Natural products derived from plant sources have gained significant attention in recent years due to their potential pharmacological activities. Althea officinalis, Hyssopus officinalis, Nymphaea alba, and Sphaeranthus indicus are widely recognized for their traditional medicinal properties and have been used for centuries in various folk medicine systems. For this purpose, the biological activities of ethanolic extract of A. officinalis, H. officinalis, N. alba, and S. indicus flowers was carried out. The phytotoxic activity revealed the highest FI₅₀ value (2007.4 µg/ml) for S. indicus while the lowest FI₅₀ value (360.0 µg/ml) had shown by H. officinalis. Among all the flowers the highest antibacterial activity was shown by the H. officinalis (24.33±2.05 mm) against P. aueroginosa at 9 mg/ml while, all the selected followers A. officinalis, H. officinalis, N. alba, and S. indicus did not show any significant activity against Bacillus subtilis in 3 mg/ml. The antifungal activity exhibited a maximum zone of inhibition (29 mm) was shown by S. indicus against Aspergillus niger while the lowest zone of inhibition (5 mm) was shown by N. alba against A. niger. The highest percentage of radical scavenging activity (83.25) were reported by H. officinalis while the lowest % RSA (39.74) showed by S. indicus followed by N. alba (50.56%). Similarly, the highest IC₅₀ values (891.09 µg/ml) were reported by H. officinalis while the lowest IC₅₀ values (0.91 µg/ml) showed by H. officinalis. The present study concluded the effective use of flowers of plants might be the presence of active secondary metabolites against various bacterial, fungal diseases and for the isolation of herbicidal compounds.

Index-term: Antimicrobial Activities, Medicinal Flowers, Phytotoxic Activity, Antioxidant Activity.