TOTAL PHENOL AND ANTIOXIDANT POTENTIAL OF FIVE SPECIES OF LAMIACEAE FAMILY

Abstract

Lamiaceae family has a cosmopolitan distribution, including about 300 genus and 7500 species. Numerous diseases have been related to free radicals overproduction. Antioxidant capacity is related to compounds capable of protecting a biological system against the potentially harmful effect of processes or reactions involving reactive oxygen and nitrogen species. In the present study, the ethanol extracts, obtained by maceration of Melissa officinalis, Mentha sp., Ocimum basilicum, Plectranthus barbatus, and Rosmarinus officinalis were evaluated for antioxidant activity, the total phenolic content was determined, and volatile compounds were identified by Gas Chromatography coupled to Mass Spectrometry (GC-MS). Ethanol extracts of M officinalis, Mentha sp., P. barbatus, and R. officinalis were able to reduce the free radical DPPH with IC50 of 3.81, 11.89, 6.92 and 11.54 μg/ml respectively, presenting better activity than the BHT, used as a standard. However, the ethanol extract of O. basilicum showed low activity and high IC50 value. Total phenols of all extracts ranged from 85.18 to 212.74 μg/ml. The highest phenolic concentration was observed in the ethanol extract of M. officinalis. Analysis of volatile compounds showed the presence of phytol in all extracts, being predominant in P. barbatus and R. officinalis, and also nonadecane and heptadecane in M. officinalis. Fractions obtained from the five species of Lamiaceae also presented antioxidant effect. In the most active fractions were mainly phenolic compounds, such as flavonoids, tannins, and coumarins. These results encourage new studies with these species in order to isolate the compounds responsible for this antioxidant activity so that in the future they can be used as natural antioxidants.