Exploring potooxidative degradation pathways of harmol and harmalol alkaloids in water: effects of pH, excitation sources and atmospheric conditions.

This work explores the photochemical degradation of cationic species of 7-hydroxy-1-methyl-2-pyrido[3,4-]indole or harmol (1C) and the corresponding partially hydrogenated derivative 7-hydroxy-1-methyl-3,4-dihydro-2-pyrido[3,4-]indole or harmalol (2C) in aqueous solution. UV-visible absorption and fluorescence emission spectroscopy coupled with multivariate data analysis (MCR-ALS and PARAFAC), HPLC and HRESI-MS techniques were used for both quantitative and qualitative analysis. The formation of hydrogen peroxide reactive oxygen species (ROS) was quantified, and the influence of pH, oxygen partial pressure and photoexcitation source on the photochemical degradation of both compounds was assessed.

Distribution of photoactive β-carboline alkaloids across Passiflora caerulea floral organs.

This study reports valuable information regarding the presence and concentration of a series of photoactive β-carboline (βCs) alkaloids (norharmane, harmane, harmine, harmol, harmaline, and harmalol) and their distribution across the floral age and organs of Passiflora caerulea. UHPLC-MS/MS data reported herein reveal that the βCs' content ranged from 1 to 110 μg kg , depending on the floral organ and age. In certain physiologically relevant organs, such as anthers, βCs' content was one order of magnitude higher than in other organs, suggesting a special role for βCs in this specific organ.

Spectroscopic and quantum chemical characterization of the ground and lowest electronically excited singlet and triplet states of halo- and nitro-harmines in aqueous media.

Halogenated and nitro β-carboline (βCs) alkaloids have garnered increasing interest for their role in a broad range of biological, pharmacological and biotechnological processes. Addressing their spectroscopic and photophysical properties provide tools to further explore the presence of these alkaloids in complex biological matrices. In addition, these studies help to elucidate processes where these alkaloids are involved.

Photophysical and spectroscopic features of 3,4-dihydro-β-carbolines: a combined experimental and theoretical approach.

3,4-Dihydro-β-carbolines (DHβCs) are a set of endogenously synthesized alkaloids spread over a great variety of living species (e.g., plants, animals and microorganisms), playing a broad spectrum of biological, biochemical and/or pharmacological roles, in a structure-dependent manner.

Photophysics and photochemistry of carminic acid and related natural pigments.

Carminic acid (CA) and other related compounds have been widely used as dyes in cultural heritage, cosmetics and the food industry. Therefore, the study of their properties upon photoexcitation is particularly important. In this work, the photophysical and photochemical properties of CA, carminic lake and other related pigments in aqueous solutions are revisited.

Light-induced full aromatization and hydroxylation of 7-methoxy-1-methyl-3,4-dihydro-2H-pyrido[3,4-b]indole alkaloid: Oxygen partial pressure as a key modulator of the photoproducts distribution.

Full-aromatic and partially hydrogenated β-carboline (βC) derivatives constitute a group of alkaloids widely distributed in a great variety of living systems. In plants and bacteria, tetrahydro-βCs are the primary product of the Pictet-Spengler enzymatically catalyzed condensation. Tetrahydro-βC skeleton is further modified giving rise to the formation of a vast set of derivatives including dihydro- and full-aromatic βCs.

DNA damage photo-induced by chloroharmine isomers: hydrolysis versus oxidation of nucleobases.

Photodynamic therapy (PDT) is an emerging clinical treatment currently being used against a wide range of both cancerous and noncancerous diseases. The search for new active photosensitizers as well as the development of novel selective delivery systems are the major challenges faced in the application of PDT. We investigated herein three chloroharmine derivatives (6-, 8- and 6,8-dichloroharmines) with quite promising intrinsic photochemical tunable properties and their ability to photoinduce DNA damage in order to elucidate the underlying photochemical mechanisms.