Maha A. Alharbia,
Amani A. Alrehailib,
Mona Othman I. Albureikanc,
Amal F. Gharibb,
Hussam Daghistanide,
Maha M. Bakhuraysahb,
Ghfren S. Alorainif,
Mohammed A. Bazuhairg,
Hayaa M. Alhuthalib and
Ahmed Ghareeb*h
aDepartment of Biology, College of Science, Princess Nourah bint Abdulrahman University, P.O. Box 84428, Riyadh 11671, Saudi Arabia. E-mail: maalharbi@pnu.edu.sa
bDepartment of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia. E-mail: Arhili@tu.edu.sa; maha1@tu.edu.sa; amgharib@tu.edu.sa; hmhuthali@tu.edu.sa
cDepartment of Biological Sciences, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia. E-mail: malboraikan@kau.edu.sa
dDepartment of Clinical Biochemistry, Faculty of Medicine, King Abdulaziz University, Jeddah 21589, Saudi Arabia. E-mail: hmdaghistani@kau.edu.sa
eRegenerative Medicine Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah 21589, Saudi Arabia
fDepartment of Medical Laboratory Sciences, College of Applied Medical Sciences, Prince Sattam bin Abdulaziz University, Al-Kharj 11942, Saudi Arabia. E-mail: g.aloraini@psau.edu.sa
gDepartment of Clinical Pharmacology, Faculty of Medicine, King Abdulaziz University, Jeddah, 21589, Saudi Arabia. E-mail: obazohair@kau.edu.sa
hBotany and Microbiology Department, Faculty of Science, Suez Canal University, Ismailia 41522, Egypt. E-mail: aghareeb@science.suez.edu.eg
First published on 4th September 2023
In the current study, Bacillus velezensis AG6 was isolated from sediment samples in the Red Sea, identified by traditional microbiological techniques and phylogenetic 16S rRNA sequences. Among eight isolates screened for exopolysaccharide (EPS) production, the R6 isolate was the highest producer with a significant fraction of EPS (EPSF6, 5.79 g L−1). The EPSF6 molecule was found to have a molecular weight (Mw) of 2.7 × 104 g mol−1 and a number average (Mn) of 2.6 × 104 g mol−1 when it was analyzed using GPC. The FTIR spectrum indicated no sulfate but uronic acid (43.8%). According to HPLC, the EPSF6 fraction’s monosaccharides were xylose, galactose, and galacturonic acid in a molar ratio of 2.0:0.5:2.0. DPPH, H2O2, and ABTS tests assessed EPSF6’s antioxidant capabilities at 100, 300, 500, 1000, and 1500 μg mL−1 for 15, 60, 45, and 60 minutes. The overall antioxidant activities were dose- and time-dependently increased, and improved by increasing concentrations from 100 to 1500 μg mL−1 after 60 minutes and found to be 91.34 ± 1.1%, 80.20 ± 1.4% and 75.28 ± 1.1% respectively. Next, EPSF6 displayed considerable inhibitory activity toward the proliferation of six cancerous cell lines. Anti-inflammatory tests were performed using lipoxygenase (5-LOX) and cyclooxygenase (COX-2). An MTP turbidity assay method was applied to show the ability of EPSF6 to inhibit Gram-positive bacteria, Gram-negative bacteria, and antibiofilm formation. Together, this study sheds light on the potential pharmacological applications of a secondary metabolite produced by marine Bacillus velezensis AG6. Its expected impact on human health will increase as more research and studies are conducted globally.
