7 results on '"Bowyer, Michael C."'
Search Results
2. Ultrasound‐assisted extraction of <italic>Catharanthus roseus</italic> (L.) G. Don (Patricia White cultivar) stem for maximizing saponin yield and antioxidant capacity.
- Author
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Pham, Hong Ngoc Thuy, Vuong, Quan Van, Bowyer, Michael C., and Scarlett, Christopher J.
- Subjects
ULTRASONIC imaging ,CATHARANTHUS roseus ,SAPONINS ,OXIDANT status ,ALKALOIDS - Abstract
Abstract: Large quantities of
Catharanthus roseus leaf have been used for the extraction of alkaloids, which results in a significant amount of waste that includes the stems, roots, and the extracted leaves. This study aimed to determine the optimal extraction conditions, by applying response surface methodology with Box–Behnken design to assess the interactive effect of ultrasonic parameters, including ultrasonic temperature, time, ratio of sample‐to‐solvent, and ultrasonic power on the extraction efficiency of saponins and antioxidants from the stems ofC. roseus . The results revealed that a maximized saponin yield (138.21 mg ESE/g) and strong antioxidant activities (8.34, 12.06, 10.53, and 19.15 mg TE/g for DPPH, ABTS scavenging capacity, FRAP, and CUPRAC, respectively) could be obtained under the optimal extraction conditions: ultrasonic temperature of 55 °C, ultrasonic time of 35 min, sample‐to‐solvent ratio of 1/100 (g/ml), and ultrasonic power of 150 W. Practical applications: Recovering bioactive compounds fromCatharanthus roseus stems, especially saponins which have been linked with various biological activities such as antimicrobial, antiherbivore, and/or cytotoxic activities, is necessary to avoid wasting bioresource from the alkaloid exploration of the leaves. This study suggested the optimal ultrasonic conditions that could be used for further extraction and isolation of saponins fromC. roseus stems for potential application in the food, nutraceutical, cosmeceutical, and pharmaceutical industries. [ABSTRACT FROM AUTHOR]- Published
- 2018
- Full Text
- View/download PDF
3. The Effects of Drying on Physico-Chemical Properties and Antioxidant Capacity of the Brown Alga ( Hormosira banksii (Turner) Decaisne).
- Author
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Dang, Thanh T., Vuong, Quan Van, Schreider, Maria J., Bowyer, Michael C., Altena, Ian A. Van, and Scarlett, Christopher J.
- Subjects
ANTIOXIDANTS ,BROWN algae ,OXIDANT status ,CHEMICAL properties ,DRYING - Abstract
Hormosira banksii is a rich source of polyphenols, which can be utilized in the food or pharmaceutical industries. This study aimed to determine the impact of six drying methods on properties of the alga H. banksii. Our data revealed that drying conditions significantly affected recovery yield, residual moisture, extraction yield, total phenolic content (TPC) as well as antioxidant capacity of H. banksii ( P < 0.05). Optimal conditions for oven, vacuum and de-humidification were 40, 50 and 50C, respectively, and microwave power is 840 W. Under optimal conditions, H. banksii prepared by freeze, de-humidification and vacuum had significantly higher levels of TPC, total flavonoid content (TFC) and proanthocyanidins as well as possessing stronger antioxidant capacity in comparison with those prepared by sun, microwave and oven drying methods. As freeze drying is costly and time-consuming, de-humidification (50C, air in and out of 11.1 and 15.4%) and vacuum (50C, 10 psi) were recommended for drying H. banksii Practical Applications Algae possess various antioxidants with potential benefits for health. Drying is considered as a method for preserving materials, transport with low costs and especially first step for extraction, isolation and purification of active compounds. Thus, it is important to investigate the effects of drying conditions on the properties of the dried alga H. banksii. From the findings, the different drying conditions significantly affected the phytochemical profile and antioxidant activity of the dried alga and the optimal drying conditions could be applied for preparation of dried H. banksii for further processing (extraction, fractionation and isolation of bioactive compounds) as well as potential industrial applications (as a reference for drying H. banksii and other algae). [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
4. Microwave-Assisted Extraction for Saponins and Antioxidant Capacity from Xao Tam Phan ( Paramignya trimera) Root.
- Author
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Nguyen, Van Tang, Vuong, Quan V., Bowyer, Michael C., Van Altena, Ian A., and Scarlett, Christopher J.
- Subjects
SAPONINS ,OXIDANT status ,HERBAL medicine ,PLANT roots ,PLANT extracts - Abstract
The aim of this study was to determine the optimal microwave-assisted extraction (MAE) parameters for saponins and antioxidant capacity from the P. trimera root. The optimal MAE parameters were found to be 100% methanol, extraction time of 40 min and ratio of solvent to sample of 100 mL/g. Saponin content, saponin extraction efficiency, ABTS radical scavenging capacity, DPPH radical scavenging capacity, cupric ion reducing antioxidant capacity, and ferric reducing antioxidant power of the P. trimera root achieved under these parameters were 520.5 mg escin equivalents (EE)/g dried sample, 62.6%, 215.3, 93.2, 24.7, 121.7 mg trolox equivalents (TE)/g dried sample, respectively, which were higher than predicted values (488.8 mg EE/g dried sample, 58.8%, 213.7, 89.5, 24.0, 115.8 mg TE/g dried sample, respectively). Therefore, the optimal MAE parameters of 100% methanol, 40 min and 100 mL/g are recommended for obtaining saponin-enriched extracts from the P. trimera root for potential application in the food industry. Practical Application This study indicated that methanol concentration had the highest effect on the extractability of saponins and antioxidant capacity from P. trimera root, followed by ratio of solvent to sample and extraction time. Therefore, the application of the optimized MAE parameters allows obtaining the highest saponin yield as well as the greatest antioxidant capacity from P. trimera root for further investigation and application. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
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5. Effect of vacuum-drying, hot air-drying and freeze-drying on polyphenols and antioxidant capacity of lemon ( Citrus limon) pomace aqueous extracts.
