Evaluation of antioxidant concentrations and activities of mixed spices and herbs

Abstract

Spices and herbs are used in culinary and are also considered medicinally important due to their antioxidant contents. In this project four spices namely, Zingiber officinale (Ginger), Allium cepa (Onion), Syzygium aromaticum (Clove), Cymbopogon citrates (Lemongrass) and four herbs such as Allium fistulosum (Bunching onion), Coriandrum Sativum (Coriander), Murraya koenigii (Curry leaves) and Ocimum tenuiflorum (Holy basil) were incorporated into three different formulations. These formulations namely F1 (mixed herbs 25% each), F2 (mixed spices 25% each) and F3 (mixed spices & herbs 12.5% each) were studied for their antioxidant/mineral profile. The three formulations were extracted with cold water, hot water & methanol and the extracts were analyzed for antioxidant contents/activities. The antioxidants like total phenolic contents (TPC) were determined by Folin- Ciocalteu method, total flavonoid contents (TFC) were determined by Aluminium chloride complex forming assay. The antioxidants such as gallic acid, catechin and quercetin were quantified chromatographically. Whereas the antioxidant activities of the extracts were determined by DPPH, HRSA and FRAP assays. Minerals such as Magnesium (Mg), Calcium (Ca), Potassium (K), and trace elements such as Manganese (Mn), Chromium (Cr), Copper (Cu), Iron (Fe) and Zinc (Zn) were determined by using ICP-MS. The collected data of the listed parameters was statistically analyzed by using SPSS. The methanolic extract of formulation F3 (mixed spices & herbs) showed significantly (p<0.05) higher TPC with the mean concentration of 4.45 ± 0.2 mg GAE/ml. The methanolic extract of formulation F3 showed significantly (p<0.05) higher TFC being 3.30 ± 0.22 mg QE/ml. Furthermore, the chromatographic evaluation of formulation F2 showed highest concentration of gallic acid, catechin and quercetin that is 86.0, 339.40 & 394.59 µg/ml respectively. The antioxidant activities in DPPH assay of the methanolic extract of formulation F3 showed significantly (p<0.05) stronger antioxidant activity with the IC50 value of 65.03 ± 2.3 µg GAE/ml. In HRSA the hot water extract of formulation F3 showed significantly (p<0.05) stronger activity with IC50 value of 1493 ± 187.4 µg AAE/ml. In FRAP assay the cold water extract of F2 showed significantly (p<0.05) stronger activity being the FRAP value of 98.9 ± 4.3 µg TE/ml. Considering the results of mineral analysis, F1 showed significantly (p<0.05) higher Potassium (K) content of 33589 ± 841 µg/g. The results of this study indicate that as a whole the formulations F2 & F3 possessed higher antioxidant contents/activities than F1. Furthermore, significant (p<0.05) associations between the antioxidant contents and activities were observed. As an outcome of this study it could be said that the use of tested formulations of spices and herbs as health supplements could be highly effective to control the drastic repercussions of the oxidative stress.