Estimation of Secondary Metabolites and Antibacterial Potential of Perilla frutescens (L.) Britton Leaf Extract against Human Pathogens

The present investigation was undertaken to explore the potential of Bhangjeera [Perilla frutescens (L.) Britton], family Lamiaceae as a source of antibacterial agents against human pathogenic bacteria, along with qualitative and quantitative estimation of its phytochemical constituents. The experiment was carried out on six germplasm (PF1 to PF6) in Botany laboratory of Shri Guru Ram Rai University, Uttarakhand, India using ethanol as a solvent. The yield of crude ethanolic extract varied from 2.4% to 3.04%, with the highest extract yield observed in germplasm PF3 (3.04%) and the lowest in PF1 (2.4%). Qualitative phytochemical screening revealed the presence of carbohydrate, protein, amino acids, glycoside, phenolic compounds, flavonoids, while saponins were absent. The total phenolic content ranged from 99±0.80 mg GAE/g to 225.06±0.80 mg GAE/g, and the total flavonoid content ranged from 83.25±0.80 mg GAE/g to 115.29±0.48 mg GAE/g. Antibacterial activity was estimated against Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Salmonella typhi, Staphylococcus aureus and Bacillus pumilis known to cause human diseases. Antibacterial assays indicated that most of the studied germplasm exhibited the highest zone of inhibition against Pseudomonas aeruginosa, followed by Klebsiella pneumoniae. Minimum Inhibitory Concentration (MIC) was determined against Pseudomonas, showing a zone of inhibition till a concentration of 31.25 µg/mL. Among Gram-positive bacteria, PF3 demonstrated the maximum zone of inhibition, while PF4 showed the highest activity against Bacillus pumilis. The findings of this study highlight the potential of Perilla frutescens as a natural source of antibacterial agents. Its bioactive compounds can be further developed for commercial applications in pharmaceuticals for the treatment and prevention of bacterial infections in humans.