Molecules

Rearrangements such as the McLafferty rearrangement are common in mass spectrometry of positive ions, but rare in negative ions. The present article searched the literature for McLafferty rearrangements of negative ions formed by negative electrospray ionization (-ESI) or by negative-ion chemical ionization (NICI). McLafferty Rearrangements have been reported for negative ions formed by -ESI, yet not for anions formed by NICI in GC-MS and GC-MS/MS. This article reports for the first time a McLafferty Rearrangement of the collision-induced dissociation (CID) of precursor ions due to [M‒PFB]⁻ generated by NICI in the GC-MS/MS analysis of pentafluorobenzyl (PFB) esters and thioesters of diethyl phosphates (CH₃CH₂O)₂PO₂, diethyl thiophosphates (CH₃CH₂O)₂PSO, and diethyl dithiophosphates (CH₃CH₂O)₂PS₂. Two specific product anions due to α,β-cleavages and formation of neutral losses of ethene and ethanol are formed. No McLafferty rearrangements were observed in the CID of 1-chloropropyl derivatives of these dialkyl organophosphates in the positive-ion chemical ionization (PICI) mode. McLafferty rearrangements of PFB esters of organophosphates have been observed in the EI mode. No McLafferty rearrangements were observed in the EI and NICI of diethyl fluoro phosphate, a representative of dialkyl fluoro phosphates. McLafferty rearrangements of negative ions seem to be more common than assumed so far.

The genus Streptomyces is the largest group within the phylum Actinobacteria, recognized for producing antibiotics and enzymes, with wide applications in medicine and biological control for crop protection against phytopathogens. In this study, the Streptomyces sp. Caat 5-35 strain, isolated from soil of the Caatinga biome in Brazil, and identified by analysis of the 16S rRNA gene, demonstrated its antagonistic effect in vitro in dual cultures against Phytophthora palmivora, Colletotrichum acutatum, Fusarium oxysporum, Rhizoctonia solani, Sclerotinia sclerotiorum, and Fusarium graminearum. Caat 5-35 inhibited mycelial growth ranging from 19% to 73.3%. Compounds purified by prep-HPLC from extracts were identified by spectral data analysis using UHPLC-triple-TOF-MS/MS, or nuclear magnetic resonance (NMR). This work demonstrated for the first time the anti-oomycete activity of albofungin, its derivatives, and albonoursin against P. palmivora. Moreover, the growth inhibition of Colletotrichum gloeosporioides by albonoursin and the antibacterial effect of 2-chloroadenosine and 5′-O-sulfamoyl-2-chloroadenosine against Pectobacterium carotovorum were demonstrated as novel findings. Caat 5-35 exhibited the ability to solubilize phosphates and produce cellulases on CMC agar. The findings of this study, in combination with in vitro bioassays on cacao pods (Theobroma cacao L.) inoculated with the antagonist strain and P. palmivora APB-35, demonstrate that Streptomyces sp. Caat 5-35 is a source of natural products with applications in agriculture and could serve as an alternative for crop protection.

Gelasia tomentosa (L.) Zaika, Sukhor. & N.Kilian which is known formerly as Scorzonera tomentosa L., a wild edible plant species in Turkey, is traditionally used against rheumatism and for wound healing. In this study, we explore its anti-inflammatory compounds, evaluating effectiveness through human red blood cell stabilization and in silico models, alongside physico-chemical and pharmacokinetic profiles. In vitro activity-guided fractionation allowed the isolation of sixteen compounds from the aerial parts of G. tomentosa, which were identified as hyperoside (1), isoquercetin (2), quercetin 3-O-β-apiofuranosyl-(1→2)-β-galactopyranoside (3), quercetin 3-O-β-apiofuranosyl-(1→2)-β-glucopyranoside (4), 7-methoxyapigenin-6-C-β-apiofuranosyl-(1→2)-β-glucopyranoside (5), apigenin-6-C-β-apiofuranosyl-(1→2)-β-glucopyranoside (6), dihydrodehydrodiconiferyl-alcohol-4-O-β-glucopyranoside (7), cichoriin (8), 7-O-methylisoorientin (9), isoorientin (10), swertisin (11), 3,5-O-dicaffeoylquinic acid methyl ester (12), 4,5-O-dicaffeoylquinic acid methyl ester (13), staphylinioside E (14), 3,5-O-dicaffeoylquinic acid (15), and 4,5-O-dicaffeoylquinic acid (16). Compound 16 displayed the highest potential anti-inflammatory activity (IC₅₀ = 0.55 ± 0.00 mg/mL). However, the fraction with compounds displayed stronger biological activity than the isolated ones. In silico findings supported the anti-inflammatory potential, enhancing TP53 expression and cell membrane protection. Cichoriin (8) and staphylinioside E (14) are in accordance with Lipinski’s, Pfizer’s, GSK’s, and Golden Triangle rules, indicating a favorable ADME profile as a drug candidate. Further studies are needed to test this potential in specific inflammation models.