Tuesday, May 29, 2007

IRIDOIDS A Review on Chemistry, Pharmacology, SAR,Extraction Methods & Structure Elucidation

Ghassemi Dehkordi, Nasrollah ;Ghannadian ,Mustafa
Faculty of Pharmacy, Isfahan University of Medical Sciences, Isfahan, I.R. Iran

The iridoids are a group of bitter tasting monoterpenoid lactones having a cyclopentano dihydropyran ring system often with glucose attachment to the hydroxyl group of the lactone ring.
Their main purpose seems to be one of the providing feeding deterrence and some are also antimicrobials , Some of these plants are used as bitter tonics e.g. Menyanthes ,Others against inflammations e.g. Euphrasia , Some have antimicrobial with a little antileukemic activity such as fulvoplumerin and allamandin and Some such as aucubin are laxative and diuretic and nonglucosid iridiods of valerianaceae are sedative.

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Tuesday, May 22, 2007

The Quassinoids, a review.

Quassinoids, (termed quassin after a man by the name of Quassi who treated fever with the bark of these plants) are bitter principles most occurring in Simaroubaceae family.

They are degraded triterpenes.

Because of the wide spectrum of their biological properties there is interest in figuring out new trends about them. One of the most important effects of them are antiviral & cytotoxic.

General structural features of the quassinoids are: 1. Most of them are C20 (tetra or pentacyclic) 2. Highly oxygenated lactones 3. Except for C4, C5, C9 & C10, there are oxygenated groups on all the other carbons.

•Main requirements for antileukaemic activity: (SAR) (as in glaucarubolone 2) are

–an a,b unsaturated ketol group at position 1 & 2 or at 2 & 3 in ring A
–an epoxymethano bridge between C8
& C11 or between C8 & C13 in ring C
–presence of a free OH group in ring A
& at C12 in addition to an ester group
at C15 &/or C6

For structural features, SAR (structure activity relationship), pharmacological effects, mechanism of action, examples of quassinoid bearing plants, biosynthesis, synthesis, extraction and ... see more

Monday, May 14, 2007

Production of Arbutin by Biotransformation of Hydroquinone Using Peganum Harmala ,Varthemia Persica and Pycnocycla Spinosa CellSuspension Cultures

Gholamreza AsgharI, Aliakbar Ihsanpourb, Azam Akbaria
a Faculty of Pharmacy and Isfahan Pharmaceutical Sciences Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
Department of Biology, Faculty of Sciences, Isfahan University, Isfahan, Iran

Cell cultures of Varthemia persica, Peganum harmala and Pycnocycla spinosa
have been studied to evaluate their abilities to bioconvert exogenous hydroquinone.
Arbutin is an important substance that has several pharmaceutical applications;
therefore, we have established V. persica and P. spinosa cultures which seem to be
able to metabolize hydroquinone. Callus cultures of V. persica were established from
seedlings, and healthy suspensions were grown using Murashige and Skoog medium
supplemented with 2,4-D and kinetin. Exogenous hydroquinone was fed to cell
suspension cultures and biotransformation reactions were detected over 24 h of
incubation. The cultures then extracted with methanol and extracts subjected to TLC
and HPLC analysis. The V. persica and P. spinosa cultured cells in this study seem
to exhibit an ability in the glucosylation of hydroquinone to arbutin. No conversion
was observed with P. harmala cell suspension cultures. The ability of cultured plant
cells for biotransformation of substrates appears to be depended on the culture strains.
Keywords: Arbutin; Biotransformation; Cell culture; Peganum harmala; Pycnocycla
spinosa; Varthemia persica.

Sunday, May 6, 2007

A serine cluster prevents recycling of the V2 vasopressin receptor

*Department of Anesthesiology and †Molecular Biology Institute, University of California School of Medicine, Los Angeles, CA 90095
Communicated by Lutz Birnbaumer, University of California School of Medicine, Los Angeles, CA, December 31, 1997 (received for review
December 22, 1997)

ABSTRACT :Receptor recycling plays a critical role in the regulation of cellular responsiveness to environmental stimuli.
Agonist-promoted phosphorylation of G protein-coupled receptors has been related to their desensitization, internalization, and sequestration. Dephosphorylation of internalized
G protein-coupled receptors by cytoplasmic phosphatases has been shown to be pH-dependent, and it has been postulated to be necessary for receptors to recycle to the cell surface. The
internalized V2 vasopressin receptor (V2R) expressed in HEK 293 cells is an exception to this hypothesis because it does not recycle to the plasma membrane for hours after removal of the
ligand. Because this receptor is phosphorylated only by G protein-coupled receptor kinases (GRKs), the relationship between recycling and GRK-mediated phosphorylation was
examined. A nonphosphorylated V2R, truncated upstream of the GRK phosphorylation sites, rapidly returned to the cell surface after removal of vasopressin. Less-drastic truncations
of V2R revealed the presence of multiple phosphorylation sites and suggested a key role for a serine cluster present at the C terminus. Replacement of any one of Ser-362, Ser-363, or
Ser-364 with Ala allowed quantitative recycling of full-length V2R without affecting the extent of internalization. Examination of the stability of phosphate groups incorporated into the
recycling S363A mutant V2Rs revealed that the recycling receptor was dephosphorylated after hormone withdrawal, whereas the wild-type V2R was not, providing molecular
evidence for the hypothesis that GRK sites must be dephosphorylated prior to receptor recycling. These experiments uncovered a role for GRK phosphorylation in intracellular
sorting and revealed a GRK-dependent anchoring domain that blocks V2R recycling.

