Atividade antioxidante e antimicrobiana in vitro de óleos essenciais e extratos hidroalcóolicos de manjerona (Origanum majorana L.) e manjericão (Ocimum basilicum L.)

Abstract

Basil (Ocimum basilicum L.) and marjoram (Origanum majorana L.) are considered a good source of nutrition with health benefits, mainly by the presence of phenolic compounds with antioxidant activity. In this study we determined the content of total phenolics, total flavonoids and antioxidant and antibacterial activity of hydroalcoholic extract and essential oils of these two herbs. The antioxidant activity of hydroalcoholic extract and essential oils was determined and compared to commercial antioxidants BHT (butylated hydroxy-toluene), BHA (butylated hydroxyanisole) and α-tocopherol using the kidnapping of free radical DPPH• (2 , 2-diphenyl- 1-picrihidrazil) and whitening system β-carotene/acid linoleic. The values obtained for total phenolics and flavonoids for basil (Ocimum basilicum L.) were 63,499 EAG mg/g (EAG: gallic acid equivalent) and 14,879 EQ mg/g (EQ: quercetin equivalent), respectively, and marjoram (Origanum majorana L.) 41,244 EAG mg/g and 7,363 mg EQ/g, respectively. We found higher activities of kidnapping for the free radical DPPH• with EC50 (concentration of antioxidant needed to reduce by 50% the initial concentration of DPPH•) of 363,992 μg/mL for the hydroalcoholic extract of basil (Ocimum basilicum L.) , 472,557 μg/mL for the hydroalcoholic extract of marjoram (Origanum majorana L.), 0,952 μL/mL for the essential oil of basil (Ocimum basilicum L.), 1,783 μL/mL for the essential oil of marjoram (Origanum majorana L. ) and 114,665 μg/mL, 72,250 μg/mL and 61,220 μg/mL for the reference substances BHT, BHA and α-tocopherol, respectively. The antioxidant activity of hydroalcoholic extract of basil (Ocimum basilicum L.) was 88,74% of DPPH• method for the hydroalcoholic extract of marjoram (Origanum majorana L.) was 86,90% for the essential oil basil (Ocimum basilicum L.) was 91,20% for the essential oil of marjoram (Origanum majorana L.) was 81,15% and for the reference substances BHT, BHA and α- tocopherol of 52,37% , 73,69% and 90,52%, respectively. It was observed that both the hydroalcoholic extract and essential oil of basil (Ocimum basilicum L.), showed a high capacity for sequestering free radical. The antioxidant activity of antioxidants used in food industry (BHA, BHT and α-tocopherol) was higher than the hydroalcoholic extract of basil (Ocimum basilicum L.) and marjoram (Origanum majorana L.), because these were considered pure. Although the hydroalcoholic extract and essential oils of basil (Ocimum basilicum L.) and marjoram (Origanum majorana L.) analyzed have presented a high content of phenolic compounds with antioxidant activity, only the essential oils of these herbs showed a non significant antibacterial activity by methods used.