Effect of storage conditions on the physicochemical properties, polyphenolic content, and biological activities of fig leaves (Ficus carica L.)

¹ Department of Microbiology and Biotechnology, University of Food Technologies, Plovdiv, Bulgaria
² Department of Food Technologies, Institute of Food Preservation and Quality, Agricultural Academy, Plovdiv, Bulgaria
³ Department of Organic Chemistry and Inorganic Chemistry, University of Food Technologies, Plovdiv, Bulgaria
⁴ Laboratory “Cell Biosystems” - Plovdiv, Department of Biotechnology, The Stephan Angeloff Institute of Microbiology, Bulgarian Academy of Sciences
⁵ Department of Analytical Chemistry and Physical Chemistry, University of Food Technologies, Plovdiv, Bulgaria

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

Fig tree leaves (Ficus carica L.) are a rich source of biologically active compounds and possess both nutritional value and therapeutic potential. This study compared the physicochemical properties, polyphenolic content, and biological activities of fig leaves processed and stored under different conditions: air-drying and freezing. Dried leaves (DL) exhibited higher protein (17.06 %) and carbohydrate (11.4 %), contents than the frozen leaves (FL) - 4.14 % and 5.93 %. DL extract exhibited higher contents of total polyphenols and flavonoids (24.53 mg GAE/g dw and 0.83 mg QE/g dw) than FL extract (1.80 mg GAE/g dw and 0.07 mg QE/g dw). DL showed greater antioxidant activity (DPPH: 183.81 vs. 8.38; FRAP: 193.60 vs. 13.81 mM TE/g dw). Antimicrobial tests revealed higher inhibitory activity (inhibition zones ≥ 12 mm) of DL extract against Bacillus subtilis, Bacillus amyloliquefaciens, Bacillus cereus, Enterococcus faecalis, Micrococcus luteus, Salmonella enteritidis, Escherichia coli, Proteus vulgaris, Proteus mirabilis, and Pseudomonas aeruginosa, while FL extract was less active. Both dried and frozen fig leaves exhibited notable biological activities, with DL showing superior antioxidant and antimicrobial potential. Consequently, drying was the more suitable storage method, better preserving the bioactivity of fig leaves and enhancing their functional and therapeutic potential.