Algal biomass as a source for novel oral nano-antimicrobial agent

Slow pyrolysis of Terminalia catappa L. municipal solid waste and the use of the aqueous fraction produced for bovine mastitis control

The Terminalia catappa L. tree is an ornamental and shade tree producter of a large amount of biological waste sent to landfills. Therefore, this plant constitutes so-called municipal solid wood waste (MSWW), which causes undesirable impacts on the environment, such as the generation of methane through the action of microorganisms. Sustainable solutions for the proper use and disposal of MSWW are a topic that has assumed great relevance at present due to the high quantities of MSWW generated worldwide. Pyrolysis constitutes an attractive alternative for the sustainable use of MSWW to produce higher value-added products. This study investigated the slow pyrolysis of Terminalia catappa L. fruit and the use of the aqueous fraction produced for bovine mastitis control. We obtained four fractions from the pyrolysis process, with average yields of the aqueous phase (36.22 ± 2.0 %), bio-oil (5.52 ± 0.4 %), biochar (37.55 ± 2.8 %) and gas (20.71 ± 2.0 %). The aqueous fraction was extracted with organic solvents and analyzed by gas chromatography coupled to mass spectrometry (GC‒MS). The extracts were composed mainly of phenols (50 %), furan derivatives, cyclic ketones, and others with lower contents, such as alcohols and esters. The aqueous fraction had bactericidal activity against Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa and Escherichia coli, which are responsible for bovine mastitis. In addition, the fraction showed low cytotoxicity against a murine melanoma cell line from a C57BL/6J mouse, B16F10 cells and mouse peritoneal cells.

New insights into the anticancer effects of Polycladia crinita aqueous extract and its selenium nanoformulation against the solid Ehrlich carcinoma model in mice via VEGF, notch 1, NF-кB, cyclin D1, and caspase 3 signaling pathway

Background: Phaeophyceae species are enticing interest among researchers working in the nanotechnology discipline, because of their diverse biological activities such as anti-inflammatory, antioxidant, anti-microbial, and anti-tumor. In the present study, the anti-cancer properties of Polycladia crinita extract and green synthesized Polycladia crinita selenium nanoparticles (PCSeNPs) against breast cancer cell line (MDA-MB-231) and solid Ehrlich carcinoma (SEC) were investigated. Methods: Gas chromatography-mass spectroscopy examinations of Polycladia crinita were determined and various analytical procedures, such as SEM, TEM, EDX, and XRD, were employed to characterize the biosynthesized PCSeNPs. In vitro, the anticancer activity of free Polycladia crinita and PCSeNPs was evaluated using the viability assay against MDA-MB-231, and also cell cycle analysis by flow cytometry was determined. Furthermore, to study the possible mechanisms behind the in vivo anti-tumor action, mice bearing SEC were randomly allocated into six equal groups (n = 6). Group 1: Tumor control group, group 2: free SeNPs, group 3: 25 mg/kg Polycladia crinita, group 4: 50 mg/kg Polycladia crinita, group 5: 25 mg/kg PCSeNPs, group 6: 50 mg/kg PCSeNPs. Results: Gas chromatography-mass spectroscopy examinations of Polycladia crinita extract exposed the presence of many bioactive compounds, such as 4-Octadecenoic acid-methyl ester, Tetradecanoic acid, and n-Hexadecenoic acid. These compounds together with other compounds found, might work in concert to encourage the development of anti-tumor activities. Polycladia crinita extract and PCSeNPs were shown to inhibit cancer cell viability and early cell cycle arrest. Concentrations of 50 mg/kg of PCSeNPs showed suppression of COX-2, NF-кB, VEGF, ki-67, Notch 1, and Bcl-2 protein levels. Otherwise, showed amplification of the caspase 3, BAX, and P53 protein levels. Moreover, gene expression of caspase 3, caspase 9, Notch 1, cyclin D1, NF-кB, IL-6, and VEGF was significantly more effective with PCSeNPs than similar doses of free extract. Conclusion: The PCSeNPs mediated their promising anti-cancerous action by enhancing apoptosis and mitigating inflammation, which manifested in promoting the total survival rate and the tumor volume decrease.

