Antibiofilm activity of neem leaf (Azadirachta indica A. Juss) ethanolic extracts against Enterococcus faecalis in vitro

Abstract

Background: Enterococcus faecalis commonly infects root canals by forming a biofilm. Extracts from neem leaves (Azadirachta indica A. Juss) have been shown to have antibacterial properties, indicating their potential in preventing or treating biofilm formation caused by bacteria. Purpose: This study aims to investigate the phytochemical compounds present in neem leaves (Azadirachta indica A. Juss) and establish the concentration of ethanol-based neem leaf extract that can effectively inhibit the in vitro growth of Enterococcus faecalis biofilm. Methods: This study employed the maceration technique for extraction, gas chromatography mass spectroscopy for the analysis of plant chemicals, and a microtiter plate assay for measuring biofilm formation with treatment concentrations of 6.25%, 12.5%, 25%, 50%, and 75%, with a positive control of 0.2% chlorhexidine. Results: A phytochemical analysis revealed that the ethanol extract of neem leaves contained 22 different metabolites, mainly terpenoids and fatty acids. The extract demonstrated antibiofilm activity only at a concentration of 12.5% with an average biofilm inhibition of 36.85%. However, lower concentrations of 6.25%, 25%, 50%, and 75% had the opposite effect, promoting biofilm formation in Enterococcus faecalis. Conclusion: Phytochemical metabolite contained in the ethanolic extracts of neem leaves might contribute a promising agent in treating a biofilm-mediated root canal infection of Enterococcus faecalis.

Phytochemical composition and antibacterial activities of Azadirachta indica (Neem): significance of traditional medicine in combating infectious diseases and antimicrobial resistance

“…Leaf extract Phenolics, tannins, saponins, flavonoids, and alkaloids Surhartono et al, 2023 [69] Indonesia The extract had antibacterial activity against E. faecalis at a concentration of 12.5% Leaf extract Terpenoids and fatty acids Sahrawat et al, 2018 [79] India The extract had antibacterial activity against E. coli at a concentration of 58.77% Leaf extract Saponins, tannins, terpenoids, and alkaloids Muhammad et al, 2019 [80] Nigeria…”

“…This plant has been reported to have antimicrobial activity against many microorganisms [65][66][67] . A. indica has been found to have antibacterial activity against both Gram-positive and Gram-negative bacteria, including activity against Escherichia coli (E. coli) [68] and Enterococcus species [69] . Additionally, it has activity against drug-resistant infections, making it a potential antibiotic [70] .…”

“…The active compounds (phytochemicals) present in A. indica, such as nimbin, nimbidin, azadirachtin, and gedunin, have been shown to exhibit remarkable bactericidal and bacteriostatic properties [71][72][73][74] . A. indica is also reported to possess many phytochemicals including phenolics, tannins, saponins, flavonoids, alkaloids [68], terpenoids and fatty acids [69] . Additionally, neem's antibacterial mechanism of action involves disrupting bacterial cell membranes, inhibiting crucial enzymes, and interfering with DNA replication, further enhancing its efficacy against microbial pathogens [75] .…”

Phytochemical composition and antibacterial activity of Azadirachta indica (Neem) against Enterococcus faecalis: Implications on benefits of traditional medicines

“…Extracts of Neem leaves have antibacterial, antifungal, antiviral, antidiabetic, insecticidal, diuretic, cardiac, antipyorrhoiec, antiscabic, and many other biological activities [7,23,[26][27][28] . Neem extracts from leaves, roots, bark, and seeds have been shown to have antimicrobial activity against Streptococcus variants and E. faecalis [29][30][31] . A wide range of Gram-positive and Gram-negative microbes, including Mycobacterium tuberculosis and strains resistant to streptomycin, are susceptible to the oil from the leaves, seeds, and bark of Neem [32] .…”

“…Neem extracts from leaves, roots, bark, and seeds have been shown to have antimicrobial activity against Streptococcus variants and E. faecalis [29][30][31] . A wide range of Gram-positive and Gram-negative microbes, including Mycobacterium tuberculosis and strains resistant to streptomycin, are susceptible to the oil from the leaves, seeds, and bark of Neem [32] . In Zambia, approximately 70% of the indigenous population use traditional medicines for their ailments, and plants are used as medicines in the treatment and prevention of several diseases [33] .…”