Influence of Drying Methods on Chemical Composition and Antioxidant Activity of Selected Malaysian Wild Edible Vegetable

• Main Authors: Zalilawati, Mat Rashid, Nashriyah, Mat, Natasha, Aziz
• Format: Conference or Workshop Item
• Language: English
• Published: 2017
• Subjects: Q Science (General)
• Online Access: http://eprints.unisza.edu.my/1171/1/FH03-FBIM-18-12436.pdf; http://eprints.unisza.edu.my/1171/

In this study, some selected and rarely studied Malaysian wild edible vegetables or commonly known as ‘ulam’ young leaves were investigated for chemicals composition and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity. The plants were Erechtites valerianifolia, Erechtites hieraciifolia, Manihot esculenta, Phyllanthusacidus, Piper sarmentosum, Ziziphus mauritiana, Gnetum gnemon, Oroxylum indicum, Acrosticum aureum and Terminalia catappa. Leaves samples were grind under liquid nitrogen, dried using either freezedrying (FD) or oven-drying (OD) drying methods, following maceration in ethanol, sonication (20 minutes) and centrifugation (10 minutes). Crude extracts were obtained after drying the supernatants under nitrogen gas. Chemicals content analysis of the extracts included total neutral sugars (TSC) via phenol-sulfuric acid assay, total phenolics (TPC) via Follin-Ciocalteau assay, total flavonoids (TFC) via aluminium chloride assay and total proteins (TP) by Bradford assay. DPPH scavenging activity was found to be consistent with TPC results in which ethanolic freeze dried (EFD) samples of T. catappa exhibited the strongest antioxidant potential (IC50=14.3 mg/mL) and the highest TPC (65.6±0.98 mg GAE/g extracts) compared to ethanolic oven dried (EOD). All EFD displayed moderate and strong DPPH scavenging activity with percentages inhibition ranging from 72.3 to 90.4% and IC50values 14.3 to 125 mg/mL, while EOD extracts activities were weaker with percentages inhibition ranging from 62 to 84.2% and IC50 values 15 to 290 mg/mL. Meanwhile, among EOD samples, O. indicum showed the strongest scavenging action (IC50 = 15 mg/mL) and greater TPC (53.4±1.32 mg GAE/ g extracts). All ethanolic extracts following FD methods displaying higher chemicals content and stronger antioxidant potential compared to OD methods could indicates that different drying methods of leaves did affect chemical composition isolation and antioxidant activity of plant extracts.