Antibacterial and antioxidant activities of endophytic fungi and nettle (Urtica dioica L.) leaves as their host.

Nettle (Urtica dioica L), as a plant rich in biologically active compounds, is one of the most important plants used in herbal medicine. Studies have shown that this plant has antioxidant, antiplatelet, hypoglycemic and hypocholesterolemia effects. In this study, we characterized three Alternaria endophytic fungi isolated from their host U. dioica. We hypothesized that these endophytic fungi can produce new bioactive metabolites, which may possess the bioactive property with potential application in the medical and pharmaceutical industries. The antibacterial activity was evaluated against reference and isolated strains, including Methicillin-Resistant Staphylococcus aureus. A wide range of antimicrobial activities similar to those measured in nettle leaves was detected especially for Alternaria sorghi. Furthermore, the highest antioxidant activity detected with DPPH free radical scavenging was measured for A. sorghi and nettle leaves ethyl acetate extracts. In addition, whereas catalase activity was similar in the three isolated fungi and nettle leaves, total thiol content and superoxide dismutase activity were significantly higher in leaves. A. sorghi showed the best activities compared to other isolated fungi. The characterization and further production of bioactive compounds produced by this endophyte should be investigated to fight bacteria and especially those that develop drug multi-resistance.

Hazelnut Shells as Source of Active Ingredients: Extracts Preparation and Characterization.

Hazelnut shells represent a waste material (about 42% of the total biomass) deriving from hazelnut harvest. These are mainly used as a heating source; however, they represent an interesting source of polyphenols useful in health field. The impact on phenolic profile and concentrations of hazelnut shell extracts obtained by three extraction methods (maceration, ultrasonic bath, and high-power ultrasonic), as well as temperature, extraction time, and preventive maceration, was studied. The prepared extracts were characterized in terms of chemical composition, antioxidant and antimicrobial activities. Eighteen different phenolic compounds were identified and quantified by chemical analysis and gallic acid was the most abundant in all the extracts analyzed. Other relevant compounds were chlorogenic acid, protocatechuic acid and catechin. Preventive maceration had a positive effect on the extraction of different types of compounds regardless of the method performed. Application of the high-power ultrasonic method had different effects, either positive or negative, depending on the type of compound and extraction time. All the prepared extracts showed antioxidant activity especially those prepared by maceration, and many of them were able to inhibit the growth of both B. subtilis and B. cereus.

Talinum paniculatum (Jacq.) Gaertn. leaves - source of nutrients, antioxidant and antibacterial potentials.

BACKGROUND: The diet of most of the population is limited to a reduced number of plants, even in areas that have a varied and extensive diversity, such as Brazil. Unconventional Food Plants (UFPs) are plants considered exotic, native, and wild that grow naturally and can be used as food. Among these is Talinum paniculatum (Jacq.) Gaertn., which is widespread throughout Brazil and can be a potential source of nutrients. Due to the potential of utilization of UFPs in human food and the lack of studies regarding the composition of T. paniculatum, this study aimed to assess the nutritional value of T. paniculatum leaves, their antioxidant capacity, and their antimicrobial activity for possible use in food. METHODS: The characterization of the leaves of T. paniculatum was carried out through analyses of proximal composition, color, ascorbic acid, mineral profile, and antinutritional factors showing the presence of condensed and hydrolysable tannins and nitrates in low concentrations. Solvents of water, ethanol, ethanol/water, methanol, methanol/water, methanol/acetic acid and acetone/water/acetic acid were used to evaluate the extraction yield of phenolic compounds, antioxidant capacity, and antibacterial activity of the extracts. RESULTS: High contents of protein (18.61 g 100 g-1), insoluble dietary fiber (34.75 g 100 g-1), ascorbic acid (81.03 mg 100 g-1), magnesium, potassium, and calcium (649.600, 411.520 and 228.117 mg 100 g-1, respectively) were observed. Extraction using the mixture of solvents of methanol/acetic acid showed the highest yield of phenolic compounds (432.73 mg EAG 100 g-1) and antioxidant capacity using the DPPH assay (3144.92 mg 100 g-1). Bacillus cereus growth was inhibited by the T. paniculatum extracts. CONCLUSIONS: T. paniculatum leaves are a source of nutrients and their extracts have antioxidant and antibacterial potentials which can be used as supplements in food to improve one's health.

