Cytotoxicity of Brazilian plant extracts against oral microorganisms of interest to dentistry

Abstract

BackgroundWith the emergence of strains resistant to conventional antibiotics, it is important to carry studies using alternative methods to control these microorganisms causing important infections, such as the use of products of plant origin that has demonstrated effective antimicrobial activity besides biocompatibility. Therefore, this study aimed to evaluate the antimicrobial activity of plant extracts of Equisetum arvense L., Glycyrrhiza glabra L., Punica granatum L. and Stryphnodendron barbatimam Mart. against Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus mutans, Candida albicans, Candida tropicalis, and Candida glabrata, and to analyze the cytotoxicity of these extracts in cultured murine macrophages (RAW 264.7).MethodsAntimicrobial activity of plant extracts was evaluated by microdilution method based on Clinical and Laboratory Standards Institute (CLSI), M7-A6 and M27-A2 standards. The cytotoxicity of concentrations that eliminated the microorganisms was evaluated by MTT colorimetric method and by quantification of proinflammatory cytokines (IL-1β and TNF-α) using ELISA.ResultsIn determining the minimum microbicidal concentration, E. arvense L., P. granatum L., and S. barbatimam Mart. extracts at a concentration of 50 mg/mL and G. glabra L. extract at a concentration of 100 mg/mL, were effective against all microorganisms tested. Regarding cell viability, values were 48% for E. arvense L., 76% for P. granatum L, 86% for S. barbatimam Mart. and 79% for G. glabra L. at the same concentrations. About cytokine production after stimulation with the most effective concentrations of the extracts, there was a significant increase of IL-1β in macrophage cultures treated with S. barbatimam Mart. (3.98 pg/mL) and P. granatum L. (7.72 pg/mL) compared to control (2.20 pg/mL) and a significant decrease of TNF-α was observed in cultures treated with G. glabra L. (4.92 pg/mL), S. barbatimam Mart. (0.85 pg/mL), E. arvense L. (0.83 pg/mL), and P. granatum L. (0.00 pg/mL) when compared to control (41.96 pg/mL).ConclusionsAll plant extracts were effective against the microorganisms tested. The G. glabra L. extract exhibited least cytotoxicity and the E. arvense L. extract was the most cytotoxic.

Anticandidal effect of endophytic bacteria isolated from Equisetum arvense L. against Candida albicans and Candida glabrata

“…Therefore, these species were tested for various biological activities to determine the active compounds responsible for the anticandidal activity. The extract and essential oil of E. arvense had anticandidal activity against pathogenic Candida strains 21,26,32,36 . This activity of E. arvense might have been due to the presence of bioactive compounds produced by the plant itself; however, more sophisticated studies are required to verify the compound production by the endophytic bacteria inside the plant tissues.…”

“…Moreover, the extract of E. arvense L. at a concentration of 50 mg/mL was found to be 100% effective against C. albicans and C. glabrata 26 . There are also reports of propylene glycol extract of E. arvense and mixture of extract and formulated gel having anticandidal and antibacterial activity 36 . The ethyl acetate extract of another species of Equisetum (E. giganteum) contained a clear presence of phenolic compounds and exerted antimicrobial activity against C. albicans 37 .…”

Acute and chronic toxicity and antimicrobial activity of the extract of Stryphnodendron adstringens (Mart.) Coville

“…Fonseca & Linbradi (2008) reported that possible toxicity of tannins in dye prepared with bark of Stryphnodendron barbatiman occurred in mammalian cells. Regarding the cytotoxicity in other mammalian cells, Oliveira et al (2013) found mild toxicity of the S. barbatiman Mart. plant extract at 50mg/mL concentration on rat macrophages and significantly reduced the production of TNF-α when compared to the control group.…”

“…Furthermore, toxicity was not observed at the orally ingested doses of 10, 100, and 200mg/kg during the 90 days of chronic toxicity tests. Oliveira et al (2013) evaluated the cytotoxicity of aqueous fractions of S. adstringens on rat macrophages at 50mg/mL doses and did not observe any decrease in cell viability.…”

Study of Inhibitory Effect of Echinops cephalotes on Candida Spp. Isolated from Vulvovaginal Candidiasis Patients in Isfahan

“…In spite of advances in modern medication, plants still make an important contribution to health care [7]. Herbal extracts prepared from medicinal plants include different compounds with numerous biological activities confirmed by in vitro and in vivo studies, such as antibacterial, antifungal, antiviral, antiseptic, anti-inflammatory, antitumor, anti oxidative, anti allergic and diuretic properties [8].…”