Antibacterial Compounds from Bacteria Isolated from Hot Springs Water in Saudi Arabia

Recently, the emergence of antimicrobial-resistant bacterial infections has been considered one of the global health crises that threaten communities. The rise and dissemination of resistance within bacterial pathogens make the effectiveness of antibiotics decline gradually over time. As a result, the search for novel antibiotics from different natural sources has increased. Some microorganisms are able to produce secondary metabolites for protection. Bacteria, for example, have the ability to yield antibiotics. One important habitat that has yet to be fully exploited for antibiotic-producing bacteria is geothermal springs. Hot springs have been used for spas as well as for treating dermatological infections. Thirty-two water samples were collected from six different hot springs in Saudi Arabia. Several biological and microbiological assays were used to assess the antibacterial activities of samples against antimicrobial-resistant- and susceptible-bacterial strains and identify the genus and species of antibiotic-producing bacteria. Moreover, chromatographic and spectroscopic techniques were utilized to isolate the active compounds, and aid structural elucidation. The cross-streak assay’s findings illustrated that there were 14 bacteria with antimicrobial activities against most of the resistant- and susceptible-bacterial strains. 16S rRNA gene sequencing demonstrated that all antibiotic-producing bacteria to be Bacillus species; Bacillus paralicheniformis (6), Bacillus licheniformis (2), Bacillus pumilus (5) and Bacillus cereus (1). Seven compounds were isolated from these bacteria: five of which were known and two compounds were novel. The outcomes of MIC assay showed that all isolated compounds had mild to moderate antibacterial activities (between 128 µg/mL and 512 µg/mL in compared to the control) against all tested strains except for one compound (cholesterol (OM2)), which had no activity. The other known compounds were phenylacetic acid (OM7), isovaleric acid (OM4), ethyl-4-ethoxybenzoate (OM5) and N-acetyltryptamine (OM1). The two new compounds were N1-(N,N-dimethylcarbamimidoyl)-N1-methylterephthalamide (OM3) that belongs to the guanidine class of antibiotics, which are commonly isolated from microbes and 3-methyl-2H,7H-pyrano[2,3-b]pyran-2,7-dione (OM6), coumarin-like structures, which are also known for their antibacterial activities. In summary, this is the first study to investigate antibiotic-producing bacteria from hot thermal springs in Saudi Arabia. Screening revealed the propensity to isolate Bacillus spp., which are known to produce antibiotics in other habitats, particularly soil and aquatic environments. New compounds of known antibacterial classes could be isolated illustrating the potential of hot thermal springs as a source of discovering antibiotics

PHYTOCHEMICAL FINGERPRINT AND BIOLOGICAL ACTIVITIES OF THREE MALAYSIAN FICUS DELTOIDEA CULTIVARS.

Background Ficus deltoidea (Moraceae), is a Malay Traditional Medicine locally known as Mas Cotek. Three varieties (angustifolia, deltoidea and kunslerii) has been indictincty used.  Aims We here aim to better understand their chemistry and bioactivities to inform future scientific and agronomic research. Methods We extracted and analyzed samples from these varieties by HPTLC and HPLC-UV. The in vitro screening looked up to the scavenging activities against both DPPH and NO radicals, inhibitory activity upon tyrosinase and cytotoxicity against human prostate cancer cells PC3, DU145 and LNCaP using the sulforhodamine B proliferation assay and the MTT mitochondrial viability assay. Results We achieved to analytically differentiate the three varieties  in term of the presence of flavonoids, establishing that vitexin, orientin and isoorientin may act as intraspecific and interorgan phytomarkers Their biological activities point out to the antioxidant value of extracts from the deltoidea and kunslerii varieties whilst the inhibition of tyrosinase is only present in the roots extract of the var. deltoidea which here we show is also endowed with cytotoxic activity against prostate cancer cells. Conclusion We suggest that the three Malaysian Ficus deltoidea botanical varieties (angustifolia, deltoidea and kunslerii) can be also considered chemovars. The least bioactive chemovar was angustifolia. The most active extract was from the roots of var. deltoidea that shows antioxidant, antimelanogenic and cytotoxic potential.  Keywords: Chemotaxonomy; Prostate Cancer; Tyrosinase; Antioxidant; Ficus

Investigation of anti-nociceptive, anti-inflammatory potential and ADMET studies of pure compounds isolated from Isodon rugosus Wall. ex Benth