Characterization of the antibacterial activity from ethanolic extracts of the botanical, Larrea tridentata.

BACKGROUND: ß-lactam antibiotics are a class of broad-spectrum antibiotics consisting of all antibiotic agents that contain a ß-lactam ring in their molecular structures. ß-lactam antibiotics are only known to be isolated from fungi (e.g. Acremonium chrysogenum, Penicillium chrysogenum and Aspergillus nidulans) and bacteria (e.g. Streptomyces clavuligerus). We have shown that botanical extracts prepared from Larrea tridentata have strong antimicrobial activity against several bacteria, including members of Staphylococcus and Streptococcus genera. METHODS: Through resistance studies, inhibitor assays, and ELISA testing, we demonstrated L. tridentata extracts may contain a ß-lactam type antibiotic activity. RESULTS: Based on the estimated ß-lactam concentration within the extract, the antimicrobial activity of the L. tridentata extract was approximately 2000-8000-fold greater against Staphylococcus as compared to other ß-lactams, penicillin or ampicillin. In the L. tridentata extract, this increased activity was found to be associated with the likely presence of a cofactor leading to increased potentiation of the ß-lactam activity. This potentiation activity was also observed to enhance the activity of exogenously added natural penicillin antibiotics. CONCLUSIONS: Although constituents were not isolated in this study, the results obtained strongly support the presence of ß-lactam type antibiotic activity and antibiotic potentiation activity present in ethanolic extracts prepared from L. tridentata.

Antibacterial activity and mechanism of action of trigonostemone against Staphylococcus aureus and Bacillus cereus.

In our present study, the hexane fraction from the root of the Thai medicinal plant Strophioblachia fimbricalyx Boerl. was purified and the purification led to the isolation of 3-acetylaleuritolic acid, trigonostemone and 3,6,9-trimethoxyphenanthropolone. The aims of this work are to evaluate antibacterial activity of these three isolated compounds from our local plant and to study their mechanism of actions toward target pathogenic bacteria (Gram positive and Gram negative bacteria). The antibacterial activity of isolated compounds was primary screened by agar well diffusion method and the active compound was subjected to determine for MIC and MBC values by microdilution method. The kinetic study of the bacteriostatic or bactericidal activity time-kill experiment (24 h) and mechanism of action on cell morphology toward target bacteria detected by scanning electron microscope of the active compound were further evaluated. Results indicate that among the tested three compounds, trigonostemone was the only active one. It exhibited an inhibitory effect on the growth of Gram positive bacteria , methicillin-susceptible Staphylococcus aureus (MSSA) DMST 2933, methicillin-resistant S. aureus (MRSA) DMST 20651 and Bacillus cereus ATCC 11778 with the MIC/MBC values of 12.5/25.0, 6.25/6.25 and 6.25/6.25 mg/mL, respectively . Trigonostemone possessed time- and concentration-dependent bacteriostatic activity against S. aureus (MSSA) DMST 2933 and bactericidal activity against B. cereus ATCC 11778. It caused bacteriostatic activity against S. aureus (MSSA) DMST 2933 at the concentration of 2 × MIC by changing cell morphology and bactericidal activity against B. cereus ATCC 11778 at the concentration of 2 × MIC after 4 h by inducing cell size variations at the concentrations of 2 × MIC, respectively. This finding suggests that trigonostemone isolated from the root of S. fimbricalyx has a potential to be used as natural antibacterial compound against S. aureus (MSSA) DMST 2933 and B. cereus ATCC 11778 bacterial strains.

Zinc oxide nanoparticles inhibit bacterial biofilm formation via altering cell membrane permeability.

