Experimental and chemometric study of antioxidant capacity of basil (Ocimum basilicum) extracts

- Basil extracts were obtained by different extraction conditions.
- All extracts showed significant antioxidant and protective activity.
- Two different chemometric techniques were used for data analysis.
- Basil extracts with the highest content of target substances were provided.

The interest in a natural and healthy lifestyle has moved the plant crops under the spotlight. The aim of the work was to test the antioxidant activity of basil (Ocimum basilicum L.) extracts obtained by extraction with water (in presence and absence of light), methanol (95%), ethanol (30, 40, 50, 60, 96%), chloroform, dichloromethane and hexane. Fragmentation of plant material was 0.3 and 2 mm and the extraction was performed during 10 and 30 min. The total phenolic content ranged from (5.17 ± 0.15 to 65.25 ± 2.19) mg of gallic acid equivalents per gram of a dry weight of extract, and the content of the total flavonoids from (0.11 ± 0.01 to 40.63 ± 2.14) mg of quercetin per gram of a dry weight of extract. All the extracts showed an antioxidant activity with an IC50 values of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical inhibition in the range from (0.22 ± 0.01 to 20.49 ± 1.54) μg/ml. The evaluation of experimental data for 44 basil extracts was performed by applying hierarchical cluster analysis (HCA) and principal component analysis (PCA). It was found that the increased time of extraction, solvent polarity and plant fragmentation increase the quality of the extracts in terms of the content of phenolic components and antioxidant effects. Extracts with the strongest antioxidant capacity were obtained by concentrated ethanol and methanol maceration. The chemometric analysis showed good correlation between the yield and total phenolic composition, and between the flavonoid content and antioxidant activity, predicting thus, basil extract quality.