Response surface methodology mediated optimization of three bioactive phenethylisoquinoline alkaloids in Gloriosa...

The present study aims for response surface methodology mediated optimization of ultrasound assisted extraction conditions to maximize the content (% dry wt.) of three bioactive phenethylisoquinoline alkaloids namely 2-demethyl colchicine (I), gloriosine (II) and colchicine (III) in Gloriosa superba L. (tubers).

A factorial central composite design (CCD) was applied considering the outcome of independent factors, extraction time (A), extraction temperature (B) and liquid to solid ratio (C) and quantification was done through high-performance thin layer chromatography (HPTLC-UV) in chloroform: acetone: diethyl-amine (5:4:1 v/v).

Twenty experimental runs containing fourteen factorial and six central points had resulted from CCD matrix and targeted metabolites were estimate at each run. The optimum experimental conditions were obtained at A: 23.11min, B: 20.48°C and C: 49.90mL/g. The content of (I), (II) and (III) was found to be 0.007, 0.027 and 0.096% respectively and is statistically insignificant (P<0.05) than predicted values (0.007, 0.027, and 0.097%) under optimal experimental condition. The method was validated as per ICH protocols, linearity was established at 100-500ng/spot, LOD and LOQ varies from 18.57 to 20.05 and 56.08 to 60.24ng/spot. The method was precise, reproducible and repeatable with accuracy ranging from 103.24 to 104.58%. The present method was found greener (AES, NEMI, GAPI, AGREE and AGREEprep) and blue (BAGI) then existing methods.

The study demonstrates RSM mediated multivariate HPTLC-UV method for maximum yield of alkaloids in G. superba with distinguished greenness and blueness.