Title:Optimization of Aqueous Extraction of the Australian Maroon Bush (Scaevola Spinescens R. Br.) to Maximize Bioactive Compound and Antioxidant Yield
Volume: 2
Author(s): Kien Q. Nguyen*, Christopher J. Scarlett and Quan V. Vuong
Affiliation:
- School of Environmental and Life Sciences, University of Newcastle, Brush Rd., Ourimbah, NSW 2258,Australia
Keywords:
Scaevola spinescens, maroon bush, response surface methodology, optimization, bioactive compounds, antioxidant
activity.
Abstract:
Background: Scaevola spinescens is an endemic Australian shrub that is linked to various
health benefits and traditionally used as a medicine by decoction. To date, the extraction efficiency
of the plant under various conditions has not been well understood. This study aimed to optimize
aqueous extraction conditions of S. spinescens, for maximum extraction of total phenolic compounds,
flavonoids and saponins, as well as antioxidant activities.
Methods: Response surface methodology was used to determine the influence of four independent
parameters including temperature, time, sample-to-water ratio and pH. The optimal ranges of temperature
(60-90°C), time (30-60 min), sample-to-water ratio (2-6 g/100 mL) and pH (3-7) were determined
in preliminary experiments. Following assessment and optimization of the response surface
methodology models, validation experiments were conducted to compare predicted and experimental
values.
Results: The RSM models showed that extraction temperature, time and sample-to-water ratio significantly
affected total phenolic compound yields. Extraction temperature and time significantly affected
flavonoid yields, while only sample-to-water ratio significantly affected saponin yields. Optimal
conditions for extraction were determined to be: 90°C, 53 min, 2:100 (g/mL), and pH of 4.5, if
saponins are the target compounds for extraction. For phenolics, flavonoids and antioxidant capacity,
a higher sample-to-water ratio of 6:100 (g/mL) is recommended.
Conclusion: Response surface methodology proved to be a reliable method for predicting yields of
bioactive compounds and antioxidant capacity in S. spinescens. These findings can be used for efficient
decoction by practitioners and end users, or by researchers for further isolation and purification
of bioactive compounds from S. spinescens extracts.