Background: Infectious diseases are one of the leading causes of death worldwide because of antibiotic resistance. Ageratum conyzoides is one of the antimicrobial medicinal plants that is being used to fight various multi-resistant pathogenic bacteria in Burkina Faso. Aim: The aim was to promote safe medicinal use of A. conyzoides by highlighting the anti-biofilm and anti-motility effects of its methanol extract. Setting: The study was conducted at the Université Joseph KI-ZERBO, Ouagadougou, Burkina Faso. Methods: The antibacterial activities of methanol extract were evaluated by evaluating swimming, swarming and twitching motilities performed in an agar medium. The anti-biofilm effect was conducted in microtiter plates using the crystal violet method. The antioxidant and enzyme inhibition activities were evaluated using 2,2-diphényl-1-picrylhydrazyl; 2,2’-azino-bis (3-éthylbenzothiazoline-6-sulfonic acid), Ferric Reducing Antioxidant Power and conducting lipoxygenase test. Results: From the study, 100 µg/mL and 200 µg/mL of extract presented significant inhibition of P. aeruginosa and E. coli swarming motility but did not exhibit a significant effect on P. aeruginosa swimming and E. coli twitching motilities. The extract was effective in reducing biofilm formation in a concentration-dependent manner without affecting bacterial growth. In addition, the extract showed some capabilities to inhibit lipoxygenase activity and exhibit antioxidant potential, which could contribute to the control of oxidative stress-related diseases. Conclusion: From this study the anti-biofilm and anti-motility potential of the A. conyzoides extract provided the experimental background for the further development of antibacterial drugs. Contribution: This study provided additional scientific evidence to support the use of A. conyzoides in traditional medicine against bacterial infections.

Oral infections pose a significant global health issue. This study assessed the antibacterial properties of methanol and dichloromethane extracts from Lippia multiflora flowers against Staphylococcus aureus ATCC 43300 and Streptococcus mutans ATCC 2517, two bacteria known to cause oral infections. The study measured the ability of these flower extracts to inhibit the growth and biofilm formation of S. aureus and S. mutans using micro-dilution and crystal violet methods, respectively. Additionally, we analyzed the presence of secondary metabolites in the extracts both qualitatively and quantitatively. The antioxidant properties of the extracts were evaluated using DPPH, ABTS, and FRAP methods. The results indicated that the dichloromethane extract demonstrated a more substantial bactericidal effect than the methanolic extract against S. mutans and S. aureus, with minimal bactericidal concentrations of 0.25 ± 0.02 mg/mL and 3.13 ± 0.30 mg/mL, respectively. Furthermore, the dichloromethane extract at a 100 µg/mL concentration exhibited the highest anti-biofilm activity against both S. aureus and S. mutans. Phytochemical screening revealed the presence of alkaloids, flavonoids, quinones, and tannins in both extracts. The total phenolic content was higher in the methanolic extract (49.57 ± 2.74 mg EAG/100 mg) compared to the dichloromethane extract (25.71 ± 0.39 mg EAG/100 mg). Similarly, the total flavonoid content was more significant in the methanolic extract (2.87 ± 0.049 mg EQ/100 mg) than in the dichloromethane extract (2.24 ± 0.02 mg EQ/100 mg). The methanolic extract also exhibited superior anti-DPPH and anti-ABTS activities, as well as a higher Fe (III) reduction potential than the dichloromethane extract (P < 0.05). These findings suggest that L. multiflora flowers could serve as a potential source of antimicrobial agents for combating oral infections.

Background: The emergence of the multidrug-resistant bacteria strain has become a global world crisis. This study was designed to evaluate the antibiofilm and synergistic effects of Lippia multiflora leaf extracts on the activity of cefotaxime against the methicillin-resistant Staphylococcus aureus (S. aureus). Methods: The synergistic effect of methanol and dichloromethane extracts on the bactericidal activity of cefotaxime was determined by using the antibiotic susceptibility test on agar medium. The antibiofilm activity of the extracts was measured by using the crystal violet method. The antioxidant potential of the extracts was assessed by using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and Ferric Reduction Activity Potential (FRAP) methods. The main secondary metabolites groups were analyzed by using different standard analytical tests. The total phenolics and total flavonoids were quantified spectrophotometrically. Results: The methanol extract (final concentration of 100 µg/ml) inhibited the formation of bacterial biofilm more than salicylic acid (p<0.05). All extracts combined with cefotaxime (20 µg and 200 µg) showed good synergistic bactericidal effect on S. aureus with inhibitory diameters of up to 40 mm. The methanol extract showed higher total phenolics (462.20±10.90 mg EAG/g) and total flavonoids (26.20±0.20 mg EQ/g) contents than the dichloromethane extract (96.70±1.70 mg EAG/g and 8.00±1.20 mg EQ/g). Moreover, the methanol extract showed a higher FRAP reducing power (353.6± 4.17 mmol EQ/g) than the dichloromethane extract (385.3±7.01 mmol EQ/g). Qualitative phytochemical analysis showed the presence of tannins, flavonoids, terpenes and sterols in both extracts. Conclusion: These data showed that L. multiflora leaves contain effective antibacterial phytomolecules for combating bacterial resistance.

