Antioxidant, Antibacterial, and Antibiofilm Activities of Selected Medicinal Plant Extracts with In Vivo Protection against E. coli Infection

MALAGASY AROMATIC PLANTS: ESSENTIAL OILS, ANTIOXIDANT AND ANTIMICROBIAL ACTIVITIES

Biofilms are responsible for over 60% of nosocomial infections. The focus of this study was to investigate the antioxidant, antibacterial, antibiofilm, and anti-motility activities of Gardenia volkensii, Carissa bispinosa, Peltophorum africanum, and Senna petersiana. Antioxidant activity was evaluated using free radical (DPPH) scavenging and ferric reducing power assays. Antibacterial and antibiofilm activities were evaluated using the broth micro-dilution and the crystal violet assays, respectively. Anti-motility was evaluated using anti-swarming activities, and the brine shrimp lethality assay was used for cytotoxicity. Gardenia volkensii and C. bispinosa acetone extracts had low EC50 values of 9.59 and 9.99μg ml-1on the free-radical scavenging activity, respectively. All the plant extracts demonstrated broad-spectrum antibacterial activity against Klebsiella pneumoniae, Pseudomonasa aeruginosa, Escherichia coli, Enterococcus faecalis, and Staphylococcus aureus [minimum inhibitory concentration (MIC)<0.63mg ml-1]. The initial cell adherence stage of P. aeruginosa and E. coli was the most susceptible stage where sub-MICs resulted in inhibitions>50%. Peltophorum africanum had the least cytotoxic effects. All extracts had anti-motility activity against P. aeruginosa and E. coli. This study showed that not only do the plants have strong antibacterial activity but had noteworthy inhibition (>50%) of initial cell adherence and may be suitable candidates for the treatment of nosocomial pathogens.

Background: The plant Gmelina arborea has been traditionally used in India for several medicinal purposes like anthelmintic, diuretic, antibacterial, antioxidant and antidiabetic. Aim: The present study is an attempt to explore the antibacterial, antioxidant and antidiabetic activities of different extracts of fruits of plant G. arborea using ethanol, ethyl acetate, n‑butanol and petroleum ether as solvents. Materials and Methods: A single dose (1000 μg/ml) of extract was evaluated for their antibacterial activities on human pathogens like Bacillus subtilis, Staphylococcus aureus and Pseudomonas aeruginosa. In‑vitro antioxidant activity of G. arborea fruits was determined by 1, 1‑diphenyl‑2‑picrylhydrazil (DPPH) free radical scavenging and reducing power assay. Ascorbic acid was used as standard and positive control for both the analyses. The antidiabetic activity of above extracts was evaluated in alloxan induced diabetic model of Wistar rats. Statistical Analysis: All data are verified for statistically significant by using one way ANOVA at 1% level of significance (P < 0.01). Results: Only ethanol extract showed significant antibacterial activity against all pathogens and the activities were compared with the standard drug, streptomycin. The n‑butanol extract did not show antibacterial activity against any pathogens, whereas ethyl acetate and petroleum ether extracts showed inhibitory action against P. aeruginosa. The extracts showed significant antioxidant activities in a dose dependent manner. The ethanol extract showed good antioxidant activity when compared to the other three extracts. All the extracts were able to reduce sugar level in blood. Ethanol extract was found to have good antidiabetic activity in comparison to other extracts. Conclusion: It can be concluded that the extracts of G. arborea possess antibacterial, antioxidant and antidiabetic activities. Key words: Antibacterial, DPPH and alloxan, gmelina arborea, scavenging, streptomycin, verbenaceae

