A new class of macrobicyclic and cation photosensitive compounds, the anthraceno-cryptands A"" is described. In these ligands, the nitrogen lone pairs form intramolecular exciplexes with the anthracene ring, inducing a dual fluorescence emission (monomer type and exciplex) sensitive to the nature of the solvent. Thus, although A22 displays an intense triple exciplex emission in aprotic solvents, only a strong monomer-type emission is observed in methanol; this behavior is ascribed to hydrogen bonds between the solvent and the nitrogen lone pairs, which maintain an out-out conformation preventing exciplex

Purpose – The purpose of this paper was to determine total polyphenols (TP), total flavonoids (TF) and (-)-epigallocatechin gallate (EGCG) in five commercial tea extracts and in their infusions at various temperatures (95-60°C) and brewing times (5-30 min). Design/methodology/approach – TP was determined by the Folin–Ciocalteu method, TF by the aluminium chloride colorimetric method and EGCG by HPLC method. Findings – The results showed that White tea – Silver needle had the highest content of TP and EGCG when extracted, but its infusions had very poor concentrations of these compounds. Green tea infusion was better source of TP and EGCG than white or black tea, although its extract did not contain a very high amount of TP compared to the latter two types. Black tea extract had a relatively high content of TP and TF in its extract. Its infusions as well contained higher concentrations of TP than white tea, but lower concentrations of EGCG than all studied teas. Originality/value – Increasing infusion time and temperature does not necessarily increase the concentration, according to the results. To the authors’ knowledge, this is the first report on comparing these types of tea, especially the white tea, with other well-known teas under various infusion conditions. The extraction of the white tea leaves was also not found in previous works.

Purpose -The purpose of this paper is to determine the total phenol content (TP) and total flavonoid content (TF) fluctuations in different infusions of lemon verbena. Dried leaves were harvested in May, July and October and prepared at various soaking times (5-20 min). Design/methodology/approach -The Folin-Ciocalteu method was used to determine TP, while TF was determined by the aluminum chloride method. Findings -According to the results, the July harvest had the highest content of TP and TF, followed by May and October. Temperature and soaking time play a role in the proportion of released phenols and flavonoids (p Ͻ 0.05), whereas the content in continuous infusion is higher than infusion (without boiling) .TP and TF in infusion increase until 20 min, while concentration is convergent in continuous infusion after10 minutes, where no significant difference is seen. In the flowering stage, TP is close in comparison with the vegetative stage. Originality/value -Harvest time plays a role in the content, so it is best to prepare infusion from lemon verbena before the flowering period, when people drink it, as the results show. According to the authors' knowledge, this is the first work that studied the variation in phenol and flavonoid content during different stages of growth with soaking time in drenched lemon verbena leaves.

Purpose This paper aims to study the effect of cooking and food additives, such as lemon juice and vinegar, on phenols and flavonoids contents and antioxidant activity of purslane. Design/methodology/approach The Folin–Ciocalteu method was used to determine total phenols content (TP), while total flavonoid content (TF) was determined by the aluminum chloride method. Two methods were used for determination of antioxidant activity: DPPH (1, 1-diphenyl-2-picrylhydrazyl) assay to determine radical scavenging activity, and ferric-reducing antioxidant power (FRAP) to measure the reducing power. Findings According to the results, leafs had higher values of TP, TF and antioxidant activity than aerial parts. Both lemon juice and vinegar retracted antioxidant properties of leafs. TP and TF of leaves showed deterioration after treatment with lemon by 58% and 21.8%, respectively, and FRAP and radical scavenging activity decreased by 75.8% and 74.5%, respectively (p < 0.001). Also, TP, TF, FRAP and DPPH radical scavenging activity decreased in leaves by 82.2%, 30.5%, 87.8% and 90.9%, respectively, after treatment of leaves with vinegar. TF increased after cooking in studied parts, where no significant statistical difference was observed in TP and antioxidant activity (DPPH assay and FRAP) of cooked aerial parts. Adding lemon juice after cooking increased antioxidant properties of purslane (p < 0.001). Originality/value Purslane has antioxidant activity because it is rich in polyphenols and flavonoids. Effects of food additives and cooking were studied using different measurements. According to the authors’ knowledge, this is the first work that studied the effect of food additives on antioxidant properties of purslane.

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