Tropaeolum majus (Nasturtium)

Tropaeolum majus (nasturtium) contains benzyl isothiocyanate and other glucosinolates that provide antibacterial and potential antiproliferative effects. The plant's bioactive compounds work through antimicrobial mechanisms and may interfere with cancer cell proliferation pathways.

Origin & History

Tropaeolum majus, or garden nasturtium, is a plant native to South America and belongs to the Tropaeolaceae family. Supplements are derived from its herb, leaves, flowers, and seeds, which are processed to create juices or concentrated essential oils using methods like microwave-assisted distillation. The plant is a rich source of glucosinolates, which break down into potent isothiocyanates.

Historical & Cultural Context

In European folk medicine, nasturtium was traditionally used as an antiscorbutic, antimicrobial, and general tonic to treat colds and respiratory illnesses. It was also employed for its diuretic, anti-inflammatory, and expectorant properties, with various parts of the plant being used.[1][3]

Health Benefits

["\u2022 May possess antiproliferative properties. Essential oil showed activity against cervical, colon, and osteosarcoma cancer cell lines in lab studies (in vitro evidence).[2]", "\u2022 Exhibits antibacterial activity. Fresh herb juice demonstrated inhibitory effects against Staphylococcus aureus, Candida albicans, Pseudomonas aeruginosa, and Escherichia coli (in vitro evidence).[1]", "\u2022 May act as a diuretic. Extracts from the plant's underground organs were shown to increase diuresis and sodium excretion in rats (animal study evidence).[1]", "\u2022 Contains antioxidant compounds. Nasturtium is a source of anthocyanins, polyphenols, and vitamin C, which are known to have antioxidant effects (mechanistic evidence).[3]", "\u2022 Provides key anti-inflammatory compounds. It contains benzyl isothiocyanate (BITC), a compound noted for its anti-inflammatory and immunomodulatory mechanisms (preclinical evidence).[1][2][4]"]

How It Works

Nasturtium's primary bioactive compounds include benzyl isothiocyanate and other glucosinolates that exhibit antimicrobial activity by disrupting bacterial cell membranes and inhibiting bacterial enzyme systems. The isothiocyanates may also interfere with cancer cell proliferation through apoptosis induction and cell cycle arrest mechanisms. These sulfur-containing compounds are released when plant tissues are damaged, converting from glucotropaeolin precursors via myrosinase enzyme activity.

Scientific Research

No human clinical trials, randomized controlled trials (RCTs), or meta-analyses were identified in the research dossier. All cited evidence is preclinical, limited to in vitro (lab-based) and animal studies.[1][2]

Clinical Summary

Current evidence for nasturtium is limited to in vitro studies and traditional use observations. Laboratory studies show essential oil activity against Staphylococcus aureus and cancer cell lines including cervical, colon, and osteosarcoma cells, though specific inhibition percentages and concentrations were not fully detailed in available data. No human clinical trials have been conducted to establish therapeutic dosages or confirm efficacy. The evidence base relies primarily on traditional use patterns and preliminary laboratory research requiring further clinical validation.

Nutritional Profile

Tropaeolum majus leaves and flowers are notably rich in vitamin C (ascorbic acid), with leaves containing approximately 130–300 mg per 100 g fresh weight, significantly higher than many common vegetables. The plant contains glucosinolates, primarily glucotropaeolin (benzyl glucosinolate), at concentrations of roughly 1–4% dry weight in leaves and seeds, which hydrolyze to form benzyl isothiocyanate (BITC), the principal bioactive compound responsible for its pungent flavor and antimicrobial properties. Leaves provide carotenoids including lutein (~40–60 mg/kg dry weight) and β-carotene (~10–30 mg/kg dry weight), contributing provitamin A activity. The flowers are rich in anthocyanins, particularly pelargonidin glycosides (in red/orange varieties) and delphinidin derivatives, with total anthocyanin content ranging from approximately 5–90 mg/100 g fresh weight depending on petal color. Flavonoids present include quercetin and kaempferol glycosides, with total flavonoid content in leaves estimated at 0.1–0.5% dry weight. The plant provides minerals including potassium (~400–500 mg/100 g fresh leaf), calcium (~50–70 mg/100 g), iron (~1.5–3.5 mg/100 g), phosphorus (~40–70 mg/100 g), and manganese in modest amounts. Leaves contain approximately 2–3 g protein per 100 g fresh weight, 0.3–0.7 g fat, 4–6 g carbohydrates, and 1–2 g dietary fiber per 100 g fresh weight, with a caloric value of roughly 20–30 kcal per 100 g. Seeds contain erucic acid (a long-chain fatty acid, C22:1) and higher concentrations of glucotropaeolin. Oxalic acid is present in moderate amounts, which may reduce bioavailability of calcium and iron. The bioavailability of benzyl isothiocyanate from glucotropaeolin is generally considered high when the fresh plant is consumed raw, as the enzyme myrosinase is active and facilitates hydrolysis; cooking significantly reduces isothiocyanate yield. Chlorogenic acid and other phenolic acids are also present, contributing to overall antioxidant capacity (ORAC values for fresh leaves are moderately high among edible flowers/herbs).

Preparation & Dosage

No clinically studied human dosage ranges are available, as all efficacy studies are preclinical. In vitro testing used essential oil at concentrations with an IC50 <5 µg/mL and extracts with an IC50 <27 µg/mL against cancer cell lines. Consult a healthcare provider before starting any new supplement.

Synergy & Pairings

Vitamin C, Garlic (Allicin), Echinacea, Turmeric (Curcumin)

Safety & Interactions

Nasturtium is generally considered safe when consumed as a food or in typical herbal preparations, though large medicinal doses have not been thoroughly studied. The plant's isothiocyanate content may cause gastrointestinal irritation in sensitive individuals or with excessive consumption. No specific drug interactions have been documented, but the herb's potential effects on bacterial flora suggest caution with antibiotic medications. Pregnancy and breastfeeding safety data is insufficient, so use during these periods should be avoided or limited to culinary amounts.