Adansonia digitata and Annona muricata are traditionally used medicinal plants with reported pharmacological properties. In this study, we aimed to elucidate the phytochemical composition, antioxidant activity, and antibacterial properties of partition fractions of Adansonia digitata and Annona muricata extracts obtained using chloroform, ethyl acetate, ethanol, and aqueous solvent systems. The plant extracts were successively partitioned using chloroform, ethyl acetate, ethanol, and aqueous solvent systems. Phytochemical analysis was performed using standard methods. Antioxidant activity was evaluated using FRAP and DPPH assays. Antibacterial activity was assessed using agar well diffusion and MIC determination. Phytochemical analysis revealed the presence of alkaloids (10.2-15.6%), flavonoids (8.5-12.1%), and phenolic acids (5.6-9.2%) in all fractions. The ethyl acetate fraction of Annona muricata exhibited the highest antioxidant activity (IC50 = 20.5 &amp;mu;g/mL) in the DPPH assay, while the chloroform fraction of Adansonia digitata showed significant antioxidant activity (IC50 = 35.2 &amp;mu;g/mL) in the FRAP assay. The antibacterial evaluation demonstrated that the chloroform fraction of Adansonia digitata exhibited broad-spectrum antibacterial activity (MIC = 0.5-1.5 mg/mL) against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa, whereas the ethyl acetate fraction of Annona muricata showed potent antibacterial activity (MIC = 0.25-1.0 mg/mL) against Gram-negative bacteria. Additionally, the ethanol fraction of Adansonia digitata displayed moderate antibacterial activity (MIC = 1.0-2.5 mg/mL) against Gram-positive bacteria, and the aqueous fraction of Annona muricata exhibited weak antibacterial activity (MIC = 2.5-5.0 mg/mL) against all tested bacterial strains. Comparison of antioxidant and antibacterial activities among fractions revealed significant variations, indicating the importance of solvent selection in extracting bioactive compounds. The study validates the traditional use of Adansonia digitata and Annona muricata, highlighting their potential as natural antioxidants and antibacterial agents.

Dau Ha Chau (DHC) was produced by selecting and growing native kinds of Baccaurea ramiflora Lour. in Vietnam, where the fruit is utilized for fresh eating not only due to its distinctive sour-sweet flavor, but also because of its vitamins and minerals for the body. With the aim to enhance the value of this fruit, the peel, pulp, and seed extracts were determined antioxidant, antibacterial and antidiabetic activities. The filtrates from ethanol extract of peel and seed powders and fruit juice from squeezing pulp were evaporated at 58°C to create the extracts. The six methods of TAC, DPPH, ABTS•+, RP, FRAP, and NO• (antioxidant activities), four bacterial strains and two enzymes (associated with type 2 diabetes mellitus) were evaluated. The results showed that the extract of DHC peel exhibited the highest antioxidant activity (EC50 value from the six methods), antibacterial activity (MIC value), enzyme inhibiting activity (IC50 value), total phenolics content and total flavonoids content, at 643.81 µg/mL, 787.42 µg/mL, 651.10 µg/mL, 718.22 µg/mL, 270.38 µg/mL, 662.44 µg/mL, 16 &lt; MIC ≤ 32 mg/mL (against Propionibacterium acnes, Escherichia coli and Bacillus cereus), 32 &lt; MIC ≤ 64 mg/mL (against Staphylococcus aureus), 2780.91 µg/mL (against α-amylase), 541.24 µg/mL (against α-glucosidase), 119.43 mg GAE/g and 207.17 mg QE/g, respectively, whereas the opposite was true for extract of DHC seed. DHC pulp extract came second in all analytical methods. Pearson correlation coefficients with r value (0.63-0.99) showed a reasonably strong relationship between total phenolics and flavonoids contents, and antioxidant and enzyme inhibiting activities. This is the first report on the antioxidant, antibacterial and antidiabetic activities of DHC Ha Chau fruit extracts, which could be developed for medicinal, pharmaceutical, food preservative purposes, or industrial foods in the future.