Marine Microalgae Schizochytrium sp. S31: Potential Source for New Antimicrobial and Antibiofilm Agent

BACKGROUND

The rise of antibiotic-resistant bacteria necessitates the discovery of new, safe, and bioactive antimicrobial compounds. The antibacterial and antibiofilm activity of microalgae makes them a potential candidate for developing natural antibiotics to limit microbial infection in various fields.

OBJECTIVE

This study aimed to analyze the antibacterial effect of the methanolic extract of Schizochytrium sp. S31 microalgae by broth microdilution and spot plate assays.

METHODS

The antibacterial effects of Schizochytrium sp. S31 extract was studied on gramnegative pathogens, Pseudomonas aeruginosa, Escherichia coli 35218, Klebsiella pneumonia, which cause many different human infections, and the gram-positive pathogen Streptococcus mutans. At the same time, the antibiofilm activity of the Schizochytrium sp. S31 extract on Pseudomonas aeruginosa and Escherichia coli 35218 bacteria were investigated by crystal violet staining method.

RESULTS

Schizochytrium sp. S31 extract at a 60% concentration for 8 hours displayed the highest antibacterial activity against P. aeruginosa, E. coli 35218, and K. pneumonia, with a decrease of 87%, 92%, and 98% in cell viability, respectively. The experiment with Streptococcus mutans revealed a remarkable antibacterial effect at a 60% extract concentration for 24 hours, leading to a notable 93% reduction in cell viability. Furthermore, the extract exhibited a dose-dependent inhibition of biofilm formation in P. aeruginosa and E. coli 35218. The concentration of 60% extract was identified as the most effective dosage in terms of inhibition.

CONCLUSION

This research emphasizes the potential of Schizochytrium sp. S31 as a natural antibacterial and antibiofilm agent with promising applications in the pharmaceutical sectors. This is the first study to examine the antibacterial activity of Schizochytrium sp. S31 microalgae using broth microdilution, spot plate assays, and the antibiofilm activity by a crystal staining method. The findings of this study show that Schizochytrium sp. S31 has antibacterial and antibiofilm activities against critical bacterial pathogens.

New investigation of anti-inflammatory activity of Polycladia crinita and biosynthesized selenium nanoparticles: isolation and characterization

BACKGROUND

Marine macroalgae have gained interest recently, mostly due to their bioactive components. Polycladia crinita is an example of marine macroalgae from the Phaeophyceae class, also known as brown algae. They are characterized by a variety of bioactive compounds with valuable medical applications. The prevalence of such naturally active marine resources has made macroalgae-mediated manufacturing of nanoparticles an appealing strategy. In the present study, we aimed to evaluate the antioxidant and anti-inflammatory features of an aqueous extract of Polycladia crinita and biosynthesized P. crinita selenium nanoparticles (PCSeNPs) via a carrageenan-induced rat paw edema model. The synthesized PCSeNPs were fully characterized by UV-visible spectroscopy, FTIR, XRD, and EDX analyses.