The strong ethnopharmacological utilization of Isodon rugosus Wall. Ex. Benth is evident in the treatment of several types of pain and inflammation, including toothache, earache, abdominal pain, gastric pain, and generalized body pain and inflammation. Based on this background, the antinociceptive effects of the crude extract, various fractions, and essential oil have been reported previously. In this research work, we isolate and characterize pure bioactive compounds from I. rugosus and evaluate possible mechanisms using various in vivo and in vitro models. The pure compounds were analyzed for analgesic and anti-inflammatory activities through various assays. The column chromatography of the chloroform fraction of I. rugosus led to the identification of two pure compounds, i.e., 1 and 2. Compound 1 demonstrated notable inhibition (62% writhing inhibition, 72.77% COX-2 inhibition, and 76.97% 5-LOX inhibition) and anti-inflammatory potential (>50% paw edema inhibition at various intervals). The possible mechanism involved in antinociception was considered primarily, a concept that has already been elucidated through the application of naloxone (an antagonist of opioid receptors). The involvement of adrenergic receptors was investigated using a hot plate model (an adrenergic receptor antagonist). The strong ethnomedicinal analgesic background of I. rugosus, supported by previous reports and current observations, leads to the conclusion that I. rugosus is a potential source of antinociceptive and anti-inflammatory bioactive compounds. It may be concluded from the results that the isolated analgesic compounds of I. rugosus may be a possible alternative remedy for pain and inflammation management with admirable efficacy and safety profiles

Characterization and Isolation of the Major Biologically Active Metabolites Isolated from Ficus retusa and Their Synergistic Effect with Tetracycline against Certain Pathogenic-Resistant Bacteria

Globally, pathogenic microbes have reached a worrisome level of antibiotic resistance. Our work aims to identify and isolate the active components from the bioactive Ficus retusa bark extract and assess the potential synergistic activity of the most major compounds’ constituents with the antibiotic tetracycline against certain pathogenic bacterial strains. The phytochemical screening of an acetone extract of F. retusa bark using column chromatography led to the identification of 10 phenolic components. The synergistic interaction of catechin and chlorogenic acid as the most major compounds with tetracycline was evaluated by checkerboard assay followed by time-kill assay, against Bacillus cereus, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumonia, and Salmonella typhi with fraction inhibitory concentration index values (FICI) of 0.38, 0.43, 0.38, 0.38, 0.38, and 0.75 for catechin and 0.38, 0.65, 0.38, 0.63, 0.38, and 0.75 for chlorogenic acid. The combination of catechin and chlorogenic acid with tetracycline significantly enhanced antibacterial action against gram-positive and gram-negative microorganisms; therefore, catechin and chlorogenic acid combinations with tetracycline could be employed as innovative and safe antibiotics to combat microbial resistance

Synergistic Effect between Amoxicillin and Zinc Oxide Nanoparticles Reduced by Oak Gall Extract against Helicobacter pylori

Helicobacter pylori (H. pylori) is a global health threat, and the World Health Organization has included H. pylori among 12 bacterial species that require high priority future strategies for the development of new antibiotics due mainly to its high rates of resistance. Metallic nanoparticles are known for their antimicrobial properties. The FDA (Food and Drug Administration) has approved zinc oxide nanoparticles (ZnONPs) as biocompatible antimicrobials. Green synthesis of ZnONPs was performed based on Oak galls extract (OGE) and was characterized by UV, IR, DLS, TEM, and SEM measurements. In addition, LC-MS/MS was used for the identification of OGE constituents. A checkerboard assay was used to evaluate the activity of synthesized Qi-ZnONPs and OGE against H. pylori, and their synergistic effects with amoxicillin were evaluated. LC-MS/MS analyses identified 20 compounds as major gallic acid conjugates. The ZnONPs had average particle sizes of 5.5 nm (DLS) and 7.99 nm (TEM). Both OGE and Qi-ZnONPs exhibited moderate activity against H. pylori. Amoxicillin and Qi-ZnONPs combinations (1:2 and 1:4 amoxicillin:/Qi-ZnONPs) significantly decreased the MIC90 by two-fold and four-fold, respectively, and FIC values for the combinations were more significant than with OGE alone. OGE is rich in phenolics. The synergism between Qi-ZnONPs and amoxicillin can provide an alternative safe agent of low cost to combat H. Pylori infections

Phytochemicals-based β-amyloid cleaving enzyme-1 and MAO-B inhibitors for the treatment of Alzheimer’s disease: molecular simulations-based predictions