Bacteria use different types of motilities in order to colonize and adapt to new environments. These motilities also play an important role in the formation of biofilm, allowing bacteria to develop resistance to antibiotics and host’s immune systems. The objective of this study was to evaluate the ability of essential oils of Lippia multiflora flowers to inhibit biofilm formation and motility in Pseudomonas aeruginosa PAO1. The capacity of essential oil of Lippia multiflora flowers to inhibit biofilm formation in Pseudomonas aeruginosa was evaluated spectrophotometrically by using the crystal violet method. The property of the essential oil to inhibit different types of motilities such as swimming, swarming and twitching was further evaluated by measuring the diameters of bacterial migration on liquid or semi-liquid Luria Bertani agar medium. The essential oil exhibited good anti-biofilm activity in Pseudomonas aeruginosa. At a concentration of 1%, essential oil presented a degree of biofilm inhibition similar to that of salicylic acid used as a reference (P > 0.05). In addition, the essential oil significantly inhibited swarming, twitching and swimming in Pseudomonas aeruginosa compared to the control (P < 0.001). The inhibition of biofilm formation as well as that of bacterial motility increases with the concentration of the essential oil. The essential oil of Lippia multiflora flowers possesses an anti-bacterial potential to fight against multi-resistant bacteria.

Background: Pseudomonas aeruginosa causes infections in human particularly immunocompromised patients with cystic fibrosis, severe burns and HIV, resulting in high morbidity and mortality. The pathogenic bacteria P aeruginosa produces virulence factors regulated by the mechanism called quorum sensing system. Objective: The aim of this study was to assess the anti-quorum sensing activity of Ageratum conyzoides extracts Method: Chromobacterium violaceum reporter strain CV026 was used to highlight any interference with bacterium QS and strains derived from P. aeruginosa PAO1 were used to reveal any interference with the expression of quorum sensing genes, and to assess any impact of extract on the kinetics of the production of pyocyanin, elastases and biofilm formation. Results: Hydro-methanolic extract at the sub-inhibitory concentration of 100 μg/mL reduced quorum sensing virulence factors production such as, pyocyanin, elastases, rhamnolipids and biofilm formation in P. aeruginosa PAO1 after 18 hours monitoring. Extract showed significant inhibition in HSL-mediated violacein production on C. violaceum CV026 after 48 hours monitoring. Biofilm formation was inhibited up to 32%. It affected QS gene expression in PAO1. The regulatory genes lasR / rhlR and the lasI synthases were most affected. At 8hours, hydro-methanolic extract reduced both QS gene to more than 30% (lasI/lasR and rhlI/R respectively 33.8% /30.2% and 36% /33.2%). RhlA and lasB genes have been relatively affected (13.4% and 28.9%). After 18 h, this extract reduced significantly the expression of regulatory 30 genes lasR (31%) and rhlR (39.6%) although synthases genes seemed to be less affected (lasI/21.2% and rhlI/11.6%). A limited impact was observed on the downstream genes (lasB /20.0% and rhlA /15.3%). No negative impact was observed on CV026 and PAO1 growth and cell viability. Our study also showed that A. conyzoides having ample amount of phenolics, flavonoids and triterpenoids. This phytochemical content could be one of the factors for showing anti quorum potential. Conclusion: Results indicate that hydro methanol 80 % extract from A. conyzoides could be a source of potential QS inhibition compounds.

Prosopis africana (Guill. & Perr.) Taub. (Fabaceae) is used in the herbal medicine of Burkina Faso to treat dental caries. This study aims to contribute to the valorization of the said plant by investigating the antioxidant, anti-inflammatory and antibacterial properties of aqueous leaves and stems extracts. The inhibitory activity on lipoxygenase was used to evaluate the anti-inflammatory effect of the extracts. The antioxidant activity of bots extracts of the plant was assessed using DPPH radical scavenging, ABTS+ radical cation decolorization. The anti-biofilm effect of the extracts was evaluated on Streptococcus mutans ATCC 25175, Staphylococcus aureus ATCC 43300, Pseudomonas aeruginosa PAOI and the anti-Quorum sensing effect on Chromobacterium CV026. Aqueous extracts of Prosopis africana stems show the highest content of phenolic compounds (30,04± 0,59 mgAGE/100 mg extract) while those of the leaves show the highest content of total flavonoids (3.29 ± 0.53 mgQE/100mg extract). The aqueous extract of stem bark show the strongest antioxidant activity ( IC50 = 4.58±0.07µg/ml for the ABTS) , a best Inhibitory action on activity of lipoxygenase (IC50 = 13.42 ± 1.26 μg/mL ), a highest anti-biofilm activity ( 63.6%; at the concentration of 100µg/ml) without affecting the bacterial growth. In addition, this extract has the strongest anti-quorum sensing activity with an percentage of inhibition 53,5%. These findings suggested that the aqueous extracts of stem bark and leaves of Prosopis africana contain promoted phytomolecules to combat dental caries infections. Keywords : Anti-biofilm, Anti-quorum sensing, Lipoxygenase, Prosopis africana

