Abstract

• The present work focused on the investigation of nutritional values, antimicrobial activity, antioxidant activity and some phytoconstituents in the leaf extracts of Mentha spicata L. (Pu Si Nan). The preliminary phytochemical tests revealed the presence of alkaloids, α-amino acids, carbohydrates, cyanogenic glycosides, flavonoids, glycosides, organic acids, phenolic compounds, reducing sugars, saponins, steroids, tannins and terpenoids. However, starch was absent. The nutritional values were determined by AOAC method providing proteins 23.68 %, ash 25 %, fibers 11.49 %, water content 15.15 %, carbohydrates 17.04 %, fats 7.64 % and energy value (232 kcal /100 g). Invitro screening of antimicrobial activity by agar well diffusion method on five different microorganisms (Escherichia coli, Enterococcus faecalis, Staphylococcus aureus, Bacillus cereus, Candida albicans) on PE, EtOAc, EtOH, CHCl3 and H2O extracts of the leaf of Mentha spicata L. (Pu Si Nan), PE, EtOH, CHCl3 and EtOAc extracts showed antimicrobial activity on four strains of microorganisms (except E. coli). Watery extract was observed activity against on E. faecalis, S. aureus and B. cereus. The highest inhibition zone was observed 20.50 ± 0.35 mm on Bacillus cereus by EtOAc extract of sample. The antioxidant activity of watery and ethanol extracts of the leaf sample was determined by DPPH assay. The IC50 values of watery and ethanol extracts were found to be 127 and 38 µg/mL respectively. Ethanol extract of the leaf sample was observed that higher antioxidant activity than watery extract but weaker activity than BHT (IC50 of BHT=11.71 μg/mL). Essential oils from the leaf of the sample were extracted by steam distillation method and analyzed by GC-MS spectroscopic method. According to the results, the components (3-carene, D-limonene, trans-carveol, D-carvone, 2-cyclohexen-1-one, 3-methyl-6-(1-methylethylidene), beta-bourbonene and alpha-copaene) were investigated in the extracted essential oils of leaf of Mentha spicata L. (Pu Si Nan).