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New active ingredients, including those of plant origin, which could protect the skin against various harmful factors, such as UV radiation and free radicals responsible for skin ageing, are still being sought. The present study was focused on the antioxidant activity of Hippophaë rhamnoides L. and Vaccinium oxycoccos L. fruit glycolic extracts. Investigations were also carried out to evaluate the effect of UVA radiation and the storage of the sea buckthorn and European cranberry extracts at an elevated temperature of 50 °C on their interactions with free radicals. The kinetics of the interactions of the extracts with DPPH were assessed using electron paramagnetic resonance (EPR) spectroscopy. The sea buckthorn and European cranberry extracts quench the EPR signal of DPPH free radicals, which indicates their antioxidant potential. The EPR method further showed that a mixture of sea buckthorn and cranberry extracts in a volume ratio of 2:1 was more potent in quenching free radicals compared to a mixture of these extracts in a ratio of 1:2. Our findings demonstrate that long-term UVA radiation exposure reduces the ability of sea buckthorn and cranberry extracts to interact with free radicals. Moreover, storage at elevated temperatures does not affect the interaction of sea buckthorn extract with free radicals, while it alters the ability of cranberry extract to interact with free radicals. This study has demonstrated that an important factor in maintaining the ability to scavenge radicals is the storage of raw materials under appropriate conditions. H. rhamnoides and V. oxycoccos extracts can be used as valuable raw materials with antioxidant properties in the pharmaceutical and cosmetic industries.

The derivatives of dibenzoxazocinone, dibenzoxadiazocine, dibenzoxadiazonine, and benzodiazepine systems were synthesized as potential lead compounds for inhibitors of HIV-1 reverse transcriptase. The suggested structures were derived from analysis of the described spatial and physicochemical requirements for HIV-1 RT inhibitors. All of the evaluated compounds (apart from the oxadiazocine derivatives) showed a week inhibitory activity on recombinant HIV-1 RT from Escherichia coli.

A series of 2-substituted thiazol-4-ylethanamines have been synthesized and tested for their histaminergic H1-receptor activities. The compounds with 2-phenyl substitution, regardless of the different physicochemical properties of the meta-substituents at the phenyl ring, showed weak H1-agonistic activity with pD2 values ranging from 4.35 to 5.36. When the phenyl group was replaced by a benzyl group, the resulting compounds all exhibited weak H1-antagonistic activity (pA2: 4.14-4.82).

We synthetized pyridobenzoxazocynone that differs in the enlarged eight-membered heterocyclic system from the basic structure of pyridobenzoxazepinones a known class of non-nucleoside HIV-1 reverse transcriptase inhibitors. Pyridobenzoxazocynone hydrochloride was found to inhibit HIV-1 reverse transcriptase activity. At concentration 0.35 microM the enzyme activity decreased by 64 +/- 14%. Higher concentrations of pyridobenzoxazocynone hydrochloride completely abolished the enzyme activity expressed as radioactivity of acid insoluble products. These results suggest that pyridobenzoxazocynones may represent a new class of HIV-1 reverse transcriptase inhibitors.

Selected 1-aryl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline derivatives were synthesized and evaluated as beta-adreno-receptor agents. Some of the compounds showed week agonistic or antagonistic activity on these receptors.

The synthesis and biological activity of new 10-13 membered oxygen-nitrogen heterocyclic systems condensed with two aromatic rings is reported. The structure-activity relationship of these new compounds in X-ray investigation has been studied. Pharmacological investigations have shown that the compounds exhibit weak neuroleptic activity.

The synthesis and biological activity of a series of 4,5-dihydro-1H-2,4-benzodiazepine is reported. The structure-activity relationship of these new compounds was studied based on X-ray investigations. Pharmacological investigations have shown that the compounds exert depressive action on the central nervous system and exhibit weak neuroleptic activity.