Anti-inflammatory and antimicrobial evaluation of Ceratonia siliqua-mediated calcium hydroxide nanoparticles synthesized using a one-pot technique in vitro study.

Plant-based nanoparticles are gaining attention in numerous fields, predominantly in medicine. This study aimed to produce carob (Ceratonia siliqua)-mediated nanoparticles by combining carob fruit extract and calcium hydroxide powder, and to evaluate their antimicrobial and anti-inflammatory effects. The synthesized carob-mediated calcium hydroxide nanoparticles (carob-CaNPs) were characterized using Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and energy dispersive spectroscopy. Carob-CaNPs were initially assessed for their cytotoxicity and inflammatory response on the RAW 264.7 murine macrophage cell line at nanoparticle concentrations ranging from 25 to 100 μg/μL, using MTT assay and quantification of IL6 and TNFα levels, respectively. The antimicrobial activity of the carob-CaNPs was determined by testing the nanomaterial against Gram-positive pathogens Staphylococcus aureus and Staphylococcus epidermidis, and Gram-negative anaerobes such as Porphyromonas gingivalis, Fusobacterium nucleatum, and Prevotella intermedia. The functional groups, crystalline nature, spherical shape, particle size (less than 100 nm), and elemental composition (48 % Calcium) of carob-CaNPs were identified and analyzed. The nanomaterial showed high cell viability (>90 %) across the tested concentrations, with values remaining comparable to the control. At 25 and 75 μg/μL, the nanoparticles showed an insignificant anti-inflammatory response in the RAW264.7 macrophage cell line. The maximum inhibition zone achieved at 100 μg/μL was against S. aureus (28 ± 0.21 mm), followed by S. epidermidis (24 ± 0.90 mm). Conversely, P. gingivalis, F. nucleatum, and P. intermedia showed 21 ± 1.03 and 17 ± 1.81 mm, and no effects, respectively. The result confirmed an enhanced susceptibility toward Gram-positive aerobic bacteria compared to Gram-negative anaerobes with a dose-dependent effect. A concentration of 10 μg/μL was enough to inhibit bacterial growth, and all strains exhibited bactericidal activity at concentrations below 100 μg/μL. Therefore, the carob-CaNPs exhibit non-toxic behavior with a broad-spectrum antimicrobial coverage and lack of inflammatory response, suggesting their potential application in dental and medical practice.