Antioxidant and Antimicrobial Effects of Nannorrhops baluchestanica: An Endemic Palm Species in Southeast Iran

Abstract

Background: Nannorrhops baluchestanica Khodash is a recently introduced shrubby species belonging to the family Arecaceae, distributed in Southeast Iran. Objectives: The antioxidant and antimicrobial potentials of this endemic plant were studied. Methods: The seeds and fruits of N. baluchestanica were collected from a natural population in Shark village, and the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity of their hydroethanolic extracts was evaluated to determine potential antioxidant properties. In addition, inhibitory, bactericidal, and fungicidal effects of seed and fruit hydroalcoholic extracts were studied against a variety of pathogens, including three fungal strains (Aspergillus fumigatus, Fusarium oxysporum, and Candida albicans), three Gram-negative (klebsiella pneumoniae, Pseudomonas aeruginosa, and Escherichia coli), and three Gram-positive bacterial strains (Bacillus cereus, Staphylococcus epidermidis, and Streptococcus pyogenes) via broth microdilution and streak plate methods. Results: The IC50 values of 26.20 and 33.90 µg.mL-1 were calculated for the fruit and seed extracts, respectively, using vitamin E with IC50 of 10.40 as standard. The MIC, MBC, and MFC values ranged from 128 to 2048 μg.mL-1. The fruit extract inhibited the growth of all microbial strains except for B. cereus and S. epidermidis, while P. aeruginosa and F. oxysporum were the only strains inhibited by the seed extract. In agreement with antioxidant properties, more broad-spectrum antimicrobial effects were observed in the fruit extract. Conclusions: Excellent antioxidant capacities of N. baluchestanica extracts indicate their great potential for treatment or prevention of oxidative stress-related diseases, but only slight effectiveness against infectious agents was observed.