Polyphenols and antioxidant capacity in different types of garlic

Abstract

Garlic contains important biologically active compounds such as phytoncides, antioxidants and others. There belong organosulfur compounds, allyl thiosulfinates and phenolic compounds (phenolic acids, flavonoids), vitamins (E and C) and some minerals, that all have several positive effects on human health. In the work five types of raw garlic (Allium sativum) of Czech, Chinese and Spanish origin, and bear's garlic (Allium ursinum), and two dried garlic products, were evaluated for polyphenols content and antioxidant capacity. The highest values of total polyphenols (TP), analyzed by spectrometric method with Folin-Ciocalteu reagent, had fresh samples of bear's and Spanish garlic; the lowest ones were evaluated for Czech garlic bulbs (92.2 - 119.6 mg GAE.100g-1 fw) and dry garlic products (70.1 - 84.5 mg GAE.100g-1). The total antioxidant capacity (TAC) was determined by spectrometric methods with DPPH and ABTS reagents. To types of fresh garlic with the best values of antioxidant capacity, evaluated by both methods, belong bear's and Spanish garlic, followed by Chinese and Czech garlic samples. These values are in agreement with polyphenols content in garlic bulbs. Dry garlic products had the highest values of TAC. Content of polyphenols and antioxidant capacity values were positively correlated, higher correlation value was detected for TP and TAC-ABTS (0.973) than for TP and TAC-DPPH (0.873). Bear's garlic and garlic belong to the vegetable types with high amount of biologically active compounds such as antioxidants.

Keywords

• garlic
• polyphenol
• antioxidant capacity
• DPPH
• ABTS