The world of herbal medicine is rich with potent plants, but a common source of confusion lies within the name "nasturtium." While gardeners recognize the vibrant, shield-leaved climber, botanists also classify the familiar aquatic green known as watercress under a different Nasturtium species. Both possess powerful health benefits, but for distinct purposes. This guide clarifies the medicinal differences and uses of these two remarkable, yet separate, healing herbs.
Tropaeolum Majus: The Garden Nasturtium
Often called Indian cress or monk's cress, Tropaeolum majus is the vibrant annual plant with round leaves and striking orange, red, or yellow flowers found climbing fences or spilling from containers. Its medicinal properties are largely attributed to pungent, sulfurous compounds called glucosinolates, which convert to potent mustard oil derivatives like benzyl isothiocyanate when the plant tissue is crushed or chewed. This process explains the plant's characteristic peppery taste and its efficacy as a natural antibiotic.
Therapeutic Applications of Tropaeolum Majus
- Antimicrobial and Antifungal: Research supports the antibacterial and antifungal capabilities of garden nasturtium extracts, which can be effective against a range of pathogens, including common bacteria like Staphylococcus aureus and Escherichia coli. This makes it a traditional remedy for infections.
- Respiratory Antiseptic: Due to its volatile mustard oils, the compounds are eliminated through the respiratory system, acting as a powerful expectorant and antiseptic. This makes it valuable for conditions like colds, flu, sinusitis, coughs, and bronchitis, helping to clear mucus and congestion.
- Urinary Tract Infections (UTIs): The same volatile compounds that benefit the lungs are also excreted via the urinary system, where they inhibit bacterial growth. This has made garden nasturtium, especially in combination with horseradish, a prescribed herbal remedy in some countries for acute UTIs.
- Topical Wound Healing: The plant's antiseptic properties can be harnessed topically. Crushed fresh leaves or flowers can be used as a poultice on minor cuts, scrapes, and infected wounds to help prevent infection and promote healing.
- Other Uses: Traditional herbalists have also employed T. majus for hair loss, as a blood tonic, and for its anti-inflammatory effects.
Nasturtium Officinale: The Medicinal Watercress
Not to be confused with its garden cousin, Nasturtium officinale, or watercress, is an aquatic perennial known for its sharp, peppery flavour and nutrient-dense leaves. It belongs to the Brassicaceae family, the same family as mustard and cabbage. Its medicinal value lies in its exceptional antioxidant capacity, high vitamin content, and anti-inflammatory properties, with a different spectrum of applications.
Healing Benefits of Nasturtium Officinale
- Powerful Antioxidant and Anti-inflammatory: Watercress is packed with antioxidant compounds like flavonoids and phenolics, which help reduce oxidative stress and protect against cellular damage. Clinical trials have confirmed its anti-inflammatory effects, showing promising results for conditions like asthma by reducing oxidative markers.
- Potential Anticancer Effects: Multiple studies have investigated watercress for its chemopreventive properties, largely due to its phenylethyl isothiocyanate (PEITC) content. Research on cancer cell lines has shown that watercress extract can inhibit cancer cell viability and suppress tumor growth.
- Cardiovascular Support: Studies have shown that watercress can positively influence cardiovascular health by helping to improve blood lipid profiles and reduce oxidative stress in hypercholesterolemic rats.
- Diuretic and Detoxifying: Traditionally, watercress has been used as a diuretic and cleansing herb. It stimulates urination, assisting the body in flushing out excess fluids and toxins.
- Nutritional Powerhouse: Watercress is an incredible source of vitamins, including very high levels of vitamin C, as well as minerals like iron and zinc, which contribute to its overall restorative and immune-boosting qualities.
Comparing the Medicinal Nasturtiums: A Table
| Feature | Tropaeolum Majus (Garden Nasturtium) | Nasturtium Officinale (Watercress) |
|---|---|---|
| Family | Tropaeolaceae | Brassicaceae |
| Growth Habit | Vining or bushy annual | Aquatic or semi-aquatic perennial |
| Primary Uses | Respiratory and urinary tract infections, external wounds, hair loss | Antioxidant support, anti-inflammatory, detoxification, cardiovascular health |
| Key Active Compounds | Glucosinolates (e.g., glucotropaeolin) and Benzyl Isothiocyanate | Glucosinolates (e.g., gluconasturtiin), Phenylethyl Isothiocyanate (PEITC), Flavonoids, Carotenoids |
| Antimicrobial Effect | Potent, especially against respiratory and urinary bacteria | Broad-spectrum, including antibacterial and antifungal properties |
| Source of Vitamin C | High levels, used historically to prevent scurvy | Also very high, a classic source of vitamin C |
| Safety Note | Can irritate kidneys or stomach in excessive doses | Generally safe in food amounts, but consult a doctor for medicinal use |
How to Use Medicinal Nasturtiums
Both nasturtium species can be easily incorporated into your diet or used as herbal preparations. For safety and effectiveness, proper identification and dosage are key.
- Dietary Inclusion: The leaves, flowers, and seeds of Tropaeolum majus can be eaten fresh, adding a peppery flavour to salads and sandwiches. Watercress is a versatile salad green and can also be blended into pesto or added to soups.
- Herbal Infusion (Tea): Infusions made from the fresh or dried leaves and flowers of garden nasturtium are used for respiratory conditions like coughs and colds. Similarly, watercress can be used for chest complaints and to stimulate the body.
- Tinctures: Tinctures are a concentrated form often used by herbalists to treat conditions like UTIs and inflamed airways more potently. In Germany, a licensed herbal antibiotic contains a combination of nasturtium and horseradish.
- Topical Application: A poultice of crushed garden nasturtium leaves can be applied to minor infections or skin issues, including acne. An infusion can also be used as a hair rinse to promote growth and scalp circulation.
Before using either plant medicinally, it is crucial to consult a healthcare professional, especially if pregnant, breastfeeding, or on medication. Excessive consumption of garden nasturtium can cause gastrointestinal or kidney irritation. For maximum benefit and safety, always use the correct plant for the intended purpose.
Conclusion
In conclusion, the question of "which nasturtium is medicinal?" has a nuanced answer: both Tropaeolum majus (garden nasturtium) and Nasturtium officinale (watercress) are medicinal, but they are different plants with unique profiles. The garden variety is a potent antimicrobial powerhouse, particularly for respiratory and urinary infections, while watercress is a nutrient-dense antioxidant champion, beneficial for detoxification and anti-inflammatory support. Understanding these differences ensures that you can harness the correct plant's healing properties safely and effectively. Always practice proper identification and, for serious medical conditions, seek professional advice.
Using Medicinal Nasturtiums Safely
Always ensure correct identification of the plant species. Harvest from clean, uncontaminated areas, especially for watercress, which can grow in water that might be polluted. For medicinal use, start with small amounts and monitor your body's reaction. It is advisable to consult a qualified herbalist or healthcare provider before beginning any new herbal treatment, especially for chronic conditions, to ensure it is appropriate for your health needs. For external use, perform a patch test on a small area of skin to check for any adverse reactions.
