High-performance thin-layer chromatography/bioautography and liquid chromatography-mass spectrometry hyphenated with chemometrics for the quality assessment of Morus alba samples.

Quality control is a crucial step in the production of effective and safe herbal remedies. The aim of this study was to develop a new, simple, and high throughput procedure for the quality assessment of herbal drugs using a high-performance thin-layer chromatography (HPTLC)/bioautography and UPLC-MS/MS approach combined with chemometrics. This was exemplarily shown for Morus alba L. root bark (sang bái pí; SBP). Bioautography assays were developed for the identification of constituents with radical scavenging (DPPH assay) and antimicrobial activities (Bacillus subtilis, Escherichia coli) of 18 different M. alba samples, which was supported by UPLC-MS/MS analysis. Further, the combination of bioautography and chemometrics identified those samples with the most bioactive constituents. Plant materials collected from Serbia (11 samples) showed higher both radical scavenging and antimicrobial activities compared to samples provided from China (7 samples). Principal component analysis (PCA) confirmed the discrimination of geographically different samples and recognized their main markers responsible for differences between Serbian and Chinese samples. Most importantly for quality assessment, the combined HPTLC/bioautography and UPLC-MS/MS approach not only allowed for a fast chemical profiling of the investigated samples and their unambiguous identification, but also for the disclosure of major and minor bioactive constituents present in SBP.

Discovery and resupply of pharmacologically active plant-derived natural products: A review.

Medicinal plants have historically proven their value as a source of molecules with therapeutic potential, and nowadays still represent an important pool for the identification of novel drug leads. In the past decades, pharmaceutical industry focused mainly on libraries of synthetic compounds as drug discovery source. They are comparably easy to produce and resupply, and demonstrate good compatibility with established high throughput screening (HTS) platforms. However, at the same time there has been a declining trend in the number of new drugs reaching the market, raising renewed scientific interest in drug discovery from natural sources, despite of its known challenges. In this survey, a brief outline of historical development is provided together with a comprehensive overview of used approaches and recent developments relevant to plant-derived natural product drug discovery. Associated challenges and major strengths of natural product-based drug discovery are critically discussed. A snapshot of the advanced plant-derived natural products that are currently in actively recruiting clinical trials is also presented. Importantly, the transition of a natural compound from a "screening hit" through a "drug lead" to a "marketed drug" is associated with increasingly challenging demands for compound amount, which often cannot be met by re-isolation from the respective plant sources. In this regard, existing alternatives for resupply are also discussed, including different biotechnology approaches and total organic synthesis. While the intrinsic complexity of natural product-based drug discovery necessitates highly integrated interdisciplinary approaches, the reviewed scientific developments, recent technological advances, and research trends clearly indicate that natural products will be among the most important sources of new drugs also in the future.