Browsing by Author "Albiston, Carly"
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- Horse chestnut (Aesculus hippocastanum L.) seed phenolic extracts obtained by ultrasound- assisted extractionPublication . Albiston, Carly; Añibarro-Ortega, Mikel; Dias, Maria Inês; Ferreira, Isabel C.F.R.; Pinela, José; Barros, LillianHorse chestnut (Aesculus hippocastanum L.) is a deciduous tree widely cultivated in urban areas with temperate climate across the Northern hemisphere. This species is known mainly for the steroidal glycosides resulting from the secondary metabolism, among which aescin is the main active component and responsible for most of its medicinal properties[1,2]. While the bark of this tree has been used to treat dermatitis, the leaves and seeds are used due to their anti- inflammatory effects[2]. In fact, horse chestnut seed is an important raw material in the pharmaceutical industry. On the other hand, bioactive phenolic compounds such as quercetin and kaempferol glycosides can also be found in this raw material[3]. Therefore, this study was carried out to characterize the phenolic composition of the horse chestnut seed kernel, shell, and coat. The different parts of the seed were hand-separated with a knife, lyophilized, and ground to a fine powder. Hydroethanolic extracts were then obtained by ultrasound-assisted extraction, using 20% ethanol and 40 min sonication at 400 W (20 kHz frequency). The phenolic profiles were characterized by high-performance liquid chromatography coupled with diode array detector and electrospray ionization tandem mass spectrometry (HPLC-DAD- ESI/MSn). The seed kernel was particularly rich in flavonoids, among which kaempferol-O- pentoside-O-hexoside-O-hexoside and isorhamnetin-O-pentoside-O-di-hexoside were predominant compounds. The coat extract contained mostly flavan-3-ols (β-type (epi)catechin derivatives). The shell also contained flavan-3-ols and flavonoids, where (-)-epicatechin and kaempferol-O-di-deoxyhexoside were the phenolic compounds with the highest abundance in each group, respectively. In general, the coat was the seed part with the highest content of phenolic compounds, followed by the kernel. Thus, this study showed that the different parts of the inedible horse chestnut seed have different phenolic profiles in qualitative and quantitative terms. Further analyses to assess the in vitro antioxidant, anti-inflammatory, antimicrobial, and cytotoxic activities of the obtained seed extracts are underway.
- HPLC-DAD-ESI/MS profiling of phytochemicals in Aesculus hippocastanum fruitPublication . Dias, Maria Inês; Pereira, Carla; Albiston, Carly; Pinela, José; Barros, LillianAesculus hippocastanum L. (Sapindaceae) is a large, broad-crowned deciduous tree cultivated as an ornamental in urban areas in the Northern hemisphere. Among the scientific community, it is known mainly for steroidal glycosides, among which aescin is the main active constituent and responsible for most of its medicinal properties [1,2]; but other bioactive compounds such as flavonol glycosides have also been described in this plant [3]. In folk medicine, while the bark has been used to treat dermatitis, the leaves and seeds are used for their antiinflammatory effect [2]. In Europe, seed extracts and supplements have been used to treat varicose veins among other venous disorders [4]. Therefore, this study aimed to characterize the phenolic and saponin profiles of the kernel, shell, and husk of the horse chestnut fruit. After separating, lyophilizing, and grinding the three fruit parts, hydroethanolic extracts were prepared by sonoextraction at 400 W (20 kHz) for 40 min. The chromatographic separation and identification of phenolic compounds and saponins were achieved by high-performance liquid chromatography coupled with photodiode array detection and electrospray ionization tandem mass spectrometry (HPLC-DAD-ESI/MS), using different elution gradients [5]. It was possible to identify 31 phenolic compounds in the hydroethanolic extracts, including phenolic acids (caffeic acid and p-coumaroyl derivatives), flavan-3-ols ((+)-catechin and (-)- epicatechin derivatives), and flavonols (O-glycosylated quercetin, isorhamnetin derivatives, and kaempferol). While flavonols and flavan-3-ols predominated in the seed kernel and shell, respectively, the husk had comparable amounts of both phenolic constituents. The four main aescin saponins were consistently detected in the seed kernel extracts, namely aescin Ia and Ib (β-aescin) and isoaescin Ia and Ib (α-aescin). Overall, the different parts of the inedible horse chestnut fruit have a different phytochemical profile in qualitative and quantitative terms. Further studies will be important to evaluate biological activities of the different seed extracts
- Optimisation of ultrasound-assisted extraction of polyphenols and saponins from different parts of the Aesculus hippocastanum seedPublication . Albiston, Carly; Pinela, José; Barros, Lillian; Dias, Maria InêsHorse 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.