In the current scenario nanoparticles (NPs) have gained a breathtaking impetus due to their multidimensional applications in varied fields. In the present effort, biogenic synthesis of Zinc Oxide nanoparticles (ZnO NPs) was carried out using aqueous extract of dried powder of Emblica officinalis (Amla). Physicochemical characterization of nanoparticles was carried out via UV-Visible (UV-Vis) spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffractometer (XRD), Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) wherein the particles were found to be quasi spherical and with a size ranging between 3 and 11 nm. The ZnO nanoparticles exhibited significant antibacterial activity against bacteria as Streptococcus pyogenes MTCC 442, Bacillus cereus MTCC 1272, Escherichia coli MTCC 1687 and Pseudomonas aeruginosa MTCC 4673. The nanoparticles displayed high anti-biofilm activity toward all the bacterial strains, when tested against three different base materials viz. glass, plastic and metal (Aluminum). Further, the nanoparticle treatment of bacterial cells caused changes in their cell membrane permeability, leading to leakage of nucleic acid from the bacterial cells, thereby defining it as the most probable mechanism for their anti-biofilm potential.

Chromone derivatives, R- and S- taeniolin, from the marine-derived fungus Taeniolella sp. BCC31839.

Two unknown enantiomeric compounds, named (R)- and (S)-taeniolin, along with six known compounds, were isolated from the marine-associated fungus Taeniolella sp. BCC31839. Chemical structures were determined by NMR spectroscopic techniques, and the absolute configurations were confirmed by Mosher application together with CD spectral analyses. Both were inactive for antimicrobial activity against multidrug-resistant malaria parasite (Plasmodium falciparum) and bacteria (Mycobacerium tuberculosis and Bacillus cereus) at maximum tested concentration.

Disruption of microbial cell morphology by Buxus macowanii.

BACKGROUND: Microbial infections are one of the major causes of death globally. This is attributed to the rising costs of primary healthcare and its inaccessibility especially in developing countries. Moreover, there has been an increase in microbial strains that have reduced susceptibility to antimicrobial drugs. Research on the antimicrobial properties of medicinal plants, which could address these problems, has become more important as they present fewer side effects when compared to the antibiotics currently in use. This study evaluated the antimicrobial properties of a methanolic extract from Buxus macowanii in order to assess its potential in the development of novel antimicrobial drugs. METHODS: Antimicrobial activity of the extract was evaluated using the broth microdilution method. The effects of B. macowanii on the morphology of B. cereus were observed using Scanning and Transmission electron microscopy. Chemical profiling of the plant extract was performed using the GCMS. RESULTS: The extract showed antimicrobial activity against all the microbial species used. Microscopic examination of the cells of B. cereus cells treated with Buxus macowanii showed some changes in morphology such as damage of the cell wall, swelling of the cells and incomplete cell division that eventually resulted in cell death. Neophytadiene, an antimicrobial compound was detected in the extract using GCMS. CONCLUSION: The morphological disruptions of the cell wall of Bacillus cereus explain the antimicrobial properties of B. macowanii and indicate its possible application in the development of natural antimicrobial drugs.

Effects of mung bean starch/guar gum-based edible emulsion coatings on the staling and safety of rice cakes.

Antimicrobial starch/gum-based edible emulsion coatings were developed to improve the storage stability of rice cakes by retarding starch retrogradation and inhibiting microbial growth. Rice cakes were coated with mung bean starch (MBS) and guar gum (GG) containing various concentrations of sunflower seed oil (SO). Among these, the (2 g MBS +0.75 g GG +1.5 g SO) / 100 g (optimum) decreased the hardness of rice cakes by 29 % and the crystallization rate (k) by 24 % compared with those of uncoated samples. The moisture loss in uncoated samples was markedly higher than that in the optimum blend-coated samples. Crystallinity analysis revealed the retarding effect of the developed coatings in starch retrogradation. Furthermore, adding 0.8 % (w/w) grapefruit seed extract to the optimum blend led to a distinct antimicrobial activity. Therefore, the newly developed edible coating was effective in maintaining the quality and safety of rice cakes.

Artocarpus altilis extracts as a food-borne pathogen and oxidation inhibitors: RSM, COSMO RS, and molecular docking approaches.

