Extraction process optimization of flavonoid and in vitro amylase inhibitory effect of purified quercetin derivative from Amorphophallus paeoniifolius tubers

Abstract

Amorphophallus paeoniifolius (Elephant foot yam) is a prominent tuberous plant utilized across several parts of India to treat various ailments such as a tumour, haemorrhage, microbial infections, cough, bronchitis, diabetes, anaemia, and hepato-gastro and cardiovascular diseases. In this context, the present study aims to optimize the extraction process of the flavonoid and to study the in vitro amylase inhibitory effect of purified flavonoid moiety. The Shake flask method with different extraction solvents was adopted to quantify the flavonoid content. Central composite design (CCD) based response surface methodology (RSM) was formulated to optimize the extraction process. Three-dimensional preparative chromatography (3D PTLC) was executed to purify the flavonoid content and high-resolution liquid chromatography-mass spectrometry (HRLC-MS) was adopted to predict the structure. 3,5-dinitrosalicylic acid (DNS) based spectrophotometry method was used to determine the amylase inhibitory property. All the analyses were subjected to standard statistical tests. The developed model for the extraction optimization process was found to be near significant (P = 0.242) with temperature as a significant variable (P = 0.029), and a 107-fold increase (71.11±0.5 mg/g tissue) of flavonoid content was recorded. A strong yellow colour spot (flavonoid fraction) was eluted using 3D PTLC technique and the molecule was identified as quercetin derivative (m/z 447) by the direct MS method. Significant amylase inhibition (36.1±2.1%) recorded by purified quercetin derivative has documented the utilization of A. paeoniifolius tubers as classical traditional medicine.