This study was undertaken to determine the total quantity of phenolic and flavonoids, as well as to find out about the HPLC quantification of some individual phenolic compounds (i.e. chlorogenic acid, vitexin 2"-O-rhamnoside, vitexin, rutin, hyperoside, quercetin, and isoquercetin) in flowers and leaves of 56 samples of different hawthorn species (Crataegus spp.) collected from different geographical regions of Iran. The amount of total phenolics ranges from 7.21 to 87.73 mg GAE/g in dry weight of the plant, and the total amount of flavonoids varied amongst species and in different plant organs ranging from 2.27 to 17.40 mg/g dry weight. Chlorogenic acid, vitexin, and vitexin 2"-O-rhamnoside were found to be the most abundant phenolic compounds in the extracts of hawthorn leaves. Meanwhile, chlorogenic acid, hyperoside, and rutin were the most abundant phenolic compounds in the extracts of hawthorn flowers in most genotypes. The antioxidant activity widely varied in species and in different organs of each individual plant, ranging from 0.9 to 4.65 mmol Fe ++ /g DW plant, calculated through the ferric-reducing antioxidant power (FRAP) method. Thus, this could provide valuable data for developing breeding strategies and plans; it can also help us in selecting genotypes with high phenolic contents for producing natural antioxidants and other bioactive compounds beneficial for food or the pharmaceutical industries.

High performance liquid chromatography data related to the concentrations of 12 phenolic compounds in vegetative parts, measured at four sampling times were processed for developing prediction models, based on the cultivar, grapevine organ, growth stage, total flavonoid content (TFC), total reducing capacity (TRC), and total antioxidant activity (TAA). 12 Artificial neural network (ANN) models were developed with 79 input variables and different number of neurons in the hidden layer, for the prediction of 12 phenolics. The results confirmed that the developed ANN-models (R2 = 0.90 – 0.97) outperform the stepwise regression models (R2 = 0.05 – 0.78). Moreover, the sensitivity of the model outputs against each input variable was computed by using ANN and it was revealed that the key determinant of phenolic concentration was the source organ of the grapevine. The ANN prediction technique represents a promising approach to predict targeted phenolic levels in vegetative parts of the grapevine.

Thymus persicus (Ronniger ex Rech. f.) Jalas is a valuable and endangered natural source of antitumor pentacyclic triterpenoids, i.e., betulinic acid, oleanolic acid and ursolic acid, which grows in northwest Iran. As the plant has a low propagation rate in nature, a suitable method for in vitro-propagation is needed. With the aim of identifying a suitable system for regenerating T. persicus via direct organogenesis, Murashige & Skoog (MS) medium supplemented with different plant growth regulators (PGRs) was tested. In vitro-grown shoot tips were exposed to the cytokinins 6-benzylaminopurine (BAP), kinetin (KN), and thidiazuron (TDZ), alone or in combination with the auxins 1-naphthalene-acetic acid (NAA), 2,4-dichlorophenoxyacetic (2,4-D), indole-3-butyric acid (IBA) and indole-3-acetic acid (IAA). The highest shoot formation (7.1 ± 0.9) was obtained with a medium fortified with 8.9 μM BAP plus 2.7 μM NAA. Regenerated shoots were easily rooted on the different tested media, with the most abundant (16.6 ± 1.4) and strongest roots obtained on half-strength MS medium containing 2.5 μM IBA. The rooted plantlets were successfully acclimatized (76.6%) in a greenhouse before transference to natural conditions. Homogeneity and phytochemical productivity of the in vitro regenerated plantlets were confirmed by random amplified polymorphic DNA (RAPD) profiles and high performance liquid chromatography (HPLC), respectively.

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Cardiac arrhythmias are major life-threatening conditions. The landmark discovery of induced pluripotent stem cells has provided a promising in vitro system for modeling hereditary cardiac arrhythmias as well as drug development and toxicity testing. Nowadays, nutraceuticals are frequently used as supplements for cardiovascular therapy. Here we studied the cardiac effects of hawthorn ( Crataegus pentagyna) leaf extract using cardiomyocytes (CMs) differentiated from healthy human embryonic stem cells, long QT syndrome type 2 (LQTS2), and catecholaminergic polymorphic ventricular tachycardia type 1 (CPVT1) patient-specific induced pluripotent stem cells. The hydroalcoholic extract resulted in a dose-dependent negative chronotropic effect in all CM preparations leading to a significant reduction at 1000 µg/ml. This was accompanied by prolongation of field potential durations, although with different magnitudes in CMs from different human embryonic stem cell and iPSC lines. Hawthorn further prolonged field potential durations in LQTS2 CMs but reduced the beating frequencies and occurrence of immature field potentials triggered by β-adrenergic stimulation in CPVT1 CMs at 300 and 1000 µg/ml. Furthermore, isoquercetin and vitexin flavonoids significantly slowed down isoproterenol (5 µM)-induced beating frequencies at 3 and 10 µg/ml. Therefore, C. pentagyna leaf extract and its isoquercetin and vitexin flavonoids may be introduced as a novel nutraceutical with antiarrhythmic potential for CPVT1 patients.-Pahlavan, S., Tousi, M. S., Ayyari, M., Alirezalu, A., Ansari, H., Saric, T., Baharvand, H. Effects of hawthorn ( Crataegus pentagyna) leaf extract on electrophysiologic properties of cardiomyocytes derived from human cardiac arrhythmia-specific induced pluripotent stem cells.