Bark, Wood And Galls

Lecture-3 By

Dr. Ahmed Metwaly

Taxus bark. 1. Origin. 2. Macroscopical properties. 3. Active constituents. 4. Uses. 5. Mechanism of action. 6. Side effects

Pine bark 1. Origin. 2. Macroscopical properties. 3. Active constituents. 4. Uses. 5. Chemical test.

Dried stem bark of Taxus brevifolia, Family: taxaceae. Syn. Pacific (western) Yew

Small trees or shrubs in the yew family. They are relatively slow-growing and can be very long-lived.

Thin, dark reddish or purplish scales shed off the trunk and expose a rose-coloured underbark.

The Taxaceae is a small family with one main genus, Taxus, which has an ancient reputation as a toxic and magical plant. The yew tree was used in ancient Greece and Rome to produce weapons.

An alkaloidal Taxus fraction, which was named “taxine” by Lucas (1856), is highly cardiotoxic

and has been implicated in many stock poisonings and human poisonings.

In 1966 Dr. Monroe Wall isolated the active principle, paclitaxol. Molecular structure of paclitaxol was published in 1971; it is a complex diterpenoidal alkaloid with an ester side chain and a unique oxetane ring.

the approval of TAXOL® (Paclitaxel) for marketing in December of 1992 was the result of 30 years of work that began with the collection of Taxus brevifolia in Washington state in 1962.”

Paclitaxel

Rotated paclitaxel molecule model

The plant need to be mature( about I00 years) to be large enough for exploitation of its bark. At this age the tree will be some 6-9 m high, and have a trunk of about 25 cm in diameter.

It requires the bark from about three mature 100-year-old trees to provide one gram of taxol.

And a course of treatment may needs 2 gms of taxol.

Taxol is now the best known and most studied member of the taxane diterpenoidal alkaloids, or taxoids.

It is only one of over 350 members of this compound class.

The reported taxol yield was 0.02% from dried bark of T. brevifolia

Taxol was also reported to be present in other Taxus species, including T. baccata and T. cuspidata.

in the therapy of breast, ovarian and lung cancers

Researchers determined that Paclitaxel binds to

microtubules, stabilizes them against depolymerisation and thus blocks cell proliferation.

Complex of α, β tubulin subunits and paclitaxel. Paclitaxel is showed as yellow stick.

Today, paclitaxel is obtained either from Tissue cultures of variousTaxus species or Semisynthesis from baccatin III and 10-

deacetylbaccatin III, which can be extracted in sufficient amounts from leaves and twigs of the common yew ( T. baccata), a tree that grows much faster than T. brevifolia.

Other approaches have involved the use of endophytic fungal fermentation.

Docetaxel (Taxotere®) is a side-chain analogue of taxol, more water-soluble and slightly more active than paclitaxel. It can be produced semisynthetically from10-deacetylbaccatin III.

Taxol is given as an injection or infusion into the vein (intravenous, IV).

There is no pill form of Taxol. Taxol is an irritant. An irritant is a chemical that

can cause inflammation of the vein through which it is given.

Because severe allergic reactions have occurred in some people taking Taxol, patient will be asked to take medications to help prevent a reaction.

Taxol is given over various amounts of times and in various schedules.

Low blood counts. Hair loss. Arthralgias and myalgias, pain in the joints

and muscles. Peripheral neuropathy (numbness and

tingling of the hands and feet) Nausea and vomiting (usually mild) Diarrhea. Mouth sores. teratogenicity.

Dried stem bark of pinus pinaster, family pinaceae Synonym: Pinus maritima

is a medium-size, reaching 20–35 m tall and with a trunk diameter of up to 1.2.

is orange-red, thick and deeply fissured at the base of the trunk, somewhat thinner in the upper crown.

proanthocyanidins Flavonoids like catechin, epicatechin phenolic acids (such as ferulic acid and

caffeic acid)

the patented extract called "Pycnogenol®"

Catechin

Proanthocyanidins

Epicatechin

Anti-inflammatory Antioxidant Antimicrobial Capillary Fragility treatment Some researches reported an antidiabetic

activity for "Pycnogenol®"

Pine bark extract is found to be very stable under thermal conditions and comparatively stable under acidic conditions. Thus, pine bark extract is easier to handle during processing or manufacturing steps and remains stable when exposed to the human digestive tract.

For flavonoids

Taxus bark. 1. Origin. 2. Macroscopical properties. 3. Active constituents. 4. Uses. 5. Mechanism of action. 6. Side effects

Pine bark 1. Origin. 2. Macroscopical properties. 3. Active constituents. 4. Uses. 5. Chemical test.