To change the subject: Some interesting Herbal News

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Plants Use Traditional Strategy to Combat Microbes

from American Society for Microbiology 24-May-00

Primary Author: Spencer Benson

 

 

Library: MED

Keywords: TRADITIONAL CHINESE MEDICINE ALTERNATIVE PLANT

COMBINATORIAL CHEMISTRY

Description: Researchers at the University of Maryland have

discovered that plants use a strategy similar to traditional Chinese

medicine to combat microbes, providing support for this ancient

medical practice.

5/23/2000

 

 

The following release is a summary of a presentation at the 100th

General Meeting of the American Society for Microbiology.

 

 

 

In Traditional (TCM) the herbalist often combines

various agents (herbs) in a holistic approach to restore or maintain

homeostasis. By combining various herbs the herbalist seeks to

accentuate and enhance the activity of the principle active

ingredient, suppress undesirable side effects, and treat accompanying

symptoms. This TCM strategy is different then traditional western

medicine approaches which historically have been to identify

single " magic bullet " drugs that are highly specific, used for

specific diseases/symptoms, and have minimal interactions with

systems of components other that the desired target. We show that

Arnebia euchroma an herbal plant of the Boraginaceae family uses a

TCM-like combinatorial strategy in its production of antimicrobial

compounds. Root extracts from Arnebia euchroma and related

Boraginaceae species have traditionally been used as topical wound

heal agents both in Asia and Europe. The roots of Arnebia euchroma

contain a mixture of six structurally related shikonin type compounds

that can be extracted from the roots using organic solvents. We have

termed the extract rubricine due to its deep red color. Rubricine is

a broad-spectrum antimicrobial agent that is active against fungi and

bacteria. Each of the six compounds individually possesses

antimicrobial activity, although not all are equally effective as

single agents. When individual components are used in pair-wise

combinations the antibacterial activity is accentuated and enhanced

beyond that expected from a simple additive effect. The parent

compound, shikonin, functions as both an antimicrobial agent and as

an accentuator for the antibacterial activities of each the other

five compounds. This finding suggest that in the natural environment

the plant produces a combination of compounds rather then increased

amounts of a single compound because of the added advantage of

synergy among the compounds. One possible reason for this is that

roots need to maintain homeostasis with the surrounding microbial

flora and the combination of compounds is more beneficial that the

actions of individual compounds. This natural combinatorial strategy

is TCM like. It suggests that an alternative paradigm for drug

discovery is to look at combinations of related compounds for

synergistic effects.