Preliminary phytochemical analysis, antimicrobial and antioxidant activity of Smilax zeylanica L. (Smilacaceae)

Objectives: Smilax zeylanica L. is a large, dioecious, scandent climbing shrub and an important medicinal plant belonging to the family Smilacaceae. The present study evaluates antimicrobial and antioxidant potential of leaf and fruit extracts of Smilax zeylanica L. (Smilacaceae). Methods: Extraction of powdered leaf and fruit materials was carried out by maceration process using methanol. Phytochemical analysis of extracts was carried out by standard tests. Antibacterial and antifungal activity was evaluated by Agar well diffusion and Poisoned food technique respectively. Antioxidant activity was evaluated by DPPH free radical scavenging assay and Ferric reducing assay. Results: Preliminary phytochemical analysis revealed the presence of alkaloids, flavonoids, tannins, triterpenoids and sterols in both leaf and fruit extracts. Leaf extract was shown to display marked antibacterial activity than fruit extract. Highest and least susceptibility to extracts was observed in case of Bacillus cereus and Salmonella typhimurium respectively. Leaf extract caused highest inhibition of test fungi than fruit extract. Susceptibility to extracts was greater in case of Bipolaris species than Aspergillus niger. Both leaf and fruit extracts scavenged DPPH radicals and exhibited ferric reducing potential in a dose dependent fashion. Leaf extract scavenged DPPH radicals more efficiently with IC50 value 20.80µg/ml than fruit extract (IC50 value 35.85µg/ml). Conclusion: Leaf and fruit extracts of S. zeylanica were shown to exhibit antimicrobial and antioxidant activity which may be attributed to the presence of secondary metabolites such as alkaloids, flavonoids, tannins, triterpenoids and sterols. Further studies on isolation of active principles from extracts and their bioactivity determinations are to be carried out. Keywords: Smilax zeylanica L., Maceration, Agar well diffusion, Poisoned food technique, DPPH, Ferric reducin