Photogeneration and quenching of singlet molecular oxygen by bacterial C carotenoids with long chain of conjugated double bonds.

Measurement of photosensitized luminescence of singlet oxygen has been applied to studies of singlet oxygen generation and quenching by C carotenoids (neurosporene, lycopene, rhodopin, and spirilloxanthin) with long chain of conjugated double bonds (CDB) using hexafluorobenzene as a solvent. It has been found that neurosporene, lycopene, and rhodopin are capable of the low efficient singlet oxygen generation in aerated solutions upon photoexcitation in the spectral region of their main absorption maxima. The quantum yield of this process was estimated to be (1.

Photodynamic activity rather than drilling causes membrane damage by a light-powered molecular nanomotor.

The chase toward endowing chemical compounds with machine-like functions mimicking those of biological molecular machineries has yielded a variety of artificial molecular motors (AMMs). Pharmaceutical applications of photoexcited monomolecular unidirectionally-rotating AMMs have been envisioned in view of their ability to permeabilize biological membranes. Nonetheless, the mechanical properties of lipid membranes render the proposed drilling activity of AMMs doubtful.

ζ-Carotene: Generation and Quenching of Singlet Oxygen, Comparison with Phytofluene.

It is known that C carotenoids with a short chain of conjugated double bonds (CDB) (5 and 7, respectively) are universal precursors in the biosynthesis of colored carotenoids in plant cells. Previously, using mainly stationary measurements of photosensitized phosphorescence of singlet oxygen (O), we discovered that phytofluene efficiently generates O in aerated solution and therefore, can serve as a source of the UV photodynamic stress in living cells [Ashikhmin et al., Biochemistry (Moscow), 2020, 85, 773].

Chlorin Endogenous to the North Pacific Brittle Star for Photodynamic Therapy Applications in Breast Cancer and Glioblastoma Models.

Photodynamic therapy (PDT) represents a powerful avenue for anticancer treatment. PDT relies on the use of photosensitizers-compounds accumulating in the tumor and converted from benign to cytotoxic upon targeted photoactivation. We here describe (3,4)-14-Ethyl-9-(hydroxymethyl)-4,8,13,18-tetramethyl-20-oxo-3-phorbinepropanoic acid (ETPA) as a major metabolite of the North Pacific brittle stars .

Phytofluene as a Highly Efficient UVA Photosensitizer of Singlet Oxygen Generation.

Phytoene and phytofluene - uncolored C carotenoids with short chain of conjugated double bonds (3 and 5, respectively) - are known to be universal precursors in biosynthesis of colored carotenoids in photosynthesizing organisms. It is commonly recognized that C carotenoids are photoprotectors of cells and tissues. We have shown that phytofluene is an exception to this rule.