The aim of the present study is (1) the screening group of plants that are traditionally used as immune-enhancers in an attempt to find the major fractions that are responsible for the activity of these plants and correlating them with already published studies. (2) The Modification of structure of the most active immunomodulatory component through semisynthetic derivatization reactions. The modifications will be made in pursuance of gaining a deeper insight of the structural requirements for immunomodulatory activity. (3) Testing the immunomodulatory activities of both natural and semisynthetic compounds. And (4) studying the mechanism of action of the active compounds as antioxidantand anti-proliferative.
Immunity is the body ability to identify and resist harmful pathogen. Metaphorically, the immunity is the body’s army that enables prevention as well as fighting of infectious diseasestoprotect self-tissues and organs from damage.
The immune system has a multi-layered construction with multiple defense stages. The skin is considered the first barrier of immunity. Then, physiological barriers take place, which are body physical conditions for examplepH and temperature that affordunsuitableenvironments for pathogens to live. Then, if a pathogen has escaped the first barriers and entered the body, it deals with innate immunity as well as acquired and/or adaptive immunity. Both systems consist of number of molecules and cells that interact in a complex manner to detect and eliminate any threat. Detection as well as elimination relay on bonding of immune cellular surface receptors as well as chemical binding to pathogens to trigger complex interaction of signaling of immune response.
Table of Contents
Introduction
Review of literature
I- Immunomodulators
II- Immunomodulatory plants
III- Immunomodulatory natural products
IV- Semisynthetic glycyrrhetinic acid derivatives
VI- Conclusion
Material and methods:
Material
Methods
I- Plant material
II- Biological assays
III- Semisynthesis of 18-β-Glycyrrhetinic acid derivatives
Results and discussion
I- Extraction
II- Fractionation
III- Semisynthetic derivatization
IV- Lymphocyte transformation assay
IV- Other biological bioassays
V- Isolation and semi-synthesis
Summary and conclusion
Research Objectives and Focus
The primary objective of this thesis is to screen various medicinal plants for potential immunomodulatory effects, specifically targeting the identification of major active fractions. Furthermore, the research aims to perform structural modifications on key bioactive components via semisynthetic derivatization to gain insight into the structural requirements for immunomodulatory activity, while also evaluating these natural and modified compounds for antioxidant and anti-proliferative mechanisms.
- Screening of traditionally used plants for immune-enhancing properties.
- Semisynthetic modification of 18-β-glycyrrhetinic acid derivatives.
- In vitro evaluation of immunomodulatory activity using PBMC transformation assays.
- Assessment of antioxidant capacities using ABTS assays.
- Evaluation of cytotoxic activities against breast, hepatic, and colorectal cancer cell lines.
Excerpt from the Book
Compound J4:
Compound J4was isolated as white crystals. The FT-IRνmax(neat) spectrum (Figure 75) showed absorption bands at 2969cm-1, 29370 cm-1 &2869cm-1 (Alkane C-H stretching) and bands at1725cm-1 &1656cm-1 (carbonyl groups). Compound J4 was assessed by co chromatography against compoundJ1 and it showed a less polarspot with Rf = 0.84, (Figure 67) using developing system (Pet.Eth-EthOAc, 2:1) and vanillin-H2SO4 as spraying agent.
Upon analysis of the 1H-NMR spectrum of compound J4 (Table 14 and Figures 68& 69) it displayed signals of an olefinic proton at δΗ 5.49 (1H, s, H-12), an upfield-shifted H-3 signal at δΗ 2.67 (1H, m) which indicated a methyl substituted hydroxyl group at C-3, a proton signal at δΗ 3.67 (3H, s, H-1``) of methoxyl group and another signal at δΗ 3.35 (3H, s, H-1`) of methyl ester group. Also, the proton signal at δΗ 2.23 (1H, s) was assigned to the proton H-9. APT spectrum (Figure 70 & 71) showed the presence of two methoxy signals at δC 57.5 (C-1`) & 52.0 (C-1``). A downfield-shifted hydroxyl methine signal at δC 88.5 assigned to C-3 confirming its methylation. Also, an upfield-shifted carbonyl group at C-30 (-2.4), indicated its esterification with a methyl group. HMBC & HSQC correlations (Figure 72, 73& 74) were used to confirm assignment of all protons and carbons. Depending on the fact that this compound is a product of known starting material (J1), with known reaction mechanism and predicted product and on the basis of these spectral evidences, the structure of compound J4 was determined to be the known compound3β-Methoxy-11-oxo-18β, 20β-olean-12-en-30-methyl-oate ester, “3β-Methoxy-18β glycyrrhetinic-30-methyl ester”, (Beseda et al., 2010), Figure 66.
