Phytoconstituents And In Vitro Antioxidant Property Of The Essential Oils Of Hibiscus Sabdariffa Seeds:- Oteri, Victory E

ABSTRACT xii Antioxidants properties play major roles in counteracting the deleterious effects of chronic inflammation in biological systems; and the antioxidant potentials of plants and plant parts are related to the phytoconstituents inherent in them. This study was therefore aimed at determining some phytoconstituent and antioxidant property of the essential oil of Hibiscus sabdariffa seeds (EOHSS) using nitric oxide spectrophotometric assay. The essential oil of Hibiscus sabdariffa seeds (HSS) were subjected to phytochemical analysis using gas chromatography coupled to flame ion detector (FID) and mass spectrometer (MS). The total phenols, total flavonoids and the antioxidant capacity were determined using standard methods. The antioxidant property was examined using the nitric oxide assay at the concentrations of 100-400mg/ml and butylated hydroxytoluene (BHT) as reference standard. The experiments were conducted in triplicate. Data was subjected to analysis of variance (ANOVA) using SPSS, while values were presented as mean ± standard deviation. Significance was set at p<0.05. According to the results, EOHSS contain bioactive compounds including: D-limonene (23.45ug/ml), ferullic acid (26.27ug/ml), vanillic acid (15.00ug/ml), tyrosol (14.66ppm), naringenin (19.24ug/ml), epicathechin (9.25ug/ml), ellagic acid (7.28ug/ml) and beta pinene (8.04ug/ml). Appreciable levels of phenols and flavonoids were also detected. The nitric oxide assay result showed that the highest scavenging activity ofthe EOHSS was detected at 200mg/ml (94.08%) compared to the standard (98.44%). A dose-dependent decrease in percentage inhibition was observed as the concentration increased from 200-400mg/ml of EOHSS. The relatively high phenol and flavonoid content of EOHSS in this study strongly contribute to its antioxidant activity. Hence it could be exploited for therapeutic purpose against oxidative stress related diseases.