Inhibitory effects of unripe, ripe peels and seed volatile oils of <i>Dennettia tripetala</i> on some pathogens and free radicals

Abstract

Dennettia tripetala is used traditionally as a spice, wound healing, and as an antidepressant agent in Nigeria. We studied D. tripetala unripe, ripe fruit peels and seeds volatile oils (VOs) inhibition effects on DPPH, different oxidative radicals (DORs) and pathogens. The VO potency to inhibit DORs and bacterial growth was investigated by spectrophotometric and micro-dilution methods  respectively. The IC value of the ripe 50  seed and unripe peel was 1.03 and 2.24mg/mLrespectively in scavenging DPPH radical.
The MIC against Listeria ivanovii, Mycobacterium smegmatis, Staphylococcus aureus, Enterobacter cloacae, and Escherichia coli ranged from3.25 - 0.10 mg/mL. The unripe seed was bactericidal against L. ivanovii at 0.20mg/mL. GC/MS revealed methyl phenyl
acetate (MPA) and linoleic acid (LA) as the valuable compounds in the seeds lacking in the peels. This study indicates that besides the local uses of the plant, the seed VO has noteworthy bioactive compounds e.g. MPA, LAand may be good candidates in the hunt
for lead phytochemicals for the synthesis of potent antibiotics in this era of emerging multi-drug resistant pathogens.

Keywords: Dennettia tripetala, volatile oil, radical inhibitor, antibacterial