Evidence of circadian effects on phytochemical content and antioxidant potential of Ficus bubu extracts

Ficus bubu Warburg is a member of the Moraceae family, which includes species of the same genus with numerous therapeutic virtues. To date, no chemical or biological studies other than antimicrobial and antiproliferative activity have been carried out on Ficus bubu Warburg. These studies aim to observe the influence of circadian rhythm on qualitative and quantitative phytochemical screening and to evaluate the antioxidant activities of ethanol extracts from leaves, stem bark, and roots harvested at 6 am, 12 pm, and 6 pm, yielding 9 samples treated separately. Secondary metabolites were qualitatively identified using insoluble complex formation or color reactions. The concentration of secondary metabolites in the extracts was determined using a spectrophotometer at specific wavelengths. Antioxidant activity was assessed using the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical-trapping assay, the iron-reduction (FRAP) assay, and the phosphomolybdenum method. Alkaloids, flavonoids, polyphenols, terpenoids, tannins, saponins, coumarins, and anthraquinones were present in all extracts. Alkaloids, flavonoids, polyphenols, and terpenoids were most concentrated in the leaves at 6 am, while the concentrations of tannins and saponins were high in the stem bark at 6 am and 6 pm. Extracts from leaves (10L1Fb), stem bark (10B3Fb), and roots (10R2Fb) showed interesting antioxidant power. The biological clock thus indicates the best times to harvest each part of the plant, and the circadian rhythm revealed that the leaves in the morning showed the best results, followed by the stem barks in the evening, and finally the roots at midday. These results show that ethanol extracts of Ficus bubu possess antioxidant properties, likely due to their high levels of secondary metabolites (alkaloids, flavonoids, polyphenols), and could provide a natural alternative for the discovery of new antioxidant drugs essential for the treatment of rheumatoid arthritis, cancer, cardiovascular disease, etc.