CC BY
11ALT'22 _B-P-7
/|\ BIOMEDICAL PHOTONICS
Antimicrobial Photoinactivation Using Medicinal Plant Extracts
A. Mikulich1, A. Tretyakova1, R. Nahorny1, T. Ananich1, N.Dudchik2, O. Emeliyanova2, A. Zhabrouskaya2, A. Sobchuk1, L. Plavskaya1, O. Dudinova1, I. Leusenka1, S. Yakimchuk1, V. Plavskii1, Tran Quoc Tien3,
Quang Cong Tong3, Thanh Phuong Nguyen4
1- State Scientific Institution "B. I. Stepanov Institute of Physics of the National Academy of Sciences of Belarus",
68-2 Nezavisimosti Ave., Minsk, 220072, Republic of Belarus 2- Republican unitary enterprise «Scientific Practical Centre of Hygiene», 8 Akademicheskaya str., Minsk, 220012, Republic of Belarus
3- Institute of Materials Science, Vietnam Academy of Science and Technology,
18 Hoang Quoc Viet, Cau Giay District, Hanoi, Vietnam
4- School of Engineering Physics, Hanoi University of Science and Technology,
No.1 Dai Co Viet, Hai Ba Trung, Hanoi, Vietnam Main author email address: a.mikulich@ifanbel.bas-net.by
Antimicrobial resistance (AMR) is serious public health problem worldwide [1]. Antimicrobial photodynamic therapy (APDT) is efficient technology against various microorganisms based on the interaction of a photosensitizer, molecular oxygen, and an appropriate light source. In this work, we show that photosensitizing effect of medicinal plant extracts can be used to overcome AMR.
The following medicinal plant extracts were used in the studies: extract from a mixture of flowers of Matricaria chamomilla and Calendula officinalis, Achillea millefolium herb (commercial name "Rotatit"); extract from Hypericum perforatum herb; extract from Eucalypti viminalis folia. Absorption and fluorescence spectroscopy were used to investigate the composition of extracts. Photosensitized production of singlet oxygen upon excitation of extracts with light was confirmed by the detection of singlet oxygen luminescence at 1270 nm. Antimicrobial photodynamic effect of extracts was studied towards the Gram-negative (P aeruginosa ATCC15442) and Gram-positive (S. aureus ATCC 6538) bacteria by colony-forming units (CFU) assay. Irradiation was performed with LED sources that emitted light with Xmax = 405 nm, X = 590 nm and X = 660 nm.
' max max
Spectral-luminescent analysis shows that all extracts under study are multicomponent and reveals the presence of compounds of chlorophyll (X , = 537; 608; 665 nm) and hypericin (X , = 550; 590 nm) nature in them able to act
r r j \ max, abs ' ' ' J r v max, abs ' '
as photosensitizers. Upon excitation with light (665 nm) the extracts generate singlet oxygen with good quantum yield - 0.64 ("Rotatit"), 0.48 (Eucalypti viminalis folia), 0.40 (Hypericum perforatum).
The extracts showed a strong activity as photosensitizers. Upon exposure to light of Xmax = 405 nm at intensity of 100 mW/cm2 complete inactivation was observed at an irradiation time of 5 min for P. aeruginosa cells preliminary incubated with extracts. Among the tested wavelengths, the 405 nm light was the most efficient in killing. In our opinion, upon exposure of blue light, photodynamic effect is due to both excitation of exogenous (extracts) and endogenous photosensitizers [2]. Effective photodynamic inactivation was also achieved for Gram-positive bacteria. In case of extracts, where hypericin component was absent, the light with 660 nm was more efficient in microbial inactivation than 590 nm light and vice versa. In general, photosensitizing effect of extracts was higher in case of Gram-positive bacteria.
We suppose that high quantum yield of singlet oxygen generation by photosensitizers, present in the investigated extracts, contributes to the effective photoinactivation of pathogens, proceeding with the participation mentioned reactive oxygen species.
This work was financially supported by Belarusian Republican Foundation for Fundamental Research, Project 021BTHr-OO1 and by the Ministry of Science and Technology of Vietnam, Project Grant Number NDT/BY/22/03.
[1] E. Polat and K. Kang, Natural Photosensitizers in Antimicrobial Photodynamic Therapy. Biomedicines, 9(6), pp. 584, (2021).
[2] V.Yu Plavskii, A.V. Mikulich, A.I. Tretyakova, I.A. Leusenka, L.G. Plavskaya, O.A. Kazyuchits, I.I. Dobysh, T.P.
Krasnenkova,Porphyrins and flavins as endogenous acceptors of optical radiation of blue spectral region determining photoinactivation
of microbial cells, Journal of Photochemistry and Photobiology B: Biology, vol. 183, pp. 172-183, (2018).
