الفهرس 
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Abstract
General summary
Family Iridaceae, the Iris family, is an important family and distributed throughout the worldwide. Iridaceae comprises about 92 genera and more than 1800 species, mostly perennial herbs with underground organs called rhizomes. Iridaceae contains a wide array of secondary metabolites including flavonoids, xanthones, triterpenoids, iridals and quinone derivatives. The great diversity of Iridaceae pharmacologically active phytoconstituents leads to have a wide range of biological activities including anti-inflammatory, cytotoxic, antimicrobial, antioxidant, antidiabetic and antihyperlipidaemic activities.
Genus Iris is considered as a one of the largest genera belonging to family Iridaceae. It consists of about 360 species and is widely distributed in Eurasia, North Africa, and North America. The name of genus “iris” comes from the Greek word “rainbow” owing to the wide diversity of colors of its magnificent flowers.
Iris pseudacorus L. (Iridaceae) (common name. Yellow flag) is a perennial herbaceous rhizomatous plant with yellow flowers. It grows in a variety of habitats, mostly preferring wetlands, places abundant with water and is native to Europe, Western Asia and North Africa. Different parts of I. pseudacorus accumulate various groups of biologically active substances including phenolic compounds, flavonoids, isoflavonoids, triterpenoids (iridals), organic acids, xanthones, anthocyanins, essential oil, and others. I. pseudacorus is used in traditional medicine as an antimicrobial, expectorant, diuretic, hemostatic agent.
Iris tectorum (Iridaceae) is a perennial herb widely distributed in China, called Yuan Wei in Chinese. In Traditional Chinese Medicine, it was used as a bitter medicine to treat disorders described as Zheng Jia Jie Ju. Iris japonica is native to temperate and tropical regions of Asia and has been used as a folk medicine for treating bronchitis, internal injuries, rheumatism and swellings. Iris laevigata, commonly known as Water Iris is geographically restricted to a very few habitats in Korea.
The aim of this thesis was to evaluate the various biological activities of several extracts obtained from different cultivars with various parts of Iris species for the first time. A detailed phytochemical investigation of the most biologically active extracts was carried out in an effort to isolate and identify the major secondary metabolites that might be responsible for such activities. Besides, in silico docking studies were performed to validate the mechanism and binding pattern of the tentatively identified compounds to their targets. In addition, ADMET prediction was performed to estimate pharmacokinetics, pharmacodynamics, and toxicity properties of these compounds. Moreover, the chemical composition and biological activity of volatile constitutes of the hexane fractions and essential oils of Egyptian I. pseudacorus rhizomes and aerial parts were investigated. Hence, the findings of the present study might enhance the knowledge regarding the therapeutic properties of I. pseudacorus.
Chapter I
Biological study on various extracts of Iris species (Iridaceae)
The biological activity and therapeutic potential of different extracts obtained from different cultivars of Iris species was investigated for the first time. A wide range of biological activities were assessed including in vitro antioxidant, antidiabetic, antihyperlipidaemic and anti-melanogenesis activities.
1. In vitro biological evaluation
1.1. In vitro evaluation of antioxidant activity using DPPH assay
In the current study, the antioxidant potential of different extracts obtained from the rhizomes and aerial parts of different cultivars of I. pseudacorus, I. tectorum, I. laevigata, and I. japonica was evaluated using DPPH assay. I. pseudacorus rhizome extracts (IPR-J and IPR-E) exhibited the highest radical scavenging activity with % inhibition of 75.84, 60.75 at a concentration of 125 μg/mL and IC50 values of 40.89 µg/mL and 97.97 µg/mL, respectively. Trolox was used as positive control exhibiting IC50 value of 14.59 µg/mL. While the lowest values were shown by the aerial part alcohol extracts of IPA-J and IPA-E with % inhibition 30.43 and 33.93 respectively. In addition, aerial parts and rhizomes alcohol extracts of ITA-J, ITR-J, ILA-J, ILR-J, IJA-J and IJR-J displayed % inhibition of 20.04, 25.02, 37.09, 31.75, 29.22 and 25.21 at a concentration of 125 μg/mL, respectively.
1.2. Enzyme inhibitory activity
In the current study, the enzyme inhibitory activity of the alcohol extracts of different Iris species were assessed in vitro against tyrosinase, α-glucosidase and lipase enzymes.
1.2.1. In vitro anti-hyperglycemic evaluation using α-glucosidase enzyme assay
The anti-hyperglycemic activity of different extracts of Iris species was evaluated in vitro using α-glucosidase inhibitory assay. Results revealed that I. pseudacorus rhizome alcohol extracts (IPR-J and IPR-E) exhibited the highest α-glucosidase inhibitory activity displaying percentage inhibition of 99.96 and 67.70 at a concentration of 100 μg/mL and IC50 values of 18.52 µg/mL and 57.89 µg/mL, respectively being more potent as compared to acarbose with IC50 value of 362.088 µg/mL. On the other hand, the aerial part alcohol extracts of Egyptian and Japanese I. pseudacorus (IPA-E and IPA-J) as well as the aerial part and rhizome alcohol extracts of Japanese I. tectorum, I. laevigata, and I. japonica (ITA-J, ITR-J, ILA-J, ILR-J, IJA-J and IJR-J) showed no α-glucosidase inhibitory activity.
1.2.2. In vitro anti-hyperlipidemic activity using pancreatic lipase enzyme assay
The antihyperlipidaemic activity of different extracts of Iris species was evaluated in vitro for potential pancreatic lipase inhibitory activity. All extracts of Iris species exerted significant lipase inhibitory activity and were potent compared to cetilistat used as positive control at concentration of 25 μg/mL.
