Inhibition of Proteus vulgaris and its associate urease by flavonoid fraction of selected plants used as spices in India

Proteus vulgaris is highly resistant to many currently available antibiotics. The bacterium is pathogenic to humans causing urinary tract infection and wound infection. The enzyme urease produced by bacterium also leads to formation of struvite stone in urinary tract. The present study was carried out to evaluate anti-P. vulgaris activity of flavonoid fraction of selected plants as well as to determine their antioxidant potential. The selected plants are popularly used as spices in India and subcontinent. Flavonoid fraction of Ammomum subulatum Roxb., (Brihat Ela); Cinnamomum tamala T. Nees., (Patra); Cinnamomum zeylanicum Garcin ex Blume., (Twak); Myristica fragrans Houtt., (Jatiphala) and Piper nigrum L., (Maricha); were evaluated against P. vulgaris and its urease inhibition using agar well diffusion method. Subsequently, the antioxidant activity of selected plants was also determined by their 1,1-diphenyl-2-picryl hydrazyl (DPPH), hydroxyl (OH), superoxide radical (SOR), reducing activity and nitric oxide free radical scavenging potential. The results obtained from study reveals that P. nigrum (minimum inhibitory concentration [MIC], 6 mg/mL) was found to be most active against P. vulgaris followed by C. tamala, M. fragrans, and A. subulatum (MIC, 7 8, and 8.5 mg/mL), respectively. The urease inhibition study indicates that all selected plants possess significant inhibitory activity in the range of 0.55-6.60 mm. Moreover, the antioxidant profile of selected plant flavonoid fractions shows that the plants have promising radical scavenging potential. The findings of present study shows P. nigrum and C. tamala have significant potential to inhibit growth of human pathogenic bacteria P. vulgaris which merits further exploration and become potential targets for natural plant drug discovery.