Compositional analysis of endogenous porphyrins from Helicobacter pylori
A Battisti1, P Morici1, G Signore2
1Istituto Nanoscienze, CNR and NEST Scuola Normale Superiore, p.zza San Silvestro 12, 56127 Pisa, Italy.
Abstract:
Bacteria able to accumulate porphyrins can be inactivated by visible light irradiation thanks to the photosensitizing properties of this class of aromatic pigments (photodynamic therapy, PDT). Since the bacterial resistance to antibiotic is growing, PDT is becoming a valid alternative. In this context, the pathogen Helicobacter pylori (Hp) is a suitable target for PDT since it spontaneously produces and accumulates porphyrins. It is then important to understand the spectroscopic behavior of these endogenous species to exploit them as photosensitizers, thus improving the results given by the application of PDT in the treatment of Hp infections. In this work we extracted porphyrins from both a laboratory-adapted and a virulent strain of Hp, and we performed spectroscopic and chromatographic experiments to collect information about the composition and the spectrophotometric features of the extracts. The main components of the porphyrin mixtures were identified and their relative contribution to the global red fluorescence was examined.
Insights
Photodynamic therapy (PDT) offers a promising alternative to antibiotics for inactivating bacteria. This study analyzed porphyrins from Helicobacter pylori, identifying their composition and spectroscopic properties to enhance PDT efficacy against infections.
Area of Science:
- Biochemistry
- Photochemistry
- Microbiology
Background:
- Antibiotic resistance necessitates alternative antimicrobial strategies.
- Photodynamic therapy (PDT) utilizes photosensitizing agents to inactivate microbes with light.
- Porphyrins, naturally produced by some bacteria like Helicobacter pylori (Hp), exhibit photosensitizing properties.
Purpose of the Study:
- To characterize the spectroscopic properties of porphyrins extracted from Hp.
- To identify the main porphyrin components in Hp extracts.
- To assess the contribution of these porphyrins to photosensitization for improved PDT.
Main Methods:
- Extraction of porphyrins from laboratory-adapted and virulent Hp strains.
- Spectroscopic analysis (e.g., fluorescence) to determine photophysical properties.
- Chromatographic techniques to identify and quantify porphyrin components.
Main Results:
- Porphyrins were successfully extracted from both Hp strains.
- The composition of the porphyrin mixtures was analyzed.
- The relative contribution of identified porphyrins to red fluorescence was quantified.
Conclusions:
- Understanding Hp-derived porphyrin composition is crucial for optimizing PDT protocols.
- Characterized porphyrins can be leveraged as endogenous photosensitizers.
- This research supports the development of more effective PDT treatments for Hp infections.
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Structure of Porins