RESULTS

FTIR analysis of Polycladia crinita extract showed several sharp absorption peaks at 3435.2, 1423.5, and 876.4 cm-1 which represent O-H, C=O and C=C groups. Moreover, the most frequent functional groups identified in P. crinita aqueous extract that are responsible for producing SeNPs are the -NH2-, -C=O-, and -SH- groups. The EDX spectrum analysis revealed that the high percentages of Se and O, 1.09 ± 0.13 and 36.62 ± 0.60%, respectively, confirmed the formation of SeNPs. The percentages of inhibition of the edema in pretreated groups with doses of 25 and 50 mg/kg, i.p., of PCSeNPs were 62.78% and 77.24%, respectively. Furthermore, the pretreated groups with 25, 50 mg/kg of P. crinita extract displayed a substantial decrease in the MDA levels (P < 0.00, 26.9%, and 51.68% decrease, respectively), indicating potent antioxidant effect. Additionally, the pretreated groups with PCSeNPs significantly suppressed the MDA levels (P < 0.00, 54.77%, and 65.08% decreases, respectively). The results of immune-histochemical staining revealed moderate COX-2 and Il-1β expressions with scores 2 and 1 in rats pre-treated with 25 and 50 mg/kg of free extract, respectively. Additionally, the rats pre-treated with different doses of PCSeNPs demonstrated weak COX-2 and Il-1β expressions with score 1 (25 mg/kg) and negative expression with score 0 (50 mg/kg). Both antioxidant and anti-inflammatory effects were dose-dependent.

CONCLUSIONS

These distinguishing features imply that this unique alga is a promising anti-inflammatory agent. Further studies are required to investigate its main active ingredients and possible side effects.

New Insight on the Cytoprotective/Antioxidant Pathway Keap1/Nrf2/HO-1 Modulation by Ulva intestinalis Extract and Its Selenium Nanoparticles in Rats with Carrageenan-Induced Paw Edema

Currently, there is growing interest in exploring natural bioactive compounds with anti-inflammatory potential to overcome the side effects associated with the well-known synthetic chemicals. Algae are a rich source of bioactive molecules with numerous applications in medicine. Herein, the anti-inflammatory effect of Ulva intestinalis alone or selenium nanoparticles loaded with U. intestinalis (UISeNPs), after being fully characterized analytically, was investigated by a carrageenan-induced inflammation model. The pretreated groups with free U. intestinalis extract (III and IV) and the rats pretreated with UISeNPs (groups V and VI) showed significant increases in the gene expression of Keap1, with fold increases of 1.9, 2.27, 2.4, and 3.32, respectively. Similarly, a remarkable increase in the Nrf2 gene expression, with 2.09-, 2.36-, 2.59-, and 3.7-fold increases, was shown in the same groups, respectively. Additionally, the groups III, IV, V, and VI revealed a significantly increased HO-1 gene expression with a fold increase of 1.48, 1.61, 1.87, and 2.84, respectively. Thus, both U. intestinalis extract and the UISeNPs boost the expression of the cytoprotective/antioxidant pathway Keap1/Nrf2/HO-1, with the UISeNPs having the upper hand over the free extract. In conclusion, U. intestinalis and UISeNPs have proven promising anti-inflammatory activity through mediating different underlying mechanisms.

An Evaluation of the Tensile Strength of Polyglactin Sutures After Immersion in Different Herbal Mouthwashes: An In Vitro Study

Background The process of suturing is essential to the healing of surgical wounds. Sutures on surgical wounds from fabric approximate ligament tissues, control haemorrhage, and assist the primary healing process in oral surgical procedures. The oral environment may cause the suture to lose its tensile strength, which causes tissue to open and spread infection. Different mouthwashes are recommended for effective oral hygiene maintenance postoperatively. Ideally, the use of mouthwashes should not alter the mechanical properties of suture materials. A suture material's tensile strength or ability to endure tension during knotting and long-term wound protection is measured. Aim The aim of the current study is to assess the tensile strength of polyglactin sutures following immersion in herbal mouthwashes. Methods Two commercially available synthetic braided polyglactin 910 absorbable sutures (Vicryl and Seamcryl) were chosen to assess their tensile strength following immersion in two kinds of herbal mouthwashes: nilavembu (Andrographis paniculata) silver nanoparticle mouthwash and clove-uni stevia mouthwash. The tensile strength of the sutures was evaluated using an ElectroPuls® E3000 (Instron, Norwood, MA, USA) universal testing machine. The data were transferred to IBM Statistical Package for Social Sciences (SPSS) software version 23.0 (IBM Corp., Armonk, NY, USA), wherein the tensile strength values of Vicryl and Seamcryl after immersion in two different mouthwashes compared with control were statistically analysed using a one-way analysis of variance (ANOVA) test. Results The tensile strength of Vicryl suture material was found to be higher in the clove-uni stevia mouthwash group than in the nilavembu silver nanoparticle mouthwash and control (p-value=0.000, which is statistically significant). The tensile strength of Seamcryl suture material was found to be higher in the clove-uni stevia mouthwash group than in the nilavembu silver nanoparticles mouthwash and control (p-value=0.001, which is statistically significant). Conclusion Nilavembu silver nanoparticle mouthwashes analysed in the present study decreased the tensile strength property of Vicryl suture material after immersion for 24 hours, whereas clove-uni stevia mouthwash was shown to increase the tensile strength of both Vicryl and Seamcryl suture materials. Therefore, the selection of suture material and the postoperative prescription of mouthwash should be considered for a better clinical outcome.

