Capsella bursa-pastoris

Capsella bursa-pastoris, commonly called shepherd's purse, contains flavonoids such as diosmin and hesperidin, along with tyramine and oxalic acid, which collectively exert vasoconstrictive and uterotonic effects. These bioactive compounds act on smooth muscle tissue and platelet aggregation pathways to reduce excessive bleeding, particularly in gynecological contexts.

Origin & History

Capsella bursa-pastoris, commonly known as shepherd's purse, is a cosmopolitan annual herb in the Brassicaceae family, native to Eurasia but now widely naturalized worldwide. It is sourced from the whole plant (aerial parts), with extracts typically prepared via hydroalcoholic or ethanol methods from dried herb material.

Historical & Cultural Context

Shepherd's purse has been used for millennia in European and Middle Eastern folk medicine as a hemostatic remedy for postpartum hemorrhage, menstrual bleeding, and wound care. Traditional applications also included treatment for infertility, cardiovascular issues, and dermatologic conditions, with formal pharmacology studies dating to the 1960s.

Health Benefits

• Reduces heavy menstrual bleeding - shown in RCT (n=90) to significantly decrease bleeding amount and duration (evidence: moderate)
• May help prevent postpartum hemorrhage - RCT (n=100) showed reduced early PPH when combined with oxytocin (evidence: preliminary)
• Traditional hemostatic effects for wounds - supported by animal model showing reduced bleeding in liver laceration (evidence: traditional/animal)
• Potential antitumor activity - mouse studies showed 50-80% inhibition of Ehrlich tumor growth with i.p. extract (evidence: animal only)
• Antioxidant and anti-inflammatory properties - in vitro studies demonstrate polyphenol-mediated effects (evidence: preliminary)

How It Works

Capsella bursa-pastoris exerts hemostatic effects primarily through tyramine-mediated stimulation of adrenergic receptors, inducing uterine smooth muscle contraction and vasoconstriction of uterine blood vessels. Flavonoids including diosmin and hesperidin inhibit prostaglandin synthesis and stabilize capillary walls by reducing vascular permeability via phospholipase A2 inhibition. Additionally, oxalic acid and peptides present in the herb promote platelet aggregation and accelerate the coagulation cascade, contributing to its overall antihemorrhagic profile.

Scientific Research

Two human RCTs have examined shepherd's purse for bleeding disorders: one triple-blinded trial (n=90, PMID: 29641247) found hydroalcoholic extract capsules significantly reduced heavy menstrual bleeding vs placebo, while another RCT (n=100, PMID: 28590768) showed sublingual drops reduced early postpartum hemorrhage when combined with oxytocin. No large-scale trials or meta-analyses exist; most evidence comes from preclinical studies.

Clinical Summary

A randomized controlled trial (n=90) demonstrated that standardized shepherd's purse extract significantly reduced both the volume and duration of heavy menstrual bleeding compared to placebo, supporting moderate-strength evidence for this indication. A second RCT (n=100) found that adjunctive use of Capsella bursa-pastoris alongside oxytocin reduced the incidence of early postpartum hemorrhage, though this represents preliminary evidence requiring replication in larger trials. Traditional use across European herbal medicine systems provides historical context, and ESCOP has formally recognized its hemostatic applications, though most clinical trials are small and methodological quality varies. Overall, evidence is promising but insufficient to displace conventional first-line hemostatic therapies without further large-scale investigation.

Nutritional Profile

Capsella bursa-pastoris (shepherd's purse) is a nutritionally notable wild edible green in the Brassicaceae family. **Macronutrients (per 100 g fresh leaf, approximate):** Protein 3.0–4.2 g; Fat 0.5–0.7 g; Carbohydrates 4.0–5.5 g; Dietary fiber 2.0–3.5 g; Energy ~30–40 kcal. **Minerals:** Calcium 200–280 mg (relatively high for a leafy green; bioavailability moderate due to oxalate content, though lower oxalate than spinach); Potassium 350–400 mg; Iron 4.5–8.0 mg (non-heme, bioavailability enhanced by concurrent vitamin C); Phosphorus 40–80 mg; Magnesium 30–50 mg; Zinc 0.7–1.2 mg; Manganese 0.5–0.8 mg. **Vitamins:** Vitamin C 40–65 mg/100 g (notable; aids iron absorption); Vitamin A (as β-carotene) 2,500–4,100 µg RAE equivalent; Vitamin K₁ (phylloquinone) estimated 200–350 µg (very high, consistent with Brassicaceae greens and relevant to its hemostatic properties); Folate ~60–80 µg; Riboflavin (B₂) ~0.1–0.15 mg; Thiamine (B₁) ~0.08–0.10 mg. **Key Bioactive Compounds:** Flavonoids — rutin (quercetin-3-O-rutinoside, 0.5–1.5% dry weight), luteolin-7-O-glucoside, hesperidin, and diosmin, contributing to vascular-stabilizing and anti-hemorrhagic effects. Sulforaphane and other glucosinolate-derived isothiocyanates (sinigrin as precursor, ~5–15 µmol/g dry weight) typical of Brassicaceae. Tyramine and related biogenic amines (trace to low levels) historically implicated in uterotonic activity. Bursic acid and fumaric acid — organic acids believed to contribute to hemostatic activity. Acetylcholine-like compounds reported in older phytochemical literature. Phenolic acids including caffeic acid, p-coumaric acid, and chlorogenic acid (total phenolics ~15–30 mg GAE/g dry weight). Carotenoids including β-carotene and lutein (total ~30–60 mg/100 g dry weight). Tannins (condensed, ~1–3% dry weight) contributing to astringent and wound-healing properties. Saponins (triterpene type, modest levels). **Bioavailability Notes:** The high vitamin C content enhances non-heme iron absorption from the plant itself. Vitamin K₁ absorption is fat-dependent (consuming with dietary fat recommended). Flavonoid glycosides (rutin) are hydrolyzed by gut microbiota to aglycones (quercetin), with variable individual bioavailability (typically 15–30% absorption). Glucosinolate conversion to bioactive isothiocyanates depends on myrosinase activity (enhanced by raw consumption or light cooking). Oxalate content is lower than many Chenopodiaceae greens, making mineral bioavailability comparatively favorable.

Preparation & Dosage

Clinically studied doses include: sublingual hydroalcoholic extract drops (10 drops immediately post-delivery with oxytocin) for postpartum hemorrhage; oral hydroalcoholic extract capsules (specific dose not reported) taken over two menstrual cycles for heavy bleeding. No standardized dosing established. Consult a healthcare provider before starting any new supplement.

Synergy & Pairings

Vitex agnus-castus, Iron, Vitamin K, Dong Quai, Raspberry leaf

Safety & Interactions

Capsella bursa-pastoris is contraindicated during pregnancy due to its uterotonic activity, as tyramine-driven uterine contractions pose a risk of premature labor or miscarriage. Individuals taking anticoagulant or antiplatelet medications such as warfarin or aspirin should exercise caution, as its pro-coagulant and platelet-aggregating properties may potentiate or antagonize drug effects unpredictably. Thyroid medication interactions are a theoretical concern, as the plant contains goitrogens that may interfere with iodine uptake when consumed in high or prolonged doses. Side effects are generally mild at typical herbal doses but may include gastrointestinal upset, and patients with a history of kidney stones should avoid high-dose use due to oxalic acid content.