GC-MS characterization and antioxidant potential of rhizome essential oil from Cyperus rotundus L. growing in North Central Nigeria

Oxidative stress has been linked to neurological diseases. The menace of stress is clinically curtailed by using synthetic drugs whose usage is associated with several draw backs. Recently, essential oils have shown promising antioxidant potential devoid of any side effect. The potential is a function of the type of phytochemicals whose presence in the oil varies from plant to plant. It is on this basis that this study investigated the antioxidant potential of characterized essential oil from rhizomes of Nigerian grown Cyperus rotundus. Rhizomes (500 g) of C. rotundus were pulverized and hydrodistilled for three hours. The hydrodistillation afforded 0.1250.02% (w/w) of essential oil. Gas Chromatography (GC) and Gas Chromatography-Mass Spectrometry (GC-MS) were used to characterize the oil and the characterization revealed abundance of sesquiterpenoids (85.9%). Major compounds in the oil were -humulene (14.3%), caryophyllene oxide (12.3%), humulene-1,2-epoxide (9.1%), valencene (8.2%), -selinene (7.9%), -caryophyllene (6.5%) and gurjunene epoxide (5.4%). The antioxidant potential of the oil was established using radical scavenging assay. The oil showed antioxidant activity by scavenging free radicals of 2,2-diphenyl-1-picryl-hydrazyl (DPPH) with IC50 of 32.60 g/mL. Although the oil was not as active as butylated hydroxytoluene (BHT, IC50 of 18.12 g/mL) that was used as standard, its activity revealed that it could serve as alternative to synthetic drugs to ameliorate the menace of oxidative stress after clinical approval.