Microbial EPSs are organic, miscible, or immiscible polysaccharides synthesized by microorganisms and released into the extracellular medium. They adhere to the cell’s surface in broth media.4 EPSs may be produced by a broad range of microorganisms, some examples of which include bacteria, cyanobacteria, fungi, and yeasts. Microbial EPSs help cells survive by attaching to surfaces, aggregating, and preventing desiccation.5 Also, a gelled polysaccharide layer around the cell may affect its diffusion properties, both into and out of the cell.6 Additionally, they help the microbial communities survive changes in temperature, saltiness, and nutrient unavailability.7
Marine microbial polysaccharides exhibit a variety of structures and unique properties, especially those produced extracellularly. In microbial polysaccharides, glucose, galactose, and mannose are the most prevalent monosaccharides, making up most of these heteropolysaccharides.8 Marine microbial polysaccharides include glucuronic acid, galacturonic acid, amino sugars, pyruvate, sulfates, and uronic acids, unlike terrestrial plant polysaccharides.9
Most EPS are linear and have high molecular weights (1–3 × 105 Da). The combination of pyruvate and uronic acid linked to ketals, along with inorganic residues such as sulfate or phosphate, is primarily responsible for the bulk of reported EPS being polyanionic.10
Due to the growing need for natural polymers in industries such as food and pharmaceuticals, there has been a recent surge in interest in polysaccharides produced by microorganisms.11 There is an increasing curiosity in discovering and identifying new polysaccharides from microorganisms that may have potential uses as anti-inflammatory, antioxidant, antimicrobial, anticytotoxic agents, and many other pharmacological applications.12–16 For example, A hetero acidic EPS produced by the isolated Bacillus cereus strain AG3 from Red Sea sediments inhibited the growth of methicillin-resistant Staphylococcus aureus (MRSA) and displayed the potential to represent a new class of anti-inflammatory drug.13 Asker et al.17 found that the Achromobacter piechaudii NRC2 EPS fraction has substantial anti-cyclooxygenase and antioxidant activities. Liu et al. isolated two polysaccharides from the fermenting fluid of Floccularia luteovirens that showed free radical scavenging activities.18 Additionally, Sulfated exopolysaccharide (levan) derived from Bacillus megaterium PFY-147 was identified by Pei et al. The substance demonstrated notable antioxidant and probiotic properties, indicating its potential efficacy in biomedical applications.19
The World Health Organization (WHO) estimates that cancer was the main cause of 9.5 million deaths globally in 2020. According to estimates, 17 million people will die from cancer by 2040 due to a growing incidence of the disease. These statistics highlight the pressing need for new and improved therapies.20
Surgery, radiation, chemotherapy, and immunotherapy all have drawbacks. Due to tumor size, site, stage, and metastasis, cancer treatment is complicated. Such therapies generally fail to control tumors due to resistance, and various side effects occur during or after treatment.21,22 Therapeutic microorganisms may overcome some these limitations of traditional cancer treatments. Bacteria alone can be effective anticancer agents, and they can be genetically modified to generate and release specific chemicals and tailor their metabolic pathways. Therapeutic microorganisms also penetrate tumor tissue and target hypoxic regions of tumors. Another application is as a carrier for delivering tumoricidal and immunotherapeutic drugs. Since then, and even today, many investigators have reported that specific live, attenuated, and modified microbes, including Clostridium, Bifidobacterium, Salmonella, Mycobacterium, Bacillus, and Listeria, have the capacity to target cancer cells specifically and function as anticancer agents.23
Deepak et al. documented anti-tumor activity of microbial EPS, where the EPS from Lactobacillus acidophilus showed in vitro effect on colon cancer cell lines.24 Also, Wang et al. reported the anticancer effects of an EPS from a newly isolated B. breve strain against head and neck squamous cell carcinoma cell lines.25 EPSR3 from marine Bacillus cereus was reported to have a cytotoxicity-inhibiting effect on the growth of T-24, MCF-7, and PC-3 carcinoma cell lines.13
Therefore, based on the remarkable ESP applicability and ongoing attempts to explore and investigate novel exopolysaccharides. This investigation extracted and characterised a new EPS from the marine Bacillus velezensis strain AG6 from the Red Sea sediments. Furthermore, the EPSF6 compound was tested in vitro to evaluate its potential as an antioxidant, anticancer, anti-inflammatory, antimicrobial, antibiofilm, and anti-acetylcholine esterase inhibitor.
The BLAST tool was employed to compare the obtained DNA sequence to the GenBank database at the NCBI. This was followed by an alignment to assess the resemblance between the isolate’s sequence and those in the database.