Ulvan as a Reducing Agent for the Green Synthesis of Silver Nanoparticles: A Novel Mouthwash

The antibacterial activity of an Ulvan-based silver nanoparticle (AgNP) system was evaluated in the current study. The green synthesis of biogenic silver nanoparticles was conducted using Ulvan, a sulphated polysaccharide extracted from Ulva lactuca. A novel mouthwash containing AgNPs was prepared, and tested for its efficacy and safety. AgNPs were confirmed with spectrophotometric analysis (UV–A visible spectrophotometer), and the characterisation was established with Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and transmission electron microscopy (TEM). The AgNPs were spherical, and their average size was 8–33 nm, as shown via TEM. The antioxidant assay was conducted via DDPH assay, wherein the AgNPs, at a concentration of 50 μL/mL, showed 93.15% inhibition. Furthermore, anticancer activity was tested by evaluating the cell viability utilising the method of an MTT assay on the 3T3-L1 cell lines. AgNPs, at 30 µL/mL, showed maximal cell viability, denoting no cytotoxic effect. The silver-nanoparticle-based mouthrinse, at a concentration of 100 µL/mL, demonstrated antimicrobial activity against Streptococcus mutans, Staphylococcus aureus, Lactobacillus, and Candida albicans. This study shows that mouthwash prepared from the Ulvan-silver nanoparticle system could be a nontoxic and effective oral antimicrobial agent.

Awareness on ill effects of tobacco usage among tobacco users

Tobacco use is reported to increase the chance of a person to get mouth, lip, and lung cancers, chronic bronchitis, cardiovascular diseases, etc. Tobacco-related deaths are reported to occur among almost six million individuals each year. The objective of the study is to assess awareness and perception on ill effects of tobacco usage among tobacco users in a dental institution. A self-administered survey form was distributed among 100 study participants. Google Forms were distributed in an online forum. The questions were related to awareness on ill effects of tobacco usage and perception regarding harmful effects of tobacco among tobacco users. Collected data were analyzed using statistical software. Among the 100 participants, 68% were males and 32% were females. 73% of the participants reported that they were aware that smoking causes lung disease. Graduated participants were more aware that reduced fertility and sexual impotence would develop among men due to tobacco use (Pearson Chi-square value - 29.380; P = 0.01). The present study suggested that even though most of the respondents had adequate knowledge about the effects of tobacco on general health, knowledge about the consequences of tobacco usage was still inadequate.

Stature estimation using the odontometric measurements of the maxilla

Stature is the height of an individual in an upright position. It is one of the key characteristics, which helps in defining any individual. Stature estimation is needed mostly in medicolegal cases where only a limited number of human fragments are left for forensic analysis. The teeth provide essential measurements that can be used to determine stature. The aim of the study is to find out whether the second maxillary interpremolar distance can be used to effectively estimate stature of individuals. For the study, the sample size taken was 60 (30 male and 30 females), and their second maxillary interpremolar distance was measured using a digital vernier caliper. The collected data were tabulated and statistical analysis was done using SPSS software (23), followed by linear regression. For male: Y = 178.65 - 1.09X, correlation coefficient, r = 0.05, For female: Y = 169.30 - 1.99X, correlation coefficient, r = 0.13. Since r < 0.2, there is no correlation between the interpremolar distance of the second maxillary premolar and the stature. From our study, we conclude that the interpremolar distance of the second maxillary premolar cannot be a reliable parameter for stature estimation in both genders.