Saturday, April 28, 2007


Sh. Dehshahri , G. Asghari

Pharmaceutical Research Center, Faculty of Pharmacy, Isfahan University of Medical Sciences, Isfahan, I.R. Iran

In recent years have seen great achievements in the production of taxoids using cell cultures.
for example paclitaxel production yield improvement: from about 1mg/l to more than 100mg/l.

in 1994, Phyton and ESCA genetic conducted taxus suspension cultures in 75,000-l and 2500-l bioreactors respectively. In 2001, the commercial production of paclitaxel using plant cell suspension cultures was achieved by Samyang Genex.

This successful industrial application of a plant cell culture will trigger future research on the production of plant-derived beneficial compounds.

What is taxol?
paclitaxel (TaxolTM ) is a diterpenoid alkaloid originally isolated from the bark of pacific yew, Taxus brevifolia .

Sunday, April 22, 2007

Factors affecting volatile terpene and non-terpene biotransformation products in plant cell cultures

W. Zhu, G. Asghari, G.B. LockwoodU
School of Pharmacy & Pharmaceutical Scienes, Uni¨ersity of Manchester, Manchester M13 9PL,
Received 7 January 2000; accepted in revised form 16 February 2000

The production and accumulation of volatile essential oil constituents in plant cell cultures has been reviewed 1,2 . Although plant cells cultured in vitro are considered to be totipotent, i.e. contain all necessary genetic material to carry out any or all of the functions shown by the intact plant, in practice many either fail to produce essential oil constituents or produce a few in only very low levels. It is often accepted that as undifferentiated cultures contain no structures such as trichomes or vittae for storage of these constituents 3 none will accumulate. In many systems particular enzyme systems needed for a biosynthetic step have been shown to be present , but inoperative, and this inhibits production of the end product(s). A number of workers have attempted to improve production and accumulation of these compounds by feeding precursors 1,2 , but levels are still well below those of intact plants. We decided to use a range of techniques to investigate if levels of biotransformation products could be increased. Biotransformation of geraniol acetate to geraniol by plant cell cultures has not previously been reported, although there is one report of the reverse reaction occurring, in a study of the biogenesis of monoterpenes using cultures derived from Muscat grapes 4.
However, a few reports have described the biotransformation of other terpene acetates into their parent alcohols by plant cell cultures 5,6, but in both instances the parent alcohol was only the major product, not the sole product. In an attempt to show variation in levels of biotransformation of volatile terpenoids and non-terpenoids, we chose suspension cultures of Peganum harmala L._Zygophyllaceae. for the feeding experiments.

Keywords: Peganum harmala; Biotransformation; Essential oil , Suspension cultures


Tuesday, April 10, 2007

Generating Genetically Modified Plants

Pharmaceutical Research Center, Faculty of Pharmacy, Isfahan University of Medical Sciences, Isfahan, I.R. Iran


Two mostly used transformation pathways for making transgenic plants are:
•Bacterial carriers

Bacterial Carriers
Agrobacterium tumefaciens contains a plasmid, a small circular piece of DNA that has its own origin of replication and is replicated independently of other nuclear material, that is key to its use in genetically modifying plants. This plasmid, called a tumor-inducing (Ti) plasmid, interacts with compounds released by fractured plant cells. When a wounded plant is exposed to A. tumefaciens, it integrates a stretch of its DNA, called transferred DNA (T-DNA), to the plant's genome.Normally, the bacterium transfers its own T-DNA, but if the T-DNA is removed and replaced with another gene, A. tumefaciens can be used to introduce that gene into the plant genome, thereby providing a vector for scientists to engineer beneficial genes into plants. Studies have shown that native T-DNA genes are not necessary for this process. Inserted genes get transferred to plants as long as two repeated border sequences of 25 base pairs flanking the genes are present in the vector.

The gene gun is part of the gene transfer method called the biolistic (also known as biobalistic or particle bombardment) method. In this method, DNA or RNA adhere to biological inert particles (such as gold or tungsten). By this method, DNA-particle complex is put on the top location of target tissue in a vacuum condition and accelerated by powerful shot to the tissue, then DNA will be effectively introduce into the target cells. Uncoated metal particles could also be shot through a solution containing DNA surrounding the cell thus picking up the genetic material and proceeding into the living cells. The efficiency of the gene gun transfer could be depended on the following factors: cell type, cell growth condition, culture medium, gene gun ammunition type, gene gun settings and the experimental experiences, etc.