Summary of Chapters
Introduction: Provides a comprehensive overview of the human immune system, including its multi-layered defense mechanisms, and introduces the rationale for researching plant-based natural immunomodulators.
Review of literature: Details the definitions, classifications, and biological mechanisms of naturally occurring immunomodulators and lists various in vivo and in vitro testing models.
Material and methods: Documents the sourcing of plant materials and the detailed chemical procedures, including extraction, fractionation, and biological assays like LTA, cytotoxicity, and antioxidant testing.
Results and discussion: Presents the findings of the plant screenings, the chemical synthesis and identification of various glycyrrhetinic acid derivatives, and the analysis of their biological activities.
Summary and conclusion: Synthesizes the results of the study, emphasizing the potential of specific plant extracts and semisynthetic derivatives as effective and safer immunomodulatory agents.
Keywords
Immunomodulators, Glycyrrhiza glabra, 18-β-Glycyrrhetinic acid, Lymphocyte transformation assay, Semisynthesis, PBMC, Antioxidant activity, Cytotoxicity, MTT assay, Natural products, Triterpenoids, Immunostimulants, Immunosuppressants, Pharmacognosy, Structural modification.
Frequently Asked Questions
What is the core focus of this thesis?
This work explores the immunomodulatory potential of various medicinal plants and utilizes chemical synthesis to modify natural compounds to improve their efficacy and understand structural activity relationships.
Which key plant species were investigated?
Key plants studied include Aralia victoria, Boswellia carteri, Cyperus rotundus, Ginkgo biloba, Glycyrrhiza glabra, Olea europaea, and Rosmarinus officinalis, among others.
What is the primary objective regarding glycyrrhetinic acid?
The aim is to synthesize semisynthetic derivatives of 18-β-glycyrrhetinic acid (the aglycone of glycyrrhizin) to enhance therapeutic potency, improve pharmacokinetic profiles, or discover new biological activities.
What scientific methods were employed?
The research employed phytochemical extraction, liquid-liquid fractionation, column chromatography for isolation, and structural elucidation via NMR and FTIR. Biological activity was assessed using LTA, MTT-based cytotoxicity assays, and ABTS antioxidant assays.
What is the clinical relevance of the research?
By identifying natural or modified compounds that modulate the immune system, the research aims to provide safer alternatives to synthetic drugs, especially for patients with immune impairment or those undergoing chemotherapy.
How is the immunomodulatory activity measured?
Activity is measured primarily through a lymphocyte transformation assay (LTA), which assesses the proliferation of human Peripheral Blood Monocytes (PBMC) when stimulated by plant extracts or specific chemical compounds.
What makes compounds J9-J12 and J14 unique in this study?
These specific derivatives are documented as novel compounds synthesized during the study, compared to the other nine known derivatives which served as reference points.
What conclusion did the author reach regarding the antioxidant activity of the derivatives?
The study concluded that the tested glycyrrhetinic acid derivatives exhibited non-significant direct antioxidant power, suggesting that this mechanism is likely not responsible for their observed immunomodulatory effects.
- Citar trabajo
- Prof. Farid Badria (Autor), Diaaeldin M. Elimam (Autor), Fatma M. Abdel Bar (Autor), Hosam M. Zaghloul (Autor), 2016, Cytokines Modulators in Plants. Chemical and Therapeutics Studies, Múnich, GRIN Verlag, https://www.grin.com/document/512548
