Phytochemical Profiling, Antimicrobial Activity, and in vivo Toxicological Assessment of Whole Plant Aqueous Extract of Coix lacryma-jobi (L.)

Abstract

Coix lacryma-jobi (L.), a plant belonging to the family Poaceae having common names of Job's tears or adlay. In particular, has been popular as a medicinal plant is widely used to treat various diseases by the tribal population of Purulia district. There is dearth of sufficient knowledge regarding the efficacy and toxicity of the aqueous whole plant extracts hence the study was conducted. Phytochemical analysis of the aqueous whole plant was conducted such as total phenolics, flavonoid content, the antioxidant assays (DPPH, ABTS), and GC-MS and UV-vis spectroscopic studies were performed. Simultaneously antibacterial efficacy was evaluated with gram-positive and gram-negative bacteria. Further, to test the toxicological effects, in vivo studies were conducted on mice with 200mg/kg, 500mg/kg and 800mg/kg b.wt doses of plant extract considering enzymatic activity and histology of certain tissues such as kidney, liver and spleen. Total phenolic contents obtained were 292.82mg GAE/gm extract and total flavonoid contents were 20.97 mg of quercetin equivalent/gm extract, GC-MS analysis showed presence of 6 compounds among which germanicol and phenol,2,4-bis(1,1-dimethylethyl) being prominent. Results of ABTS and DPPH assays demonstrated a good level of antioxidant activity of the extract and possess potent antibacterial property against gram positive (Staphylococcus epidermidis) bacteria with minimum inhibitory concentration 3mg/ml. In vivo toxicological evaluation indicated that 200mg/kg body weight dose of Coix lacryma-jobi (L.) extract had no negative effect on the organs than other two doses i.e. (500, and 800 mg/kg body weight) had caused slight negative effects on the relative organs or body weight, or on enzyme activities (p<0.001) these doses were selected based on LD50 which was about 2000 mg/kg body weight. In summary, the wild form of Coix lacryma-jobi exhibits potential as a herbal source of antibacterial and antioxidant compounds, as well as a possible helper for cholesterol control.  To avoid any potential harmful effects, its use should be restricted to small dosages. To fully realize the plant's medicinal potential, future research should focus on isolating particular bioactive compounds and examining their mechanisms of action.