Evaluation of effective protein extraction procedure to profile petiole of Moringa oleifera

Abstract

Moringa oleifera is widely known as multipurpose tree since all of its parts confer multiple functions. The leaf is highly favourable among consumers while the petiole is mostly wasted. There are numerous studies on the flavonoid and antioxidant property of the stem and twig. However, study on the petiole has never been done. There-upon, this study was conducted to develop protein profiling of the petiole. In this study, 6 different protein extraction methods were tested on the fresh petiole before its protein quantity and quality were checked via Bradford assay and Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis (SDS-PAGE) respectively. The in-solution digestion was then done prior to LC-MS/MS analysis. The protein electrophoretic pattern from the SDS-PAGE proves that method 6 using Tris HCl buffer with incorporation of dithiothreitol (DTT) and phenylmethylsulfonyl fluoride (PMSF) confers the best quality of protein. It produced the highest number of visible individual bands compared to other methods. Meanwhile, 93 proteins were successfully identified via LCMS analysis where the protein, signal response and carbohydrate metabolism categories confer the highest percentage. High quality and content of the protein extracted from the petiole including the antioxidant, anticancer and antidiabetic protein identified suggested that consuming this part of the plant could enhance nutrients of human body.