From yellow petals of Iceland poppy, besides the known flavonoid gossypitrin, seven kaempferol derivatives were isolated. In addition to kaempferol 3-O-beta-sophoroside and kaempferol 3-O-beta-sophoroside-7-O-beta-glucoside, known from other plants, the mono- and dimalonyl conjugates of the latter were identified by MS and NMR spectroscopy. Structure analyses of a set of co-occurring pigments, the nudicaulins, revealed that they have the identical acylated glycoside moieties attached to a pentacyclic indole alkaloid skeleton for which the structure of 19-(4-hydroxyphenyl)-10H-1,10-ethenochromeno[2,3-b]indole-6,8,18-triol was deduced from MS and NMR as well as chemical and chiroptical methods.
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http://dx.doi.org/10.1016/j.phytochem.2005.11.002 | DOI Listing |
Bioorg Chem
December 2024
State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing 100191, PR China; Ningbo Institute of Marine Medicine, Peking University, Beijing 100191, PR China. Electronic address:
Prenylated indole diketopiperazines represent a diverse array of alkaloids with complex chemical scaffolds and with a wide range of biological activities. Aiming to discover bioactive metabolites with structural novelty, genomic annotation in association with the MS/MS-based molecular networking demonstrated a deep-sea derived fungus Aspergillus puulaauensis F77 containing a profile of diketopiperazines. Targeted separation of the cultured fungus led to the isolation of 19 undescribed austamide-type diketopiperazines namely versicoines A-S.
View Article and Find Full Text PDFToxins (Basel)
December 2024
Cawthron Institute, Molecular Algal Ecology, Nelson 7010, New Zealand.
This study reports the first documented accumulation of lyngbyatoxin-a (LTA), a cyanotoxin produced by marine benthic cyanobacteria, in edible shellfish in Aotearoa New Zealand. The study investigates two bloom events in 2022 and 2023 on Waiheke Island, where hundreds of tonnes of marine benthic cyanobacterial mats (mBCMs) washed ashore each summer. Genetic analysis identified the cyanobacterium responsible for the blooms as sp.
View Article and Find Full Text PDFFront Microbiol
December 2024
College of Engineering, Abu Dhabi University, Abu Dhabi, United Arab Emirates.
The growing threat of antimicrobial resistance (AMR) has underlined the need for a sustained supply of novel antimicrobial agents. Endophyte microorganism that reside within plant tissues as symbionts have been the source of potential antimicrobial substances. However, many novel and potent antimicrobials are yet to be discovered from these endophytes.
View Article and Find Full Text PDFJ Org Chem
December 2024
Beijing National Laboratory of Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing 100871, China.
The construction of C-C bonds to form all-carbon quaternary centers remains a significant challenge in synthetic chemistry. Herein, we report a tandem process involving a 1,2-migration of a tetra-coordinated boron intermediate followed by a Claisen rearrangement of the boron enolate, achieved through a reaction between allyl diazoacetates and trialkylboranes. The transformation forms two C-C bonds at the carbenic position of diazo substrate in a single-step operation under neutral conditions.
View Article and Find Full Text PDFInt J Nanomedicine
December 2024
Department of Respiratory Disease, The First Affiliated Hospital, Jinzhou Medical University, Jinzhou, 121000, People's Republic of China.
Introduction: Pulmonary hypertension (PH) is a progressive and life-threatening condition. Recent research has demonstrated that exosomes derived from mesenchymal stem cells (MSC) exhibit significant therapeutic potential in the treatment of PH. The composition of these exosomes is often substantially influenced by the characteristics of their parental cells.
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