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Univerziteta u Beogradu
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Maceration and heat-assisted extraction of polyphenols from Aloe vera
Čutović, Natalija
Jovanović, Aleksandra A.
Elferjane, Muna Rajab
Milutinović, Violeta
Petrović, Predrag
Marinković, Aleksandar
Bugarski, Branko
ABSTRACT Aloe vera (L.) Burm. f. (Asphodelaceae) contains anthraquinones, their glycosides, flavonoids, tannins, terpenoids, saponins, resins, mono- and polysaccharides, polypeptides, lectins, enzymes, vitamins, and minerals. The plant is used in traditional medicine due to its antitumor, antioxidant, anti-inflammatory, antiulcerogenic, immunomodulatory, analgesic, and dermal protection properties. Maceration and heat-assisted extraction (HAE) are frequently used extraction procedures because of their simple operation and low costs. In the present study, A. vera dried leaves were extracted using ethanol (50%, V/V; drug solvent ratio 1:30, w/V). The influence of different extraction times (30-120 min for maceration and 15-60 min for HAE), and various extraction temperatures (40, 60, and 80ºC) in HAE on the total polyphenol content (TPC) and radical scavenging potential (ABTS and DPPH methods) was evaluated, while for the most prominent extracts (with the highest TPC) zeta potential and conductivity were additionally analyzed. Regarding maceration, the TPC was correlated with the rise in extraction time up to 45 min (from 7.8±0.72 to 9.66±0.51 mg gallic acid equivalents (GAE)/g of plant material) and after that reached the steady state (~9.1 mg GAE/g). In HAE, no statistically significant differences between the TPC of the extracts obtained after 15, 30, and 45 min (9.77±0.32, 9.76±0.18, and 9.95±0.50 mg GAE/g) were observed, while the extract prepared after 60 min showed significantly lower TPC (8.14±0.08 mg GAE/g). The TPC was in correlation with the increase of extraction temperatures (9.08±0.21 at 40ºC, 9.38±0.10 at 60ºC, and 9.86±0.24 mg GAE/g at 80ºC). As in the case of TPC results, anti-ABTS activity was significantly different between 30 and 45 min of maceration and reached the steady state after 45 min (~2.01 mmol Trolox/g of plant material). In HAE, the anti-ABTS potential of the extracts obtained at different extraction times was comparable (1.44-1.64 mmol Trolox/g), whereas the activity of the extract obtained at 40ºC was lower. DPPH radical scavenging activity rose after 45 min of maceration when also reached the steady state (~40.4 mg/mL), but there were no significant differences between the extracts prepared at different extraction times in HAE, and IC50 was lower for the extract obtained at 80ºC. Hence, the macerate prepared after 45 min and HAE extract obtained after 15 min at 80ºC exhibited very low zeta potential (0.14±0.06 and 0.50±0.01 mV), and conductivity (1.05±0.07 and 0.98±0.01 mS/cm). This study was an initial step in the production of A. vera polyphenol extracts aimed to be used for the formulation of foodstuffs, medicines, and cosmetics.
engleski
2023
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Aloe vera, antiradical activity, conductivity, polyphenols, zeta potential