Stature estimation using head circumference

Stature is an essential measurement in anthropometry that resolves individual representation of the body. Forensic determination is the resolution of origin, sex, and natural height. Many previous study has been done on estimation of height using various measurements of teeth and skull. The aim of this study was to estimate stature from head circumference and to derive a linear regression formula between them. The study was conducted in Saveetha Dental College among 70 1^st year students (35 males and 35 females). Stature was measured using a stadiometer and head circumference was measured using measuring tape. All the measurements were tabulated and linear regression equation was done using the SPSS software (version 23). For males, Y = 1.85x + 71.12, r = 0.487; for females, Y = 2.07x + 46.24, r = 0.433. By the study, we know that in both genders, head circumference has moderate correlation in estimating stature. From the present research, we conclude that head circumference is a moderately reliable parameter for stature estimation in both genders.

Marine-Bioinspired Nanoparticles as Potential Drugs for Multiple Biological Roles

The increased interest in nanomedicine and its applicability for a wide range of biological functions demands the search for raw materials to create nanomaterials. Recent trends have focused on the use of green chemistry to synthesize metal and metal-oxide nanoparticles. Bioactive chemicals have been found in a variety of marine organisms, including invertebrates, marine mammals, fish, algae, plankton, fungi, and bacteria. These marine-derived active chemicals have been widely used for various biological properties. Marine-derived materials, either whole extracts or pure components, are employed in the synthesis of nanoparticles due to their ease of availability, low cost of production, biocompatibility, and low cytotoxicity toward eukaryotic cells. These marine-derived nanomaterials have been employed to treat infectious diseases caused by bacteria, fungi, and viruses as well as treat non-infectious diseases, such as tumors, cancer, inflammatory responses, and diabetes, and support wound healing. Furthermore, several polymeric materials derived from the marine, such as chitosan and alginate, are exploited as nanocarriers in drug delivery. Moreover, a variety of pure bioactive compounds have been loaded onto polymeric nanocarriers and employed to treat infectious and non-infectious diseases. The current review is focused on a thorough overview of nanoparticle synthesis and its biological applications made from their entire extracts or pure chemicals derived from marine sources.

Unveiling antimicrobial activity of microalgae Chlorella sorokiniana (UKM2), Chlorella sp. (UKM8) and Scenedesmus sp. (UKM9)

Microalgae represent promising sources of bioactive compounds for pharmaceutical and industrial applications. The emergence of antibiotic resistant bacteria leads to the need to explore new cost-effective, safe, and potent bioactive compounds from the microalgae. This study aimed to investigate the potential of local microalgae for their antimicrobial properties and bioactive compounds. Three local microalgae namely Chlorella sorokiniana (UKM2), Chlorella sp. UKM8, and Scenedesmus sp. UKM9 biomass methanol extracts (ME) were prepared and tested against Gram-positive and Gram-negative bacteria. Chlorella sp. UKM8-ME showed the highest antibacterial activity. UKM8-ME minimum inhibitory concentrations were in the range of 0.312 to 6.25 mg/mL. Cytotoxicity evaluation using MTT assay showed that the microalgae methanolic extracts did not exhibit cytotoxicity against Vero-cells. The UKM8-ME was mainly containing 28 compounds from the Gas Chromatography-Mass Spectrometry (GC–MS) analysis. Major compounds of UKM8-ME included phenol (18.5%), hexadecanoic acid (18.25%), phytol (14.43%), 9,12-octadecadienoic acid (13.69%), and bicyclo[3.1.1]heptane (7.23%), which have been previously described to possess antimicrobial activity. Hence, Chlorella sp. (UKM8) methanol extracts showed promising antibacterial activity. More comprehensive studies are required to purify these antimicrobial compounds and develop our understanding on their mechanism in UKM8-ME to unleash their specific potential.

