A study of flavonoid composition and antimicrobial activity of Scutellaria altissima L. from different floristic regions of Bulgaria.

INTRODUCTION: Scutellaria extracts and its constituents, especially the characteristic flavonoids such as baicalein and its glycoside baicalin, exhibit significant antimicrobial activity. AIM: To perform a comparative analysis of flavonoid composition and antimicrobial activity of extracts obtained from aerial parts and roots of Scutellaria altissima from the regions of Mezek and Bachkovo, Bulgaria. MATERIALS AND METHODS: 70% ethanol and aqueous extracts of aerial parts and roots of S. altissima were used. HPLC analysis of S. altissima extracts was performed. Microbiological tests were done on clinical isolates of Streptococcus mitis, Staphylococcus aureus, Escherichia coli, and Candida albicans. Minimal bactericidal and minimal bacteriostatic concentrations of S. altissima extracts were determined by the agar method. RESULTS: The ethanol extracts contain flavonoids approximately twice as much in comparison with the aqueous extracts. The baicalin content in the aerial parts of S. altissima from the region of Mezek is 5 times higher than that in the roots. S. altissima extracts have effective antimicrobial activity against S. mitis only. The minimal bactericidal concentration of ethanol extracts of S. altissima aerial parts and S. altissima roots is 2000 µg/ml and 8000 µg/ml at 24 hours, respectively. The bactericidal effect of aqueous extracts occurs at 48 hours at minimal bactericidal concentration of S. altissima aerial parts - 2000 µg/ml and of S. altissima roots - 6000 µg/ml. CONCLUSIONS: The finding that extracts of Bulgarian S. altissima possess effective antimicrobial properties against S. mitis suggests that it can be used as a potential source for the development of natural antimicrobial agents to suppress oral pathogens and prevent some oral infections.

Antidepressant Effect and Recognition Memory Improvement of Two Novel Plant Extract Combinations - Antistress I and Anti-stress II on Rats Subjected to a Model of Mild Chronic Stress.

BACKGROUND: Chronic stress is one of the main factors which lead to depression - a psychiatric disorder affecting millions of people and predicted to be the second ranked cause of premature death in 2020. Depression is often associated with cognitive disturbances and memory deficit. Plant based therapy could be effective in the treatment of mild to moderate depression due to its low level of adverse reaction, its good tolerability and compliance. MATERIALS AND METHODS: 72 male Wistar rats, divided in 9 groups were given orally for 8 weeks two combinations of dry plant extracts - Antistress I and Antistress II and five individual dry extracts obtained from Serratula coronata, Hypericum perforatum, Valeriana officinalis, Crataegus monogyna and Melissa officinalis. The animals were exposed to a chronic unpredictable mild stress for 8 weeks. The depression-like symptoms were evaluated with Forced swim test while the assessment of the memory deficit was performed with Novel object recognition test. RESULTS: Antistress II demonstrates antidepressant effect while Antistress I doesn't improve the depressive-like symptoms. The individual extracts of Hypericum perforatum and Valeriana officinalis also possess antidepressant properties. Antistress II improves the cognition as well as the individual extracts of Hypericum perforatum, Valeriana officinalis and especially Serratula coronata. Dry extract from Serratula tend to have the best effect regarding the recognition memory. The effect of Antistress I on memory deficit is negligible. CONCLUSIONS: Antistress II possesses antidepressant effect and improves the recognition memory while Antistress I doesn't demonstrate any of the above-described effects.

A study of chemical composition and antimicrobial activity of Bulgarian propolis.

UNLABELLED: Propolis is a natural product which exhibits pronounced antimicrobial and anti-inflammatory effects. AIM: To analyze the chemical composition and antimicrobial effect of Bulgarian propolis, p-cumaric acid and ferulic acid on certain Gram-positive and Gram-negative microorganisms. MATERIAL AND METHODS: Ethanol extract of Bulgarian propolis (Propolin) and water extract of Bulgarian propolis (Propolstom), ferulic acid and p-cumaric acid were used. The chemical HPLC-analysis of propolis was performed with Varian Prostar system. Microbiological tests were done on isolates of Streptococcus beta-haemolyticus, Enterococcus faecalis, Candida albicans and Escherichia coli. Non-treated and ethanol-treated cultures of the corresponding strains were used as controls. Minimal bactericidal and bacteriostatic concentration of Propolin were determined by agar method. RESULTS: The concentration of p-cumaric acid and ferulic acid in ethanol extract of propolis is about 1%. The minimal bactericidal concentration of Bulgarian propolis against Streptococcus beta-haemolyticus is 281 +/- 89.3 microg/ml, against Enterococcus faecalis--3490 +/- 633.1 microg/ml, against Candida albicans--1375 +/- 255.2 microg/ml, and against Escherichia coli--24306 +/- 1706.4 microg/ml. The minimal bactericidal concentration of p-cumaric acid and ferulic acid against Streptococcus beta-haemolyticus is 212 +/- 6.5 microg/ml and 208 +/- 7.7 microg/ml, against Enterococcus faecalis--3013 +/- 176.6 and 3032 +/- 203.4 microg/ml, against Candida albicans--157 +/- 15.5 microg/ml and 149 +/- 23.2 microg/ml, and against Escherichia coli--798 +/- 7.7 microg/ml and 801 +/- 22.8 microg/ml, respectively. CONCLUSIONS: The phenolic compounds p-cumaric acid and ferulic acid are 10 times less extracted in water extraction than in ethanol extraction. The most susceptible strains to the Bulgarian propolis and phenolic compounds are Streptococcus beta-haemolyticus and Candida albicans and the least affected are Escherichia coli and Enterococcus faecalis.