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Current
Organic Chemistry
ISSN: 1385-2728
Current Organic
Chemistry
Volume 10, Number 8, May 2006
Contents
Natural Product Chemistry
Guest Editors: K. Hostettmann
Editorial Pp.
823
Natural Product Inhibitors of Acetylcholinesterase
Pp.825-847
K. Hostettmann, A. Borloz, A. Urbain and A. Marston
[Abstract]
New Biologically Active Metabolites from Chinese Higher
Fungi Pp. 849-871
Gao Jin-Ming
[Abstract]
Progress in the Research on Naturally Occurring Flavones
and Flavonols: An Overview Pp. 873-898
Goutam Brahmachari and Dilip Gorai
[Abstract]
Natural Products in Drug Discovery - Concepts and
Approaches for Tracking Bioactivity Pp. 899-920
O. Potterat and M. Hamburger
[Abstract]
Abstracts
[Back to top]
Editorial
The 2006 Natural Product Chemistry issue of Current Organic
Chemistry contains four contributions covering different
themes. One of these involves methodology, in which Potterat
and Hamburger look at approaches to the localization and characterization
of bioactivity. New technologies and concepts have been introduced
over the last few years and these are the subject of this
article. Sensitive and rapid methods are required to accelerate
the discovery of new plant-based drugs and provide lead compounds.
These methods include HPLC-based bioassays, molecular imprinted
polymers, biosensors and chips. Bioassays for the screening
of natural products are also presented in a review of natural
inhibitors of acetylcholinesterase. This enzyme degrades acetylcholine
and as cholinergic deficit is associated with the cognitive
impairments observed in Alzheimer’s disease, inhibitors
of the enzyme are at present actively being sought in order
to find new therapeutics for the management of this widespread
affliction of elderly people. Many alkaloids with an effect
on the enzyme have been discovered but there is also a need
to find non-alkaloidal natural products which show inhibition
as these might have fewer side effects. Some of the compounds
isolated are, in fact, more active than the currently used
drugs, such as galanthamine from Galanthus nivalis
(Amaryllidaceae). The third contribution is a review by Brahmachari
and Gorai of recently reported flavones and flavonols from
plant sources during the period 1999 to 2004. Many of these
have interesting biological and pharmacological activities.
Finally, Gao reviews metabolites from Chinese fungi. Chinese
higher fungi, apart from certain species such as Ganoderma
lucidum (Ganodermataceae), have received little attention
and previous research has been confined mainly to several
traditionally-used medicinal higher fungi, from which the
number of secondary metabolites so far discovered is only
about 150. China is one of the richest resources of fungi
in the world, with approximately 10,000 species of higher
fungi. Edible and inedible mushrooms represent about 600 and
500 species, respectively, including some 100 toxic species.
Higher fungi have a large and diversified variety of secondary
metabolites, as exemplified in this review.
I would like to express my sincere thanks to all contributors
in this volume for the excellent reviews of natural product
research that they have produced.
Prof. K. Hostettmann
Université de Genève
Laboratoire de Pharmacognosie et Phytochimie
CH1211 Genève 4
Switzerland
[Back to top]
Natural Product Inhibitors of Acetylcholinesterase
K. Hostettmann, A. Borloz, A. Urbain and A. Marston
Effective methods for localization and characterization of
bioactivity are a cornerstone for natural product based drug
discovery efforts. Over the last decade, a wealth of new technologies
and conceptual approaches for bioactivity screening have emerged.
These developments are reviewed under the perspective of their
applicability in the field of natural products discovery.
The methods discussed here include bioautography, HPLC-based
activity profiling, HPLC-based on-flow bioassays, assays based
on capillary electrophoresis, molecular imprinted polymers,
various MS- and NMR-based methods, biosensors, and chip-based
technologies for affinity separation and expression profiling.
Selected examples illustrate the potential and limitations
of the different approaches for contemporary natural products
lead discovery.
[Back to top]
New Biologically Active Metabolites from Chinese Higher
Fungi
Gao Jin-Ming
The chemical constituents produced by Chinese higher fungi,
including thirty two basidiomycete and six ascomycete species,
have been investigated in the past decades. A variety of new
secondary metabolites associated with diverse structural types
of terpenoids, steroids, sphingolipids, perylenequinones,
p-terphenyls, pyranones, and heterocyclic compounds,
which exhibited antitumor, anti-inflammatory, cytotoxic, enzyme
inhibitory, antiviral, neuritogenic, antibiotic, and other
activities, have been discovered. Recent progress in the structures
and interesting biological properties of compounds isolated
from these higher fungi is discussed in this review.
[Back to top]
Progress in the Research on Naturally Occurring Flavones
and Flavonols: An Overview
Goutam Brahmachari and Dilip Gorai
The present review deals with recently
reported novel natural flavones and flavonols (mid-1999 to
early 2004), along with various biological and pharmacological
activities as exhibited by these important groups of flavonoids.
The present resumé lists 252 new naturally occurring
flavones and flavonols reported during the period. Natural
distribution by plant family of the flavonoids is considered;
a variety of plant species belonging to fifty-two different
plant families is mentioned as their natural sources. Therapeutic
efficacies of these constituents are also cited. The review
covers 231 references.
[Back to top]
Natural Products in Drug Discovery - Concepts and
Approaches for Tracking Bioactivity
O. Potterat and M. Hamburger
Various natural products, such as physostigmine, have long
been recognized as inhibitors of the enzyme acetylcholinesterase.
Since the recent approval of galanthamine for the treatment
of Alzheimer’s disease by the blockage of acetylcholine
degradation, attempts to find other inhibitors of the enzyme
have multiplied, leading to promising candidates such as huperzine
A. In this review, a listing is presented of natural product
inhibitors, both alkaloid and non-alkaloid in origin. These
have been isolated from plant, animal and microbial sources.
Details of current testing methods on cholinesterases are
given, including solution assays and screening techniques
by TLC and HPLC.
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