The objectives of this study were to determine and to compare total phenolic and flavonoid contents (TPC and TFC), antioxidant, antibacterial and anti-inflammatory activities and toxicities of ethanol extracts from Curcuma mangga, Zingiber officinale and Zingiber montanum. The study was performed by determinations of 1) TPC using Folin-Ciocalteu reagent method and TFC using colorimetric method of aluminum chloride, 2) antioxidant activities using DPPH, ABTS and FRAP assay, 3) antibacterial activities through evaluation inhibition of bacterial growth, MIC and MBC against Bacillus cereus, Bacillus subtilis, Escherichia coli, and Staphylococcus aureus, 4) anti-inflammatory activity using Griess reaction to measure nitric oxide (NO) production in LPS-stimulated RAW 264.7 macrophage cells and 5) toxicities using lethality assay in brine shrimps and MTT assay in the RAW 264.7 cells. The results revealed that all the extracts possess TPC and TFC, antioxidant, antibacterial and anti-inflammatory activities which the highest TPC and TFC and strongest activities were found in the Z. montanum extract. However, the extracts showed mildly to moderately toxic to brine shrimps, consider to Artemia salina nauplii, and nontoxic to the RAW 264.7 cells. And also, the results confirm the utilization of these extracts for the treatment and/or management of diseases that related to antioxidant, antibacterial and anti-inflammatory activities.

The aim of the present study was to examine the antioxidant and antibacterial activity of 21 types of honey derived from Mount Olympus (Mt. Olympus), a region with great plant biodiversity. The antibacterial activity was examined against the growth of Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa) by the agar well diffusion assay and the determination of the minimum inhibitory concentration (MIC). The antioxidant activity was assessed by using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS•+) free radical scavenging assays. These activities were compared to Manuka honey which is used as an alternative medicine. The results revealed that all tested honey types exhibited antibacterial activity against S. aureus and P. aeruginosa. The MIC of the tested honey types against S. aureus ranged from 3.125 to 12.5% (v/v), while MIC of Manuka honey was determined to be 6.25% (v/v). The MIC values of the tested honey types against P. aeruginosa ranged from 6.25 to 12.5% (v/v) and the MIC of Manuka honey was determined at 12.5% (v/v). Moreover, the results suggested that the presence of hydrogen peroxide and proteinaceous compounds in the honey types accounted, at least in part, for the antibacterial activity. In addition, the total polyphenolic content (TPC) of the honey types seemed to contribute to the antibacterial activity against P. aeruginosa. Furthermore, some of the tested honey types exhibited potent free radical scavenging activity against DPPH and ABTS•+ radicals, which was greater than that of Manuka honey. The results indicated that not only the quantity, but also the quality of the polyphenols were responsible for the antioxidant activity. Moreover, four honey types exhibiting great antioxidant activity were converted to powder using a freeze drying method. The results indicated that following conversion to powder all honey types, apart from one, retained their antioxidant activity, although their TPC was reduced. On the whole, and at least to the best of our knowledge, the present study is the first that extensively examined the bioactivities of different types of honey derived from Mt. Olympus.

This study was aimed to examine the antibacterial and antioxidative properties of seven edible plants from Thailand to develop alternative antibiotics as feed additives. The plants include Citrus aurantifolia Swingle (Lime) fruits and its leaves, Sesbania grandiflora L. (Agati sesbania) leaves, Piper sarmentosum Roxb (Wild betal) leaves, Curcuma domestica Valeton (Turmeric) roots, Morinda citrifolia L. (Beach mulberry) leaves, Cassia siamea britt (Siamea cassia) leaves, and Cocos nucifera L. (Coconut) peels. The plants were extracted by methanol, n-hexane, chloroform, ethyl acetate, butanol and water. Antibacterial activities with minimum inhibitory concentration (MIC) were determined by agar diffusion assay against Escherichia coli, Burkholderia sp., Haemopilus somnus, Haemopilus parasuis, and Clostridium perfringens that were considered pathogenic strains in livestock infection. Methanol extracts of C. aurantifolia Swingle fruits and leaves showed the broadest spectrum of antibacterial activities except for C. perfringens. Butanol extract of S. grandiflora L. leaves showed the strongest activity against Burkholderia sp. with MIC, 135 μg/mL. P. sarmentosum Roxb leaves showed antibacterial activities against E. coli, Burkholderia sp. and H. parasuis. Ethyl acetate and water extracts from C. domesitca Valeton roots showed MIC of 306 μg/mL and 183 μg/mL, respectively against only C. perfringens. Antioxidative activity was determined by 2-diphenyl-2-picryl hydrazyl photometric assay. The methanol extracts of C. aurantifolia Swingle fruits and P. sarmentosum Roxb leaves showed the highest antioxidant activity among all the extracts with 3.46 mg/mL and 2.70 mg/mL effective concentration 50% (EC50) values, respectively. Total contents of phenolics and flavonoids were measured from the plant extracts. Methanol extracts of S. grandiflora L. and chloroform extracts of C. domestica Valeton were found to have the highest amount of total phenolics, 41.7 and 47.8 μg/mL, respectively. Flavonoid content of methanol extracts in S. grandiflora L. T was 22.5 μg/mL and the highest among plant extracts tested. These results indicated that C. aurantifolia Swingle, S. grandiflora L., P. sarmentosum Roxb, and C. domestica Valeton have antibacterial and antioxidant activities and can be used as alternative antibiotics or potential feed additives for the control of animal pathogenic bacteria.

