Abstract
India has rich biodiversity and a large number of medicinal plants that are
weeds. Usually, weeds are seen as troublemakers in the yard and interfere with the
man's land utilization for a specific purpose. Farmers and field botanists recognized
these weeds as medicinal plants such as Adonis vernalis, Phyllanthus amarus, Eclipta
alba, Centella asiatica, etc. used in folk and indigenous medicines. Most of the plants
that are considered weeds have not yet explored phytochemically and
pharmacologically. Simultaneously, many of these weeds were reported for their
secondary metabolites like alkaloids, glycosides, flavonoids, phenolics, saponins, etc.
having medicinal values like anticancer, antioxidant, and anti-inflammatory activities.
Many therapeutically important weeds are more popular in India, like Achyranthes
bidentata, Artemisia nilagirica, etc. with preferable medicinal benefits such as a
diuretic, anti-malarial, and brain tonic. Weeds are storehouses and chemical libraries
with simple to complex bioactive secondary metabolites, which serve as drug leads
against several resistance diseases like cancer and tuberculosis. Weed biomolecules
like Atropine from Atropa belladonna, Berberine from Berberis vulgaris, Colchicine
from Colchicum autumnale, Phenoxodiol from Glycine max, Ingenol 3-angelate from
Euphorbia species, Combretatin from Combre vulgaris have been reported. This
chapter explains various cytotoxic Indian weed flora, reported phytochemicals, drug
leads, ethnomedicinal values, modern pharmacology, mechanism of action and clinical
safety and efficacy issues.