- Phenolic profiles of horse chestnut seed extracts obtained by ultrasound-assisted extractionPublication . Albiston, Carly; Dias, Maria Inês; Pinela, José; Añibarro-Ortega, Mikel; Ferreira, Isabel C.F.R.; Barros, LillianThe horse chestnut (Aesculus hippocastanum L.) is a deciduous tree widely cultivated in urban areas with temperate climate across the Northern hemisphere [1]. Among the scientific community, this species is known mainly for the steroidal glycosides or polycyclic terpenes resulting from the secondary metabolism, among which aescin is the main active component and responsible for most of its medicinal properties [2,3]. While the bark has been used to treat dermatitis, the leaves and seeds are used due to their anti-inflammatory effects [3]. In fact, horse chestnut seed is an important raw material in the pharmaceutical industry. On the other hand, bioactive phenolic compounds such as quercetin and kaempferol glycosides can also be found in this raw material [4]. Therefore, this study was carried out to characterize the phenolic composition of the horse chestnut seed kernel, shell, and pellicle. The different parts of the seed were hand-separated with a knife, lyophilized, and ground to a fine powder. Hydroethanolic extracts were then obtained by ultrasound-assisted extraction, using 20% ethanol and 40 min sonication at 400 W (at 20 kHz frequency). The phenolic profiles were characterized by high- performance liquid chromatography coupled with diode array detector and electrospray ionization tandem mass spectrometry (HPLC-DAD-ESI/MSn). Quantification was made based on calibration curves contracted with commercial standards of the most similar phenolic compounds. The horse chestnut seed kernel was particularly rich in flavonoids, among which kaempferol-O- pentoside-O-hexoside-O-hexoside and isorhamnetin-O-pentoside-O-di-hexoside were predominant compounds. In turn, the seed pellicle extract contained mostly flavan-3-ols (β-type (epi)catechin derivatives). The shell also contained flavan-3-ols and flavonoids, where (-)- epicatechin and kaempferol-O-deoxyhexoside-O-deoxyhexoside were the phenolic compounds with the highest abundance in each group, respectively. In general, the pellicle was the seed part with the highest content of phenolic compounds, followed by the kernel. Thus, this study showed that the different parts of the inedible horse chestnut seeds have different phenolic profiles in qualitative and quantitative terms. Further analyses to assess the in vitro antioxidant, anti- inflammatory, antimicrobial, and cytotoxic activities of the obtained seed extracts are underway.
- Relevance of horse chestnut (Aesculus hippocastanum L.) saponins in health and cosmeticsPublication . Albiston, Carly; Pinela, José; Añibarro-Ortega, Mikel; Ferreira, Isabel C.F.R.; Barros, LillianSaponins are steroidal glycosides or polycyclic terpenes resulting from the secondary plant metabolism and have many beneficial characteristics and applications. They can be used to fight and cure many diseases and health issues, as well as in cosmetics and as natural alternatives for food preservation and packaging [1,2]. Due to the finite resources our planet can provide and the increasing potential for saponins in various sectors, it is necessary to find alternative sources of these pharmacologically active high-added values compounds. This study aims to provide an overview of the bioactive properties of saponins that can be found in Aesculus hippocastanum L. The saponins found in this plant have a trisaccharide chain at C3 of the aglycone and a ꞵ-glucopyranosyl unit attached at C4 of the glucuronic acid. Aescin (Figure 1) is the main active component and responsible for most of its medicinal properties [2,3]. These saponins have already been described as more antioxidants than vitamin E and capable of protecting cells from free radicals and reactive species [2,4]. These compounds shown positive effects on venous insufficiency and associated conditions, reduce capillary fragility, and help prevent the leakage of fluids into surrounding tissues, thus presenting beneficial effects on human skin [2]. Due to these properties, A. hippocastanum saponins can be used in cosmetic formulations with anti-aging capacity [2]. The bark of this plant has also been used to treat dermatitis, while the leaves and seeds are used due to their anti-inflammatory effects [3]. ꞵ-Aescin (the main active compound of aescin) is a natural inhibitor of leukemic cell proliferation and may be useful for new anti-leukemic drugs [5]. ꞵ-Aescin has also been reported to be effective for the treatment of colon cancer [4]. Therefore, given the high added-value of aescin, it would be interesting to develop an extraction method that maximizes the recovery of these compounds from this plant in a sustainable way to promote resource use efficiency.
- Sonoextraction of phenolic compounds and saponins from Aesculus hippocastanum seed kernels: modeling and optimizationPublication . Dias, Maria Inês; Albiston, Carly; Añibarro-Ortega, Mikel; Ferreira, Isabel C.F.R.; Pinela, José; Barros, LillianThe sonoextraction (SE) of aescin saponins and phenolic compounds from the inedible seed kernels of Aesculus hippocastanum was optimized using a central composite rotatable design coupled with response surface methodology, where the joint effects of ultrasonic power, sonication time, and ethanol proportion were investigated. Flavonol glycosides (≥90 % of the phenolic fraction), flavan-3-ols, phenolic acids, and aescin saponins were identified by HPLC-DAD-ESI/MSn, and the quantitative data was fitted to a quadratic model to predict the optimal SE conditions. After validating the models, the significant effect of the three factors was confirmed. The extraction of flavonols was maximized to 48 ± 2 mg/g extract by SE at 105.9 W for 4.1 min in 83.9 % ethanol, while 19.9 min sonication at 100.9 W in 95.8 % ethanol favored the recovery of 3.8 ± 0.1 mg/g extract of aescin saponins. A process for simultaneous SE of both classes of phytochemicals was also established. Overall, these SE processes proved to be time-saving and selective for the A. hippocastanum seed active constituents, which are cognized for their wide range of bioactivities and applications in the pharmaceutical, cosmetic, and food industries.