Assessment of Phytoconstituents and Antimicrobial Activity of Tea Plant (Camellia sinensis)

Abstract

This study investigated the phytoconstituents and antimicrobial activity of Camellia sinensis leaves, with emphasis on their antioxidant potential. Ethanol extraction was carried out on dried leaf samples, followed by qualitative and quantitative phytochemical analyses using standard methods. Antimicrobial activity was evaluated using agar well diffusion and broth dilution techniques, while antioxidant activity was assessed using the DPPH radical scavenging assay. Qualitative analysis revealed the presence of alkaloids, carbohydrates, terpenoids, flavonoids, tannins, anthocyanins, phenols, and steroids, whereas saponins and glycosides were absent. Quantitatively, phenols (176.40 mg/mL) were most abundant, followed by tannins (42.28 mg/mL) and flavonoids (28.31 mg/mL). The extract exhibited concentration-dependent antimicrobial activity, with the highest inhibition observed against Salmonella typhi (51.7 mm) and Enterococcus faecalis (48.3 mm) at 100 mg/mL. MIC values ranged from 40–60 mg/mL. Synergistic studies showed enhanced antibacterial activity when the extract was combined with chloramphenicol discs, with notable effects against Pseudomonas aeruginosa and S. typhi, and induced antifungal activity against the fungal isolates tested. Antioxidant analysis showed moderate activity, with IC50 values of 71.7–88.5 µg/mL compared with standard antioxidants. The study revealed that Camellia sinensis leaves are rich in bioactive phytochemicals, particularly polyphenols, and exhibit significant antimicrobial and moderate antioxidant properties, supporting their potential use in therapeutic applications.