UDK 577.164.2:582.711.714           535.234:577.164.2 Vitamin C or ascorbic acid content has been determined by spectrophotometric method in fruits of some Bosnian hawthorns (Crataegus L). species. Spectrophotometric method used in this study is based on the kinetic reaction between Vitamin C and methylene blue. Measurements were carried out at absorption maximum, λmax= 665 nm. Titrimetric method was used as the reference method for comparison of the obtained results. We found that the lowest content of vitamin C was 106.12 mg/100 g of a dry sample in fruits of the C. monogyna, and the highest level of Vitamin C was found in the C. microphylla (231.96 mg/100 g of a dry sample) fruits. Recoveries of the results obtained by the spectrophotometric method were 101.4% - 108.0% with relative standard deviation (RSD) values ranging between 0.40% - 3.37%. Obtained results showed that fruits of studied Crataegus L. species are a good source of vitamin C with its potential to be used in food industry as the natural antioxidant.

Hydrodistilled essential oil and the corresponding headspace volatiles of Bosnian wild growing Thymus praecox ssp. polytrichus (A. Kern. Ex Borbàs) Jalas and Thymus praecox ssp. skorpilii (Velen.) Jalas were subjected to capillary GC-MS analysis. This work presents a detailed essential oil analysis of these two rare Thymus subspecies from Bosnia, as well as the very first report on their headspace composition. Eighty-seven volatile constituents were identified in four samples. Two alcohols were the major constituents in the essential oil of T. praecox ssp. polytrichus, a monoterpene, linalool (13.9%), and a sesquiterpene, (E)-nerolidol (10.4%), while linalyl acetate (36.7%) and linalool (22.7%) were the most abundant volatiles in the corresponding headspace sample. Oxygenated monoterpenes (57.5%) predominate in the essential oil of T. praecox ssp. skorpilii with linalyl acetate (28.7%) and linalool (14.4%) as the main representatives. Headspace sample of this subspecies also showed richness in linalyl acetate (52.4%), while the second most abundant compound was α-pinene (14.5%), a monoterpene hydrocarbon.

Essential oil of Thymus aureopunctatus (Beck) K. Malý, obtained by hydrodistillation and headspace technique, was subjected to capillary GC-MS analysis, and its volatile composition was compared with essential oil profile of Thymus serpyllum L. and a botanically undetermined thyme species, Thymus spp., all growing wild in the same habitat in Bosnia and Herzegovina. This paper presents the first report on phytochemical analysis of the rare T. aureopunctatus species, and also the first report on headspace analysis of plants belonging to the genus Thymus. One hundred and two volatile constituents were identified. The investigated Thymus species of Bosnian origin clearly belong to the thymol-chemotype with relatively abundant level of this main constituent varying from 30.5% for T. serpyllum, and 34.5% for T. aureopunctatus, to 44.2% for Thymus spp., while their corresponding headspace samples contain very high percentage of p-cymene, thymol biosynthesis precursor, in the range from 29.1% to 68.1%.