Alzheimer’s disease (AD) is among the highly prevalent neurodegenerative disorder of the aging brain and is allied with cognitive and behavioral abnormalities. Unfortunately, there is very limited drug discovery for the effective management of AD, and the clinically approved drugs have limited efficacy. Consequently, there is an immediate demand for the development of new compounds that have the ability to act as multitarget-directed ligands (MTDLs). As major pathological targets of the disease, the current study aimed to investigate lead natural bioactive compounds including apigenin, epigallocatechin-3-gallate, berberine, curcumin, genistein, luteolin, quercetin, resveratrol for their inhibitory potentials against β-amyloid cleaving enzyme-1 (BACE1) and monoamine oxidase-B (MAO-B) enzymes. The study compounds were docked against the target enzymes (MAO-B and BACE1) using MOE software and subsequent molecular dynamics simulations (MDS) studies. The molecular docking analysis revealed that these phytochemicals (MTDLs) showed good interactions with the target enzymes as compared to the reference inhibitors. Among these eight phytocompounds, the epigallocatechin-3-gallate compound was an active inhibitor against both drug targets, with the highest docking scores and good interactions with the active residues of the enzymes. Furthermore, the docking result of the active one inhibitor in complex with the target enzymes (epigallocatechin-3-gallate/BACE1, epigallocatechin-3-gallate/MAO-B, reference/BACE1 and reference/MAO-B) were further validated by MDS. According to the findings of our study, epigallocatechin-3-gallate has the potential to be a candidate for use in the treatment of neurological illnesses like AD. This compound has MTDL potential and may be exploited to create new compounds with disease-modifying features. Communicated by Ramaswamy H. Sarma</p

Human Lung Cancer (A549) Cell Line Cytotoxicity and Anti-Leishmania major Activity of Carissa macrocarpa Leaves: A Study Supported by UPLC-ESI-MS/MS Metabolites Profiling and Molecular Docking

Lung cancer and cutaneous leishmaniasis are critical diseases with a relatively higher incidence in developing countries. In this research, the activity of Carissa macrocarpa leaf hydromethanolic extract and its solvent-fractions (n-hexane, EtOAc, n-butanol, and MeOH) against the lung adenocarcinoma cell line (A549) and Leishmania major was investigated. The MeOH fraction exhibited higher cytotoxic activity (IC50 1.57 &plusmn; 0.04 &mu;g/mL) than the standard drug, etoposide (IC50 50.8 &plusmn; 3.16 &mu;g/mL). The anti-L. major results revealed strong growth inhibitory effects of the EtOAc fraction against L. major promastigotes (IC50 27.52 &plusmn; 0.7 &mu;g/mL) and axenic amastigotes (29.33 &plusmn; 4.86% growth inhibition at 100 &mu;g/mL), while the butanol fraction exerted moderate activity against promastigotes (IC50 73.17 &plusmn; 1.62), as compared with miltefosine against promastigotes (IC50 6.39 &plusmn; 0.29 &mu;g/mL) and sodium stibogluconate against axenic amastigotes (IC50 22.45 &plusmn; 2.22 &mu;g/mL). A total of 102 compounds were tentatively identified using UPLC-ESI-MS/MS analysis of the total extract and its fractions. The MeOH fraction was found to contain several flavonoids and flavan-3-ol derivatives with known cytotoxic properties, whereas the EtOAc fractions contained triterpene, hydroxycinnamoyl, sterol, and flavanol derivatives with known antileishmanial activity. Molecular docking of various polyphenolics of the MeOH fraction with HDAC6 and PDK3 enzymes demonstrates high binding affinity of the epicatechin 3-O-&beta;-D-glucopyranoside and catechin-7-O-&beta;-D-glucopyranoside toward HDAC6, and procyanidin C2, procyanidin B5 toward PDK3. These results are promising and encourage the pursuit of preclinical research using C. macrocarpa&rsquo;s MeOH fraction as anti-lung cancer and the EtOAc fraction as an anti-L. major drug candidates

Process optimization, antioxidant, antibacterial, and drug adjuvant properties of bioactive keratin microparticles derived from porcupine (Hystrix indica) quills

A structural protein called keratin is often employed in the medical industry to create medication carriers. Process improvement, antioxidant, antibacterial, and adjuvant drug studies of synthetic bioactive keratin microparticles made from lipids and keratin derived from porcupine (Hystrix indica) quills are the main objectives of this study. After coating the keratin microparticles with lipids which were obtained from the same porcupine quills, the bioactive keratin microparticles were produced. The response surface technique was applied to optimize the conditions for extraction of the keratin protein and sizing of the keratin microparticles. An infrared spectroscopy was used to analyze the chemical shifts in compositions of keratin microparticles while the optical microscopy was used to measure the size of the keratin microparticles. The results of this work revealed that a yield 27.36 to 42.25% of the keratin protein could be obtained from porcupine quills. The keratin microparticles were sized between 60.65 and 118.87 µm. Through response surface optimization, mercaptoethanol and urea were shown to be the main variables which positively affected the yield and the size of the keratin protein. The lipid stacking on the keratin microparticles’ surface was confirmed by infrared spectroscopy. The 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulphonate) assay confirmed the keratin microparticle’s antioxidant activity of 29.83%. Compared to lipid alone, the antibacterial properties of the keratin microparticles against Escherichia coli—a gram-negative—and Staphylococcus aureus—a gram-positive—bacteria enhanced by up to 55% following the coating of the microparticles with the lipids. The pharmacological action against these bacterial species was further improved by the lipid-loaded erythromycin that was carried on the surface of keratin microparticles. This work has demonstrated the design and uses of the keratin microparticles obtained from porcupine quills for clinical applications

