In the master's thesis, we investigated the composition of hydrosols of common rosemary (Salvia rosmarinus) using the method of gas chromatography coupled with mass spectrome-try (GC-MS). Hydrolates are solutions of volatile water-soluble components formed during the distillation of herbal drugs. In contrast to essential oils, hydrosols have been poorly stud-ied in terms of their chemical composition, mechanisms of action, and use for medicinal purposes.
As part of our research, we obtained hydrolates of common rosemary from 11 producers, and prepared our own hydrolates from freshly picked rosemary leaves in the laboratory using steam and water distillation. We analyzed the chemical composition of the hydrolates and their extracts using the GC-MS method. The composition of the hydrolates from the market was analyzed in June and August, while the composition of the hydrolates prepared in the laboratory was analyzed at eight time points over two-month period. Half of each hydrolate was stored at room temperature and the other half in the refrigerator. Using standard solu-tions of known concentration, we determined the concentrations in the samples of the five compounds most commonly present in the hydrolates.
We found that in August we detected more compounds than in June and that the concentra-tions of camphor or verbenone, the most abundand compound in hydrosols, were higher in August than the concentrations of camphor in June. We found that hydrolates from the mar-ket and laboratory prepared hydrolates have similar compositions, as monoterpenoids domi-nated in all hydrolates. We found that hydrolates from the market contained more com-pounds, which were present in higher concentration. The concentration of eucalyptol in hy-drolate from the market, which contained the highest concentration of eucalyptol, was 5300% higher than in hydrolates prepared in laboratory. The dry matter residues after drying were less than 1% for all hydrolates. As expected, the pH values of the hydrolates varied in the acidic range between 3.22 and 6.91. Storage time and temperature did not affect the acid-ity of the samples. When evaluating the organoleptic properties of the hydrolates over time, we did not observe any particular changes in the appearance of the hydrosols.
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