Environmental Engineering Reference
In-Depth Information
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Introduction
Our ancestors largely relied upon drugs such as antibiotics, pain killers, cancer ther-
apies, and anti-inlammatory drugs derived from organic products (bioactive natural
products or secondary metabolites) of plants and animals from time immemorial
to improve and enrich their own lives. It has been reported that about 50% of the
currently marketed drugs have their origin in natural products yielded by plants and
animals. In the case of anti-infective and anticancer agents, the natural products have
contributed more than 70%. However, modern medicines and therapies are either
not capable of completely controlling the target diseases or are in limited supply.
Further, owing to the emergence of antibiotic resistance in bacteria and the vast
spread of devastating diseases such as AIDS, there is an urgent need for the discov-
ery of new drugs.
In this context, natural products of freshwater plants provide a diverse and
unique source of novel bioactive lead compounds for drug discovery. The fresh-
water blue-green algae (cyanobacteria) that are the primitive forms of life have been
reported to yield several bioactive compounds for the development of antiviral, anti-
tumor, antibacterial, and anti-HIV drugs.
Freshwater plants (algae and macrophytes) inhabiting stationary water bodies
(lacustrine systems) such as lakes, ponds, and reservoirs and lowing waters (streams
and rivers) are important in the health of the ecosystems, as they help the water bod-
ies largely by enhancing dissolved oxygen content, nutrient cycling, and substrate
stabilization, and reducing or regulating water temperature, unwanted phytoplank-
ton blooms, and hazardous chemicals. Besides improving water quality, these plants
also provide refuge or habitat and food for associated micro- and macrofauna.
FRESHWATER PLANTS AS SOURCES OF DRUGS
Herbal medicines have been in use as prophylactic measures and for curative treat-
ments since the dawn of human civilization. Crude extracts of herbal origin are
nowadays widely used in pharmaceutical formulations, and the search for drugs
(Sivarajan and Balachandran, 1994; Li, 2011) and dietary supplements from fresh-
water has accelerated in recent years.
FRESHWATER PLANTS AND THEIR BIOACTIVE COMPOUNDS
Freshwater plants have been reported to produce a variety of structurally novel bioac-
tive compounds or secondary metabolites such as antibiotics, mycotoxins, alkaloids,
and phenolic compounds, which are considered to be valuable sources of pharma-
ceutical or biomedical compounds in the discovery of modern drugs.
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