Characterization, Preclinical Efficacy and Toxicity Evaluations of Flavonoids Glycosides based Standardized Fenugreek Seed Extract (FEFLG)

Abstract

Introduction: Fenugreek seeds, a natural food chain raw material, is known to have many flavonoid glycosides. Objective: Characterization, preclinical efficacy, and safety evaluation of flavonoid glycosidebased standardized fenugreek seed extract (FEFLG). Methods: FEFLG was characterized for a group of flavonoid glycoside marker compounds by HPLC. The CD38+ enzyme inhibition efficacy was assessed in vitro. In addition, acute oral toxicity (AOT) and subchronic, 90-day repeated-dose oral toxicity (in vivo), mutagenicity (AMES test, in vitro) and chromosome aberration test (in vitro) of FEFLG were evaluated. Results: The FEFLG was found to have 49.85% of total flavonoid glycosides content in FEFLG (25.15% of Group 1: vitexin, isovitexin and vitexin 2-o- rhamnoside and 24.70% of Group 2 (vicenin derivatives, schaftoside, iso-schaftoside, orientin and iso-orientin). FEFLG showed CD38+ enzyme inhibition in vitro (IC50= 0.96 μg/ml) equivalent to the positive control, apigenin. FEFLG did not show any toxicity at an acute oral dose of more than 2000 mg/kg (median lethal dose, LD50) with a limit dose of 5000 mg/kg. The 90-day repeated-dose oral administration of FEFLG did not induce significant toxicological changes till the maximum dose of 1000 mg/kg in male and female rats, indicating no observed adverse effect level, NOAEL ≥ 1000 mg/kg. FEFLG did not show mutagenicity (up to a concentration of 5000 μg/plate) or structural chromosomal aberrations (up to 5000 μg /ml). Conclusion: The CD38+ enzyme inhibitor efficacy in vitro, oral safety in vivo and absence of mutagenicity or genotoxicity of FEFLG indicated its potential for anti-aging applications. Key words: Fenugreek seeds, Flavonoid glycosides, CD38+ enzyme inhibition, Acute toxicity, Subchronic toxicity, Mutagenicity, Chromosomal aberration.