosyl-(1 --> 4)-[beta-D-glucopyranosyl-(1 --> 2)]-beta-D-fucopyranoside, 13beta, 28-epoxy-16beta, 23-dihydroxyolean-11-ene-3beta-yl-O-beta-D-glucopyranosyl-(1 --> 4)-[beta-D-fucopyranosyl-(1 --> 2)]-beta-D-glucopyranoside and 12beta, 28-epoxy-16beta, 23-dihydroxyolean-11-ene-3beta-yl-O-beta-D-glucopyranosyl-(1 --> 3)-[beta-D-glucopyranosyl-(1 --> 2)]-beta-D-glucopyranoside. The known compounds identified were octadecyl caprate, beta-sitosterol, (22E, 20S, 24R)-5alpha, 8alpha-epidioxy-ergosta-6, 22-dien-3-beta-ol, daucosterol, alpha-spinasterol-3-O-beta-D-glucopyranoside, quercetin-3, 7-di-O-beta-D-glucopyranoside, kaempferol-3, 7-di-O-alpha-L-rhamnopyranoside and kaempferol-3-O-beta-D-glucopyranosyl-7-O-alpha-L-rhamnopyranoside, respectively.