Lipid oxidation and microbial contamination are the major factors contributing to food deterioration. Food additives like antioxidants and antibacterials can prevent food spoilage by delaying oxidation and preventing the growth of bacteria. Artocarpus altilis leaves exhibited biological properties that suggested its use as a new source of natural antioxidant and antimicrobial. Supercritical fluid extraction (SFE) was used to optimize the extraction of bioactive compounds from the leaves using response surface methodology (yield and antioxidant activity). The optimum SFE conditions were 50.5 °C temperature, 3784 psi pressure and 52 min extraction time. Verification test results (Tukey's test) showed that no significant difference between the expected and experimental DPPH activity and yield value (99%) were found. Gas-chromatography -mass spectrometry (GC-MS) analysis revealed three major bioactive compounds existed in A. altilis extract. The extract demonstrated antioxidant and antibacterial properties with 2,3-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity, ferric reducing ability of plasma (FRAP), hydroxyl radical scavenging activity, tyrosinase mushrrom inhibition of 41.5%, 8.15 ± 1.31 (µg of ascorbic acid equivalents), 32%, 37% and inhibition zone diameter of 0.766 ± 0.06 cm (B. cereus) and 1.27 ± 0.12 cm (E. coli). Conductor like screening model for real solvents (COSMO RS) was performed to explain the extraction mechanism of the major bioactive compounds during SFE. Molecular electrostatic potential (MEP) shows the probability site of nucleophilic and electrophilic attack during bacterial inhibition. Based on molecular docking study, non-covalent interactions are the main interaction occurring between the major bioactive compounds and bacteria (antibacterial inhibition).

Alkaloids from the nearly ripe fruits of Evodia rutaecarpa and their bioactivities.

Two novel quinolone alkaloids (1 and 2) and two novel indole alkaloids (5 and 8), together with eleven known analogues, were isolated from the nearly ripe fruits of Evodia rutaecarpa. Their structures were determined by extensive spectroscopic data, including NMR, HRESIMS, and ECD. Additionally, the anti-tumor, hypoglycemic, and anti-bacterial activities of the isolated alkaloids were evaluated in vitro. Compound 5 as a new alkaloid displayed moderate inhibitory effect against four human cancer cell lines (MCF-7 IC50 = 30.7 µM, Hepg-2 IC50 = 65.2 µM, A549 IC50 = 39.1 µM, and SHSY-5Y IC50 = 24.7 µM), α-glucosidase (IC50 = 23.9 µM) and PTP1B (IC50 = 75.8 µM). Compound 11 showed better inhibitory effect against PTP1B (IC50 = 16.2 µM) compared with that of the positive control. Compounds 5, 13, and 14 showed moderate inhibitory effects against Bacillus cereus with MIC values of 50, 25, and 10 µM, respectively.

Assessment of Agaricus Bisporus S-II Extract as a Bio-Controlling Agent against Human Pathogenic Bacterial Species.

Agaricus bisporus mushrooms are well known for their nutritional and medicinal values. A. bisporus is a source of protein (about 40% on a dry basis), ergosterol, several minerals, carbohydrate, and fat. The present study was conducted to investigate the effect of A. bisporus S-II extracts on human pathogenic bacteria in-vitro condition. Totally, three human pathogenic bacterial strains (MTCC culture type) were procured from the Institute of Microbial Technology, India. Out of these three bacterial strains, one was Gram-negative (namely P. aeruginosa MTCC741), and the other two were Gram-positive (B. cereus MTCC9786 and S. aureus MTCC740). Microdilution assay was applied for the evaluation of the minimum inhibitory concentration (MIC). The highest antimicrobial activity was observed in methanol extract (26.5%) against S. aureus MTCC740, compared to ethanol extract (17%). Similar results were obtained for P. aeruginosa MTCC741 (21.8%) and B. cereus MTCC9786 (15%) in methanol extract. Least microbial growth inhibition observed for B. cereus MTCC9786 (13.82%) followed by P. aeruginosa MTCC741 (14%), compared to control in ethanol extract. The highest antimicrobial activity up to 17% with ethanolic extracts recorded against S. aureus MTCC740. The MIC results in microtitre plates showed the growth inhibition of P. aeruginosa MTCC741 and S. aureus MTCC740 at extract concentrations of 15 mg/ml and 20 mg/ml, respectively. However, no MIC detected for B. cereus MTCC9786 below 20 mg/ml extract concentration. Regarding minimum bactericidal concentration, the bactericidal value for P. aeruginosa MTCC741 and S. aureus MTCC740 was obtained at 10 mg/ml concentration. The present study indicated that the extracts of the A. bisporus S-II mushrooms had promising antimicrobial activities against the tested organisms.

