Scientific Name(s): I. biflora Willd., I. capensis Meerb., I. pallida Nutt., Impatiens balsamina L.
Common Name(s): Garden balsam, Jewel balsam weed, Jewel weed, Jewelweed, Touch-me-not, Zhi hin nonxe thionbaba (Native Americans, the Omaha)
Impatiens capensis and the closely related I. balsamina are tender, succulent herbs commonly found at wet woodland borders, shaded riverbanks, and roadside ditches, which are locations also preferred by poison ivy. They grow 2 to 5 feet in height and either bear orange to yellow, or pink to purple flowers, respectively, and are commonly grown as bedding and house plants.17 Jewelweed is sometimes called the "touch-me-not." This name alludes to the presence of a seed capsule made of a soft fleshy tissue that tends to expel its contents if touched or shaken.
Jewelweed has long been recognized as an herbal remedy for the treatment of topical irritation, most notably for the treatment of poison ivy rash. The sap of the jewelweed has been used by American Indians, particularly those living in Appalachia, as a prophylactic against poison ivy rash and as a treatment after the eruptions have occurred.3, 4 The Southern Cherokee, Potawatomi, Chippewa, Meskwaki, and Omaha used I. capensis for a variety of pruritic dermatites besides treating and preventing poison ivy rash and itch, including treatment of stings from other plants (eg, stinging nettle) and insect bites.17 In Japan the juice of the corolla from white balsamina flowers is painted on the skin as an antipruritic.5, 6, 17 And the aerial parts of Impatiens spp have been used in Chinese herbal medicine for treating pain and swelling, and as an antimicrobial.17
The aerial parts of the plant are used in Chinese herbal medicine for rheumatism, beriberi, bruises, pain, and swelling, and as an antimicrobial agent.6, 7, 8 Impatiens seeds have been used to promote blood flow, including menstruation, and for the suppression of post-childbirth pain, as an expectorant and, in some Asian countries, as an antidote for fish poisoning.9
Commercial poison ivy–prevention products containing jewelweed are widely available.17
Chemical compounds identified in the white petals of I. balsamina include kaempferol, kaempferol 3-glucoside, kaempferol 3-rutinoside, kaempferol 3-rhamnosyldiglucoside, quercetin, quercetin 3-rutinoside, 2-hydroxy 1,4-napthoquinone, and 2-methoxy 1,4-napthoquinone.5 Aerial parts of balsamina contain phenolics, flavonols, anthocyanin pigments, quinones, and saponins8 as well as a testosterone 5 alpha-reductase inhibitor impatienol.6, 7
Four novel peptides with antimicrobial properties have been isolated from the seeds of I. balsamina,10 in addition to several saponins.9 2-methoxy 1,4-napthoquinone, lawsone (2-hydroxynapthoquinone), spinasterol, scopoletin, methylene 3,3-bilawsone (diphthiocol), and isofraxidin (8-methoxyscopoletin) have been identified in the roots as well as cysteine-rich compounds with antimicrobial and antifungal activity.11, 17 In addition to antimicrobial activity, lawsone has demonstrated antioxidant, immunomodulatory, and COX-2 inhibitory actions.17
Uses and Pharmacology
Poison ivy treatment
Several attempts have been made to verify that jewelweed extracts, when applied topically, have a beneficial effect on poison ivy eruptions. Approaches, formulations, and preparations have been varied (ie, glycerin or aqueous extracts, whole-plant mashes, juice from aerial parts, sprays, soaps, creams).17
A study using an ethanol extract of the white petals of I. balsamina suggested that there might be 2 different compounds responsible for antipruritic activity demonstrated in mice.5
The results of a small clinical trial suggest an aqueous extract of jewelweed stem was ineffective in reducing the erythema, vesicles, and edema associated with poison ivy, but the subjects did report decreased pruritus.4 An experimental controlled study seeking to validate ethnopharmacological use of jewelweed for prevention of poison ivy as well as to determine any correlation of jewelweed formulation and lawsone concentration of efficacy enrolled 40 volunteers 18 to 65 years of age across 6 US locations. Both I.capensis and balsamina were studied. Preparations varied from fresh, frozen, and dried material prepared as a mash of whole plants and plant parts that were harvested at different times during the growth season, to cold aqueous infusions, soap preparations, ethanol extraction, olive oil extraction, neutral decoction, and a basic decoction. The comparators included distilled water administered as a single wash and double wash, a lawsone solution equivalent to the I. capensis infusion, and Dawn dish soap. Lawsone concentration was highest in fresh aqueous extract and fresh mash of I. balsamina mid-season harvest (744 to 750 mcg/g of plant material) and lowest in olive oil extraction and the ethanol extract of dried material. Approximately half of the participants developed significant poison ivy dermatitis with a median rash development score of 10 on a scale of 0 to 14. On