Agrobacterium versus biolistics (particle bombardment)
In general Agrobacterium is considered the method of choice for transformation. Advantages include:
•Low copy number of the transgene
•Higher proportion of stable transformants
•Large DNA segments can be transferred
•More time efficient

Other techniques that can be used:

Calcium phosphate precipitation
Gene silencing
Gene splicing
Viral carriers

Protein Based Testing Methods

•Transgenes encode for novel proteins
•Immunoassay techniques using antibodies
•Analyte must be known
•Interference from non-specific interactions of proteins, surfactants (saponins), phenolics, fatty acids and phosphatases
•Polyclonal antibodies
•Monoclonal antibodies

Key words: Western Blot ,ELISA Microwell Plate , Antibody-coated Tube ,ELISA Considerations , DNA-Based Methods , Southern Blot , PCR Fragment Confirmation

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Cloning and Mutagenesis


Pharmaceutical Research Center, Faculty of Pharmacy, Isfahan University of Medical Sciences, Isfahan, I.R. Iran


Some Necessary Tools of Genetic Engineeirng
Restriction enzymes

Restriction endonucleases cleave only double stranded DNA by recognition of specific sequences within the DNA molecule.

•Protruding Ends (also referred to as "sticky" ends or "staggered" ends).
A. Protruding 5' (PO4) ends: occurs when the enzyme cuts to the left of the central axis of symmetry
5'......GOH PO4AATTC......3'
3'......CTTAAPO4 OHG......5'


The reaction requires the expenditure of two high energy phosphate bonds. Notice that the phosphate on the 5' end of the nick is used to make the phosphodiester bond. ATP provides only energy, not a phosphate.


Plasmids are molecules of DNA that are found in bacteria separate from the bacterial chromosome. They:
•are small (a few thousand base pairs)
•usually carry only one or a few genes
•are circular
•have a single origin of replication
Plasmids are replicated by the same machinery that replicates the bacterial chromosome. Some plasmids are copied at about the same rate as the chromosome, so a single cell is apt to have only a single copy of the plasmid. Other plasmids are copied at a high rate and a single cell may have 50 or more of them.

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Pharmaceutical Research Center, Faculty of Pharmacy, Isfahan University of Medical Sciences, Isfahan, I.R. Iran

The most commonly engineered crops are canola, chicory, corn, cotton, squash, tomatoes, and soy. Currently in the US, 35% percent of all corn is genetically engineered as well as 55% of all soy and cotton. Although cotton is most commonly thought of as a material, cottonseed oil is used in foods. Soy is more widely consumed than many would think, as 60% of processed foods contain soy. Consumer Reports of September 1999 shows that products such as Boca Burgers, Jiffy Corn Mix, Ovaltine Malt, Bravo Tortilla Chips, various infant formulas, and Bac-Os Bacon Flavor Bits contain genetically engineered ingredients
Nutritional effects

No tests have been conducted on the effects of genetically engineered food on the human body. At this time, we could not do longitudinal studies on people who are consuming foods containing genetically engineered ingredients because foods are not labeled. Thus, it would be impossible to develop a control group.
One significant problem with genetically engineered foods is the risk to people with specific food allergies. For example, Brazil nut genes were inserted into soybeans to increase their protein content. The product was ready to go to market when tests showed that the soybeans caused allergic reactions in people with allergies to Brazil nuts. In addition, new allergens may be introduced into the food system through genetic engineering.
Why are crops genetically engineered?

Currently, 85% of genetically engineered crops are engineered for herbicide or pest resistance. The other 15% are engineered to be viral resistant or have more "desirable traits" such as increased oil content or shelf life. These desired traits are not necessarily preferred by or beneficial to the consumer, but they fit within the framework of our industrialized, concentrated agriculture system, which entails large-scale production and long distance transport.

Key words: Genetic , Transgenic organism , Genetic Engineering
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Tuesday, March 6, 2007

Avian Influenza

What is Avian Influenza / Bird Flu?

Ghanadi.A - Sadeghi.H - Rahmani.M
Pharmaceutical Research Center, Faculty of Pharmacy, Isfahan University of Medical Sciences, Isfahan, I.R. Iran

An infection caused by influenza viruses that occurs naturally in birds. Wild birds can carry the viruses, but usually do not get sick. Some domesticated birds can become infected, usually fatally . Strains of avian flu may infect other types of animals, incl. pigs, cats and tigers . In this article reveiw we discuss about following related drugs.

1-Neuraminidase cleaves terminal sialic acid residues from carbohydrate moieties on the surfaces of infected cells.

2-Oseltamivir is an antiviral drug that is used in the treatment and prophylaxis of both Influenzavirus A and Influenzavirus B. It is a neuraminidase inhibitor

3-Shikimic acid derivatives , shikmic acid byself is an important biochemical intermediate in plants and microorganisms
Such as the aromatic amino acids phenylalanine and tyrosine , indole, indole derivatives and tryptophan , many alkaloids and other aromatic metabolites , tannins, flavonoids, and lignins.

4-Quinic acid , C7H12O6 is a crystalline acid obtained from cinchona bark, coffee beans, and other plant products and made synthetically by hydrolysis of chlorogenic acid