MODULATION ACTIVITY OF SIDA CORDIFOLIA L. AND SIDA RHOMBIFOLIA L. IN STAPHYLOCOCCUS AUREUS SA-1199 B

Abstract

Methicillin-resistant Staphylococcus aureus (MRSA) is responsible for several infections in humans. The infections caused by this bacterial strain 
are difficult to treat due to resistance of MRSA to clinically used antibiotics. Over past two decades medicinal plant extracts and their 
phytoconstituents have been reported to possess modulation and efflux pump inhibitory (EPI) activity against MRSA strains. Sida cordifolia aerial 
parts, roots and Sida rhombifolia aerial parts have been reported to be used in Ayurveda for several ailments including bacterial/fungal infections. 
Based on this information and in continuation of our efforts to discover EPIs from Indian medicinal plants, we describe modulation activity of 
methanol extracts of aerial parts and roots of S. cordifolia and S. rhombifolia and alkaloid-rich fraction prepared from methanol extracts. Methanol 
extract of S. cordifolia and S. rhombifolia aerial parts showed 4-fold reduction each in MIC of norfloxacin at 125 µg/mL concentration whereas 
alkaloid-rich fraction of both the plants did not show any reduction in MIC of norfloxacin. Fractionation of bioactive MeOH extract of S. cordifolia 
aerial resulted in isolation and characterization of 8 compounds including 2 alkaloids, 5 flavonoids and 1 coumarin compound whereas LC-MS 
analysis of alkaloid-rich fraction of S. rhombifolia aerial parts revealed presence of alkaloids including cryptolepine and 11-methoxyquindoline. 
Although the methanol extracts of aerial parts of S. cordifolia and S. rhombifolia showed weak modulatory activity in NorA over expressed S. 
aureus 1199B strain, the present study helped to assess EPI activity potential of these plants.