Antibacterial activity of Azadirachta indica, Pongamia pinnata, Psidium guajava, and Mangifera indica and their mechanism of action against Streptococcus mutans

Abstract

Background:Curative plants have reportedly been used to make chewing sticks/toothbrushes intended for the treatment of oral diseases.Objective:The in vitro antibacterial activities of Azadirachta indica, Pongamia pinnata, Psidium guajava, and Mangifera indica were evaluated against Streptococcus mutans, along with the cytotoxicity and antioxidant and synergistic potentials. The effect of M. indica on the expression of crucial virulence genes spaP and gtfB of S. mutans was determined.Materials and Methods:The antibacterial activity was determined using a modified microdilution method. The antioxidant potential was evaluated using diphenyl picrylhydrazyl (DPPH), Griess reagent, and nitroblue tetrazolium calorimetric assays. The synergistic activity was investigated using a modified checkerboard method, while the cytotoxicity was determined according to a cell proliferation 2,3-Bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide salt assay. Reverse transcription was the chosen method for determining the difference in expression of the spaP and gtfB genes after treatment with the plant sample.Results:M. indica and A. indica had the highest antibacterial activity at concentrations of 0.3 mg/ml and 6.25 mg/ml, respectively. A. indica had the best free radical scavenging of DPPH, exhibiting 50% inhibition at 28.72 μg/ml; while M. indica showed better superoxide scavenging potential than the positive control quercetin. Both M. indica and A. indica had adequate activity against the nitric oxide-free radical (12.87 and 18.89 μg/ml, respectively). M. indica selectively reduced the expression of the gtfB gene, indicating a mechanism involving Glucotranferases, specifically targeting bacterial attachment.SUMMARY Mangifera indica and Azadirachta indica had very good antibacterial activity against Streptococcus mutans and moderate toxicity against Vero cellsM. indica had the best antioxidant capacity overallM. indica reduced the expression of gtfB gene at 0.5 mg/ml. Abbreviations used: AA: Ascorbic acid; BHI: Brain–heart infusion; CHX: Chlorhexidine; DPPH: Diphenyl picrylhydrazyl; DMSO: Dimethlysulfoxide; NBT: Nitroblue tetrazolium; NO: Nitric oxide;

Microbial Etiology and Prevention of Dental Caries: Exploiting Natural Products to Inhibit Cariogenic Biofilms

“…More studies are, however, required to unveil more details about the mechanism of action of anti-caries bioactive compounds. In addition to their antibacterial activity, plants often possess natural antioxidants due to the presence of polyphenols and flavonoids [ 32 ]. Natural plants can be an adjunct therapy to mechanical dental biofilm control.…”

“…Phytochemicals isolated from plants that can be used as effective and economical treatments are needed [ 31 ]. However, many plant products such as herbs and spices show toxicity to cells, and hence, cytotoxicity tests and dose controls are needed for their safe use [ 32 ]. According to the randomized controlled clinical trial of Usha et al (2017), a 0.5% extract of Stevia rebaudiana leaves reduced cariogenic organisms significantly and promoted the buffering capacity of the saliva in patients at high for caries [ 33 ].…”

Comparison of the Antibacterial Activity of the Ethanol Extract vs Hydroalcoholic Extract of the Leaves of Mangifera indica L. (Mango) in Different Concentrations: An In Vitro Study

“…Among stomatological infections, bacteremia and osteomyelitis are common as a result of invasive dental procedures whose multifactorial origin includes a very varied microflora, finding opportunistic microorganisms such as S. aureus, which is related to the onset of these diseases. 7,9,10 In recent years, research shows various medicinal plants of stomatological interest, including Mangifera indica L., to which antibacterial properties are attributed due to its active substance that is mangiferin. As the phenolic compound is one of the most abundant chemical components in this plant, it is considered that it gives it the ability to inhibit or block the growth of certain microorganisms.…”

Caracterización química y actividad antibacteriana del aceite esencial de Mangifera indica L. de tres regiones de Venezuela

“…Dado lo anterior, en este estudio se analizó la composición química y la actividad antibacteriana del aceite esencial obtenido de las hojas de la especie M. indica L., las cuales fueron recolectadas en tres regiones de la República Bolivariana de Venezuela. La investigación se basó en la descripción de la actividad antibacteriana en los extractos obtenidos de diferentes partes de la planta de M. indica L. [9][10][11][12][13][14], con el objetivo de contribuir con la caracterización de esta especie. Este es el primer estudio comparativo acerca de la actividad antibacteriana del aceite esencial procedente de las hojas de M. indica L. de tres regiones de Venezuela.…”

“…48, no. 3, pp [13][14][15][16][17][18]. 2019 R. Aparicio-Zambrano, J. Velasco-Carrillo, R. Paredes-Uzcategui & L. Rojas-Fermin 14 Las hojas de M. indica L. fueron recolectadas en los estados de Mérida (Herbario MERF, Facultad de Farmacia y Bioanálisis), en octubre del año 2014, Barinas (Barinas) y Portuguesa (Guanare), en septiembre del año 2014, en la República Bolivariana de Venezuela.…”