Mass Spectrometric Profiling, Quantification of Phenolic Content and Exploration of Oxidation Resistant Activity of Mallotus philippensis Leaves

Abstract

Mallotus philippensis is a commonly growing plant belonging to the family “Euphorbiaceae”. It possesses numerous ethnopharmacological applications. Literature survey revealed the existence of great structural diversity in the whole genus. Polyphenolic compounds possesses numerous applications like cytotoxic, antibacterial, antioxidant activity e.t.c. There is no report revealing the presence of phenolic constituents from leaves of Mallotus philippensis. It would be of great significance to explore such constituents. Now a days HPLC-DAD-ESI-MS is considered as a very rapid and accurate technique for identification of phenolics. So, the objective was to analyze phenolic phytoconstituents present in leaves of this plant by HPLC-DAD-ESI-MS. Many biological activities have been documented in this plant so far. But there is no evidence regarding its antioxidant potential. So, leaves were targeted to determine oxidation resistant activity. Mallotus philippensis leaves were extracted with various solvents and extraction yield showed comparative ability of different solvents to leach out phytoconstituents. Paper chromatography was performed to determine number and types of flavonoids present. Phytochemical analysis of extract was performed by following standard protocols regarding existence of important classes of compounds. Presence of sugars was determined by acid catalyzed hydrolysis. Methanolic extracts were analyzed by LC-MS. Phenolic content and flavonoid content was estimated by Folin-Ciocalteu and aluminium chloride colorimetric assay respectively. Oxidation resistant activity was determined by DPPH colorimetric assay. Greater extraction yield indicated methanol:water (70:30) as the best extractant. So, this extract was further analyzed by 2D-PC and phytochemical analysis. 2D-PC indicated presence of glycosides of flavones, flavanones, and isoflavones. Results of phytochemical analysis indicated presence of important classes of compounds like flavonoids, cardiac glycosides, tannins, and saponins. As a result of acid hydrolysis sugars were cleaved from aglycones and their identity was established as rhamnose, xylose, and glucose. GC-MS unveiled presence of three new compounds including two pentenoates and an important hydroxy chroman derivative. LC-MS analysis revealed the presence of eight novel polyphenolic glycosides. Total phenolic and flavonoid content was estimated as 63.13 mg GAE and 20.18 mg QE per grams of dried leaves. vii Oxidation resistant activity was determined in terms of IC50 value which was 0.2096 mg/mL for MPM and 0.070 mg/mL for ascorbic acid. This novel LC-MS profile of phytoconstituents led to the conclusion that M. philippensis leaves are an important source of vital constituents that possesses significant oxidation resistant potential so it can be used in therapeutics.