- Author
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Papoutsis, Konstantinos, Pristijono, Penta, Golding, John B., Stathopoulos, Costas E., Bowyer, Michael C., Scarlett, Christopher J., and Vuong, Quan V.
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VACUUM technology ,FREEZE-dried foods ,LEMON ,AQUEOUS solutions ,OXIDANT status ,POLYPHENOLS - Abstract
The aim of this study was to investigate the effect of freeze-drying, hot air-drying and vacuum-drying at 70, 90 and 110 °C, on dried lemon pomace polyphenols and antioxidant capacity. The total phenolic content and antioxidant capacity were higher in lemon pomace dried by hot air or under vacuum than those dried by freeze-drying and increased as the temperature increased. The highest total flavonoid content was recorded in the pomace dried under vacuum at 70 and 90 °C. Lemon pomace dried by freeze-drying had the highest neohesperidin content, whereas pomace dried under vacuum at 70 °C had the highest rutin and p-coumaric acid content. The highest gallic acid content was recorded in the pomace dried by hot air at 110 °C. The results of this study indicate that drying technique should be carefully selected according to the bioactive compounds aimed to be extracted. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
6. Phytochemical retention and antioxidant capacity of xao tam phan ( Paramignya trimera ) root as prepared by different drying methods.
- Author
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Nguyen, Van Tang, Pham, Ngoc Minh Quynh, Vuong, Quan Van, Bowyer, Michael C., van Altena, Ian A., and Scarlett, Christopher J.
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PHYTOCHEMICALS ,OXIDANT status ,PLANT drying ,ANTIOXIDANTS ,PROANTHOCYANIDINS ,MICROWAVE drying - Abstract
Xao tam phan (Paramignya trimera(Oliv.) Guillaum) has been used as an herbal medicine for the treatment of cancer or cancer-like diseases in recent years, particularly in Vietnam. Drying is an important step for preparation of dried materials for storage and further investigation; however, the effects of drying must be taken into account when processing samples, because this can have profound effects on the stability of phytochemical compounds and the biological activity of the driedP. trimeraroot. As such, this study assessed the effects of four different drying methods (conventional, hot air, vacuum, and microwave) on phytochemical retention and antioxidant capacity ofP. trimeraroot, to identify an optimal drying method forP. trimeraroot. The results showed that the drying methods significantly affected phytochemical levels and antioxidant capacity ofP. trimeraroot and that among the four drying methods tested, microwave drying (400 W) had the highest levels of phytochemical compounds, with total phenolic, total flavonoid, proanthocyanidin, and saponin contents of 11.27 mg GAE, 19.88 mg RE, 3.98 mg CE, and 267.15 mg EE/gram of dried sample, respectively. Dried sample prepared using this method had antioxidant capacity comparable to that of other drying methods. In addition, this method had the shortest drying time (0.28 h) and consumed the least energy (0.28 kWh). Therefore, microwave drying should be considered for dryingP. trimeraroot for further investigation and utilization. [ABSTRACT FROM PUBLISHER]
- Published
- 2016
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- View/download PDF
7. Effects of Different Drying Methods on Bioactive Compound Yield and Antioxidant Capacity of Phyllanthus amarus.
- Author
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Nguyen, Van Tang, Van Vuong, Quan, Bowyer, Michael C., Van Altena, Ian A., and Scarlett, Christopher J.
- Subjects
BIOACTIVE compounds ,OXIDANT status ,PHYLLANTHUS ,FOOD industry ,FOOD preservation methodology ,EUPHORBIACEAE - Abstract
Phyllanthus amarus(P. amarus) has been used as a herbal medicine, particularly for liver support, in many countries and its extracts have been shown to possess potent antioxidant and anticancer propertiesin vitro. The preparation of dried sample is crucial for further extraction and isolation of phytochemicals. In this study, the effects of six different drying methods (hot air, low-temperature air, infrared, microwave, sun, and vacuum drying) on the phytochemical yield and antioxidant capacity were determined to identify the optimal drying method forP. amarus. The results showed that different drying methods, as well as different drying conditions within each method, significantly affected phytochemical yield and antioxidant capacity ofP. amarusextracts. Infrared drying at 30°C was the best method for both retention of bioactive compound yield and antioxidant capacity ofP. amarusextract, with 12 compounds were identified. In contrast, low-temperature-air drying at 25°C not only required the longest drying time but also significantly reduced the levels of bioactive compounds and antioxidant capacity ofP. amarus. Therefore, infrared drying at 30°C is suggested for dryingP. amarusfor subsequent assessment of bioactivity. [ABSTRACT FROM PUBLISHER]
- Published
- 2015
- Full Text
- View/download PDF
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