The presence of uronic acid in EPSF6 samples was detected using a colorimetric method described by Filisetti-Cozzi and Carpita. The method involved diluting the sample with concentrated sulfuric acid(2 mL), boiling the mixture for 20 minutes at 100 °C, cooling it to room temperature, and then adding m-hydroxydiphenyl (150 μL). The absorbance of the resulting mixture was measured at 520 nm after an hour.32 The amount of sulfate in EPSF6 was determined using the Garrido’s method. Five milligrams of EPSF6 was hydrolyzed in a sealed tube with 5 mL of formic acid (88%) at 105 °C for 5 hours. After dryness, In a 100 milliliter measuring flask, 10 mg of BaCl2 was dissolved in a small quantity of H20. 20 mL of Tween 20 was added, and the final volume was adjusted to 100 mL with distilled H20. To 10 milliliters of the hydrolysate solution, 1 mL of dilute hydrochloric acid (0.3 N) and 1 mL of the BaCl2-Tween 20 reagent was added. After mixing, the solution was allowed to stand for 15 minutes and then mixed again. The optical density of the mixture was then read at 500 nm against a blank containing distilled water instead of the sulfate solution.33 The method outlined by Randall et al. were used to determine the monosaccharide quantity EPSF6 was hydrolyzed with 2 M trifluoroacetic acid at 120 °C for 2 hours.34 The resulting mixture was diluted with methanol and dried under vacuum. The residue was then dissolved in water and analyzed on an Aminex carbohydrate HP-87C column(300 × 7.8 mm) using water as the eluent and a flow rate of 0.5 mL min−1(Agilent 1100 Series System, Santa Clara, CA, USA). The standards used were mannose (Man), glucose (Glc), D-glucuronic acid (GlcA), galactose (Gal), and D-galacturonic acid (GalA).
UV absorption spectra between 200 and 800 nanometers were examined for proteins and nucleic acids.30
The microtiter plate assay (MTP) method was utilized to examine the ability of EPS to inhibit biofilm formation against (Staphylococcus aureus NRRLB-767 and Escherichia coli ATCC-25922).43
Scheme 1 Flow chart displaying production, isolation, and purification of exopolysaccharide (EPSF6). |
The Uronic acid (43.8%) but no sulfate was in EPSF6. These acidic fractions are xylose, galactose, and galacturonic acid monosaccharides, with molar ratios of 2.0:0.5:2.0 (Fig. S1†). EPSF6 molecules in the GPC chromatogram were widely scattered (Fig. 2B) with a polydispersity index (PI) of 1.1, revealed (Mw) of 2.7 × 104 g mole−1, and (Mn) of 2.6 × 104 g mole−1.
The stretching vibration of O–H in sugar residue components caused the FTIR spectra fraction to peak at 3443.28 cm−1. Circular vibrations also produced a band at 1647.87 cm−1. The band at 864.917 cm−1 disrupted the C–O glycosidic bond’s stretching vibration. The band at 863.953 cm−1 showed pyranose ring vibrations (Fig. 2A).
Fig. 4 H2O2 scavenging activity of EPSF6 at different concentrations and time intervals. Data are presented as mean ± SD. ANOVA one-way was used for data analysis (n = 3, P < 0.05). |
Fig. 5 EPSF6 scavenging activity against ABTS at different concentrations and time intervals. Data are presented as mean ± SD. ANOVA one-way was used for data analysis (n = 3, P < 0.05). |
Fig. 6 Cytotoxicity activity of different concentrations of EPSF6 on % inhibitory of different cancer cell lines. Data represent mean ± SD of triplicate measurements. |
Fig. 7 IC50 of EPSF6 on % viability of the tested cancer cell lines. The data is presented as the mean ± SD of three measurements. |
These cell lines' respective IC50s for EPSF6 were (471.88 ± 15.2 μg mL−1, 532.81 ± 12.5 μg mL−1, 1.089 ± 21.58 μg mL−1, 483.54 ± 19.82 μg mL−1, 1586.22 ± 14.8 μg mL−1 and 450.45 ± 12.1 μg mL−1). As the concentration of EPSF6 decreased in the cell lines examined, the percentage of viable cells increased. At 125 μg EPSF6 per mL concentrations and above, the percentage of viable cells in most cell lines began to drop significantly compared to the control cells. This decline continued as the concentration increased (Fig. 8).
