Aidilla Mubarak School of Medicine and Pharmacology and School of Plant BiologyFaculty of Medicine, Dentistry and Health SciencesFaculty of Natural and Agricultural Sciences

Aidilla completed a Bachelor of Science degree with Honours in Molecular Bioscience, followed by a Masters in Nutrition in her home country of Malaysia. After working as an academic fellow and later a tutor in the Department of Agriculture and Food Science, at the Universiti Malaysia Terengganu, she was sponsored by the government of Malaysia to undertake full-time PhD at UWA. Upon completion of her PhD she will take up a lecturing position at her former university in Malaysia.

Her current research investigates the links between plant polyphenol compounds and dietary health. Dietary polyphenols have been associated with reduced risk of cardiovascular disease. Fruit such as plums are a rich source of polyphenolic antioxidants. The objective of her study was to evaluate and quantify total phenolic content, selected individual polyphenols and total antioxidant capacity in 32 new Western Australia plum cultivars.

Plum Polyphenol Composition In Relation To Total Antioxidant Capacity

Aidilla Mubarak

Supervisors: Assc. Prof Michael Considine, Prof Kevin Croft, Prof Jonathan Hodgson

The UWA Institute of Agriculture

Acknowledgement

• Supervisors• Dr Ewald Swinny (ChemCentre)• Dr Simon Ching (PathWest)• Department of Agriculture and Food, Western Australia 

• ARC (LP0882884) • Malaysian Ministry of Higher Education

Polyphenols

Secondary metabolites of plants

Widely dispersed in plants

Diverse biological functions

Chlorogenic Acid CatechinQuercetin

Why is polyphenol important?

Quality in fruits

• Visual appearance

• Taste

Interest from consumers and food manufacturers. Why?• Prevention of diseases• Acts an antioxidant

• Most abundant antioxidant from diet

Why is polyphenol important?

Dietary sources

Distribution In Fruits

Varies with different factors 

Different cultivar Storage condition

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Empire McIntosh Cortland Red Delicious Northern Spy

Concentrationµg/g FW

Apple Cultivars

Polyphenol distribution in apple skin of different cultivars

Catechin

Epicatechin

Tsao et al,  J. Agric. Food Chem., 2003, 51 (21), pp 6347–6353   

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Cortland Cortland Red Delicious Red Delicious

Concentration µg/g FW

Apple cultivars

Polyphenol distribution in apple skin and flesh

Chlorogenic acid

Catechin

Skin Flesh Skin Flesh

Tsao et al,  J. Agric. Food Chem., 2003, 51 (21), pp 6347–6353   

Information on phenolic content • few cultivars• single group of compounds

Polyphenol compositions among different cultivars of plums is important – breeding program

Research Objective

To quantify polyphenols and antioxidant capacity of 32 new Western Australia plum 

cultivars (DAFWA)

To demonstrate a correlation between polyphenols composition and the 

antioxidant capacity

Methods

Selected individual polyphenol identified & quantified:

Reversed‐phase HPLC‐DAD

Total phenolic content measurement:

Folin Ciocalteu’s colorimetric reaction

Total antioxidant capacity quantified:

Antioxidant inhibition of oxygen radicals (AIOR) assay

32 Western Australian Plum

Major polyphenol compound in plums

• Neo‐chlorogenic acid Mean:  29 ± 54 mg/kg Range: 0 – 221 mg/kg

• QuercetinMean: 52 ± 41 mg/kg Range: 9 ‐ 240 mg/kg

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32

Conc. (mg/kg)

Plum cultivars

Neo‐chlorogenic acid

Quercetin

Variation of polyphenol amongst cultivars

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1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31

TPC (mg/kg GAE)

Plum cultivar

Mean: 701 ± 322 mg/kg GAERange: 222 – 1711 mg/kg GAE

Total Phenolic Content in Plum

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TAC (mol/kg TE)

Plum cultivar

Mean: 13720 ± 6142 mol/kg TERange: 4795 – 36187 mol/kg TE

Total Antioxidant Capacity in Plum

Relationship of total antioxidant capacity with measured polyphenol content

Measurements N Pearson Correlation

Sig. (2‐tailed)

Total Phenolic Content

32 0.954 ** 0.000

Neo‐chlorogenic acid content

32 0.242 0.182

Quercetin content 32 0.180 0.324

Conclusion

Total phenolic content – positive relationship with the antioxidant capacity (P<0.001)

Neochlorogenic acid & quercetin glycoside –predominant polyphenols 

Do not individually account for the antioxidant capacity 

Future analysis

• Ascorbic acid, glutathione and total thiols

• Controlled human intervention study: effect of chlorogenic acid on cardiovascular function