Purpose : To investigate the in vitro antioxidant, antibacterial and anti-tumor activities of total flavonoids from Elsholtzia densa Benth of Sichuan Province, China. Methods : The total flavonoids of Elsholtzia densa Bent were extracted utilizing the ultrasonic extraction method, and purified by D101 macroporous adsorption resin. An in vitro antioxidant test, 3-(4,5dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay and iCELLigence system were used to evaluate their antioxidant, antibacterial and anti-tumor activities. Results : The results showed that the total flavonoids exhibited good scavenging ability in hydroxyl radical (•OH), DPPH free radical (DPPH•), and super oxide anion radical (O 2 - •). Antioxidant activity was higher than for control (ascorbic acid). Their antibacterial activity was good with minimum inhibitory concentration (MIC) of 2, 4 and 14 μg/mL against Escherichia coli, Staphylococcus aureus and Bacillus subtilis, respectively. Anti-proliferation data from the iCELLigence system studies showed that the total flavonoids significantly inhibited the growth of five types of cells, including a normal human hepatocytes cell line (L02), two human hepatocellular carcinoma cell line (SMMC-7721 and HepG-2), a human cervical cancer cell line (Hela) and a Baby Hamster Syrian Kidney cell line (BHK-21) (p < 0.05). AO/EB staining indicate that the total flavonoids might cause apoptosis of Hela cells. Conclusion : The results suggest that the total flavonoids from Elsholtzia densa Bent are potential natural antioxidants and antimicrobial agent, with anti-cancer properties. Keywords : Elsholtzia densa Benth., Total flavonoids, Antioxidant activity, Antibacterial activity, Antitumor activity

Essential oils (EOs) have been utilized as a growth inhibitor of microorganisms. This study was aimed to recognize the composition, antioxidative‎, antibacterial‎‎‎‎‎‎‎‎, and time-kill activities of Origanum vulgare, Zataria multiflora, Syzygium aromaticum; and Cinnamomum verum EOs against Listeria monocytogenes, Escherichia coli O157:H7, Shewanella putrefaciens and Pseudomonas fluorescens. Gas chromatography-mass spectrometry was used to determine the chemical composition of EOs. Disc diffusion, minimum inhibitory concentration, minimum bactericidal concentration, and time-kill methods were used to determine the antibacterial ‎‎activity of EOs. The antioxidative ‎ activity of EOs were determined by 2, 20-diphenyl-1-picrylhydrazyl radical scavenging and ferric reducing antioxidative ‎ power methods. All EOs exhibited antibacterial ‎‎activity, however, Z. multiflora EO was the most effective followed by O. vulgare EO. The lowest antibacterial‎‎‎‎‎ activity was observed in C. verum EO. The most sensitive among tested bacteria to Z. multiflora and O. vulgare EOs was E. coli O157:H7 and to S. aromaticum; and C. verum EOs were S. putrefaciens and P. fluorescens, respectively. Z. multiflora and O. vulgare EOs were able to kill 85.00% and 80.00% of the E. coli O157: H7 and S. putrefaciens cells in 4 hr, respectively. The highest antioxidative ‎activity was observed in Z. multiflora EO. The tested EOs showed the highest antioxidative ‎activity at a concentration of 2.00 g L-1. Ferric reducing antioxidant power value of Z. multiflora, O. vulgare, S. aromaticum and C. verum was 2.01 ± 0.03, 1.47 ± 0.04, 1.01 ± 0.03, and 0.66 ± 0.34, respectively. High concentrations of tested EOs showed a decrease in antioxidative ‎ activity.

