Watercress

Botanical Profile

Watercress is derived from Nasturtium officinale, a water-associated crucifer of clear springs and running waters. The raw material is characterised by pungent glucosinolates and a fresh leaf matrix.

Nasturtium officinale R.Br. is a perennial water-loving plant of the Brassicaceae. It grows in clear springs, streams, ditches and shallow running waters and forms creeping to ascending shoots with pinnate, succulent green leaves.

The fresh aerial plant parts, particularly leaves and young shoots, are used. Watercress must be botanically distinguished from garden cress and nasturtium, although all three may be associated with the name 'cress' in common usage.

The plant requires clean water and hygienically controlled cultivation conditions. Wild collection from contaminated waters is problematic because microbiological contamination, parasites and environmental contaminants may occur.

Botanically, watercress represents a classic aquatic and culinary Brassicaceae plant closely linked to site quality and freshness.

Phytochemistry

Watercress contains glucosinolates, particularly gluconasturtiin, which can be enzymatically degraded to phenethyl isothiocyanate. Flavonoids, phenolic acids, chlorophyll, carotenoids, vitamins, minerals and the typical green leaf matrix are also present.

As in other crucifers, formation of pungent-tasting isothiocyanates depends on cell disruption, myrosinase activity, freshness and processing. Heating, drying and storage can substantially alter the profile of glucosinolates and their degradation products.

The plant has a peppery, pungent taste shaped by sulfur-containing compounds. Fresh material differs chemically and sensorially from dried or heavily processed raw materials.

Phytochemically, watercress is a water-associated Brassicaceae leaf raw material with characteristic glucosinolate reaction chemistry.

Traditional Uses

Watercress has been known since antiquity and throughout Europe as a pungent aquatic plant. It was used as a fresh leafy vegetable, salad plant and herb ingredient and was particularly associated with springs, streams and clear water.

Traditionally, watercress was eaten fresh and used in soups, salads, herbal preparations and springtime cuisine. Its pungent taste and early seasonal availability made it a valued wild and cultivated plant.

Traditional use should be understood primarily in terms of food and culinary history. Historical herbal traditions also described watercress in various preparations, but modern public profiles should not derive medicinal claims from these accounts.

For presentation, differentiation from garden cress and nasturtium is important because these are different botanical species with their own constituent profiles.

Current Research

Current research on Nasturtium officinale investigates glucosinolates, phenethyl isothiocyanate, polyphenols, nutrient profiles, water quality, cultivation and food safety. A particularly relevant question is how cultivation, harvest and processing influence the glucosinolate-myrosinase system.

Food-chemistry studies examine antioxidant analytics, mineral profiles and comparability of fresh versus processed plants. Microbiological safety and hygienically controlled water management are central to raw-material quality.

Ecological and agronomic research considers watercress as an aquatic plant whose quality depends strongly on its site. Contaminated water can lead to undesirable contaminants.

Scientifically, watercress is a well-described fresh Brassicaceae raw material in which phytochemistry and hygiene are equally important.

Sources

• Plants of the World Online. Kew Science. Royal Botanic Gardens, Kew: Nasturtium officinale R.Br.
• Specialist literature on watercress, glucosinolates and phenethyl isothiocyanate.
• PubMed literature on Nasturtium officinale, water quality and food analytics.
• Food-chemistry literature on Brassicaceae leafy vegetables and myrosinase systems.
• European food-hygiene literature on fresh sprout and leafy-vegetable raw materials.