Fig. 9 Anti-Inflammatory activity of EPSF6 using different methods (A) 5-LOX (B) COX-2. Data are presented as mean ± SD. ANOVA one-way was used for data analysis (n = 3, P < 0.05). |
Compounds | Antimicrobial activity (%) | |||||
---|---|---|---|---|---|---|
Gram positive | Gram negative | Yeast | Fungi | |||
S. aureus NRRLB-767 | B. Subtilis ATCC 6633 | E. Coli ATCC 25922 | K. pneumoniae ATCC 10145 | C. albicans ATCC 10231 | Aspergillus niger NRRLA-326 | |
EPSF6 | 27.32 ± 0.75 | 34.19 ± 0.91 | 19.05 ± 0.61 | 13.64 ± 0.66 | 7.58 ± 0.17 | 5.92 ± 0.41 |
Ciprofloxacin | 96.01 ± 0.43 | 97.24 ± 0.18 | 98.07 ± 0.35 | 98.10 ± 0.27 | — | — |
Nystatine | — | — | — | — | 97.16 ± 0.90 | 98.23 ± 0.16 |
Further, EPSF6 antibiofilm activity was tested by the microtiter plate assay (MTP) method against two bacterial strains (Staphylococcus aureus NRRLB-767 and Escherichia coli ATCC-25922), with no significant antibiofilm inhibition for either of the tested bacteria 35.673 ± 0.79 and 16.932 ± 098 respectively (Table 2).
Biofilm inhibition ratio (%) | ||
---|---|---|
E. Coli ATCC 25922 | S. aureus NRRLB-767 | |
EPSF6 | 16.932 ± 098 | 35.673 ± 0.79 |
Fig. 10 Acetylcholine esterase inhibition activity by different concentrations of EPSF6. Data presented as mean ± SD. ANOVA one-way was used for data analysis (n = 3, P < 0.05). |
The EPS explored was derived from a spore-forming, Gram-positive, non-capsulated marine Bacillus velezensis strain AG6 (accession no.: OP185337.1) (Fig. 1). Of the eight strains of bacteria studied, the F6 strain was identified as the most significant producer of EPS (EPSF6). The EPSF6 weighed 5.79 g L−1 with a main fraction of 89.8% (three-volume ethanol). The chemical analysis of EPSF6 revealed a (Mw) of 2.7 × 104 g mol−1 and a (Mn) of 2.6 × 104 g mol−1 comprised of xylose, galactose, and galacturonic acid with a molar ratio 2.0:0.5:2.0 respectively. Also, there was no sulfate present but 43.8% uronic acid, which signifies that it is an acidic polysaccharide (Fig. 2B and 1S†). As previously stated, EPSF6 has a high (Mw) of 2.7 × 104 g mol−1. Most marine exopolysaccharides are composed of linear chains of mono sugars. On average, the molecular weight ranges from 1 × 105 Da to 3 × 105 Da10. Even though the vast majority of EPS polymers are neutral, the vast majority are polyanionic because they include uronic acid. One example of this is EPSF6.
Moving to EPSF6 antioxidant investigation by DPPH, H2O2, and ABTS assays, the maximum antioxidant activates were (91.34 ± 1.1, 80.20 ± 1.4, and 75.28 ± 1.1%). The antioxidant activity increased with increased tested concentration (Fig. 3–5). It is important to note that glutathione, a potent non-enzymatic antioxidant, is synthesized with the help of secreting enzymes like superoxide dismutase, which can be related to free radical scavenging ability.48
Additionally, various side chemical groups, such as the sulfated, hydroxyl, and uronic acid groups, promote the scavenging of antioxidant.49 The explored EPSF6 by FTIR revealed it has no sulfate but uronic acid (43.8%) (Fig. 2B).
An EPS derived from Bacillus albus DM-15, obtained from ayurvedic treatment in India, has a notable effect on scavenging the activity of three different radicals: DPPH (58.1%), ABTS (70.4%), and NO (58.9%) depending on the concentration., which is consistent with our findings.50 Also, B. cereus strain AG3 was reported with a peak antioxidant capacity of 90.4 ± 1.6% at 1500 μg mL−1 after approximately 2 hours and an IC50 of around 500 μg mL−1 after 1 hour when tested against the DPPH radical. Also, it was observed that at 1500 μg mL−1, the scavenging activity of H2O2 was 75% after 60 minutes and the IC50 was reported to be around 1500 μg mL−1 after 15 minutes.13 Additionally, from marine Pseudomonas PF-6, Ye et al.51 identified and purified an acidic β-type EPS that exhibited antioxidant action. Additionally, it was shown that an EPS isolated from Bacillus amyloliquefaciens 3 MS 2017 could scavenge DPPH free radicals with a maximal activity of 99.39% at a concentration of 1000 μg mL−1.52 As well, Streptomyces carpaticus produced an EPS with DPPH antioxidant potential with an IC50 value of 111 μg mL−1.53
The reductive ability of such monosaccharides may cause EPS’s ability to scavenge radicals.54 In several studies, purified polysaccharides derived from crude polysaccharides were found to be more functional in vitro than crude polysaccharides.55,56 Compositionally, the chemical analysis of EPSF6 by HPLC revealed three different monosaccharides, xylose, galactose, and galacturonic acid, with molar ratios of 2.0:0.5:2.0, respectively (Fig. S1†). These monosaccharides, with the exception of glucuronic acid, are powerful reductive agents due to the presence of an aldehyde group in their structures.
