Phytochemical and antioxidant studies of Cleome heratensis (Capparaceae) plant extracts

Background: In this research, different active phytochemical constituents present in Cleome heratensis (C. heratensis) from Capparaceae family were investigated. Moreover, the fatty acids present in the seed and aerial parts of the plant were identified by gas chromatography (GC) after esterification of the oil. Antioxidant activity of the aerial parts and seed of C. heratensis methanolic extract over 2,2'-diphenylpicryl-1-hydrazyl (DPPH) was investigated using ultraviolet- visible (UV-Vis) spectrophotometer. Methods: To study total phenolic compounds and flavonoids, the plant was extracted from ethanol by ultrasonic method, then further extracted with other solvents. Amounts of anthocyanins and tannins/condensed tannins were determined by their corresponding ethanolic and acetone extracts. Antioxidant activity of the plant species was studied by a spectrophotometric method using 80% methanolic extract. Results: The high content of phenolics as 16.915 mg tannic acid equivalents per gram of dry matter (TAE/g DM), tannins (12.231 mg TA/gr DM) and condensed tannins (4.086 mg TA/g DM) was obtained for the C. heratensis extract. The most flavonoids content was found 4.444 rutin equivalents (in mg) per gram of dry matter (mg RE/g DM) in plant's aerial extract. The most amount of anthocyanin (0.48 mmol/gr WM) was observed in flowering stage. Antioxidant activity of the aerial parts and seed of C. heratensis methanolic extract were 11.92 and 63.54 mg/mL IC50, respectively. Conclusion: High level of phenolic components including flavonoids, proanthocyanidins and tannins was detected in the extract of aerial parts of the plant. The oil of seed of this plant is a rich source of saturated and unsaturated fatty acids. Finally, C. heratensis aerial part extract was found as an excellent natural antioxidant.