Radical quenching activity, ferric-reducing antioxidant power, and ferrous ion-chelating capacity of 16 Ballota species and their total phenol and flavonoid contents.

The ethyl acetate, methanol, and water extracts of 16 Ballota species (Family Lamiaceae)-Ballota acetabulosa, Ballota antalyanse, Ballota cristata, Ballota glandulosissima, Ballota inaequidens, Ballota larendana, Ballota latibracteolata, Ballota macrodonta, Ballota nigra ssp. anatolica, B. nigra ssp. foetida, B. nigra ssp. nigra, B. nigra ssp. uncinata, Ballota pseudodictamnus ssp. lycia, Ballota rotundifolia, Ballota saxatilis ssp. brachyodonta, and B. saxatilis subsp. saxatilis-were screened for their 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical quenching, ferric-reducing antioxidant power, and ferrous ion-chelating capacity at 1mg/mL. Hispanolone, a major diterpene found in the Ballota genus, was also tested in the same manner. Total phenol and flavonoid contents of the extracts were determined by Folin-Ciocalteau and AlCl(3) reagents, respectively. The extracts showed insignificant quenching activity against DPPH radical, but they had moderate antioxidant activity (0.597 ± 0.03 to 1.342 ± 0.01) in the ferric-reducing test compared to chlorogenic acid (the reference compound) (3.618 ± 0.01). All of the extracts (ranging from 65.1 ± 0.64% to 96.3 ± 0.09%) and hispanolone (97.31 ± 0.30%) exerted a remarkable ferrous ion-chelating effect. The highest total phenol (gallic acid equivalent) and flavonoid (quercetin equivalent) contents were found in the ethyl acetate extract of B. glandulosissima (393.7 ± 3.03 and 140.6 ± 1.97 mg/g of extract, respectively). Therefore, Ballota species could be a good source of natural preservatives in foodstuffs.