In-vitro hepatoprotection study, free radical scavenging activity and gc/ms analysis of Cyperus esculentus essential oils from hydrodistillation and mae techniques

A sample of essential oil is prepared from Cyperus esculentus tubers by hydrodistillation (HD) and another is prepared using microwave assisted extraction (MAE) techniques. When compared using GC/MS, they reveal the presence of at least 60 terpenoids and 7 non-terpenoid volatile chemicals. Sesquiterpenoids are the predominant constituents of both samples making 67.46% of the sample obtained by HD and 54.97% of that obtained by MAE. The percentages of monoterpenes in the same samples are 6.87% and 15.32% respectively. Free radical scavenging activity test (0.2% DPPH) is carried out to investigate the essential oils of C. esculentus on a TLC plate. A compound that appears as a yellow spot on the TLC plate due to the decolourization of the DPPH radical is identified as a sesquiterpene (2-naphthalenecarboxylic acid, 8-ethenyl-3,4,4a,5,6,7,8,8a-octahydro-5-methylene) using GC/MS. The essential oil obtained by MAE does not show IC₅₀ effect on monolayer culture of rat hepatocytes up to a concentration of 1000 µg/mL. But, the essential oil obtained by hydrodistillation shows toxic activity with an IC₅₀ value equal to 125 µg/mL. Using silymarin as a positive control, the essential oils obtained using both techniques show protective activity against paracetamol induced hepatotoxicity at a concentration of 12.5 µg/mL. Recently, it was concluded that different extraction techniques show diverse results in both the constituents and biological activities of plant materials (Sasidharan S, Chen Y, Saravanan D, Sundramand KM, Yoga Latha L (2011). Extraction, Isolation and Characterization of Bioactive Compounds from Plants' Extracts. Afr J Tradit Complement Altern Med.; 8(1): 1 – 10) From our study, the essential oils obtained using HD and MAE techniques differ in both the constituents and the tested biological activity.