ISOLATION AND PURIFICATION OF FORSYTHOSIDE A AND SUSPENSASIDE A FROM FORSYTHIA SUSPENSA BY HIGH-SPEED COUNTER-CURRENT CHROMATOGRAPHY

Screening of Antimicrobial Ingredients in Forsythia Leaves Using Target Constituent Knock-out/Knock-in Strategy and Evaluation of the Combination Effects with Antibiotics

To screen and identify the antimicrobial ingredients of Forsythia suspensa leaves (FL). A screening method based on a constituent knock-out/knock-in strategy was conducted. The antimicrobial activities of FL components against seven commonly infective strains were determined using the Oxford cup method. Their antimicrobial effects when used in combination with common antibiotics were investigated by a checkerboard titration method. Two of the seven strains, Staphylococcus aureus and methicillin-resistant S. aureus (MRSA), were considered to be the most sensitive to the inhibitory effect of FL. The main antimicrobial components in FL were forsythoside I and forsythoside A. The co-administration of vancomycin with forsythoside A was found to have a significant synergistic inhibiting effect on MRSA. Some phenylethanol glycoside components play a major contribution to the antimicrobial effect of FL. This provides a reference for the research and development of FL for both medicinal and food purposes.

The rapid identification of chemical constituents in Fufang Xiling Jiedu capsule, a modern Chinese medicine, by ultra-performance liquid chromatography coupled with quadrupole-time-of-flight tandem mass spectrometry and data mining strategy

Fufang Xiling Jiedu capsule is an effective Chinese medicine widely used for the treatment of cold and influenza. However, its chemical constituents had not been determined, which entailed a huge obstacle to further pharmacological studies, clinical-safe medication administration, and quality evaluation. To identify the chemical constituents in Fufang Xiling Jiedu capsule, an efficient and systematic approach using ultra-high-performance liquid chromatography coupled with a quadrupole time-of-flight mass spectrometry in conjunction with a data mining strategy was adopted in this study. As a result, 145 compounds were qualitatively identified, including 26 phenolic acids, 46 flavonoids, 39 triterpenes, and 34 other compounds, among which 6 were potentially new and 144 were being reported from Fufang Xiling Jiedu capsule for the first time. This research not only provides useful information for quality control of Fufang Xiling Jiedu capsule and its involved single herbs but also serve as basis data for further study of Fufang Xiling Jiedu capsule in vivo. Moreover, it provides a reference for the characterization of the chemical constituents of other Chinese medicine preparations.

Antifungal Phenylpropanoid Glycosides from Lippia rubella

Lippia species share various pharmacological activities and are used in traditional cooking and medicine worldwide. Combined chromatographic techniques such as column chromatography, high-performance liquid chromatography, and countercurrent chromatography led to the purification of two new antifungal phenylpropanoid glycosides, lippiarubelloside A (1) and lippiarubelloside B (2), by bioactivity-directed fractionation of an ethanol-soluble extract from Lippia rubella, in addition to the known active related compounds forsythoside A (3), verbascoside (4), isoverbascoside (5), and poliumoside (6). The structures of compounds 1 and 2 were determined by comparison of their NMR spectroscopic data with the prototype active compound 4. Cryptococcus neoformans, which causes opportunistic lung infections, was sensitive to compounds 1-6 in the concentration range of 15-125 μg/mL. A synergistic effect (FIC_index = 0.5) between 3 and amphotericin B was demonstrated. The glycosylated flavonoids pectolinarin (7), linarin (8), and siparunoside (9) were also isolated.

Counter-current chromatography for the separation of terpenoids: a comprehensive review with respect to the solvent systems employed

Natural products extracts are commonly highly complex mixtures of active compounds and consequently their purification becomes a particularly challenging task. The development of a purification protocol to extract a single active component from the many hundreds that are often present in the mixture is something that can take months or even years to achieve, thus it is important for the natural product chemist to have, at their disposal, a broad range of diverse purification techniques. Counter-current chromatography (CCC) is one such separation technique utilising two immiscible phases, one as the stationary phase (retained in a spinning coil by centrifugal forces) and the second as the mobile phase. The method benefits from a number of advantages when compared with the more traditional liquid-solid separation methods, such as no irreversible adsorption, total recovery of the injected sample, minimal tailing of peaks, low risk of sample denaturation, the ability to accept particulates, and a low solvent consumption. The selection of an appropriate two-phase solvent system is critical to the running of CCC since this is both the mobile and the stationary phase of the system. However, this is also by far the most time consuming aspect of the technique and the one that most inhibits its general take-up. In recent years, numerous natural product purifications have been published using CCC from almost every country across the globe. Many of these papers are devoted to terpenoids-one of the most diverse groups. Naturally occurring terpenoids provide opportunities to discover new drugs but many of them are available at very low levels in nature and a huge number of them still remain unexplored. The collective knowledge on performing successful CCC separations of terpenoids has been gathered and reviewed by the authors, in order to create a comprehensive document that will be of great assistance in performing future purifications.