PHYTOCHEMICAL SCREENING, EVALUATION OF TOTAL TANNINS, ANTIOXIDANT POTENTIAL AND ANTIBACTERIAL ACTIVITY FROM LEAF AND FLOWER EXTRACTS OF SPILANTHES CALVA D.C.

The present study deals with the phytochemical screening, total tannin content and antibacterial activity from leaf and flower extracts of Spilanthes calva. Phytochemical screening of various extracts such as aqueous, ethanol, acetone, chloroform and petroleum ether, revealed the presence of active ingredients such as tannins, saponins, quinones, flavonoids, phenols, cardiac glycosides, terpenoids, steroids and alkaloids in the leaf and flower extracts of Spilanthes calva. The leaf and flower extracts were quantitatively estimated for tannin content with tannic acid (TA) as standard. The optimal yield of tannin was found in flower extract 31.5 ± 0.19 mg Tannic Acid Equivalents (TAE) / g) followed by leaf extract 22.8 ± 0.14 mg Tannic acid Equivalents (TAE) / g) of Spilanthes calva. The leaf and flower extracts of Spilanthes calva were evaluated for antioxidant activities by DPPH (1,1-Diphenyl-2-picryl-hydrazyl) radical scavenging assay. Among five different solvent extracts of leaf and flower of Spilanthes calva, the results recorded that the maximum antioxidant activity was found in the ethanolic leaf (86.41±0.19%) and flower extract (94.87±0.37%) of Spilanthes calva followed by other solvent extracts. Different concentrations of ethanolic leaf and flower extracts were tested using the agar disc diffusion method for the antibacterial activity against Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli. It was concluded that the powerful antibacterial effect is attributed to the greater amount of tannin compounds in the ethanolic flower extracts of Spilanthes calva.