Aims: To investigate the ethnomedicinal uses of Prosopis africana (Guill. & Perr.) Taub and to screen the antimicrobial property as well as determine the phytochemical constituents of leaves, stems and root bark. Study Design: Ethnobotanical surveys, antibacterial activity and phytochemical screening of extracts of P. africana. Place and Duration of Study: The ethnobotanical survey was conducted during June 2015 in Zounweogo Province. The experiments were conducted at the Department of Medicine and Traditional Pharmacopeia-Pharmacy (MEPHATRA-PH) of the Institute of Research in Health and Laboratory of Applied Biochemistry and Chemistry (LA.BIO.C.A), University Joseph KI-ZERBO. Methodology: The semi-structured questionnaires were administrated to 36 traditional healers and elucidated out on the ethnomedicinal uses of P. africana in treating bacterial infections, the plant parts used and the mode of administration. The antimicrobial activity of different polar extracts of the leaves, the stem and root were evaluated by using the agar diffusion method and the determination of the minimal inhibitory concentration (MIC) of extracts via microdilution method. The phytochemical constituents of all extracts were also screened air Ciulei method. Results: The traditional healers consisted of 64% women and 36% men were surveyed. P. africana is used to treat tooth decay, childhood diarrhoea and chronic wounds. Leaves and the stem bark are the most commonly used plant part in treating bacterial infections while the roots are primarily used for other therapeutic purposes. The main method of administration was decoction. Methanol extracts of the leaves showed better antibacterial activity on all bacterial strains than aqueous extracts: Escherichia coli ATCC 25922 (MIC = 390 µg/ml; diameter of inhibition = 13.00 ±1.00 mm), Staphylococcus aureus ATCC 25923 (MIC = 390 µg/ml; diameter of inhibition = 12.33 ± 1.53 mm), Escherichia coli ATCC 35218 (MIC = 3120 µg/ml; diameter of inhibition = 13±1,00 mm), Pseudomonas aeruginosa PAO1 (MIC = 12500 µg/ml; diameter of inhibition = 12.33±0.58 mm). Alkaloid salts, tannins, sterols and triterpenes, saponosides, flavonic glycosides and leucoanthocyans were found in extracts of the leaves, as well as in the barks of the stem and root. Conclusion: These results demonstrated that P. africana is a potent source of antimicrobial compounds and could justify its traditional use of in the folklore medicine of Zounweogo Province.

Aims: This current study was designated to assess the ability of Cassia occidentalis, Crossopteryx febrifuga and Zanthoxylum zanthoxyloides traditionally used for the treatment of infectious diseases, to reduce the production of virulence factors. Place and Duration of Study: The study was conducted at the Laboratory of Applied Biochemistry and Chemistry (LABIOCA), University Ouaga 1 Pr Joseph KI-ZERBO between September 2018 to January 2019. Methodology: Methanol extracts from C. occidentalis (leaves and stem), C. febrifuga (leaves and stem) and Z. zanthoxyloides (Stem bark) were used for the investigations. The reporter strain Pseudomonas aeruginosa PAO1 was used to measure the impact of extracts on elastase and pyocyanin production. Antioxidant activity was measured through 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays. Results: All extracts at the concentration of 100 µg/mL inhibited significantly the production of pyocyanin without affect negatively the growth of P. aeruginosa PAO1 with a reduction of 39%, 52% and 28% respectively for C. occidentalis, C. febrifuga and Z. zanthoxyloides. C. febrifuga showed the highest inhibition level on the production of elastase with a rate of 48%. The results demonstrated varying level of reduction of pyocyanin and elastase production in the reporter strain. Moreover, the antioxidant polyphenols evidenced are capable to reduce the oxidative stress induced by pyocyanin. Conclusion: The antioxidant and anti-virulence properties of these medicinal plants could justify their traditional use in the treatment of infectious diseases.

The development of antibiotic resistance raises an urgent need for new treatment strategies. The purpose of this current investigation was to evaluate the free radicals scavenging ability and the anti-biofilm potent of fractions of ethanol extract from six tropical edible fruits. The capacity of extract to quench free radicals was measured spectrophotometrically by using four antioxidant models. Furthermore, the ability of fruit extract to inhibit Pseudomonas aeruginosa biofilm formation was examined by using the crystal violet assay. Ethyl acetate and methanol fractions of Parkia biglobosa, Zizipus mauritiana, Saba senegalensis and Adansonia digitata showed strong antioxidant activities through their DPPH, ATBS and nitric oxide radicals scavenge abilities as well as their inhibitory potent of deoxyribose degradation. Moreover, fractions of fruit extracts inhibited significantly the P. aeruginosa biofilm formation (up to 72% inhibition) without affect the bacterial growth. Chloroform fraction of Z. mauritiana showed the highest anti-biofilm activity (72.11 ± 0.20% inhibition). In general, chloroform and methanol fractions of fruit extract exhibited more anti-biofilm activity than hexane and ethyl acetate fractions. Tropical edible fruits are potent sources of effective antimicrobial agents. Extensive phytochemical investigation is necessary to isolate the effective antimicrobial drugs for fighting multi-resistant pathogens.