Study of the Antimicrobial Potential of the Arthrospira platensis, Planktothrix agardhii, Leptolyngbya cf. ectocarpi, Roholtiella mixta nov., Tetraselmis viridis, and Nanofrustulum shiloi against Gram-Positive, Gram-Negative Bacteria, and Mycobacteria

Abstract

The incidence of diseases brought on by resistant strains of micro-organisms, including tuberculosis, is rising globally as a result of the rapid rise in pathogenic micro-organism resistance to antimicrobial treatments. Secondary metabolites with potential for antibacterial activity are produced by cyanobacteria and microalgae. In this study, gram-positive (S. aureus, E. faecalis) and gram-negative (K. pneumoniae, A. baumannii, P. aeruginosa) bacteria were isolated from pulmonary tuberculosis patients receiving long-term antituberculosis therapy. The antimicrobial potential of extracts from the cyanobacteria Leptolyngbya cf. ectocarpi, Planktothrix agardhii, Arthrospira platensis, Rohotiella mixta sp. nov., Nanofrustulum shiloi, and Tetraselmis (Platymonas) viridis Rouchijajnen was evaluated. On mouse splenocytes and peritoneal macrophages, extracts of cyanobacteria and microalgae had inhibitory effects. In vitro studies have shown that cyanobacteria and microalgae extracts suppress the growth of bacteria and mycobacteria. At the same time, it has been demonstrated that cyanobacterial and microalgal extracts can encourage bacterial growth in a test tube. Additionally, the enhanced fucoxanthin fraction significantly reduced the development of bacteria in vitro. In a mouse experiment to simulate tuberculosis, the mycobacterial load in internal organs was considerably decreased by fucoxanthin. According to the information gathered, cyanobacteria and microalgae are potential sources of antibacterial compounds that can be used in the manufacturing of pharmaceutical raw materials.

Keywords: antimicrobial potential; cyanobacter; diatoms; gram-positive and gram-negative bacteria; green microalgae; mycobacteria.

Figure 1

Content of the primary biochemical substances in the various cyanobacteria and microalgae taxa’s DMSO extracts.

Figure 2

Cell viability of the Balb/c mice’s peritoneal macrophages and splenocytes after a 24-h exposure period with various cyanobacteria and microalgae water-extract by MTT assay. FX, fucoxanthin from Nanofrustulum shiloi. Statistical notations: * p < 0.05.

Figure 3

Fucoxanthin and Arthrospira platensis water extract both have antimycobacterial properties. Statistical notations: * = p < 0.05 compared with basal mycobacteria growth; # = p < 0.05 with rifampicin. Rifampicin was added to wells in doses of 100 µg/mL, A. platensis in doses of 1% v/v, and FX in doses of 35 µg/mL.

Figure 4

Comparison of the antimycobacterial properties of DMSO from microalgae and chlorophyllipt extracts (M ± SD). Statistical notations: * = p < 0.05 compared with basal mycobacteria growth; # = p < 0.05 with rifampicin. Rifampicin was added in wells in doses of 100 µg/mL, chlorophyllipt and microalgae extracts in doses of 1% v/v, and FX in doses of 35 µg/mL.

Figure 5

The amount of Mycobacterium tuberculosis CFU growth on Lowenstein–Jensen solid medium from the liver, spleen, and lungs of tuberculosis-infected mice (M ± SD). CFU, colony-forming units; Rif, rifampicin-treated group; FX, fucoxanthin-treated group. Statistical notations: * = p < 0.05 compared with TB-untreated group; # = p < 0.05 with rifampicin-treated group.