Saccharin Supplementation Inhibits Bacterial Growth and Reduces Experimental Colitis in Mice.

Non-caloric artificial sweeteners are frequently discussed as components of the "Western diet", negatively modulating intestinal homeostasis. Since the artificial sweetener saccharin is known to depict bacteriostatic and microbiome-modulating properties, we hypothesized oral saccharin intake to influence intestinal inflammation and aimed at delineating its effect on acute and chronic colitis activity in mice. In vitro, different bacterial strains were grown in the presence or absence of saccharin. Mice were supplemented with saccharin before or after induction of acute or chronic colitis using dextran sodium sulfate (DSS) and the extent of colitis was assessed. Ex vivo, intestinal inflammation, fecal bacterial load and composition were studied by immunohistochemistry analyses, quantitative PCR, 16 S RNA PCR or next generation sequencing in samples collected from analyzed mice. In vitro, saccharin inhibited bacterial growth in a species-dependent manner. In vivo, oral saccharin intake reduced fecal bacterial load and altered microbiome composition, while the intestinal barrier was not obviously affected. Of note, DSS-induced colitis activity was significantly improved in mice after therapeutic or prophylactic treatment with saccharin. Together, this study demonstrates that oral saccharin intake decreases intestinal bacteria count and hence encompasses the capacity to reduce acute and chronic colitis activity in mice.

Microbial radiosensitization using combined treatments of essential oils and irradiation- part B: Comparison between gamma-ray and X-ray at different dose rates.

Stored rice and rice products are prone to contamination by pathogenic fungi and bacteria such as Aspergillus niger, Bacillus cereus, and Paenibacillus amylolyticus. Treatment with antimicrobial essential oils (EOs) and irradiation are options to control spoilage organisms. Microbial samples with or without fumigation with an oregano/thyme EO mixture were irradiated at 0.5, 0.75, 1.0, 1.5, 2.0, 2.5, 3.0 and 3.5 kGy for calculation of a D10 value. The relative sensitivity was calculated as the ratio of D10 values for the irradiation plus oregano and thyme EO combination and irradiation alone treatments. In all cases, irradiation plus fumigation with the oregano and thyme EO mixture showed increased efficacy compared with irradiation alone. The relative sensitivity of γ-ray irradiation against A. niger was 1.22, 1.33, and 1.24 for radiation dose rates of 10.445, 4.558, and 0.085 kGy/h, respectively, however against B. cereus it was 1.28, 1.45, and 1.49, and against P. amylolyticus it was 1.35, 1.33, and 1.38, for respective γ-ray irradiation dose rates. The relative sensitivity of X-ray irradiation against A. niger, B. cereus, and P. amylolyticus was 1.63, 1.21, and 1.31, respectively, at the X-ray dose rate of 0.76 kGy/h. The results showed that the relative sensitivity of γ-ray irradiation was higher against the two bacteria than the fungus, whereas X-ray showed higher sensitivity against the fungus than the two bacteria. There was no consistent positive or negative relationship between dose rate and relative sensitivity. The results demonstrated the potential of an oregano and thyme EOs mixture as an antimicrobial agent and its efficacy to increase the radiosensitization of A. niger, B. cereus, and P. amylolyticus during γ-ray or X-ray irradiation treatments.

Antibacterial Activity and Mode of Action of ß-caryophyllene on Bacillus cereus.

