Phenolic profile, brine shrimp toxicity and antimicrobial properties of leaves from Ficus vasta Forssk. (Moraceae)

Several members of the genus Ficus (Moraceae) are used as traditional remedies all over the world in the treatment of many infectious diseases [1]. Phytochemical investigations of some Ficus species revealed phenolic compounds as their major components; moreover, a number of authors have documented the antibacterial and antifungal activities of these compounds [2,3]. Ficus vasta Forssk. is a very large tree growing over 25 m tall, widespread throughout the dry north and eastern Africa, Sudan, Ethiopia, Saudi Arabia and Tanzania [4]. Very few studies have been carried out on this species; thus it seemed interesting to characterize the phenolic profile and to evaluate the toxicity and the antimicrobial properties of the hydroalcoholic extract (80% methanol) obtained from leaves of F. vasta collected in Egypt. Preliminary phytochemical screening of F. vasta leaves extract revealed the presence of carbohydrates, tannins, flavonoids, coumarins, and triterpenes. Flavonoids such as luteolin, quercetin, vitexin, quercetin-3-galactoside and rutin were identified by paper chromatography. The quali-quantitative characterization of the phenolic compounds present in the extract was accomplished by HPLC-PDA-ESI-MS. The analysis revealed the presence of phenolic acids and flavonoids, and quercetin-3-galactoside was the main compound (81.75 mg/g ± 0.88% RSD), followed by gallic acid (76.36 mg/g ± 2.70% RSD) and isoquercitrin (22.5 mg/g ± 2.02% RSD). In order to predict the potential toxicity of F. vasta extract, the Artemia salina Leach (brine shrimp) lethality bioassay was employed [5]. The extract showed no toxicity against brine shrimp larvae (LC50 > 1000 µg/mL). The antimicrobial properties of F. vasta extract were tested against a representative set of Gram-positive and Gram-negative bacterial strains and the yeast Candida albicans. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) were determined by the broth microdilution method, according to CLSI guidelines [5]. The extract exhibited bacteriostatic activity against almost all the bacteria tested (MIC: 250-62.5 μg/mL), with Staphylococcus aureus and S. epidermidis being the most sensitive strains. A bioassay-guided fractionation procedure is currently going on aimed at characterizing and isolating the active constituents of the extract. Acknowledgments The authors wish to thank the “University of Messina” within the “Research and Mobility” Project. References [1] Alqasoumi S.I., Basudan O.A., Al-Rehaily A.J., et al. (2014). Saudi Pharm. J. 22, 460-471. [2] Abdel-Hameed E-S.S. (2009). Food Chem. 114, 1271-1277. [3] Cowan M.M. (1999). Clin. Microbiol. Rev. 12(4), 564-582. [4] Rashed K., Ono L. (2013). Int. Curr. Pharm. J. 3(1), 211-218. [5] Taviano M.F., Marino A., Trovato A., et al. (2013). Food Chem. Toxicol. 58, 22-29.