Introduction: Streptococcus pyogenes remains a significant human pathogen responsible for a spectrum of infections, including severe invasive diseases such as streptococcal toxic shock syndrome, and serious post-infectious sequelae like acute rheumatic fever and glomerulonephritis. Considering the recognized antimicrobial properties of Capsicum annuum L. (C. annuum L.) and the persistent clinical challenge presented by S. pyogenes, this study investigated the in vitro antimicrobial activity of an aqueous extract of Capsicum annuum L., Capsaicin (C₁₈H₂₇NO₃), amoxicillin, and a combination of Capsaicin with amoxicillin against S. pyogenes (ATCC 19615). The primary objective was to evaluate both the inhibitory and bactericidal effects of these agents, specifically exploring the potential for synergistic or additive interactions between a plant-derived compound and a conventional antibiotic to improve therapeutic potential. Methods: The antimicrobial activities were evaluated using broth microdilution to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Time-kill kinetics were assessed spectrophotometrically by monitoring bacterial growth. Additionally, disk diffusion assays were performed to evaluate antimicrobial susceptibility. Statistical analyses were conducted using one-way analysis of variance (ANOVA), followed by Tukey’s post hoc test to determine significant differences between treatment groups. Results: The aqueous extract of C. annuum L. and Capsaicin both demonstrated significant in vitro inhibitory and bactericidal activity against S. pyogenes. Specifically, MIC and MBC of the aqueous extract were determined to be 12 mg/mL and 14 mg/mL, respectively. For Capsaicin, the MIC was 15 μg/mL, and the MBC was 20 μg/mL. Consistent with these findings, disk diffusion assays revealed distinct zones of inhibition for both agents. Notably, the combination of Capsaicin with amoxicillin exhibited enhanced antimicrobial activity, resulting in a statistically significant reduction in the MIC (P < 0.05) and MBC (P < 0.01) compared to each agent alone. Conclusion: The combination of Capsaicin with amoxicillin demonstrated enhanced bactericidal efficacy in a dose-dependent manner. Notably, Capsaicin exhibited bactericidal activity at microgram concentrations, whereas amoxicillin required milligram concentrations to achieve a comparable effect, highlighting the potent antibacterial properties of Capsaicin. These findings suggest that both the aqueous extract of C. annuum L. and Capsaicin hold significant potential as promising candidates for the development of novel antimicrobial therapies against S. pyogenes.

BACKGROUND AND OBJECTIVE: Dental caries is the most common means of ingress of bacteria to the dental pulp and pulp infection. Different materials have been introduced for pulp therapy but they were not effective in producing an acceptable coronal seal. The aim of this study was to evaluate anti- inflammatory effect of local capsaicin on dental pulp of cat.METHODS: Twenty–four canine teeth of six domestic short hair cats weighing approximately 3-4 kg were selected for this experimental study. After cats had been anesthetized, the crown of teeth were cut 3 mm upper than cementoenamel junction (CEJ) and exposed under sterile condition. The teeth were divided into two groups. In group I the exposed pulp was capped with zinc oxide–eugenol as control. In group II dental pulp capped with capsaicin as experimental group. All access cavities were sealed with glass ionomer cement (Fuji IX). The animals were sacrificed at 1, 2 and 4 weeks after procedure. The canine teeth were extracted for histopathologic evaluation. The specimens were sectioned serially at 6 mm thickness parallel to tooth long axis. The sections were stained with H & E and studied by light microscopy.FINDINGS: Result of this study showed that signs of necrosis in zinc oxide-eugenol group during 1, 2 and 4 weeks decreased significantly (p=0.026). In capsaicin group hyperemia during 1, 2 and 4 weeks decreased significantly (p=0.019). In comparison of the effect of two drugs on pulp in 4 weeks and all weeks the sign of necrosis in capsaicin group was increased significantly (p=0.029, p=0.039). Two groups showed difference in dental barrier formation, type of inflammatory responses and soft tissue changes but these differences were not statistically significant.CONCLUSION: According to findings of this study capsaicin could decrease the intensity of the inflammation but was not successful in dental barrier formation.

Capsaicin causes direct irritation of the eyes, mucous membranes, and respiratory tract. It is used in self-defense, in crowd control, and as a less lethal weapon in police work. Controlled trials suggest that capsaicin has minimal serious acute effects. Herein, we report a woman who had a 20-minute exposure to capsaicin during a jail riot. She subsequently developed episodic dyspnea and cough, and increased sensitivity to scents, perfumes, and cigarette smoke. She has not had wheezes on physical examination or abnormal pulmonary function tests. Her response to inhaled steroids and long-acting beta-agonists has been incomplete. She appears to have developed airway sensory hyperreactivity syndrome after the inhalation of capsaicin, which likely injured sensory nerves and/or caused persistent neurogenic inflammation.

Introduction: Pruritus is one of the common problems in patients on hemodialysis. There are several causes for pruritus, and different treatment modalities are applied to control it. The aim of this study was to evaluate the therapeutic effect of capsaicin on pruritus, compared with placebo, in patients on hemodialysis.Materials and Methods: This randomized double-blinded crossover clinical trial was performed on 34 patients on hemodialysis with uremic pruritus. The patients were divided into 2 groups, one group received capsaicin 0.03% and the other, placebo, for 4 weeks. Treatment was stopped for 2 weeks as washout period and continued as a cross-over technique. Pruritus scores were analyzed and compared.Results: Thirty-four patients on long-term hemodialysis, 14 men and 20 women with a mean age of 57.0±18.6 years were studied. The mean of pruritus score before capsaicin treatment was 15.9±6.3, which was reduced to 6.4±3.9, 4.7±3.1, 3.2±2.9, and 2.5±2.5 on weeks 1 to 4, respectively (P<.001). In the placebo group, pruritus score before treatment was 15.0±6.0 on average, and it was 11.7±5.8, 9.4±5.9, 7.9±5.5, and 7.2±5.5, respectively, on weeks 1 to 4 (P<.001). There was no significant difference in pruritus scores before the treatment between the two groups, but after each week, the difference was significant (P<.001). Repeated measurement test showed that decreasing in pruritus severity in the capsaicin group was more than that in the placebo group during treatment period (P<.001).Conclusions: Capsaicin is a new safe and effective topical treatment for hemodialysis-induced pruritus in patients with end-stage renal disease.