Nutritional, Antioxidant, Antimicrobial, and Anticholinesterase Properties of <i>Phyllanthus emblica</i>: A Study Supported by Spectroscopic and Computational Investigations

Dietary fruits and vegetables play a vital role as food and drugs and are the main sources of antioxidant defences against degenerative diseases, such as brain dysfunctions, cardiovascular diseases, immune system deteriorations, and cancers, brought on by oxidative damage. Phyllanthus emblica is a significant herbal remedy used in conventional medicine to recover lost strength and power. In this research, the potential value of Phyllanthus emblica as a food and drug is researched. The total phenolic, total flavonoid, and total tannin contents as well as the nutritional value, vitamin C, vitamin E, and mineral contents of different organs of P. emblica were evaluated. The antioxidant and antimicrobial activities of extracts and fractions of different organs of P. emblica were determined. A total of eleven flavonoids, simple phenolic, tannin-related phenolic, and tannin molecules were isolated from a hydroalcoholic extract of the leaves and fruits. The structures were identified by spectroscopic data and comparison with the literature values as gallic acid (1), naringenin 7-O-(6″-O-galloyl)-β-D-glucopyranoside (2), 3,3′-di-O-methyl ellagic acid-4′-O-β-d-glucopyranoside (3), 1-O-galloyl glycerol (4), 1,6-di-O-galloyl-β-d-glucopyranoside (5), flavogallonic acid bislactone (6), corilagin (7), ethyl gallate (8), urolithin M5 (9), (E)-p-coumaroyl-1-O-β-d-glucopyranoside (10), and 1,2,4,6-tetra-O-galloyl-β-d-glucopyranoside (11). Among them, compounds 3 and 10 are first isolated from the plant. Molecular docking was performed to investigate the comparative interactions between positive controls (galantamine and donepezil) and selected compounds utilizing acetylcholinesterase (4EY7) as a target receptor. Results exhibited the potency of these compounds against the target receptor. In summary, P. emblica has a wealth of minerals, vitamins C and E, and polyphenolic phytochemicals that may work together to treat infectious disease, prevent and/or treat oxidative-damage-related illnesses including Alzheimer’s disease

In Vitro Antibacterial Activity of Green Synthesized Silver Nanoparticles Using Azadirachta indica Aqueous Leaf Extract against MDR Pathogens

Rice is the most important staple food crop feeding more than 50% of the world&rsquo;s population. Rice blast is the most devastating fungal disease, caused by Magnaporthe oryzae (M. oryzae) which is widespread in rice growing fields causing a significant reduction in the yield. The present study was initiated to evaluate the effect of green synthesized silver nanoparticles (AgNPs) on the biochemical constituents of rice plants infected with blast. AgNPs were synthesized by using Azadirachta indica leaf extract and their characterization was performed using UV-visible spectroscopy, particle size analyser (PSA), scanning electron microscope (SEM), and X-ray diffraction (XRD) which confirmed the presence of crystalline, spherical shaped silver nanoparticles with an average size of 58.9 nm. After 45 days of sowing, artificial inoculation of rice blast disease was performed. After the onset of disease symptoms, the plants were treated with AgNPs with different concentrations. Application of nanoparticles elevated the activity of antioxidative enzymes such as superoxide dismutase, catalase, peroxidase, glutathione reductase, and phenylalanine ammonia-lyase compared to control plants, and total phenol and reducing sugars were also elevated. The outcome of this study showed that an increase in all biochemical constituents was recorded for A. indica silver nanoparticles-treated plants. The highest values were recorded in 30 ppm and 50 ppm AgNPs-treated plants, which showed the highest resistance towards the pathogen. Green synthesized AgNPs can be used in future for disease control in susceptible varieties of rice. The synthesized AgNPs using A. indica leaf extract have shown promising antibacterial activity when tested against 14 multidrug-resistant (MDR) bacteria comprising Gram-negative bacteria Escherichia coli (n = 6) and Klebsiella pneumoniae (n = 7) with a good zone of inhibition diameter, tested with the disc diffusion method. Based on these findings, it appears that A. indica AgNPs have promise as an antibacterial agent effective against MDR pathogens