The effectiveness of jewelweed, Impatiens capensis, the related cultivar I. balsamina and the component, lawsone in preventing post poison ivy exposure contact dermatitis

(3,3'-Methylene)bis-2-hydroxy-1,4-naphthoquinones induce cytotoxicity against DU145 and PC3 cancer cells by inhibiting cell viability and promoting cell cycle arrest

We developed a novel method for the synthesis of bis-naphthoquinones (BNQ), which are hybrids of lawsone (2-hydroxy-1,4-naphthoquinone) and 3-hydroxy-juglone (3,5-dihydroxy-1,4-naphthoquinone). The anticancer activity of three synthesized compounds, named 4 (RC10), 5 (RCDFC), and 6 (RCDOH) was evaluated in vitro against two metastatic prostate cancer (PCa) cell lines, DU145 and PC3, using MTT assays. We found that 4 (RC10) and 5 (RCDFC) induced cytotoxicity against DU145 and PC3 cells. Flow cytometry analysis revealed that these two compounds promoted cell cycle arrest in G1/S and G2/M phases, increased Sub-G1 peak and induced inhibition in cell viability. We also showed that these effects are cell-type context dependent and more selective for these tested PCa cells than for HUVEC non-tumor cells. The two BNQ compounds 4 (RC10) and 5 (RCDFC) displayed promising anticancer activity against the two tested metastatic PCa cell lines, DU145 and PC3. Their effects are mainly associated with inhibition of cell viability, possibly through apoptotic cell death, besides altering the SubG1, G1/S and G2/M phases of cell cycle. 5 (RCDFC) compound was found to be more selective than 4 (RC10), when comparing their cytotoxic effects in relation to HUVEC non-tumoral cells. Future work should also test these compounds in combination with other chemotherapeutic drugs to evaluate their effects on further sensitizing drug-resistant metastatic PCa cells.

Mannich bases derived from lawsone and their metal complexes: synthetic strategies and biological properties

Lawsone (2-hydroxynaphthalene-1,4-dione) is a natural product which shows significant biological activity.

Untargeted MS-based small metabolite identification from the plant leaves and stems of Impatiens balsamina

The identification of plant metabolites is very important for the understanding of plant physiology including plant growth, development and defense mechanism, particularly for herbal medicinal plants. The metabolite profile could possibly be used for future drug discovery since the pharmacological activities of the indigenous herbs have been proven for centuries. An untargeted mass spectrometric approach was used to identify metabolites from the leaves and stems of Impatiens balsamina using LC-DAD-MS/MS. The putative compounds are mostly from the groups of phenolic, organic and amino acids which are essential for plant growth and as intermediates for other compounds. Alanine appeared to be the main amino acid in the plant because many alanine derived metabolites were detected. There are also several secondary metabolites from the groups of benzopyrones, benzofuranones, naphthoquinones, alkaloids and flavonoids. The widely reported bioactive components such as kaempferol, quercetin and their glycosylated, lawsone and its derivatives were detected in this study. The results also revealed that aqueous methanol could extract flavonoids better than water, and mostly, flavonoids were detected from the leaf samples. The score plots of component analysis show that there is a minor variance in the metabolite profiles of water and aqueous methanolic extracts with 21.5 and 30.5% of the total variance for the first principal component at the positive and negative ion modes, respectively.

Depside derivatives with anti-hepatic fibrosis and anti-diabetic activities from Impatiens balsamina L. flowers

Eighteen compounds (1-18), seven new (3-9) and eleven previously reported (1, 2, and 10-18), were isolated from the flowers of Impatiens balsamina (Linn). The structures of the isolated compounds were elucidated using different spectroscopic methods, including NMR (1D and 2D), UV, IR, and HR-ESI-MS. Analysis of the bioassay results showed the compounds had notable anti-hepatic fibrosis activity against murine Hepatic Stellate Cells (t-HSC/Cl-6) and anti-diabetics activity against α-glucosidase. Specifically, new compounds 7, 8, 9 showed significant inhibitory activity on t-HSC/Cl-6 cells with IC50 values of 42.12, 109.2, and 34.04 μg/mL respectively, while the IC50 values of positive control Silymarin and Fufang Biejia Ruangan Pian were 202.34 and 231.56 μg/mL, respectively. In addition, compounds 2, 4, 7, 8, 10, 11, 17, and 18 exhibited excellent α-glucosidase inhibitory activity. Among these compounds, 7 exhibited the highest activity with an IC50 value of 0.72 μg/mL, while the IC50 value of the positive control acarbose was 3.36 μg/mL. This is the first study evaluating the anti-hepatic fibrosis and anti-diabetic activities of compounds isolated from the flowers of I. balsamina.

Efficacy of the saponin component of Impatiens capensis Meerb.in preventing urushiol-induced contact dermatitis

ETHNOPHARMACOLOGICAL RELEVANCE

Many different tribes of American Indians used jewelweed, Impatiens capensis Meerb, as a plant mash to reduce development of poison ivy dermatitis. Saponins are a natural soapy constituent found within plants. A 2012 study suggested that saponins may be present in jewelweed which could be responsible for its efficacy in preventing rash development following contact with Toxicodendron radicans (L.) Kuntze (poison ivy). This study validated this hypothesis and demonstrated additional biological activity of the jewelweed saponin containing extract.

MATERIALS AND METHODS

Fresh I. capensis leaves were extracted with methanol and further partitioned between ethyl acetate and water, with a final separation between water and n-butanol, to obtain a saponin containing extract. The presence of saponins in the extract was demonstrated by the observation of foaming and using a vanillin colorimetric assay for total saponins. Efficacy of the saponin containing extracts in rash reduction was tested by brushing poison ivy (PI) onto the forearms of volunteers (N=23) in six locations and treating these PI exposed areas with distilled water (control), saponin containing extracts, fresh plant mashes, and soaps made with and without plant extracts. Saponin containing extracts were further tested for biological activity against both gram negative and gram positive bacteria and against cancer cell lines A-375, HT-29, and MCF-7. Additionally, because saponins have been shown to have a stimulatory effect in cardiac muscle 2 µl saponin extract was applied superficially to black worms, Lumbriculus variegatus (N=5).

RESULTS, AND CONCLUSIONS

Both saponin containing extracts and all soaps tested were effective in reducing poison ivy dermatitis; thus, saponin content correlates with PI rash prevention. No apparent antibiosis was observed against any bacteria tested; however, dose response cytotoxicity was documented against MCF-7 breast cancer cells and cytostatic activity was seen against the HT-29 colon cancer cell lines. Lumbriculus variegatus exhibited a 138% increase in heart rate over baseline rate five minutes post treatment implying a possible positive chronotropic effect.

Lawsone in organic synthesis

Lawsone has been used as the starting material for the synthesis of a variety of biologically active compounds and materials.