Green synthesis of selenium nanoparticles using Rosmarinus officinalis and investigated their antimicrobial activity

The interest of many has been attracted by plant-mediated synthesizing procedures for nanoparticles since they provide certain qualities including being cost-effective, quick, and compatible with the environment. In this regard, this work introduces the production of selenium-nanoparticles (Se-NPs) in a biological manner utilizing aqueous extracts of Rosmarinus officinalis (R. officinalis). Production of Se-NPs was confirmed using UV-visible (UV-Vis) spectrophotometry. Also, dynamic light scattering (DLS) analysis was used for determination particle size distribution, while we distinguished the identification of crystalline construction of nanoparticles through the means of X-ray diffraction (XRD) pattern, DLS, and transmission electron microscopy (TEM) examination indicated that Se-NPs are often spherical with a size about 20 to 40 nm. The minimum inhibitory concentration (MIC) of the synthesized Se-NPs by R. officinalis extract against Mycobacterium tuberculosis (M. tuberculosis), Staphylococcus aureus (S. aureus), Streptococcus mutans (S. mutans), Escherichia coli (E. coli), and Pseudomonas aeruginosa (P. aeruginosa) was 256, 16, 32, 128, and 64 µg/mL, respectively. The synthesized Se-NPs had no significant effect on Mycobacterium simiae (M. simiae) and had exhibited a strong antimicrobial functionality towards the gram-positive and gram-negative bacteria and can stand as a potent antibacterial agent.

Marine Macroalgae Display Bioreductant Efficacy for Fabricating Metallic Nanoparticles: Intra/Extracellular Mechanism and Potential Biomedical Applications

The application of hazardous chemicals during nanoparticle (NP) synthesis has raised alarming concerns pertaining to their biocompatibility and equally to the environmental harmlessness. In the recent decade, nanotechnological research has made a gigantic shift in order to include the natural resources to produce biogenic NPs. Within this approach, researchers have utilized marine resources such as macroalgae and microalgae, land plants, bacteria, fungi, yeast, actinomycetes, and viruses to synthesize NPs. Marine macroalgae (brown, red, and green) are rich in polysaccharides including alginates, fucose-containing sulfated polysaccharides (FCSPs), galactans, agars or carrageenans, semicrystalline cellulose, ulvans, and hemicelluloses. Phytochemicals are abundant in phenols, tannins, alkaloids, terpenoids, and vitamins. However, microorganisms have an abundance of active compounds ranging from sugar molecules, enzymes, canonical membrane proteins, reductase enzymes (NADH and NADPH), membrane proteins to many more. The prime reason for using the aforesaid entities in the metallic NPs synthesis is based on their intrinsic properties to act as bioreductants, having the capability to reduce and cap the metal ions into stabilized NPs. Several green NPs have been verified for their biocompatibility in human cells. Bioactive constituents from the above resources have been found on the green metallic NPs, which has demonstrated their efficacies as prospective antibiotics and anti-cancer agents against a range of human pathogens and cancer cells. Moreover, these NPs can be characterized for the size, shapes, functional groups, surface properties, porosity, hydrodynamic stability, and surface charge using different characterization techniques. The novelty and originality of this review is that we provide recent research compilations on green synthesis of NPs by marine macroalgae and other biological sources (plant, bacteria, fungi, actinomycetes, yeast, and virus). Besides, we elaborated on the detailed intra- and extracellular mechanisms of NPs synthesis by marine macroalgae. The application of green NPs as anti-bacterial, anti-cancer, and popular methods of NPs characterization techniques has also been critically reviewed.