Browsing by Author "Henriques, Joana"
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- Phenolic compounds from Actinidia deliciosa leaves: Caco-2 permeability, enzyme inhibitory activity and cell protein profile studiesPublication . Henriques, Joana; Fale, Pedro; Pacheco, Rita; Florêncio, Maria Helena; Serralheiro, Maria LuisaChemical compounds from leaves of fruit-producing trees, a waste from agricultural activity can be isolated and used as a source of natural bioactive chemicals. Boiling water was used as an extractant of bioactive compounds from Actinidia deliciosa leaves and co-extracted fibres were removed with ethanol precipitation. Rutin and quercitrin were the main flavonoids identified and quantified by RP-HPLC-DAD. No cytotoxicity was detected for any of the extracts towards Caco- 2 cell line. A permeation of approx. 14% of extract components through the cells monolayer was determined. The cell protein profile of Caco-2 cells was modified when in the presence of the fibre-free extract and transketolase was the protein over-expressed in the presence of polyphenols. Acetylcholinesterase inhibitory activity was also studied, IC50 of 0.56 mg/mL was obtained with the fibre-free extract. A. deliciosa leaves are a good source of phenolic compounds and, therefore, some advantage may be taken of this agricultural residue, due to their biological activity.
- Valorization of kiwifruit production: leaves of the pruning branches of Actinidia deliciosa as a promising source of polyphenolsPublication . Henriques, Joana; Ribeiro, Maria João; Fale, Pedro L; Pacheco, Rita; Ascenso, Lia; Florêncio, Maria Helena; Serralheiro, Maria LuisaThe present work concerns the novel application of a phenolic compound extraction methodology to leaves of Actinidea deliciosa. Recent studies have shown that crop residues could be raw material for recovery of natural bioactive compounds. Phenolic compounds from Actinidea deliciosa leaves were extracted with hot water, purified using reverse phase chromatography and mucilage precipitation with ethanol. The composition of the purified fraction was determined by HPLC-DAD and LC-MSn. Quercitrin, rutin, proantocyanidin B and C, quinic acid, myricitrin, and triterpene acid-O-hexoside were found. These compounds were present in all the fractions. The antioxidant activity was determined as general radical scavenging capacity, lipid peroxidation prevention, and NO radical scavenging activity. Values of EC50 of 9.4 mu g/mL, IC50 of 152.5 mu g/mL, and IC50 of 81 mu g/mL were determined, respectively. The best period of the year to obtain a high fraction of phenolic compounds (120 A mu g/mg of extract) from A. deliciosa leaves was December. The phenolic fraction obtained with hot water and ethanol precipitation is a promising good source of natural bioactive compounds and an easy method of taking advantage of the leaves from A. deliciosa. To the best of our knowledge, there are no previous works on the use of the residual leaves of this fruit tree. Several phenolic compounds with high antioxidant activity were extracted and identified in this plant for the first time.