Determination of Antioxidant and Antimicrobial Properties of Abaca (Musa textilis Née) Pseudostem Extracts

Aim: This study aimed to identify and quantify the phytochemicals extracted from the pseudostem sap of the two varieties of Musa textilis namely, Luno and Maguindanao collected from the mountainous parts of Cavite, Philippines. The pseudostem sap extracts were assessed for their antioxidant activity through 2,2-Diphenyl-1 Picrylhydrazyl (DPPH) free radical scavenging assay and Ferric Reducing Antioxidant Power (FRAP) assay; and for their antimicrobial properties against four human bacterial strains: Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa, and Escherichia coli and two human pathogenic fungal strains Trichoderma harzianum and Candida albicans using agar well diffusion assay. Materials and Methods: Two varieties of M. textilis were identified by the representative of Philippine Fiber Industry Development Authority (PhilFIDA) and harvested from Gen. Emilio Aguinaldo, Cavite, Philippines. Luno and Maguindanao pseudostems were subjected to manual and mechanical decortication processes in which the abaca fiber and sap were collected while ensuring the cleanliness of the decorticating machine and borosilicate glass containers to maintain the integrity of the sap. Extracted pseudostem saps were filtered using vacuum filters and were frozen at -86ºC before being subjected to freeze-drying. Solid particles were suspended in aqueous solution obtaining a concentration of 10 mg/mL. 100 mL of the aqueous sap extracts were delivered to Central Analytical Services Laboratory, National Institute of Molecular Biology and Biotechnology in University of the Philippines Los Bano, Laguna for the conduct of the quantitative phytochemical analysis and DPPH and FRAP assays. Four human bacterial strains and one fungal pathogenic strain: S. aureus, E. faecalis, P. aeruginosa, and E. coli and T. harzianum were selected and acquired from Philippine National Collection of Microorganisms and C. albicans from the University of Santo Tomas Collection of Microbial Strains for the conduct of agar well diffusion assay. Results and Conclusion: The phytochemical components of the abaca pseudostem sap extracts were determined, which revealed the presence of flavonoids, phenols, quinones, and tannins for both extracts. Results showed that the ‘Luno’ variety had 65.36% to 66.31% scavenging activity through DPPH assay and 50% to 54.14% antioxidant activity through FRAP assay. The ‘Maguindanao’ variety showed 60.62% to 67.26% scavenging activity and 70.85% to 71.98% antioxidant activity. In addition, both varieties showed no antimicrobial activity against the four bacterial and two fungal strains. These results exhibit the pertinence of the organic solvents in the extraction process in drawing out necessary bioactive compounds from the pseudostem sap extracts. The statistical analysis showed no significant difference between the percent scavenging activity and the percent antioxidant activity of the extracts from both varieties.