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Thermotectonic modeling was performed for the crystalline rocks of South Tuva using the apatite fission-track analysis. Thermotectonic modeling made it possible to visualize the Late Mesozoic and Cenozoic cooling history of the Pre-Mesozoic basement rocks, and to reconstruct the chronology and scale of the denudational processes over the last 125 myr and the evolution of paleorelief of South Tuva over the last 100 myr. The modeling results depicted several Mesozoic-Cenozoic episodes of cooling due to differential denudation and exhumation of the Pre-Mesozoic basement rocks. A differential denudation is related to an asynchronous activation of fault structures controlling the tectonic evolution of South Tuva. It is shown that the Early Cretaceous (~125–100 Ma) activation of the Agar-Dag-Oka thrust fault zone could result from the post-collisional processes after the collision between Siberia and Amuria and/or consecutive collision between the Cimmerian blocks. An intense activation of the Agar-Dag-Oka fault zone in the Late Cretaceous (~100–75 Ma), accompanied by significant basement rock exhumation in the eastern South Tuva to absolute heights of 1200 m, could be caused by the Karakoram-Pamir collision in the south of Eurasia. The Late Cenozoic (25–0 Ma) activation of the main fault zones of South Tuva represents a far-field effect of the Indo-European collision on the southern Eurasian continent. At the same time, there were the maximum basement uplift in the junction zone between the South Tannuola and Ubsunur-Bii-Khem fault zones and the transformation of relief of South Tuva from moderately dissected, with absolute heights of 500 to 1400 m, to modern, with absolute heights of 800 to 2600 m.

A comprehensive study of the stratotype section of the Kinterep formation of the North-Western Salair was carried out, including geochemical and isotope (Sr, C, O) studies of carbonate rocks, and U-Pb dating (LA-ICP-MS) of igneous zircon crystals from tuffites. The studied carbonate rocks are pure limestones with Mg/Ca less than 0.007 and a low proportion of insoluble residue (average 5 %). Kinterep limestones are characterized by δ18OSMOW values from 19.8 to 23.8 ‰ and δ13СPDB values from –0.7 to +0.9. The Sr isotope composition in limestones of the Kinterep formation varies in a narrow range of 87Sr/86Sr values between 0.70851 and 0.70859. Comparison of the obtained isotopic characteristics (87Sr/86Sr and δ13СPDB) of Kinterep formation limestones with the generalized global 87Sr/86Sr variation curve and δ13СPDB values in the pale-ocean suggests two equally probable interpretations of the time of accumulation of Kinterep formation limestones: 550–540 and 525–510 Ma. U-Pb dating of magmatic zircon crystals from tuffite, which forms an interlayer among limestones of the Kinterep formation, showed the age at the boundary of ~515 Ma. Thus, using a combination of isotope (Sr, C) chemostratigraphy of carbonate rocks and U-Pb dating of igneous zircon crystals from tuffites syngenetic to limestones, the age limit of 525–510 Ma was established for the time of the formation of the Kinterep formation of the Salair basin. Carbonate rocks of similar age and similar features of the isotopic composition are known in neighbouring areas (for example, the Kuznetsk Alatau) and in regions of the Siberian Platform and microcontinents of Central Asia (Tuva-Mongolian and Dzabkhan) spatially distant from the Salair basin.

For the first time, the complexation of pentacyclic triterpenes of licorice (glycyrrhizic acid (GA) and its aglycone, glycyrrhetinic acid (GLA)) with the novel Russian antiviral drug Camphecene (Camph) was investigated. The complexes obtained at different molar ratios were studied using both UV/Vis spectroscopy and mass spectrometry (ESI MS). Formation of the host:guest complexes were registered: GA and GLA molecular complexes (Camph+2GA; Camph+2GLA) with stability constants К = 6.94 106 М-2 and К = 2.89 106 М-2, respectively. The research results demonstrate a considerable potential of ESI MS as a technique for simple and fast detection of formation of the complexes of GA /GLA and the novel drugs.

Traditionally, glycyrrhizic acid has been used to form polydentate complexes. For the first time in the presented paper, the complexation of the Plant’s Flavonoids (Quercetin (Qu) and its glycoside - Rutin (Rut)) with the novel Russian antiviral drug Camphecene (Camph) was investigated. The complexes obtained at different molar ratios were studied using UV/Vis spectroscopy. Formation of the host: guest complexes were registered: Qu and Rut molecular complexes (Camph+2Qu; Camph+2Rut) with a stability constant K = 3.3·108 M-2. Comparison of the binding constants of the obtained complexes shows that the efficiency of Camphecene complexation with the participation of flavonoids is more efficient than with the participation of triterpenoids. Besides, it was found that the complexes of Camphecene with the quercetin and rutin are soluble in water, in contrast to the complexes with triterpenoids, which makes it possible to increase the bioavailability of both Camphecene and flavonoids. The obtained results demonstrate the high potential of flavonoids Qu and Rut to the development of novel pharmaceutical forms using the example of Camphecene in the form of molecular complexes, as the novel forms of delivery.