Antioxidant Potential and Anti-Sickling Activity of Different Organs of Curcuma longa: Correlation of the Antioxidant Capacity on Anti-Sickling Activity

Aims: The aim of this research was to evaluate comparatively the anti-sickling activity of aqueous and methanol extracts of different organs of C. longa, to determine the polyphenolic compounds and to evaluate the antioxidant potential of different parts of C. longa. Also, to establish a possible correlation between the antioxidant potential of the extracts on the anti-sickling activity.

Study Design: The study used an experimental design. The antioxidant and anti-sickling activities of the aqueous and methanol extracts of different organs of C. longa were assessed along with their correlation.

Place and Duration of Study: The study was carried out at the Laboratory of Natural Products, Faculty of Science and at Centre for the Study of Natural Products from Plant Origin (CESNOV), Faculty of Pharmaceutical Sciences, both at University of Kinshasa in 2018.

Methodology: C. longa was planted in an experimental monoculture setting from where were collected different organs of this plant. After processing these parts, they were macerated in methanol and water respectively. After filtration of the macerates, the filtrates were dried in the oven to obtain aqueous and methanol extracts which were used for biological analyses and the determination of polyphenolic compounds. This determination was performed using a spectrophotometer while the biological activities was performed using the ABTS, DPPH and Emmel tests respectively. Data were analyzed using GrapPad Prism 6.0 software for statistical analyzes and the determination of IC50.

Results: The findings showed that the polyphenolic compounds are not distributed in the same way in different organs of C. longa. The extracts of different parts of C. longa do not all have a great antioxidant potential. However, the rhizome and root extracts showed a better anti-scavenging activity using ABTS method compared to other organs, while rhizome and leaf extracts showed better anti-scavenging activity using the DPPH test. The analyses carried out revealed: a positive correlation between (i) the total polyphenol contents and the anti-sickling activity of the studied extracts (r = 0.08328) and (ii) between the antioxidant activity using ABTS and DPPH tests along with the anti-sickling activity of different extracts (r = 0.1221, 0.4900 and 0.3114 respectively).

Conclusion: The tested extracts displayed good antioxidant and anti-sickling activities. Thus, different organs of C. longa are a source of natural antioxidants, which can be used to manage sickle cell disease. The effect of the antioxidant potential of the extracts tested on their anti-sickling activity was demonstrated. Nevertheless, in-depth studies are required in order to confirm this correlation.