Tamarindus indica is one of the tropical medicinal plants that has been attributed curative potential of numerous diseases by many rural dwellers. This study was designed to evaluate the antioxidant, antibacterial activities and also to determine the various chemical constituents responsible for its pharmacological activities. The methanol extract of Tamarindus indica fruit pulp was analyzed by Gas Chromatography/Mass Spectrometer to determine the volatile compounds present. The antioxidant activities were performed using DPPH and FRAP method and the antibacterial activity was tested against some common pathogens by macro broth dilution method. The GCMS analysis shows the presence of 37 compounds, out of which 14 had their peak area percentages ≥ 1% and only two compounds had no reported pharmacological activities. Most of the bioactive compounds including 5-Hydroxymethylfurfural (31.06%)-3-O-Methyl-d-glucose (16.31%), 1,6-anhydro-β-D-Glucopyranose (9.95%), 5-methyl-Furancarboxaldehyde (3.2%), Triethylenediamine (1.17%), 1-(2-furanyl)-1-Propcanone (2.18%), Methyl 2-furoate (3.14%), Levoglucosenone (3.21%), methyl ester-Hepta-2,4-dienoic acid, (8.85%), 2,3-dihydro-3,5-dihydrox-4H-Pyran-4-one (3.4%), O-α-D-glucopyranosyl-(1.fwdarw.3)-β-D-fructofuranosyl-α-D-Glucopyranoside (2.18%), n-Hexadecanoic acid (1.38%), 2-Heptanol, acetate (1.29%), 5-[(5-methyl-2-fur-2-Furancarboxaldehyde (1.08%), 3-Methyl-2-furoic acid (1.05%) and cis-Vaccenic acid (2.85%)have been reported with different activities such as antibacterial, antifungal, antitubercular, anticancer, antioxidant and other prophylactic activities. The extract demonstrated inhibitory potential against all tested pathogen. However, Plesiomonas shigellosis ATCC 15903 and Bacillus pumillus ATCC 14884 are more sensitive with the MIC of 0.22 and 0.44 mg/ml respectively. The antioxidant activity was relatively low due to the low phenolic content of the extract. This shows that there is a strong correlation between antioxidant activities and phenolic content. GC–MS analysis revealed the presence of bioactive phytoconstituents with various biological activities and this justifies the rationale behind its usage as a curative therapy by many local dwellers.

BackgroundThe Fabaceae family is the second largest family of medicinal plants, containing more than 490 species which are being used as traditional medicine. The aim of this study was to determine the antioxidant and antibacterial activity as well as the cytotoxicity of acetone leaf extracts of nine tree species from the Fabaceae family that have not been investigated well previously for possible use in animal health and production.MethodsThe antibacterial activity was determined by a serial microdilution method against three Gram-positive and three Gram-negative bacteria. Antioxidant activity was determined using free-radical scavenging assays. The safety of the extracts was ascertained using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay on Vero African green monkey kidney cells.ResultsSix of the nine acetone extracts had significant antibacterial activity against at least one of the six bacterial species with (MIC 20–80 μg/mL). The Crotalaria capensis extract had the highest activity against Salmonella typhimurium, followed by Indigofera cylindrica with MICs of 20 μg/mL and 40 μg/mL respectively. The Dalbergia nitidula extract had free radical scavenging capacity (IC50 of 9.31 ± 2.14 μg/mL) close to that of the positive control Trolox in the DPPH assay. The Xylia torreana extract also had high activity (IC50 of 14.56 ± 3.96 μg/mL) in the ABTS assay. There was a good correlation between antioxidant activity and total phenolic content (R2 values > 0.8). The extracts had weak or no toxicity to Vero cells, compared to the positive control doxorubicin with the LC50 varying from 10.70 ± 3.47 to 131.98 ± 24.87 μg/mL at the concentrations tested.ConclusionExtracts of D. nitidula, X. torreana, C. capensis and I. cylindrica had a low cytotoxicity and high antimicrobial and/or antioxidant activity. These species are therefore promising candidates for the development of useful antimicrobial/antioxidant preparations with a low cytotoxicity that may be useful in promoting animal health and productivity.