After that, the MTT assay was used to investigate the cytotoxic potential of EPSF6 in six different cell lines. These cell lines' respective IC50s for EPSF6 were (471.88 ± 15.2, 532.81 ± 12.5, 1.089 ± 21.58, 483.54 ± 19.82, 1586.22 ± 14.8 and 450.45 ± 12.1 μg mL−1), respectively (Fig. 8) where control Cisplatin IC50 against same cancerous cell lines were (1.29, 4.08, 2.36, 3.41, 4.21, 3.79 μg mL−1) respectively (Table S4†).
In line with our findings, recent research investigated whether or not EPSR5 isolated from marine Kocuria sp. had a suppressive impact on the growth of cancer cells.12 The highest IC50s was (1691.00 ± 44.20 μg mL−1) for MCF-7, and the lowest was (453.46 ± 21.80 μg mL−1) for HepG-2. An exopolysaccharide from Bacillus albus DM-15 isolated from Indian Ayurvedic had an IC50 value of 20 ± 0.97 μg mL−1 against lung cancer cell line (A549), and cellular staining showed necrotic, apoptotic properties in damaged A549 cells.50
Additionally, a new strain of Bacillus subtilis generated an acidic EPSR4 that displayed notable antiproliferative effects on the HepG-2, A-549, and T-24 cell lines.57 He et al., 2015 examined the anti-tumor effects of an exopolysaccharide LEP-2b from Lachnum YM405 on hepatic, colon, and lung cell lines after modifying and adding sulfates and phosphates to the EPSs. They found an increase in their cytotoxic activity.58 Moreover, The EPSs from strains of P. aeruginosa were found to be cytotoxic against HT-29 cells with IC50 values at 44.8 (EPS-A) and 12.7 (EPS-B) μg mL−1, which renders them as natural and effective anticancer drugs.59
Among EPS-generating species, L. helveticus, L. acidophilus, and L. plantarum produced the most frequently associated EPS with promising anticancer potential.55 Even within the same species, EPS’s ability to inhibit proliferation varied from strain to strain.60 EPS has been reported to influence or obstruct the activity of genes involved in carcinogenesis, including p53, BCL2, and many others.61 Moreover, the antiproliferative properties of EPS may be explained by the presence of distinctive structures such as uronic acid and sulfate.62 In our explored polymer, EPSF6 contained no sulfate but uronic acid (43.8%) in contrast to our findings, (EPSR4) from the marine Bacillus subtilis isolated from the Red Sea and found it sulfated (48.2%) and had no uronic acid.57 However, as mentioned earlier, the chemical composition of EPS varies from one habitat to another and from species to another, and even within the same species.4
Moving to investigate the anti-inflammatory influence of EPSF6 by evaluating its inhibitory impact on 5-LOX and COX-2. Following our findings, EPSR3 isolated from marine Bacillus cereus had Lipoxygenase (LOX) inhibitory more potent than the control Ibuprofen and the COX-2 inhibitory compared to Celecoxib.13 Also, The anti-inflammatory effectiveness of EPS fractions produced by polluted soil bacteria has been studied by Gangalla and colleagues. Compared to the indomethacin drug, it had significant anti-inflammatory effects (65 ± 0.14, 61 ± 0.15 μg mL−1).63
Microbial metabolites cause activated macrophages to produce pro-inflammatory cytokines TNF-, IL-1, IL-6, and IL10, as well as other cytokines and transcription factors connected to them.64 For example, TNF-α and interleukins 12, 15, and 18 were observed to be downregulated by peptides extracted from Yersinia pestis.65 Its structure and cyclooxygenase inhibition effect is thought to be responsible for this anti-inflammatory property.31 Also, it was reported that a lipopeptide produced by Bacillus liceniformis VS16 increased IL-10 and TGF and decreased TNF-α and IL Iβ.66 Further, EPSF6 was tested by MTP plate assay antimicrobial and antibiofilm agent against two G +ve, two G −ve bacteria, C. albicans ATCC 10231 and A. niger NRRLA-326, but neither activity was significantly considered (Tables 1 and 2).
