Phytochemical analysis, antimicrobial and antioxidant activities of Allium roseum var. odoratissimum (Desf.) Coss extracts

Polyphenolic extracts from fresh aerial parts (stalk, leaf, and flower) and bulbs of Allium roseum var. odoratissimum (Rosy garlic) harvested from Tunisian sandy soil were analyzed by high performance liquid chromatography (HPLC)-diode array detector (DAD) coupled with tandem mass spectrometry (MS), and tested for their antioxidant, antimicrobial, cytotoxic and antiviral activities.
Leaves, stalks and flowers showed the highest total antioxidant capacity, scavenger activity against stable DPPH radical, and β-carotene bleaching capacity, with leaves and flowers extracts showing the highest total polyphenolic (84.39 mg gallic acid equivalents/g plant organs dry residue) and total flavonoid [5.88 mg (+)-catechin equivalents/g plant organs dry residue] contents, respectively. The metabolic profiles registered for the polyphenolic extracts revealed the presence of one hydroxycinnamic acid derivative, three flavones, and ten flavonols never detected before, with the only exception of kaempferol-3-O-glucuronide.
Overall, all the tested polyphenolic extracts possessed high activity against Gram positive and Gram negative bacteria, and Candida spp. Strains, generally recognized as the most important pathogens affecting food dishes. Conversely, no toxicity on VERO cells line and no antiviral activity against Coxsakievirus B-3 and Herpes Simplex Virus type 2 were registered.
This study gives a better insight into the potential healthy effects of Rosy garlic and the possibility of using it in food dishes to prevent contamination by the most common bacteria.