As a medicinal plant, Conyza blinii is known to contain a wealth of bioactive constituents, including flavonoids, terpenes, and triterpenoid saponins, which contribute to its anti-inflammatory and anticancer properties. Endophytic fungi, which symbiotically inhabit plant tissues, are recognized for their ability to synthesize bioactive metabolites analogous to those of their hosts. However, the potential of C. blinii-associated endophytes remains underexplored. This study aims to isolate and characterize phenols-producing endophytic fungi from C. blinii, evaluate their biological activities, and analyze their chemical components to provide new insights for drug development. During the study, 20 endophytic fungi were isolated from C. blinii. The Folin-Ciocalteu method was used to screen for strains capable of producing phenolic compounds. To assess their bioactivity, ethyl acetate extracts of different concentrations were tested for antibacterial and antioxidant activities. Antibacterial activity was evaluated using minimum inhibitory concentration (MIC) determinations, while antioxidant activity was assessed through 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical, 2,2'-Azinobis-(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical, hydroxyl radical, and superoxide anion radical scavenging assays. Additionally, liquid chromatography-mass spectrometry analysis was conducted to quantify the active components in the extracts. Among the isolated 20 endophytic fungi, four strains successfully produced phenolic compounds, with the highest total phenolic content of 77.17 ± 1.93 mg milligrams of gallic acid equivalents per gram of extract (GAE/g). All ethyl acetate extracts from the endophytic fungi exhibited good antibacterial and antioxidant properties. Notably, Fusarium circinatum demonstrated exceptional antioxidant activity, with scavenging rates for DPPH and ABTS radicals reaching 94.28 ± 0.042% and 96.60 ± 0.017%, respectively. The ethyl acetate extract of F. foetens showed remarkable antibacterial effects against Escherichia coli and Staphylococcus aureus, with MIC values as low as 0.5 mg/mL. Furthermore, liquid chromatography-mass spectrometry (LC-MS) analysis revealed that F. foetens could produce various high-value phenolic compounds, including tyrosol (626.1884 ng/mL) and homovanillic acid (369.15486 ng/mL), which hold potential pharmaceutical value. This study isolated 20 endophytic fungi from C. blinii, discovering that four strains, produced phenolic compounds with strong antioxidant and antimicrobial properties. Among them, F. circinatum exhibited the highest antioxidant activity. Additionally, the fungi produced bioactive metabolites with potential applications in health care, medicine, and agriculture. These findings highlight the potential of C. blinii endophytes for sustainable bioactive compound production.

Total phenolic contents, antibacterial and antioxidant activities of aqueous and ethanolic extracts from Thai medicinal plants were investigated in this study. The antibacterial activity was carried out using agar disc diffusion and broth dilution methods against Escherichia coli O157:H7, Propionibacterium acnes, Pseudomonas aeruginosa, Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pyogenes, and methicillin resistant S. aureus. The aqueous and ethanol extracts of Senna alata showed the most effective activity against Gram positive bacteria, with inhibition zone ranging from 10.3 to 23.0 mm. The highest activity was observed from S. alata extracts against P. acnes, with minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) values of 1.9 and 3.9 mg/ml, respectively. The antioxidant activity was evaluated using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2’– azinobis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) methods. The strongest antioxidant activities of aqueous extract of S. alata were 22.11 ± 0.324 mg gallic/g extract and 214.99 ± 17.279 mg trolox/g extract when determined by DPPH and ABTS assay, respectively. Moreover, the highest total phenolic content of 70.90 ± 1.048 mg gallic/g extract was measured from the aqueous extract of S. alata. Therefore, the biological activities of these plants observed in this study will be useful to develop the plant extracts for primary treatment of diseases as new therapeutic agents. Key words: Medicinal plants, antibacterial activity, pathogenic bacteria, antioxidant activity, total phenolic content.

Antioxidant, antibacterial, and cytotoxic activities of cimemoxin derivatives and their molecular docking studies