Antioxidant and antibacterial activity of callus and adventitious root extracts from Rumex vesicarius L.

The present work has been carried out for the in vitro production of biologically active constituents from Rumex vesicarius L. cultures. Calli and adventitious roots were tested for their antioxidant and antibacterial activities. Results of preliminary phytochemical screening revealed that cultures were rich in flavonoids, alkaloids, tannins, carbohydrates and/or glycosides, coumarins and cardiac glycosides. Sterols and/or triterpenodis, chlorides and sulphates were found in some cultures only. Calli and roots in all treatments were devoid of saponins, anthraquinones, irodoids and sublimable substances. Total phenolic content in roots produced by culture of leaf blade explant on media containing 1 mg/L kinetin (K) + 4 mg/L 2,4-Dichlorophenoxyacetic acid (2,4-D) and calli produced on media containing 2 mg/L K + 2mg/L 2,4-D produced high total phenolic content (21.48 ± 0.24 and 18.15 ± 0.238 mg/explants, respectively). Total flavonoid content of calli and roots produced on media containing 2 mg/L K + 2mg/L 2,4-D and 1 mg/L K + 4 mg/L 2,4-D produced high total flavonoid contents (52.82 ± 0.56 and 49.27 ± 0.56 µg/explant, respectively). Results of high performance liquid chromatography (HPLC) analysis of flavonoids of calli obtained on 2 mg/L K + 2mg/L 2,4-D showed high concentration of quercetin (7.35 ± 0.245 µg/g D.W.). High total antioxidant activity was found in the extract of calli obtained on 2 mg/L K + 2 mg/L 2,4-D (617.85 ± 20.11 GAEs, ppm). Highest 2,2-diphenylpicrylhydrazyl  (DPPH) scavenging activity was obtained using adventitious roots and calli extracts (IC50 = 1.57 ± 0.02 and 1.76 ± 0.021 mg/ml, respectively). Antibacterial activity of adventitious roots and calli extracts was negative against all 6 human pathogenic isolates investigated.   Key words: Polygonaceae, flavonoids, phenolics, HPLC analysis, callus, in vitro culture, plant growth regulators.