Phytochemical profiling, FT-IR spectroscopy, and antioxidant evaluation of select Lamiaceae species

The present study aimed to conduct a preliminary phytochemical analysis of aqueous, ethanol, and hexane leaf extracts from Anisomeles malabarica (L.) R.Br. ex Sims, Leucas aspera (Willd.) Link., Ocimum tenuiflorum L., and Plectranthus amboinicus (Lour.) Spreng. The analysis revealed the presence of terpenoids, saponins, glycosides, phenolics, fats, oils, tannins, quinines, and phlobatannins. Quantitative measurements showed soluble sugars at 1.92, 3.76, 2.45, and 2.07 mg/g, amino acids at 0.53, 4.74, 2.3, and 3.25 mg/g, and proteins at 5.43, 2.8, 7.32, and 4.75 mg/g, respectively. Flavonoid contents were 2.43, 6.85, 4.8, and 3.20 μg/g. Phenolic content was highest in Anisomeles malabarica (1.2 mg/g). Chlorophyll levels ranged from 0.4 to 2.15 mg/g, while carotenoids were highest in Plectranthus amboinicus (5.45 μg/g). All leaf extracts exhibited hydroxyl radical and superoxide anion scavenging activities, which increased with extract concentration. FT-IR analysis confirmed the presence of various functional groups. These findings suggest the potential of these Lamiaceae leaves in developing antibiotics and insecticides.