Rheum rhaponticum Root Extract Improves Vasomotor Menopausal Symptoms and Estrogen-Regulated Targets in Ovariectomized Rat Model

Ovarian insufficiency and ovariectomy are characterized by deregulated heat loss mechanisms. Unlike hormone therapy, ERr 731 (a standardized botanical extract of Siberian rhubarb Rheum rhaponticum L. high in rhaponticin) acts like a selective estrogen receptor modulator for ERβ receptors and may offer a higher degree of safety while maintaining the desired efficacy profile. In this study, we examined the relationship between oral administration of ERr 731 and the underlying components of skin vasomotion responses in an ovariectomized (OVX) rat model. ERr 731 dose-dependently reduced tail skin temperature (Tskin) values by an average of 1 °C. The rapid onset of this effect was observed in 1 and 3 mg/kg/day ERr 731 groups as early as day 2 of administration, and remained in place for the duration of the treatment (2 weeks). Substituting ERr 731 after E2 withdrawal helped maintain body temperature similarly to E2 alone, suggesting the usefulness of ERr 731 for replacing existing hormonal therapy in humans. ERr 731 also acted as a highly selective agonist for ERβ in the hypothalamus of OVX rats, as well as in ERα/β cell-based reporter assays. These data validate the OVX/Tskin rat model as a suitable screening platform to evaluate botanical and pharmaceutical treatments of menopause, while providing further evidence for the efficacy of ERr 731 towards alleviating vasomotor menopausal symptoms and improving wellbeing during the menopausal transition.

Ozone Treatment as a Process of Quality Improvement Method of Rhubarb (Rheum rhaponticum L.) Petioles during Storage

The aim of the study was to identify the effects of ozone treatment reflected by the microbial, mechanical properties and selected chemical parameters during the storage of rhubarb petioles. For this purpose, after they were harvested, rhubarb petioles were treated with gaseous ozone at concentrations of 10 and 100 ppm, for the duration of 5, 15 and 30 min. Subsequently, the plant material was stored at room temperature for 14 days. After this time, the raw material was subjected to a number of chemical and mechanical tests. It was shown that the rhubarb petioles treated with ozone at a rate of 100 ppm for 30 min were characterized by the lowest loss of water content. It was also found that, compared to the control, most samples subjected to ozone treatment presented better mechanical properties, as well as higher oxidative potential and contents of polyphenols and vitamin C. Based on these findings, it was determined that ozone treatment largely increases storage stability of rhubarb.

Application of multifunctional compositions based on Rheum rhaponticum L. extracts for the elaboration of plant protection products

Relevance.Extract-based compositions, combining various types of biological activity were created and tested, to reveal the potential of genus Rheum (Polygonaceae)plants bioactive substances. The aim of the work was to determine the composition of bioactive substances in R. rhaponticum L. plants extracts and assess the possibility of their use as a means of protecting vegetable plants from powdery mildew.Materials and methods. The methods of cultivation and research of R.rhaponticum plant materials was carried out at the Institute of Genetics, Physiology and Plant Protection, Chisinau, Republic of Moldova (2012-2019). The subject of our study the bioactive substances of rhubarb roots and leaves were used. Results.The localization zones of anthracene derivatives were identified: in the main parenchyma of the secondary cortex and the parenchyma of the core rays of the rhubarb root. The amount of flavonoids and phenols in the root extract is 2 times more than in the leaf extract. To study the fungicidal and stimulating properties of rhubarb root extract in the control of powdery mildew, we conducted studies in a greenhouse on vegetable plants using artificial infection of seedlings. It was found that the chlorophyll transmittance index of leaves treated with rhubarb root extract increases until the concentration of the extract (R) reaches 1.5% (157.3 rel. units)(In the control – 119.2 rel. units). With increasing concentration of the extract to 2%, the chlorophyll index falls 1.2 times lower than the control values. The highest immunostimulating and fungicidal activity, intensifying with the addition of rhubarb leaf extract, was shown by rhubarb root extract. Its biological effectiveness was high at any intervals between treatment and infection (4 and 72 hours), and was directly proportional to concentration. Adding rhubarb leaf extract to the rhubarb root extract enhances the activity of the composition, and the risk of developing pesticide resistance among plant pathogens decreased.

Antimycobacterial Effect of Extract and Its Components from Rheum rhaponticum

The global threat of tuberculosis demands the search for alternative antimycobacterial drugs. The present study examined roots and petioles from Rheum rhaponticum for antimycobacterial activity. Crude methanol extracts and eight phenolic compounds isolated by preparative column chromatography were tested against Mycobacterium tuberculosisH37Ra and M. bovis using the broth dilution method. The extract from roots and its components, such as rhaponticin, deoxyrhaponticin, resveratrol, barbaloin, aloe-emodin, and chrysophanol were found to have antimycobacterial activity against both microorganisms. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration of all the investigated samples ranged from 32 to 512 μg/mL. The anthracene derivatives were the most active; their MICs were 32, 64, and 64 μg/mL (M. tuberculosisH37Ra) and 128, 64, and 64 μg/mL (M. bovis), respectively. The microorganisms were resistant to stimulation with extract from petioles, as were quercetin and rutin. The results showed that anthracene and stilbene derivatives play a prominent role in the antimycobacterial properties of R. rhaponticum.