Chemical profiling, in vivo antioxidant effect and antimutagenic evaluation of melilotus indicus (L.) all. extracts

Abstract

Melilotus indicus (L.) All. is used as a vegetable and known to possess valuable remedial uses. The whole plant was extracted using 70% methanol to give the total aqueous methanol extract (AME) which was defatted with petroleum ether to give petroleum ether extract (PEE) and defatted AME (DAME). PEE was analyzed by GC-MS and LC-ESI-MS. In addition, the chromatographic investigation of DAME led to the isolation of thirteen flavonoids and one phenolic acid. Their structures were elucidated through chemical and spectroscopic analysis (ESIMS, UV and NMR). Prospective activity of AME, PEE and DAME against alloxan-induced oxidative stress, diabetes and mutagenic effect in male rats was investigated. GC-MS analysis detected thirty-five non-polar compounds while the LC-ESI-MS revealed the presence of additional eight metabolites. AME and PEE significantly (P < 0.01) increased serum GSH content in rats (35.3 ± 0.8 and 34.9 ± 0.6 mmol/L) compared to diabetic rats (21.8 ± 0.3) and vitamin E (36.2 ± 1.1). Also, AME and DAME revealed a significant acute anti-hyperglycemic effect potentiated after 4 weeks of treatment with blood glucose levels of 96.9 ± 6.2 and 98.7 ± 6.1 mg/dL, respectively, compared to diabetic rats (263.4 ± 7.8) and Metformin group (81.9 ± 2.4) at P < 0.01. Additionally, AME revealed a significant inhibitory effect on the irregularity of bone marrow cells and sperm abnormalities appeared from higher inhibitory indices which were 75 and 76, respectively.