Phytochemical Identification and Comparative In-vitro Anti-Oxidant Studies of Aqueous, Ethanol and Methanol Rootbark Extracts of Simarouba glauca DC (Paradise Tree)

Aims: The study was conducted to determine the presence of selected phytochemicals and in-vitro antioxidant potency of aqueous, ethanol and methanol rootbark extracts of Simarouba glauca. Study Design: True experimental study.

Place and Duration of Study: Department of Biochemistry, University of Benin, Benin City, Nigeria, between July and August 2017.

Methodology: Rootbark of the plant was harvested from a private farm at Ubiaja, Esan south-east part of Edo State, air dried, pulverized and extracted with water, ethanol or methanol solvents and freeze-dried to obtain respective fractions of extracts. An alkaloid, total phenol, tannins and Flavonoid content of rootbark extracts were evaluated by established standard experimental methods and principles. DPPH radical scavenging activity, reducing power activity, total antioxidant activity, hydroxyl free radical scavenging activity, ABTS+ radical scavenging activity and nitric oxide radical scavenging activity were also evaluated based on established standard methods and principles.

Results: Alkaloids and flavonoids were observed in aqueous, ethanol and methanol rootbark extracts; flavonoid was, however, absent in the aqueous fraction. Total phenols and tannin were absent in all fraction. DPPH radical scavenging activity of aqueous, ethanol or methanol fraction extracts recorded no values at 50% inhibition concentration (IC50); although the extracts demonstrated the anti-DPPH radical effect at lower inhibitory concentrations, while BHT recorded an IC50 of 18 µg. Reducing power activity of aqueous, ethanol or methanol fraction at IC50 was 11 µg, 10 µg and 11 µg respectively while BHT was 11 µg. The total antioxidant activity of aqueous, ethanol or methanol rootbark extracts at IC50 are 23, 21 and 58 µM FeSO4 equivalent/µg of Fe2+ liberated respectively relative to 388 µM FeSO4 equivalent/µg of Fe2+ liberated by BHT. Hydroxyl free radical activity of aqueous, ethanol and methanol fraction at IC50 was 11 µg, 100 µg and 11 µg respectively while BHT was 11 µg. ABTS+ radical scavenging activity of aqueous, ethanol or methanol fraction extracts at IC50 was 29 µg, 25 µg and 34 µg respectively whereas BHT was 21 µg. Nitric oxide radical scavenging activity of aqueous, ethanol or methanol fraction extracts at IC50 was 14 µg, 14 µg and 14 µg respectively whereas Quercetin was 16 µg. Butylated hydroxytoluene (BHT) and Quercetin was utilized as standard antioxidant.

Conclusion: The outcome of the research study revealed that the aqueous, methanol and ethanol rootbark extracts of Simarouba glauca possess significant phytochemicals and antioxidant potency, although, the methanol fraction appears to be more effective against investigated radicals.