ANTIOXIDANT ACTIVITY AND ANTIBACTERIAL SCREENING OF TUBERS OF AMORPHOPHALLUS KONKANENSIS AND AMORPHOPHALLUS BULBIFER (ARACEAE)

Objective: Antioxidant activity (AOA) and antibacterial screening of tubers of unexplored Amorphophallus konkanensis Hett., Yadav & Patil (AKT) and Amorphophallus bulbifer (Roxb.) Bl. (ABT). Methods: Antioxidant activity was evaluated by using ferric reducing antioxidant power (FRAP), 1 1-diphenyl-2-picrylhydrazyl (DPPH) radical, hydroxyl (OH•) radical, nitric oxide (NO∙) radical scavenging activities. Phenolics were determined by total phenolic content (TPC) assay. Antibacterial screening of different solvent extracts of tubers was tested against Gram positive and Gram negative bacterial strains by using the agar diffusion method. HPLC analysis was carried out for active phenolic compounds. Results: Tubers were extracted with three different solvents (ethanol, acetone and water). Acetone extracts of AKT and ABT exhibited the highest phenolic content 29.37±0.83 and 20.62±1.04 mg GAE/g. The AKT and ABT acetone extracts possesses highest free radical scavenging activity towards FRAP (0.632 & 0.586 O. D), DPPH (85.78% & 82.68%), hydroxyl (OH∙) radical (82.43% & 80.26%), nitric oxide (NO∙) radical (81.34% & 80.8%). The phenolic compounds tannic acid, gallic acid, quercetin, p-coumaric acid, catechin were identified by the HPLC method in acetone extracts. Among the different extracts, acetone extract of both the species of Amorphophallus showed significant antibacterial activity against all Gram positive and Gram negative bacterial strains tested. Conclusion: The results indicated that AKT and ABT can be considered as good sources of natural antioxidant for medicinal, commercial, nutraceutical and functional food applications. Antibacterial efficacy shown by these plants provides a scientific basis for their traditional uses in remedies

ANTIBACTERIAL ACTIVITY OF AMORPHOPHALLUS KONKANENSIS AND AMORPHOPHALLUS BULBIFER TUBER

Objective: Evaluation of antibacterial activity of unexplored, endemic Amorphophallus konkanensis (AKT) Hett., Yadav & Patil and Amorphophallusbulbifer (ABT) (Roxb.) Bl.Methods: Acetone and ethanol extracts of tubers of AKT and ABT were evaluated for in vitro antibacterial activity against Bacillus subtilis, Micrococcusaureus, Pseudomonas aeruginosa, Escherichia coli, Salmonella typhi, Klebsiella pneumoniae using agar diffusion method, minimum inhibitoryconcentration (MIC), minimum bactericidal concentration (MBC) and growth pattern of test organisms. High-performance liquid chromatography(HPLC) analysis was carried out for active phenolic compounds.Results: AKT and ABT extracts for both solvents showed significant antibacterial activities. The zone of inhibition was ranged from 12-25 mm to 11-23 mm for AKT and ABT extracts respectively. Highest significant activity was observed against M. aureus. The MIC values of acetone extracts wereranged from 200-350 μg/ml (AKT) to, 200-400 μg/ml (ABT). Ethanol extracts of AKT and ABT were showed MIC at 250-450 μg/ml and 300-450 μg/ml respectively. MBC value of acetone extracts ranged from 260-460 μg/ml (AKT) to 300-500 μg/ml (ABT) and for ethanol extracts 340-500 μg/ml(AKT) and 380-540 μg/ml (ABT). The effect of extracts on growth of microorganisms was also studied. HPLC analysis showed phenolic compoundsviz. tannic acid, gallic acid, quercetin, p-coumaric acid, and catechin. This polyphenolic rich extracts of AKT and ABT have demonstrated variousdegree of microbial growth inhibition.Conclusion: Antibacterial activity of AKT and ABT implies that, these plants have the potential for preparation of alternative medicines for infectionscaused by microorganisms that have become resistant to the current therapeutic measures.Keywords: Amorphophallus konkanensis, Amorphophallus bulbifer, Antibacterial activity, Minimum inhibitory concentration, minimum bactericidalconcentration, High-performance liquid chromatography