PHYTOCHEMICAL SCREENING, IN VITRO EVALUATION OF ANTIOXIDANT AND ANTIMICROBIAL ACTIVITIES OF ETHANOLIC SOLANUM VIRGINIANUM FRUIT EXTRACT

Oral diseases, particularly dental caries, are closely associated with cariogenic microorganisms such as Streptococcus mutans, Lactobacillus acidophilus and Enterococcus faecalis. The increasing interest in medicinal plants as natural sources of bioactive compounds has encouraged the investigation of Solanum virginianum for its potential antimicrobial and antioxidant properties. The present study was undertaken to evaluate the phytochemical constituents, in-vitro antioxidant activity and antimicrobial potential of the ethanolic fruit extract of Solanum virginianum against selected oral pathogens associated with dental caries. The fruits of S. virginianum were collected, authenticated, shade-dried and powdered, followed by extraction using ethanol. Preliminary phytochemical screening was carried out, and in-vitro antioxidant activity was evaluated by phosphomolybdate, superoxide radical scavenging and DPPH assays. Antimicrobial activity was evaluated using the agar well diffusion method, along with minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and anti-biofilm activity. The phytochemical screening revealed the presence of alkaloids, terpenoids, phenols, carbohydrates, saponins, flavonoids, proteins, steroids, tannins and glycosides, while quinones were absent. The total antioxidant activity of the extract was found to be 351 mg/g, while ascorbic acid showed 640 mg/g. The extract showed 54.02% superoxide radical scavenging activity at 20 µg/mL. The extract exhibited concentration-dependent antibacterial activity, with a maximum zone of inhibition of 17.8 ± 0.6 mm against S. mutans and 17.8 ± 0.5 mm against E. faecalis. The MIC was 250 µg/mL for S. mutans and E. faecalis and 500 µg/mL for L. acidophilus, while the MBC was 500 µg/mL for S. mutans and E. faecalis and 1000 µg/mL for L. acidophilus. The extract also demonstrated concentration-dependent anti-biofilm activity, with 73.5 ± 1.3% inhibition against S. mutans at 500 µg/mL. The findings suggest that the ethanolic fruit extract of S. virginianum possesses appreciable phytochemical, antioxidant, antibacterial and anti-biofilm activities and may serve as a potential natural source of bioactive compounds for further investigation in dental-caries-associated oral infections.