day 7, 11 of 12 (91.67%) patients exhibited significantly less of a rash in the areas treated with either of the Impatiens spp. compared to the control (water). The rash score averaged 6.7 for the Impatiens spp extracts, which was not significantly different from the control (9.3); however, both Impatiens mashes resulted in significantly lower rash scores (4.7). Interestingly, all 3 soap products (Impatiens soaps and Dawn soap) provided significantly improved mean rash scores of 3.1 (a 67% reduction in rash), irrespective of the lawsone concentration. The lawsone solution produced a rash score of 7, and therefore, appeared to play no significant role on its own in preventing rash development. The efficacy of the soaps and the mashes is likely associated with the water content washing away the urushiol with the plant material serving as an abrasive, which supports earlier findings with commercial soaps (ie, Dial, Technu, Goop) that produced 62.7% reduction in rashes.17 An additional study by this author using the same methodology in 23 volunteers, investigated the role of saponins (the major constituent of soap) in contributing to efficacy of jewelweed for prevention of poison ivy dermatitis. In patients exhibiting severe rash response, the greatest rash score reductions were from the soaps and a double-strength extract (P < 0.05) compared with fresh mash, plant strength extracts, and control. The soaps provided a reduction of 48% and 46% with and without addition of jewelweed extract, respectively, and the double-strength extract a 33% reduction compared to control. These data indicate that the detergent action of the soaps was effective in reducing rash development likely due to emulsification of the urushiol oil. (18)
Effect on blood pressure
Researchers have evaluated the protective effect of extracts of I. balsamina and I. textori species flowers on severe hypotension resulting from simulated anaphylaxis in mice. The results suggest the presence of a platelet activating factor antagonist, as well as a compound with weak antihistamine effect.12, 13, 14, 15
Compounds having antibacterial and antifungal activity have been isolated from the aerial parts of I. balsamina8 as well as from the seeds.10, 16 The potential may be limited to the plant's ability to resist pathogens, despite the reported traditional use of jewelweed tea for systemic and fungal infections.8 Neither antimicrobial nor antifungal activity was evident with saponin-containing extracts at concentrations of 1 g plant material/g saponin when tested against gram-negative or -positive bacteria (ie, Staphylococcus epidermidis, Bacillus subtilis, Pseudomonas aeruginosa, or Escherchia coli) or Candida albicans.
More recent studies have identified chemical compounds supporting traditional uses of jewelweed: the identification of COX-2 inhibitory napthoquinone salts supports the use of jewelweed for articular rheumatism, pain, and swelling6 and the presence of a testosterone 5 alpha-reductase inhibitor supports its use against male pattern baldness;7 however, further studies are needed before any conclusions can be drawn.
In vitro anticancer activity was investigated in breast, melanoma, and colon cancer cell lines with test solution made from dried extract and applied at concentrations of 100, 80, 64, 48, and 34 mcg/mL. Dose response cytotoxicity was observed in breast cancer cells that also demonstrated characteristics typical of apoptosis with low concentrations producing a 39.8% reduction in cell growth and high concentrations resulted in no growth. Cytostatic activity was documented in the colon cancer cells and no growth inhibition was observed in the melanoma cell line; neither of these latter 2 cell lines exhibited apoptotic characteristics.18
A possible positive chronotropic effect was observed with the addition of I. capensis saponin extract to the controlled aqueous "pond water" environment of black worms (Lumbriculus variegatus) at a concentration of 100 mg extracted plant material/mL of "pond water." Resting heart rate of the 5 black worms increased immediately to 107.5% of resting rate, and within 5 minutes to 138% of heart rate; no increase in heart rate was seen in the 3 controls.18
Crushed jewelweed has been used as a topical salve for poison ivy. No other specific dosing information is available.
Pregnancy / Lactation
Information regarding safety and efficacy in pregnancy and lactation is lacking. Considering its traditional use as an emmenagogue9 use in pregnancy should probably be avoided until further evidence is available.
None well documented.
Research reveals little information regarding adverse reactions with the topical use of this product. Use of Impatiens spp tea has been reported to cause digestive upset, while consumption of the whole plant induces vomiting and diuresis.17
There are no published reports of toxicity associated with the topical use of jewelweed extracts. The safety of internal ingestion is not well-defined.
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