Natural products such as essential oils (EOs) are secondary metabolites that can be obtained from either plant or animal sources or produced by microorganisms. Much attention has been given to exploring the use of secondary metabolites as natural antibacterial agents. This study investigates the antibacterial activity and mechanism of ß-caryophyllene, a compound that can be found in various EOs, against Bacillus cereus. The minimum inhibitory concentration of ß-caryophyllene against B. cereus was 2.5% (v/v), whereas killing kinetics of ß-caryophyllene at minimum inhibitory concentration recorded complete bactericidal activity within 2 hours. Zeta-potential measurement in the cells treated with half the minimum inhibitory concentration of ß-caryophyllene at 1.25% (v/v) showed an increase in the membrane permeability surface charge to -3.98 mV, compared to untreated cells (-5.46 mV). Intracellular contents leakage of UV-absorbing materials was detected in the cells treated with ß-caryophyllene. Additionally, ß-caryophyllene does not interfere with the efflux activity of B. cereus via the ethidium bromide influx/efflux activity. The results revealed that ß-caryophyllene was able to alter membrane permeability and integrity of B. cereus, leading to membrane damage and intracellular content leakage, which eventually caused cell death.Natural products such as essential oils (EOs) are secondary metabolites that can be obtained from either plant or animal sources or produced by microorganisms. Much attention has been given to exploring the use of secondary metabolites as natural antibacterial agents. This study investigates the antibacterial activity and mechanism of ß-caryophyllene, a compound that can be found in various EOs, against Bacillus cereus. The minimum inhibitory concentration of ß-caryophyllene against B. cereus was 2.5% (v/v), whereas killing kinetics of ß-caryophyllene at minimum inhibitory concentration recorded complete bactericidal activity within 2 hours. Zeta-potential measurement in the cells treated with half the minimum inhibitory concentration of ß-caryophyllene at 1.25% (v/v) showed an increase in the membrane permeability surface charge to ­3.98 mV, compared to untreated cells (­5.46 mV). Intracellular contents leakage of UV-absorbing materials was detected in the cells treated with ß-caryophyllene. Additionally, ß-caryophyllene does not interfere with the efflux activity of B. cereus via the ethidium bromide influx/efflux activity. The results revealed that ß-caryophyllene was able to alter membrane permeability and integrity of B. cereus, leading to membrane damage and intracellular content leakage, which eventually caused cell death.

Potential synergistic antimicrobial efficiency of binary combinations of essential oils against Bacillus cereus and Paenibacillus amylolyticus-Part A.

The checkerboard method was used to study the potential interactions between eight essential oils (Basil, Cinnamon, Eucalyptus, Mandarin, Oregano, Peppermint, Tea tree, and Thyme) when used as antibacterial agents against Bacillus cereus LSPQ 2872 and Paenibacillus amylolyticus ATCC 9995. The minimum inhibitory concentration (MIC) of each essential oil (EO) and the fractional inhibitory concentration (FIC) index for the binary combinations of essential oils (EOs) were determined. According to FIC index values, some of the compound binary combinations showed an additive effect; however, Thyme/Tea tree and Cinnamon/Thyme EOs exhibited a synergistic effect against P. amylolyticus and B. cereus, respectively. Cinnamon/Thyme EOs mixture exhibited no interactive effect against P. amylolyticus, but a synergistic effect against B. cereus. The combination of Oregano/Thyme EOs displayed the best antibacterial activity and showed a synergistic effect against B. cereus and P. amylolyticus bacteria. The Oregano/Thyme EOs mixture has potential application in food preservation to reduce the contamination of B. cereus and P. amylolyticus.

Smart film based on chitosan/Melissa officinalis essences/ pomegranate peel extract to detect cream cheeses spoilage.

Antibacterial/biodegradable film based on Chitosan (CS)/pomegranate peel extract (PPE) and Melissa officinalis Essences (MOE) was prepared. To study the effects of PPE and MOE on the film characteristics, a central composite design (CCD) was used. The physicochemical characteristics of the film, including moisture, water vapour permeability (WVP), antioxidant activity, microbial properties, FT-IR/SEM/XRED spectrum, etc. were studied. The results showed that the addition of PPE significantly reduced the amount of moisture loss. The WVP increased with the addition of MOE and decreased with the addition of PPE. MOE and PPE increased the antioxidant activity of the films. In terms of microbial properties, the antimicrobial effect of MOE on B. cereus was greater than on E. coli. The results of SEM showed that the PPE particles were uniformly distributed in the film matrix and the MOE slightly reduced the surface compression of the film. The CS/PPE/MOE film was used for smart packaging of cream cheese and detection of cheese spoilage. It was observed that with increasing storage time and storage temperature, with regard to the change in the pH of the cream cheese, samples become acidic. The PPE contains anthocyanin pigments that are sensitive to pH changes so the film colour was changed (from blue to red) during storage. The colour change of the film was visible with the naked eye and can be used to estimate the expiry date of the cheese.

