Effects of extraction conditions on total phenolic content and antioxidant capacity of the extract from Thai basil (Ocimum basilicum var. thyrsiflora) leaves
Nhu Bich Ma, Ngoc Lieu Le
Thai basil (Ocimum basilicum var. thyrsiflora) is a common herb in many regions with health benefits. In this study, the effects of different extraction conditions (including water/methanol ratio as solvent, temperature, shaking time and sample/solvent ratio) on total phenolic content of the crude extracts of Thai basil leaves were investigated. The results showed that the extraction condition significantly influenced the total phenolic content of the extract. The highest phenolic content was obtained using 75% methanol in water as the solvent with the shaking duration of 35 min at the temperature of 55oC and with 1/100 (w/w) sample-solvent-ratio. Also, the total phenolic and the flavonoid contents of the extract using the optimal condition were 43.6 ± 0.03 mg GAE/g dry weight and 10.2 ± 0.05 mg RE/g dry weight, respectively. The antioxidant capacity of the extract measured as 2,2-diphenyl-picrylhydrazyl (DPPH) scavenging capacity was 38.2 ± 1.1%. As the result, the extract of Thai basil leaves could be used as a good source of phenolic compounds for further studies.