Toxicological Evaluation of the Repeated Dose Administration of the Ethanolic Extract of <i>Azolla microphylla</i> in Wistar Albino Rats

Abstract

Azolla microphylla is an easily cultivable aquatic plant with the commendable nutritious property. Recent reports on Azolla species emphasize the therapeutic potential of the plant extracts. Moreover, the same genus of plant also had displayed antioxidant potential owing to its free radical scavenging tendency. Although these attributes were identified, a study investigating the toxicological property of different dosages of ethanolic extract of A. microphylla (EAM) is not yet reported. Thus the present study aims for the in vivo toxicological evaluation of the EAM in Wistar strain of rats. Daily doses of 0, 250, 500, 1000 and 2000 mg/kg body weight of EAM were administered orally to group-I, group-II, group-III, group-IV & group-V rats, respectively for 14 days. Biochemical and histopathological studies were established through standard methods. The acute toxicity results suggest the non-toxic nature of the extract supported with the absence of mortality and toxic symptoms until 72 h of observation. The results of sub-acute toxicity study in the extract-treated rats (group-II to group-IV) indicate non-significant changes to the biochemical (total protein, AST, ALT, LDH, albumin, globulin, urea, creatinine, cholesterol, & triglycerides), hematological (Hemoglobin, RBCs, WBCs, platelets, monocytes, lymphocytes, & neutrophils), and histopathological observations when compared to the control group of rats. However, group-V rats were treated with 2000 mg/kg b.w. exhibited statistically significant variations to most of the biochemical and hematological parameters although no mortality/physical toxic signs were reported till the end of the experimental period. Thus, the sub-acute toxicity results suggest that the extracts were non-toxic and safe to rats between 250-2000 mg/kg b.w. concentration under 14 days observational period. Moreover, as there was no mortality upto 2000 mg/kg b.w., 50% lethal dose (LD50) could not be determined, and hence it is considered to be greater than 2000 mg/kg/day.