HPLC and HPTLC methods by design for quantitative characterization and in vitro anti-oxidant activity of polyherbal formulation containing Rheum emodi.

Safoof-e-Pathar phori (SPP) is a traditional polyherbal formulation and has been used since long time for its anti-urolithiatic activity. It contains three plant constituents Didymocarpous pedicellata, Dolichous biflorus and Rheum emodi. Emodin and chrysophanic acid were selected as chemical markers for SPP and quantified using simultaneous HPTLC and RP-HPLC methods in R. emodi and in SPP. The simultaneous methods were found linear r(2) = 0.991 in a wide range (10-800 ng spot(-1) with HPTLC, 5-500 µg mL(-1) with HPLC) precise, accurate and robust for both the drugs. Anti-oxidant activity of SPP, R. emodi as well as standard emodin and chrysophanic acid were determined by using DPPH (2,2-diphenyl-1-picryl hydrazyl radical), which showed better activity of R. emodi (IC50 = 12.27) extract when compared with SPP (IC50 = 32.99) and standard drugs (IC50 = 66.81). The robustness of methods were proved by applying the Box-Behnken response surface design software and other validation parameters evaluated were satisfactorily met; hence, the developed method found suitable for application in the quality control of several formulations containing emodin and chrysophanic acid.