Potential Antioxidant Anthraquinones Isolated fromRheum emodiShowing Nematicidal Activity againstMeloidogyne incognita

Abstract

Antioxidant and nematicidal properties were evaluated forR. emodiextractives which are extracted by standardizing and adopting accelerated solvent extraction (ASE) method along with traditional Soxhlet extraction. The extracted material was separated using flash chromatography and the separation conditions and solvents were standardized for the extracted plant constituents. The purity was detected by using analytical reverse phase high pressure liquid chromatography (HPLC). LC-MS/MS detection in the direct infusion mode of the isolated, purified products afforded four anthraquinones, characterized by their infrared spectra (IR) and1H spectra as chrysophanol, physcion, emodin, and aloe-emodin. Five antraquinone glucoside derivatives and piceatannol-3-O-β-d-glucopyranoside have also been detected from the extracted product. Duringin vitroevaluation the antioxidant potential of methanolic crude extract (CE1) was the highest, followed by ethyl acetate crude extract (CE2) and chloroform extract (CE3) in DPPH radical scavenging activity. The CE1 also demonstrated outstanding nematicidal activity as compared with other extracts, pure anthraquinones, and even positive control azadirachtin. The study conclusively demonstrated the antioxidant potential ofR. emodiextracts and also its ability in extenuating theMeloidogyne incognita(root-knot nematode). The bioassay results can be extrapolated to actual field condition and clinical studies.