Determination of antibacterial activity mechanism of red rose petal extract

Roses have been celebrated for centuries for their beauty, fragrance, and potential health benefits. Among the many bioactive compounds in red rose petals, anthocyanins stand out for their vibrant color and wide range of physiological effects. Anthocyanins, known for their antiatherogenic, anticancer, antidiabetic, anti-inflammatory, and antioxidant activities, are the primary pigments in red rose petals. Extracting these compounds can provide a visually appealing natural coloring agent suitable for various food products. Each component of a plant encompassing the trunk, bark, stems, leaves, fruits, roots, flowers, and seeds harbors a variety of chemical compounds, including phenolic acids, flavonoids, anthocyanins, and carotenoids. These compounds function as natural antioxidants, thereby mitigating the risk of plant diseases by delaying or preventing oxidative processes. This study focuses the antimicrobial properties of red rose petal extract and it is potential as natural preservative in the food industry. The extraction process involved freeze-drying the petals to preserve their bioactive constituents, followed by 70% ethanol extraction to obtain the desired extract. Frozen leaves were subjected to the vacuum freeze-dryer for a duration of 48 h. Moisture content was determined and the moisture content of the rose petal powder obtained in this study was found to be 4.65±0.05%. The antioxidant properties of red rose petal extract contribute to preserving food quality by preventing oxidative degradation and extending shelf life. Rose extract is used in medicinal chemistry to treat bacterial illnesses, targeting both Gram-positive and Gram-negative bacteria. This study assesses the antimicrobial activity and antioxidant potential of the extracted red rose petal extract. Through well diffusion assays and determination of Minimum Inhibitory Concentration (MIC) values, the study aims to identify susceptibilities of common foodborne pathogens against the extract as well as its antibacterial activity mechanism. The inherent antimicrobial properties of the rose extract position it as a promising candidate for utilization as a preservative in food products, thereby diminishing the risk of spoilage and ensuring food safety. Utilizing well diffusion assays, the efficacy of the extract against a spectrum of foodborne pathogens, including S. Typhimurium (31 mm), S. Enteritidis (23 mm), B. cereus (23 mm), S. aureus (25 mm), E. coli O157:H7 (23.5 mm), E. coli Biotype I (25mm), and L. monocytogenes (32.5 mm), was assessed. The discernible formation of zones of inhibition around the extract-treated discs signified inhibition of microbial growth, underscoring the extract's potential as an antimicrobial agent. Furthermore, MIC (Minimum Inhibition Concentration) values ranged from 114.07 mg/mL to 57.03 mg/mL. The determination of MIC values revealed S. Typhimurium and E. coli Biotype I had the highest MIC values and S. Enteritidis and B. cereus had the lowest MIC values. The petals of flowers are known as an ideal natural source of antioxidants from plant fiber due to their high flavonoid compound element level which includes anthocyanins.the red coloration of roses is attributed to the presence of carotenoids and anthocyanin. Plant based anthocyanins and carotenoids are valuable for food, nutrition, and pharmaceutical preparations due to low toxicity. The extract's total phenolic content (23.10 ± 0.81 mg GAE/g) and antioxidant activity were determined using established methods, including the FCR and DPPH assay, respectively. The observed antiradical activity ranged from 16.60 % to 74.15 %, indicating a dose-dependent response. The potential applications of red rose petal extract in food preservation are diverse. Its antioxidant activity can help retard lipid oxidation and preserve the quality of fats and oils in food products. Several studies were carried out to assess the time-dependent decrease in bacterial cell viability in the presence of rose petal extract. Initially, 24-hour bacterial cultures were prepared and supplemented with the rose petal extract, followed by incubation at 37°C to simulate optimal bacterial growth conditions. Sampling was conducted at predetermined intervals (0, 2, 4, 6, 24, and 48 hours) to monitor changes in bacterial cell viability over time. Each sampled culture was plated onto a Tryptic Soy Agar (TSA) medium to facilitate bacterial enumeration. A control group consisting of extract-free bacterial cultures was maintained to establish baseline bacterial growth patterns without the extract. The number of viable cells in the control tubes increased during the 24-hour incubation period for all bacterial cultures. In contrast, in the extract-added culture tubes, the number of viable cells reduced gradually, revealing the bactericidal effect of the red rose extract. A series of experiments assessed the potential damage to bacterial cytoplasmic membranes induced by rose petal extract. The extract was added to bacterial cultures at twice the Minimum Inhibitory Concentration (MIC × 2) and then incubated at 37°C for 24 hours. After the incubation period, the number of viable cells was determined by seeding onto two types of agar media: Tryptic Soy Agar (TSA) and TSA supplemented with 3% NaCl. Adding 3% NaCl to TSA created an osmotically stressful environment to challenge bacterial growth. Petri dishes containing the seeded agar were subsequently incubated at 37°C for 48 hours to facilitate colony formation. Following the incubation period, colonies were manually counted, and the difference in colony counts between TSA and TSA with 3% NaCl represented the number of cells with damaged membranes. The reduction percentages varied significantly among the tested strains: E. coli O157:H7 exhibited the highest reduction percentage at (80.83%), followed by S. Enteritidis at (64.52%), S. aureus at (34.51%), E. coli Biotype I at (14.86%), L. monocytogenes at (19.38%), S. Typhimurium at (11.5%) and B. cereus (6.72%). The investigation into the impact of rose petal extract on the tricarboxylic acid (TCA) cycle activity of pathogenic bacteria involved a series of experimental procedures. The extract was subsequently introduced into the suspension, adjusting bacterial cell concentration to 108 colony-forming units per ml (CFU/mL) during the logarithmic growth phase. Following a one-hour incubation period at 37°C, the mixture underwent centrifugation at 8000×g for ten minutes, forming a pellet. This pellet was then re- suspended in a 0.9% NaCl solution. Iodonitrotetrazolium chloride (INT) was then added to the suspension at a concentration of 1 mmol/L, and the mixture was further incubated for 30 minutes at 37°C. After the incubation, the maximum absorbance at 630 nm was measured using a spectrophotometer. By quantifying the maximum absorbance at 630 nm, changes in metabolic activity associated with the TCA cycle could be determined. Of note, the extract had a relatively minimal impact on the xxi metabolic activity of E. coli O157:H7. However, it demonstrated a more pronounced effect on the TCA cycle of Salmonella Typhimurium. Roses are emblematic of beauty, bravery, passion, and love, often revered as the king or queen of flowers. Their extensive range of applications offers significant advantages over most other flowers. The polyphenols from rose petals can enhance the value of by-products in fruit processing. Utilizing an enzyme-assisted extraction followed by spray drying, this green technology offers an eco-friendly alternative to traditional methods like organic solvent extraction. This natural oil and its constituents offer safe alternatives for incorporation into various applications within the food sector. Specifically, they may serve as additives in dietary supplements or functional food products. This study emphasizes the potential of red rose petal extract as a natural preservative and antimicrobial agent in food products. It highlights its promising applications in the food industry, suggesting it as a natural and health-promoting ingredient. Further research is needed to explore its effectiveness in different food matrices and ensure its safety for consumption, paving the way for its integration into various food products.