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HPLC is widely used in analytical practice because of its rapidness, sensitivity, selectivity of the corresponding procedures, and the possibility of determination of several analytes simultaneously [1, 2]. At the [...], Some features of the HPLC determination of two hydrophilic substances that poorly absorb in the UV spectral region (chondroitin sodium sulfate and glucosamine hydrochloride), associated with the absorption in the near UV region (195 nm) of components of buffer solutions with different pH values (1.2, 4.5, and 6.8), are considered. Such solutions are used, for example, in comparative dissolution kinetics tests in pharmaceutical practice. At some pH, the subtraction of the areas of system peaks from the total areas of analyte peaks made it possible to compensate for the negative effect of the solvent. To determine glucosamine hydrochloride in 0.1 M HCl, a procedure was developed and validated, involving the synthesis of o-phthalic derivatives. The revealed analytical features are caused by that the solvent of the samples and the eluent do not match; the effect can be most pronounced in measurements in the near UV region and in the determination of ionic compounds. Keywords: glucosamine hydrochloride, chondroitin sulfate, HPLC, quantitative determination, buffer solutions, comparative dissolution kinetics test DOI: 10.1134/S106193481708007X

Ziziphora clinopodioides subsp. bungeana (Juz.) Rech.f. is a subshrub that is widely distributed in China, Kazakhstan, Kyrgyzstan, Mongolia, Russia, Tajikistan, Turkmenistan, and Uzbekistan. The species is used in traditional medicine for the relief of symptoms connected to cardiovascular diseases like coronary heart disease or hypertension. was to validate traditional use of Z. clinopodioides subsp. bungeana for the treatment of coronary hearth diseases using in vivo models and to find active compounds responsible for the activity. Multiple extracts were obtained from the aerial parts of Z. clinopodioides subsp. bungeana using maceration, liquid-liquid extraction, CO2 extraction and ultrasound-assisted extraction. Preliminary screening studies for the evaluation of the efficacy of Z. clinop odioides subsp. bungeana extracts on the model of hemic hypoxia were performed. The most effective samples were selected and included in the main study. Stage 2 of the study evaluated the cardiotropic activity of the selected extracts on a model of chronic heart failure. Preparations were administered to animals intragastrically once a day for 28 days. For the isolation of individual compounds plant material was extracted with 96% ethanol. The obtained crude extract was sequentially extracted with n-hexane and dichloromethane and separated by chromatography on a Diaion HP-20 column. The obtained fractions were further subjected to Sephadex LH-20 column chromatography and eluted isocratically with 96% ethanol (EtOH) to yield subfractions, which were further separated by preparative HPLC to obtain 13 individual compounds. Extracts obtained from Ziziphora clinopodioides subsp. bungeana (Juz.) Rech.f. herb were subjected to pharmacological screening for the evaluation of their efficacy on hemic hypoxia. Based on the obtained results, out of the sixteen tested extracts two (AR and US 60%) were selected for further evaluation of their cardiotropic activity. Modeling of chronic heart failure was carried out in accordance with the following stages: 1) anesthesia with chloral hydrate at a dose of 450 mg/kg, intraperitoneally, 2) artificial ventilation of the lungs, 3) thoracotomy, 4) modeling of permanent ischemic or ischemic-reperfusion damage. Both extracts effected the indicators of contraction and output, comparable to the reference drug - Monopril. Based on the extraction methods used to obtain RAF and US60 and data from the literature, it can be assumed that they contain compounds with medium polarity, including polyphenols and terpenoids. At the next stage three previously undescribed monoterpenoid derivatives – Ziziphoric acid (1), Ziziphoroside D (2) and 6′-malonylziziphoroside A (3), along with two previously described megastigmane glucosides – blumenol C glucoside (4), blumenol C 9-O-(6′-O-malonyl-beta-D-glucopyranoside (5) and two previously described monoterpenoids 7a-hydroxymintlactone (6), 7-hydroxypiperitone (7) together with six polyphenols – pinocembrine-7-O-rutinoside (8), chrysine-7-O-rutinoside (9), acacetin-7-O-rutinoside (10), luteolin-7-O-rutinoside (11), rutin (12) and rosmarinic acid (13) were isolated from Z. clinopodioides subsp. bungeana extracts. Our results support the traditional use of Z. clinopodioides subsp. bungeana for the treatment of coronary diseases. As a result of Z. clinopodioides subsp. bungeana extracts screening in vivo , two extracts were selected as potential cardiotropic agents. Phytochemical analysis of the plant material led to the isolation of five terpenoid derivatives, two megastigmane glycosides, five flavonoids and one cinnamic acid derivative, which could be responsible for the reported biological activity. Future experiments are required to understand the mechanisms of action for the isolated compounds. [Display omitted] • The traditional use of Z. clinopodioides subsp. bungeana for treatment of coronary diseases was supported experimentally. • Extracts effected the indicators of contraction and output, comparable to the reference drug. • Three new monoterpenoid derivatives – Ziziphoric acid, Ziziphoroside D and 6′-malonylziziphoroside were isolated. [ABSTRACT FROM AUTHOR]