Phytochemical analysis, antimicrobial and antioxidant activities of different parts of Pleocaulus sessilis (Nees) Bremek (Acanthaceae)

Abstract

Aim: This study aims to investigate antimicrobial and antioxidant activity of leaf, stem, and inflorescence of Pleocaulus sessilis (Nees) Bremek belonging to Acanthaceae. Materials and Methods: The leaves, inflorescences, and stems were separated, dried under shade, powdered, and extracted using methanol by maceration process. Preliminary phytochemical analysis was carried out by standard phytochemical tests. Antibacterial and antifungal activity was carried out by agar well diffusion and poisoned food technique, respectively. Antioxidant activity was evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging, 2,2-azinobis 3-ethylbenzothiazoline 6-sulfonate (ABTS) radical scavenging and ferric reducing assays. Folin-Ciocalteu reagent method was employed to estimate the total phenolic content of extracts. Results and Discussion: Flavonoids, saponins, steroids, and phenols were present in all three extracts. Extracts were inhibitory to all test bacteria with maximum activity against Klebsiella pneumoniae. Overall, inflorescence extract exhibited high inhibition of test bacteria when compared to other extracts. Extracts were effective in reducing mycelial growth of test fungi. Leaf extract was more effective against test fungi followed by inflorescence and stem extracts. All extracts exhibited dose-dependent radical scavenging and ferric reducing activity. Leaf extract exhibited marked antioxidant activity when compared to other two extracts. The leaf extract scavenged DPPH and ABTS radicals with an inhibitory concentration value of 27.16 μg/ml and 9.16 μg/ml, respectively. Total phenolic content was high in leaf extract (112.13 mg gallic acid equivalents [GAE]/g) followed by inflorescence (85.65 mg GAE/g) and stem (42.42 mg GAE/g) extracts. Conclusion: The plant can be used to treat diseases caused by pathogenic bacteria, prevention, and control of phytopathogens and oxidative damage caused by free radicals. Further studies are to be carried out to isolate and characterize active principles from the plant and to determine their biological activities.