Antioxidant properties of methanol extracts of wild garlics (genus Allium L., sect. Allium)
The medical use of some plants in the genus Allium L., especially onion (A. cepa L.) and garlic (A. sativum L.) is well known from ancient times and the therapeutic use is approved by national committees for the registration of plant medicines. However, wild growing Allium species are not investigated in detail from any point of view. Their chemical composition is only partially known , and data of the possible therapeutic activity is very few [2, 3]. With respect to this, in the present study the results of the scavenging effects of methanol extracts of some wild species in the Allium section (A. scorodoprasum subsp. scorodoprasum and A. scorodoprasum subsp. waldsteinii, A. sphaerocephalon, A. guttatum subsp. sardoum and A. guttatum subsp. dalmaticum), and garlic (A. sativum) in two phenophases are presented. The antioxidant effects were evaluated by neutralization of stable 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and hydrogen peroxide.
In the DPPH-assay all examined extracts exhibited dose dependent neutralization in applied concentrations from 12.5 to 250µg dry extract per ml of DPPH solution. All investigated extracts reached 50% neutralization of DPPH radical (IC50). Most effective ones were the extracts of A. scorodoprasum subsp. scorodoprasum and A. scorodoprasum subsp. waldsteinii (IC50=25µg/ml). Investigated extracts neutralised H2O2 (IC50 ranging from 20µg/ml –A. scorodoprasum subsp. waldsteinii to 11.27mg/ml – mature garlic bulb extract) also in dose dependent manner. Various levels of phenolics (0.10–1.07mg gallic acid equivalents/g of dry extract) the investigated plants extracts could at least partially explain the obtained differences in the obtained results.
References: 1. Fritsch, R.M., Keusgen, M. (2006) Phytochemistry 67: 1127–1165. 2. Tepe et al. (2004) Food Chem. 92: 89–92. 3. Stajner et al. (1998) Phytotherapy Res. 12: S13-S14.