The AChE enzyme is highly found in the brain, nerve cells, and RBCs, and it is involved in hydrolyzing the acetylcholine ester.67 In some neurological illnesses, the activity of the acetylcholinesterase (AChE) enzyme and other cholinergic system enzymes is decreased. The amyloid deposition has been linked to the etiology of Alzheimer’s disease and CNS neuronal impairment. Where the metabolism of beta-amyloid precursor has been attributed to cholinergic hyperactivity,68 given its effects on beta-amyloid metabolism, there is a potential for AChE inhibitors to be used as a clinical neuroprotective therapy for neurological disorders like senile dementia, ataxia, myasthenia gravis, and Alzheimer’s disease.69–71
By preventing Ach hydrolysis, altering the AChE activity may help to restore the cholinergic balance, slow the progression of Alzheimer’s disease, and improve cognition. Finding new AChE inhibitors for therapeutic use remains challenging and complex, though, due to problems with gastrointestinal function absorption and bioavailability.72
Interestingly, secondary metabolites produced by marine fungi are now found to have neuroprotective properties.73 Additionally, research using animal models revealed that COX-2’s inhibitory action lowers inflammation, which is essential for the progression of the neurodegeneration associated with Alzheimer’s disease.74 Consequently, several studies have highlighted the potential therapeutic use of non-steroidal COX-2 inhibitors to delay the advancement of Alzheimer’s disease.75 Therefore, for such purpose and as another step forward to in vitro test EPSF6 anti-AChE activity. EPSF6 was tested at different concentrations (100–1000 μg mL−1) with IC50 = 439.05 (Fig. 10) compared to IC50 Eserine control = 0.09 (μg mL−1) (Table S7†).
Accordingly, EPSR4, a compound from the bacteria Bacillus subtilis, exhibited a dose-dependent and moderate restraining effect towards AChE action when its IC50 was compared to Eserine’s of 0.09 μg mL−1, which had an IC50 of 786.38 μg mL−1.57 Also, EPSR5 from marine Kocuria sp. yielded IC50 = 797.02 compared to Eserine’s IC50 = 0.09 μg mL−1.12 Furthermore, Gangalla et al., 2021 reported the anti-Alzheimer effect of a polysaccharide derived from Bacillus amyloliquefaciens RK3 in mice which can be a potential basis for the treatment of many diseases which are characterized by a deficiency in acetylcholine, such as Alzheimer and myasthenia gravis.76 Streptomyces lateritius, or Streptomyces sp. UTMC 1334 produces pyrroles and other AChE inhibitors.77
It is important to mention that the Astrocytes protect the nervous system against oxidative damage driven by the generation of ROS. Myxobacterial extracts protect human primary astrocytes from oxidative stress.78 Myxobacterial extracts from Archangium sp. UTMC 4070 and Cystobacter sp. UTMC 4073 pretreatments with astrocytes increased brain glutathione, an antioxidant protein complex.79 To this end, and because of its specific anti-cyclooxygenase properties, capacity to inhibit acetylcholine esterase, and antioxidant properties, EPSF6 extracted from Bacillus velezensis strain AG6 from the Red Sea sediments could be a promising natural heteropolysaccharide for treating or preventing Alzheimer’s disease.
There have been fewer investigations on marine microorganisms' EPS production and recovery but more on its industrial uses. The scarcity of EPSs is due to the limited amount obtained during extraction. A more efficient method for obtaining EPSs, particularly for their synthesis, is needed to increase the availability of EPSs.
Due to the growing demand for EPSs due to their biocompatibility, biodegradability, and non-toxicity, researchers are mixing them with other natural and synthetic polymers to create novel EPSs with new applications in many sectors.80 More research is required to ascertain the precise chemical composition and the molecular formula of EPSF6, as well as to determine its biocompatibility in vivo, its mode of action, and whether it can alter the composition of the gut microbiome and finally modify them by adding sulfates or phosphate groups to yield derivatives which are more potent and more selective is highly recommended.
Footnote |
† Electronic supplementary information (ESI) available. See DOI: https://doi.org/10.1039/d3ra04009g |
This journal is © The Royal Society of Chemistry 2023 |