ABSTRACT

 This study characterized essential oils and oleoresins produced from Monodora myristica (seeds) and Tetrepleura tetrapetra (fruits) and evaluated their antioxidant and antimicrobial properties. The essential oils were extracted dry steam distillation in nil-glass Clevenger apparatus, while the oleoresins were extracted with ethanol using maceration technique. The essential oils and oleoresins were characterized using gas chromatography - mass spectrophotometry. Antioxidant activities of the essential oils and oleoresins were investigated using three different approaches, namely 1,1-diphenyl-2-picrylhydrazyl (DPPH), total antioxidant capacity (TAC) and ferric reducing antioxidant power (FRAP). The antibacterial activities were investigated using agar diffusion method against the pathogens Escheriche coli and Staphylococcus aureus. Essential oils and oleoresins from Monodora myristica respectively had 6 and 5 constituents, with p - Cymene (50.58%) and 2 -Acetylcyclopentanone (85.42%) as the major constituents. The essential oils and oleoresins from Tetrepleura tetrapetra respectively had 32 and 16 constituents, with acetic acid (35.02%) and y -Terpinene (25.63%) as the major constituents. Both the essential oil and oleoresin scavenged DPPH at 53.76% to 93.46% capacity; exhibited total antioxidant capacity in the range of0.07 nmto 15.75 nm; and significantly (p <0.05) reduced Fe+3 to its lower valency state ofFe+2. The extracts showed dose-dependent antioxidant activities-, but the extracts of T. tetrapetra showed superior antioxidant activities than those ofM. myristica. Also, M. myristica essential oil exhibited higher antioxidant actities than its oleoresin. Both the oils and oleoresins, however, exhibited lower antioxidant activities than an ascorbic acid standard.'used as a positive control in this study. The two spice essential oils and oleoresins inhibited growth of E. coli (from 6.65 to 0.00 x 107 CFU / ml) and S', aureus (from 9.05 to 0.00 x 107 CFU /.ml). The oleoresins at the used highest concentration inhibited growth E. coli only to 12 - 15; mm. Staphylococcus aureus was less susceptible to these spice extracts than Escherichia coli. It is evident that the two spices possess some natural antioxidant and antimicrobial constituents; and would be useful in reducing oxidative spoilage in foods, combating free radical damages in cells^ and reducing microbial loads and food poisoning in foods.