Assessment of biological activities of chitosan Schiff base tagged with medicinal plants.

A chitosan Schiff base with an aromatic aldehyde was synthesized and characterized by FTIR and NMR spectroscopies. Furthermore, the degree of substitution was calculated based on the ratios of the area of the proton of the imine (Aimine ) and the area of the peak of the proton of the pyranose ring (AH-2 ). The antimicrobial activities were determined against bacterial and fungal strains, as well as multiple drug-resistant (MDR) bacteria. The chitosan Schiff base was also tagged with medicinal plants, for example, Curcuma longa, Peganum harmala, Lepidium sativam, and cruciferous vegetables, and the biological activities determined against pathogenic bacterial and fungal strains. The chitosan Schiff base showed maximum zone of inhibition of 22 mm against Staphylococcus aureus with a minimum zone of inhibition of 15 mm against Bacillus cereus. The chitosan Schiff base was fused with C longa, isothiocyanates and a combined mixture of P harmala and L sativam that has shown activities against Escherichia coli with a zone of inhibition of 28, 24, and 30 mm, respectively. The Schiff base of chitosan fused with medicinal plants also showed significant inhibitory activities against MDR bacteria.

Xanthones from a lignicolous freshwater fungus (BCC 28210).

Four xanthones (1‒4) and a known compound, mansonone D (5), were isolated from the lignicolous freshwater fungus BCC 28210 (family, Chaetosphaeriaceae). The structures of these compounds were elucidated by extensive spectroscopic analysis. Among the isolated metabolites, compound 2 and the known mansonone D (5) displayed antimalarial activity against Plasmodium falciparum K1 with IC50 values of 7.75 and 0.55 µg/mL, respectively. Compound 4 displayed antibacterial activity against Bacillus cereus with an MIC value of 6.25 µg/mL.

Metabolic profiling of a polyphenolic-rich fraction of Coccinia grandis leaves using LC-ESI-MS/MS and in vivo validation of its antimicrobial and wound healing activities.

A polyphenolic-rich fraction (CG50) was obtained from the methanol extract of Coccinia grandis leaves by chromatographic fractionation over a Diaion column using 50% aqueous methanol. LC-ESI-MS/MS analysis of CG50 showed the presence of six flavonoids, namely quercetin-hexoside deoxyhexoside (rutin), quercetin-hexoside deoxyhexoside (quercetin-3-O-neohesperidoside), kaempferol-hexoside deoxyhexoside (kaempferol-3-O-rutinoside), kaempferol-hexoside deoxyhexoside (kaempferol-3-O-neohesperidoside), kaempferol-3-O-glucoside, and kaempferol-hexoside in addition to the presence of two secoiridoids which are oleuropein and ligstroside. CG50 hydrogel showed a pronounced inhibition of the bacterial growth in wounds infected by Bacillus cereus in rats comparable to those treated with hydrogel base only showing 85.08 and 16.50% inhibition for the bacterial growth for the CG50 hydrogel and hydrogel base, respectively. The antimicrobial activity of CG50 hydrogel was close to that of fucidin during all days of treatment. Rats treated with CG50 hydrogel showed remarkable healing ability of the wound compared to other groups and approaching that of fucidin. This was clearly manifested by the clear formation of scars with obvious reduction in the wound size together with the appearance and re-growth of hair. This was further confirmed by the histopathological study of skin tissues as well as by the evaluation of the percentages of collagen fiber deposition. CG50 hydrogel showed 18.71% collagen fiber deposition comparable to the untreated group that showed 6.84% collagen fiber deposition and approaches that of the fucidin group. It was concluded that Coccinia grandis could be used as a natural wound healing agent that further consolidated its traditional use as a wound dressing.