LAUSR

The genus Geranium L. (Geraniaceae) numbers about 300 species, of which 13 grow in Uzbekistan [1, 2]. In continuation of phytochemical research on plants of this genus [3], we analyzed the volatile constituents isolated from the aerial parts of G. collinum Stephan ex Willd. and G. transversale Vved. ex Pavlov, which are broadly distributed in Uzbekistan. Tanning agents (7–27%) were reported from the aerial parts of both plants in addition to saponins, alkaloids, phenolic carboxylic acids, and flavonoids from leaves of G. collinum and hydrocarbons, linoleic acid, phthalates, and bisabolene from G. transversale [3, 4]. Furthermore, the essential-oil (EO) compositions of G. columbinum L. and G. lucidum L. growing in Serbia [5], G. sanguineum L. from Tunisia [6], and G. sylvaticum L. from Turkey [7] were analyzed. However, such information about the species studied by us is lacking. Previously, eicosane and linoleic acid were detected in significant quantities in the hexane extract of the aerial part of G. transversale using GC-MC [3]. Aerial parts of G. transversale and G. collinum were collected in Zaamin District of Jizzakh Oblast in May and September 2015, respectively, during flowering. Volatile substances were isolated by steam distillation in a Clevenger apparatus for 4 h using high-purity hexane as a solvent-trap. This allowed volatile constituents present in small quantities in the plants to be isolated [8]. Air-dried aerial part (20.0 g) of G. transversale was ground in a coffee grinder and worked up with hexane (4 100 mL) by standing for 24 h in the first extraction step. All extracts were combined. The solvent was removed in a rotary evaporator (40–50°C) to afford extracted substances (0.32 g). The yield of hexane extract from G. transversale was 1.6% of the dry plant mass. The yields of volatile substances from air-dried aerial parts of G. collinum and G. transversale that were obtained by steam distillation were 0.015 and 0.01%, respectively, of the dry plant mass. Tables 1 and 2 list the volatile constituents found by GC-MS. Volatile substances from G. collinum contained 39 identified constituents representing 92.37% of the total mass and were dominated by 1-octanol, nonanal, pulegone, anethole, and hexahydrofarnesylacetone. Volatile substances from G. transversale included 26 identified constituents (93.83% of the total mass, Table 2). The predominant constituents from this species were -bisabolene, hexahydrofarnesylacetone, n-heneicosane, and n-tricosane. Hexahydrofarnesylacetone was observed earlier in G. sylvaticum, G. columbinum, and G. lucidum and in Geranium spp. studied by us. According to the literature [5], it may be formed via dehydration of chlorophylls. Thus, volatile constituents of G. collinum and G. transversale were studied for the first time. A comparison of the chemical compositions of the volatile substances from the Geranium species studied by us indicated that they differed substantially both quantitatively and qualitatively. Analysis of the hexane extract using TLC showed that it contained additional types of lipids and lipophilic compounds such as fatty-acid esters with aliphatic alcohols (waxes) and phytosterols, free fatty acids, free triterpenols and sterols, hydrocarbons, carotenoids, and chlorophyll pigments. The major constituents of the extract were free fatty acids.