Anti-cancer effect of Rumex obtusifolius in combination with arginase/nitric oxide synthase inhibitors via downregulation of oxidative stress, inflammation, and polyamine synthesis

Cancer continues to be a leading cause of death worldwide, making the development of new treatment methods crucial in the fight against it. With cancer incidence rates increasing worldwide, ongoing research must focus on identifying new and effective ways to prevent and treat the disease. The combination of herbal extracts with chemotherapeutic agents has gained much interest as a novel strategy to combat cancer. Rumex obtusifolius L. is a wild plant known for its medicinal properties and is widely distributed worldwide. Our preclinical evaluations suggested that R. obtusifolius seed extracts possessed cancer-inhibiting properties and we also evaluated the beneficial effects of the arginase inhibitor NG-hydroxy-nor-L-arginine and nitric oxide inhibitor NG-nitro-L-arginine methyl ester in the treatment of breast cancer. The current study aimed to combine these observations and evaluate the antioxidant and antitumor properties of R. obtusifolius extracts alone and in combination with the arginase and nitric oxide synthase inhibitors. Metabolic characterization of the plant extract using a liquid chromatography/high-resolution mass spectrometry advanced system revealed the presence of 240 phenolic compounds many of which possess anticancer properties, according to the literature. In vitro studies revealed a significant cytotoxic effect of the R. obtusifolius extracts on the human colon (HT29) and breast cancer (MCF-7) cell lines. Thus, a new treatment approach of combining R. obtusifolius bioactive phytochemicals with the arginase and nitric oxide synthase inhibitors NG-nitro-L-arginine methyl ester and/or NG-hydroxy-nor-L-arginine, respectively, was proposed and could potentially be an effective way to treat breast cancer. Indeed, these combinations showed immunostimulatory, antiproliferative, antioxidant, anti-inflammatory, and antiangiogenic properties in a rat breast cancer model.

Evaluation of the Effects of Rumex obtusifolius Seed and Leaf Extracts Against Acanthamoeba: An in vitro Study

BACKGROUND

Acanthamoebiasis treatment is a major and challenging problem due to the presence of resistant cyst form. Many herbal extracts and their derivatives have been used against trophozoites and cysts of Acanthamoeba, but no effective therapeutic agent has yet been discovered. Therefore, the present study aimed to evaluate the effect of Rumex obtusifolius (R. obtusifolius) extracts against a clinical strain of Acanthamoeba genotype T4 in vitro.

METHODS

In this experimental study, after genotyping the clinical isolate, the hydroalcohlic extracts of R. obtusifolius seeds and leaves were prepared. Different concentrations (1.25, 2.5, 5 and 10 mg/ml) of extracts were tested in triplicate (24, 48 and 72h) on trophozoites and cysts of Acanthamoeba. The mortality of the parasite was assessed by trypan blue vital staining and flow cytometry analysis.

RESULTS

Results showed that the extract of R. obtusifolius leaves at the concentration of 10 mg/ml killed 100% of trophozoites and cysts after 72 h. However, the seed extract of R. obtusifolius had weak inhibitory effects on trophozoites and cysts of Acanthamoeba. In the presence of 10 mg/ml of hydroalcoholic seed extract of R.obtusifolius in culture medium after 72 h, 28.6% of trophozoites and 0% of cysts of Acanthamoeba were killed. After analysis by flow cytometry, seeds and leaves extract indicated apoptosis effect. Seed and leaf extracts caused 2.6% and 0.4% percent apoptosis.

CONCLUSION

These extracts are not promising candidates for further medicine development on acanthamoebiasis. Nonetheless, further research is necessary to clarify the effects of effective fractions of seed and leaf extracts of R. obtusifolius and their mechanisms of action.

caused by ion beam irradiation

Some Rumex species such as sorrel are edible as baby leaf salad greens. On the other hand, Rumex plants accumulate soluble oxalate, a toxic metabolite which causes serious diseases such as renal syndrome. We attempted to produce low-oxalate plants of R. obtusifolius, a perennial weed which has higher vitamin C and amino acid content and higher tolerance to stress than many other Rumex species. Ion beams are ionising radiation with high linear energy transfer that causes a wide spectrum of mutations. Thus, in the present study we evaluated the effects of ion beams on oxalate and other primary metabolites in leaves of R. obtusifolius using CE-MS. The results showed that oxalate content was increased by irradiation with carbon ion beams. Metabolome analysis revealed that ion beams affected carbon flow to the isocitrate pathway, which is involved in oxalate synthesis. These observations suggested that modulation of carbon flow to the isocitrate pathway is important to regulate oxalate levels in plants.