Publicação
Optimisation of ultrasound-assisted extraction of polyphenols and saponins from different parts of the Aesculus hippocastanum seed
| Resumo: | Horse chestnut (Aesculus hippocastanum L.) is a deciduous tree cultivated as an ornamental in urban areas with temperate climate across the Northern hemisphere. Among the scientific community, this species is known for the steroidal glycosides, among which aescin is the main active component and is responsible for most of its medicinal properties. Other bioactive compounds such as quercetin and kaempferol glycosides can also be found in this species. Therefore, this study aimed to characterize the phenolic and saponin profiles of the kernel, coat, and husk of the horse chestnut seed, and to optimise the ultrasound-assisted extraction (UAE) of these valuable compounds from the target seed samples using the response surface methodology (RSM). The polyphenol and saponin profiles of the samples were initially characterised by high-performance liquid chromatography coupled with mass spectrometry (HPLC-DAD-ESI/MS). The highest yields of solids (extract weight) were obtained from the kernel and husk of the horse chestnut seed. The kernel mostly contained flavonoids and the coat mostly contained flavan-3-ols, while both classes of polyphenols were found in the husk in comparable amounts. Saponins were also prominent in the kernel of the seed. A five-level central composite rotatable design (CCRD) combining the effects of the independent variables (time, ultrasonic power, and ethanol concentration) was implemented to optimise the UAE of the groups of phytochemicals identified in each sample. The polynomial models were fitted to the experimental data, statistically validated, and used to determine the optimal UAE conditions. Extraction of the target compounds was greatly affected by the three independent variables through linear, quadratic and/or interactive effects. The global optimal processing conditions for the extraction of phenolic compounds and saponins from the kernel, were somewhat similar, with exception to the solvent concentration. On the other hand, the extraction of phenolic compounds from the kernel required a longer processing time and higher ultrasonic power, which can be related to the intrinsic nature of the plant material. The results of this study could be exploited by companies interested in phenolic- and saponin-rich natural ingredients, such as the pharmaceutical, cosmetic, and food industries. |
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| Autores principais: | Albiston, Carly |
| Assunto: | Aesculus hippocastanum Phenolic compounds Saponins Ultrasound-assisted extraction Process optimisation Chromatographic analysis |
| Ano: | 2021 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso restrito |
| Instituição associada: | Universidade Politécnica de Bragança |
| Idioma: | inglês |
| Origem: | Biblioteca Digital da UPB |
| Resumo: | Horse chestnut (Aesculus hippocastanum L.) is a deciduous tree cultivated as an ornamental in urban areas with temperate climate across the Northern hemisphere. Among the scientific community, this species is known for the steroidal glycosides, among which aescin is the main active component and is responsible for most of its medicinal properties. Other bioactive compounds such as quercetin and kaempferol glycosides can also be found in this species. Therefore, this study aimed to characterize the phenolic and saponin profiles of the kernel, coat, and husk of the horse chestnut seed, and to optimise the ultrasound-assisted extraction (UAE) of these valuable compounds from the target seed samples using the response surface methodology (RSM). The polyphenol and saponin profiles of the samples were initially characterised by high-performance liquid chromatography coupled with mass spectrometry (HPLC-DAD-ESI/MS). The highest yields of solids (extract weight) were obtained from the kernel and husk of the horse chestnut seed. The kernel mostly contained flavonoids and the coat mostly contained flavan-3-ols, while both classes of polyphenols were found in the husk in comparable amounts. Saponins were also prominent in the kernel of the seed. A five-level central composite rotatable design (CCRD) combining the effects of the independent variables (time, ultrasonic power, and ethanol concentration) was implemented to optimise the UAE of the groups of phytochemicals identified in each sample. The polynomial models were fitted to the experimental data, statistically validated, and used to determine the optimal UAE conditions. Extraction of the target compounds was greatly affected by the three independent variables through linear, quadratic and/or interactive effects. The global optimal processing conditions for the extraction of phenolic compounds and saponins from the kernel, were somewhat similar, with exception to the solvent concentration. On the other hand, the extraction of phenolic compounds from the kernel required a longer processing time and higher ultrasonic power, which can be related to the intrinsic nature of the plant material. The results of this study could be exploited by companies interested in phenolic- and saponin-rich natural ingredients, such as the pharmaceutical, cosmetic, and food industries. |
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