Abstract
Antimicrobial photodynamic therapy has emerged as a powerful approach to tackle microbial infections. Photodynamic therapy utilises a photosensitiser, light, and oxygen to generate singlet oxygen and/or reactive oxygen species in an irradiated tissue spot, which subsequently react with nearby biomolecules and destroy the cellular environment. Due to the possibility to irradiate in a very precise location, it can be used to eradicate bacteria, fungus, and parasites upon light activation of the photosensitiser. In this regard, natural products are low-cost molecules capable of being obtained in large quantities, and some of them can be used as photosensitisers. Alkaloids are the largest family among natural products and include molecules with a basic nature and aromatic rings. For this study, we collected the naturally occurring alkaloids used to treat microorganism infections using a photodynamic inactivation approach. We gathered their main photophysical properties (excitation/emission wavelengths, quantum yields, and oxygen quantum yield) which characterise the ability to efficiently photosensitise. In addition, we described the antibacterial activity of alkaloids upon irradiation and the mechanisms involved in the microorganism killing. This review will serve as a reference source to obtain the main information on alkaloids used in antimicrobial photodynamic therapy.
Highlights
The spread of resistant parasites, fungi, and bacterial strains is one of the main threats to humanity as recognised by the World Health Organisation (WHO) in its report in 2014 [1]and its priority list of pathogens published in 2017 [2]
A class of polycyclic alkaloids includes the isoquinolines described as protoberberA class of polycyclic alkaloids includes the isoquinolines described as protoberberines ines (42–46, Figure 8), which are isolated from Berberis vulgaris, Sanguinaria canadensis, or
Alkaloids are an important class of natural products with biomedical applications, and the combination of their photoactivation with light paves new avenues to inactivate microorganisms
Summary
The spread of resistant parasites, fungi, and bacterial strains is one of the main threats to humanity as recognised by the World Health Organisation (WHO) in its report in 2014 [1]. The microbial infections have arisen in recent years and are estimated to cause an annual death toll of 10 million worldwide by 2060, making many of the medical advances of the 20th century obsolete [6,7] In this line, drugs with novel mechanisms of action and/or new approaches are needed to overcome this global health issue. This review seeks to integrate the new therapeutic applications of alkaloids in antimicrobial photodynamic inactivation to date Through this approach, alkaloids can potentially kill microorganisms by either the mechanism of action of the molecule or by the reactive species generated under irradiation or a combination of both of them. This opens the wave for enhancing the antimicrobial activity and the application of this approach for clinical treatments in the near future
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
