Wild Edible Allium Species from Arid Zones of Tunisia: New Perspectives of Natural Compounds

Abstract

Allium is the largest and the most important representative genus of the Alliaceae family. For many centuries, several Allium species have been used as vegetables and spices, and as folk medicines for curing various diseases. Besides the well-known garlic and onion, other species are either, widely cultivated for culinary use, such as leek, scallion, shallot and chive, or found as wild endemic species grown spontaneously. This chapter presents an integrated view on new advances and recent trends in the nutritional value, bioactive compound and health effect of various extracts prepared from the spontaneous species, A. roseum (rosy garlic) and A. ampeloprasum (Kurrath). Chemical composition of A. roseum leaves was investigated. The analyses showed that A. roseum contained high amounts of soluble carbohydrate (32.8%), crude protein (22.7%), dietary fibre (12.3%), ash (7.2%) and fat (3.6%). The most abundant minerals were K, Ca and SO4 2-with 1530.5 and 712.5 mg/100 g DW, respectively. Mn, Cu and Zn were also detected in appreciable amounts ranging from 1 to 2 mg/100 g DW. Extracted leaf oil was composed of 14.93% saturated and 85.28% unsaturated fatty acids. Linolenic acid represents 53% of the unsaturated fatty acids and palmitic acid represents 13% of the saturated fatty acids. Phytochemical screening of A. roseum and A. ampeloprasum showed the presence of bioactive agents exhibit a positive effect on human health as antioxidants and antibacterial compounds such as saponins, tannins, flavonoids, coumarins, steroids, cardiac glycosides, free quinone and iridoids. The most abundant phytonutrients in A. roseum edible leaves included polyphenols, flavonoids, anthocyanidins, vitamin C, carotenoids and allicin which were at 736.65 mg of equivalent catechol/100 g DW, 3.37 mg of equivalent catechin/g DW, 1239.62 mu g/100 g DW, 1523.35 mg/100 g DW, 242.25 mu g/100 g DW and 657 mg/100 g DW, respectively. The content of polyphenols, flavonoids and tannin in A. ampeloprasum was 29,278 mg of equivalent gallic acid/g DW, 5.840 mg of equivalent quercetein/g DW and 5.509 mg of equivalent catechin/g DW, respectively. The results indicate that leaves of A. roseum and A. ampeloprasum present a higher antioxidant capacity with a quenching DPPH value equal to 3.78 and 30.12 mg Trolox/ g DW respectively. The study revealed that rosy garlic and kurrath are a rich source of many important nutrients and bioactive compounds responsible for many promising health beneficial physiological effects and they may be considered a functional food.