Characterization of AgNPs biosynthesized from stem and leaf extracts of Cissus quadrangularis and C. rotundifolia.

Antimicrobial activity of silver nanoparticles biosynthesized from leaf and stem extracts of Cissus quadrangularis and C. rotundifolia was assessed against two pathogenic microbes (Micrococcus, Proteus vulgaris). Methanolic extracts of both stem and leaves of C. quadrangularis and C. rotundifolia were prepared using soxhlet method. Qualitative profiling of secondary metabolites confirmed the presence of saponins in C. quadrangularis extracts, while tannins and flavonoids were present in extracts of both the plants. AgNPs biosynthesized from both leaf and stem extracts were characterized using SEM and FTIR. Antimicrobial assays of all the four crude extracts and NPs derived from leaf and stem extract revealed that none of the crude extracts of C. quadrangularis showed antimicrobial against either P. vulgaris or Micrococcus, while nanoparticles derived from stem extracts exhibited higher (∼2.5 times) activity against P. vulgaris than that against Micrococcus. In contrast, both the extracts of C. rotundifolia and AgNPs derived from stem extract showed similar inhibitory effect on growth of both tested microorganisms. Nanoparticles biosynthesized from leaf extract of C. rotundifolia showed higher activity (∼1.6 times) against P. vulgaris than that against Micrococcus. AgNPs derived from C. quadrangularis stem extract exhibited ∼1.5 times higher activity than that of C. rotundifolia derived AgNPs against P. vulgaris. This study therefore indicates that the rich phytochemical profile and antimicrobial potential of Cissus sp. can further be used to develop non-toxic herbal formulations with multiple medicinal properties. [ABSTRACT FROM AUTHOR]