1.2.3. In vitro anti-melanogenesis activity using tyrosinase enzyme assay
The tyrosinase inhibitory activity of different extracts of Iris species was evaluated in vitro. No anti-melanogenesis activity was observed for all extracts of Iris species up to 500 µg/mL. Arbutin was used as a positive control and displayed an IC50 value of 120 µg/mL.
Chapter II
Phytochemical study on Egyptian and Japanese Iris pseudacorus aerial parts and rhizomes (Iridaceae)
1- Phytochemical screening of Egyptian Iris pseudacorus aerial parts and rhizomes
The phytochemical tests carried out on Egyptian I. pseudacorus aerial parts and rhizomes allowed the qualitative identification of the following secondary metabolites including carbohydrates and /or glycosides, flavonoids, condensed tannins, sterols and/or triterpenes. However, anthraquinones, saponins and alkaloids were absent.
2- Isolation, purification and identification of the phytochemical compounds from Egyptian Iris pseudacorus rhizome
The air dried rhizomes of Egyptian Iris pseudacorus were percolated in methanol to prepare the rhizome methanol extract. The extract was subjected to an in-depth phytochemical investigation. It was fractionated into several fractions that were subjected to several chromatographic separation techniques. Different isolation techniques were conducted resulting in the isolation and purification of five compounds. The structures of the isolated compounds were elucidated by various techniques as 1H-NMR, APT, HSQC and HMBC techniques. The isolated compounds are:
Compound 1: 5,7-Dihydroxy-6,2′-dimethoxyisoflavone
Compound 2: trans-3-Hydroxy-5-methoxy-6,7-methylenedioxyflavanone
Compound 3: trans-3-Hydroxy-5,7-dimethoxyflavanone
Compound 4: 5,7,4′-Trihydroxy-6-methoxyisoflavone (Tectorigenin)
Compound 5: 5,7,4′-Trihydroxy-6,3′-dimethoxyisoflavone (Iristectorigenin A)
Phytochemical study of the rhizomes of Iris pseudacorus utilizing sequential liquid-liquid extraction and various chromatographic techniques resulted in the isolation of five compounds including two rare dihydroflavonols 3-hydroxy-5-methoxy-6, 7-methylenedioxyflavanone (first report in genus Iris) and 3-hydroxy-5, 7-dimethoxy flavanone (second report in genus Iris). In addition, three isoflavonoid compounds including tectorigenin, iristectorigenin A and 5, 7-dihydroxy-6, 2′-dimethoxyisoflavone.
3- Metabolites profiling of Egyptian and Japanese I. pseudacorus aerial parts and rhizomes crude extracts using UPLC-ESI-MS/MS
Metabolic profiling of Egyptian and Japanese I. pseudacorus aerial parts and rhizome crude extracts was carried out using UPLC-ESI-MS/MS analysis to obtain better insight into the phytochemical profile that may contribute to the studied biological activities. Forty-three compounds were tentatively identified. The identified metabolites belonged to various chemical classes including: 33 flavonoids, 3 xanthones, 3 phenolic acid derivatives, 1 amino acids, 1 sugar, 1 benzophenone, 1 fatty acids. Whereas, xanthones were detected only in the aerial parts of each cultivar. While isoflavonoids were tentatively identified only in the different parts of Egyptian cultivar.
Chapter III
In silico molecular docking studies for the major identified compounds in Egyptian and Japanese Iris pseudacorus aerial parts and rhizomes alcohol extracts within the active sites of human α-glucosidase and human pancreatic lipase
1. In silico molecular docking studies
1.1. Molecular docking
Molecular docking studies were conducted for the major identified compounds in I. pseudacorus extracts within the active sites of human α-glucosidase (HAG) and human pancreatic lipase (HPL). In silico molecular modelling revealed that quercetin, galloyl glucose, and irilin D exhibited the highest fitting scores within the active sites of human α-glucosidase and pancreatic lipase.
1.2. ADMET prediction
Most of phytoconstituents have displayed pharmacokinetics, good pharmacodynamics and tolerable toxicity properties in ADMET plot.
Chapter IV
Chemical composition of the essential oils and lipophilic fraction of Iris pseudacorus (Iridaceae) and their biological activities
In this chapter, a comparative analysis between the lipophilic fractions of different parts of Egyptian Iris pseudacorus was carried out using GC/MS analyses for the first time. In addition, another comparative analysis between the essential oils isolated from the same parts of the same plant was conducted aiming to assign the differences in their chemical composition. Moreover, the antiaging activities for the aerial parts and rhizomes (lipophilic fraction and essential oils) were assessed against elastase and collagenase enzymes for the first time.
1. GC/MS analyses
A total of 36 compounds accounting for 85.95% and 89.95% were identified in the lipophilic fraction obtained from Iris pseudacorus aerial parts and rhizomes, respectively through GC/MS analyses. Besides, a total of 11 components were tentatively identified, accounting for 95.79% and 97.12% of total aerial parts and rhizomes essential oils, respectively. Fatty acids and their esters predominated in I. pseudacorus rhizome lipophilic fraction and the essential oils obtained from the rhizomes and the aerial parts.
2. In vitro evaluation of the anti-aging activity
The anti-aging activity of the essential oils and lipophilic extracts from Iris pseudacorus aerial parts and rhizomes was evaluated in vitro by measuring the inhibition percentages of collagenase and elastase. Results revealed that the essential oils of I. pseudacorus rhizome and aerial parts (IPRE-EO and IPAE-EO) exhibited the highest collagenase and elastase inhibitory activity.