Antioxidant properties of selected wild edible plants in Sabah

• Main Author: Wong, Jin Yi
• Format: Thesis
• Language: English
• Published: 2012
• Subjects: TX Home economics
• Online Access: https://eprints.ums.edu.my/id/eprint/18693/1/Antioxidant%20properties%20of%20selected.pdf; https://eprints.ums.edu.my/id/eprint/18693/
• Institution: Universiti Malaysia Sabah

The objective of this study was to evaluate in vitro antioxidant activity and identify antioxidant compounds of six wild edible plants from Sabah. Methanolic, ethanolic, acetone, cold water and hot water extracts of six freeze dried wild edible plants with separate edible part (leaf, stem and flower) were evaluated through total phenolics, total flavonoids content and antioxidant activity by using oxygen radical absorbing capacity (ORAC), ferric reducing antioxidant power (FRAP), ABTS (2,2- azino-bis-(3-ethylbenzothiazoline-6-sulfonica cid) diammonium salt) radical scavenginga nd 2,2-diphenyl-l-picryhydrazyl free radical scavenginga ctivities. Hot water and methanolic extracts from wild edible plants have been found significantly higher (p<0.05) in phenolics, flavonoids and total antioxidant activities than other extracts. The leaves of all the plants have higher levels of total phenolics, flavonoids, and antioxidant capacity than the stem and flower edible part. Integrated antioxidant capacity index showed the leaf of Heckeria umbellatum and Aniseia martinicense possess a marked antioxidant activity for all the extracts found in the assays. Principal component analysis (PCA) indicated phenolic group was the primary factor contributing to ORAC and FRAP for hot water and methanolic extract. The leaves of Schismatoglottis ahmadii contained a significantly( p<0.05) higher amount of alpha-tocophero(l 38.75 mg/100g DW) and the stem of Aniseia martinicense contained highest gamma-tocopherol (10.49 mg/100g DW) compared to other plant species. On the other hand, ascorbic acid showed the highest content In the leaf of Heckeria umbe/latum (53.81 mg/100g FW). The leaf of Heckeria umbellatum (656.54 mg/100g FW) and Helminthostachys zeylanica (1809.96 mg/100g FW) showed the highest beta carotene and lutein contents respectively among all the wild edible plants. Crude extract of the plants were extracted and further purified with Strata-X cartridges, and the identification and quantification of phenolic compounds and phenolic acid were achievedu sing High Performance Liquid Chromatography( HPLC)-diodearray detection. Typical HPLC profiles of phenolics from the leaf of Heckeria umbellatum, Aniseiam artinicensea nd Gonostegiah irta showed kaempferol,glycoside of luteolin and apigenin and phenolic acids such as chlorogenic acid and coumaric acid as the main compounds contributing to the high antioxidant activity of the plant species. In conclusion, the leaves of Heckeria umbellatum, Anisela martinicense and Gonostegia hirta have excellent potential in the future to emerge as nutraceutical products