TLC-based strategies were proposed in 1979 (Hostettmann et al.) and 2005 (Friesen & Pauli; GUESS method) to minimize the number of partitioning experiments required for countercurrent separation (CCS) solvent system selection. As semi-empirical approaches, both proposed that the K values defining the sweet spot of optimal CCS corresponded to a matching Rf value range from the silica gel TLC plate developed in the organic phase of a biphasic or a corresponding monophasic solvent system. Despite their simplicity, there has been an absence of theoretical support and a deficiency of reported experimental evidence. The present study explores the theory required to develop correlations between Rf and K. All theoretical models surmise that the optimal Rf value range should be centered at 0.5. In order to validate the feasibility of the concept of matching Rf and K values, 43 natural products and six solvent system families were investigated. Out of 62 correlations, 45 resulted in matched Rf and K values. Based on this study, practical guidelines for the TLC-based prediction strategy are provided. These approaches will equip CCS users with an updated understanding of how to apply the TLC-based solvent system selection strategy to accelerate a targeted selection of CCS conditions.

Introduction: We studied the chemical composition and antimicrobial, antioxidant, and antiproliferative activities of essential oils from flowers of Lavandula angustifolia grown in Southern Bosnia and Herzegovina. Methods: The chemical profile of essential oil was evaluated by means of gas chromatography-mass spectrometry. Antimicrobial activity was tested against six bacterial strains. The antioxidant activity by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) test and the antiproliferative activity against three human cancer cell lines, MCF-7, NCI-H460, and MOLT-4, were investigated using 3-(4,5-dimethylthiazol-2-Yl)-2,5-diphenyltetrazolium bromide tests. Results: In L. angustifolia essential oil, monoterpene alcohols were the most represented class of volatiles (51.8%), including linalool, lavandulol, and terpinen-4-ol, α-terpineol as the major components, followed by monoterpene esters (22.6%). The most important antibacterial activity of essential oil was expressed on Gram-negative strains. Investigated essential oil was able to reduce DPPH radicals into the neutral DPPH-H form (inhibitory concentration 50% [IC50] = 0.421 mg/ml), and this activity was dose dependent. The essential oil showed significant antiproliferative activity against three cancer cell lines, MOLT-4, MCF-7, and NCI-H460 cells, with IC50 values of 17, 94, and 97 µg/ml, respectively. The result of the antiproliferative assay indicates that MOLT-4 cell line was the most sensitive to investigated essential oil. Conclusion: The results revealed that L. angustifolia essential oil may be important growth inhibitor against the microbes studied. It also possesses significant antioxidant activity and demonstrated excellent antiproliferative activity against MOLT-4 cells.

Platelet hyperactivity and platelet interaction with endothelial cells contribute to the development and progression of many cardiovascular diseases such as atherosclerosis and thrombosis. The impact of platelet activity with different pharmacological agents, such as acetylsalicylic acid and coumarin derivatives, has been shown to be effective in the prevention of cardiovascular disease. Artemisia dracunculus, L. Asteraceae (Tarragon) is used for centuries in the daily diet in many Middle Eastern countries, and it is well known for its anticoagulant activity. The present study investigates the presence of coumarins in tarragon leaves and subsequently determines the extract with a major amount of coumarin derivatives. The solvents of different polarities and different pH values were used for the purpose of purifying the primary extract in order to obtain fractions with the highest coumarin content. Those extracts and fractions were investigated for their anticoagulant activity by determining prothrombin time (PT) and the international normalized ratio (INR), expressed in relation to the coagulation time of the healthy person. Purified extracts and fractions obtained from plant residue after essential oil distillation, concentrated in coumarin derivatives, showed the best anticoagulant activity, using samples of human blood. INR maximum value (2.34) and consequently the best anticoagulant activity showed the methanol extract at concentration of 5%.  The INR value of normal plasma in testing this extract was 1.05.

Five methanolic extracts obtained from different parts of birch, Betula pendula, Roth. (external and internal bark, flowers, leaves and buds), were evaluated for their antibacterial activity in this study. Triterpene compounds, betulin, betulinic acid, oleanolic acid and lupeol, were isolated from the external parts of birch bark using the method of dry column chromatography (DCC) as well as preparative thin layer chromatography (TLC). These compounds were also investigated for their antibacterial activity. Taking into account that decoction is the most commonly used pharmaceutical form of herbal drug, decoctions made from external bark, leaf, flower and bud were investigated for their antibacterial activity. Antibacterial screening, against selected Gram-positive bacteria, Bacillus subtilis ATCC 6633, Staphylococcus aureus ATCC 6538P and Gram-negative bacteria, Escherichia coli ATCC 8739 and Pseudomonas aeruginosa ATCC 9027 was carried out. The methods of diffusion and dilution were used for this investigation according to European Pharmacopoea, 1996. The most prominent antibacterial activity showed oleanolic acid against bacterial species Staphylococcus aureus, expressed as minimal inhibitory concentration (MIC): 1.25% and Bacillus subtilis MIC: 0.625%. Escherichia coli showed resistance on all investigated samples.

Introduction: Present study describes the antimicrobial activity and free radical scavenging capacity (RSC) of essential oil from Mentha longifolia (L.) Huds. Aim of this study to investigate the quality, antimicrobial andantioxidant activity of wild species Mentha longifolia essential oil from Bosnia and Herzegovina.Methods: The chemical profi le of essential oil was evaluated by the means of gas chromatography-mass spectrometry (GC-MS) and thin-layer chromatography (TLC). Antimicrobial activity was tested against 6bacterial strains. RSC was assessed by measuring the scavenging activity of essential oils on 2,2- diphenyl-1-picrylhydrazil (DPPH).Results: The main constituents of the essential oil of M. longifoliae folium were oxygenated monoterpenes,piperitone oxide (63.58%) and 1,8-cineole (12.03%). Essential oil exhibited very strong antibacterial activity.The most important antibacterial activity essential oil was expressed on Gram negative strains: Escherichia coli, Pseudomonas aerginosa and Salmonella enterica. subsp.enterica serotype ABONY. Antioxidant activity was evaluated as a RSC. Investigated essential oil was able to reduce DPPH radicals into the neutral DPPHH form (IC50=10.5 μg/ml) and this activity was dose –dependent.Conclusion: The study revealed signifi cant antimicrobial activity of the investigated essential oil. The examined oil exhibited high RSC, which was found to be in correlation to the content of mainly monoterpeneketones and aldehydes. These results indicate that essential oils could serve as safe antioxidant and antiseptic supplements in pharmaceuticals.