Bioactivity-Guided Discovery of Human Carboxylesterase Inhibitors from the Roots of Paeonia lactiflora

Oleanane and 30-noroleanane triterpenoids from the roots of Paeonia lactiflora

An investigation of EtOAc extract from the roots of Paeonia lactiflora yielded three new 30-noroleanane triterpenoids paeonenoides L-N (1-3) and one new oleanane triterpenoid paeonenoide O (4) together with 7 known compounds (5-11). Extensive spectrographic experiments were applied to identify the structures of 1-4, and their absolute configurations were unambiguously determined by theoretical calculations of ECD spectra, as well as the single-crystal X-ray diffraction analysis. Compounds 8, 9 and 10 were isolated from the Paeonia genus for the first time. Moreover, compounds 8, 9 and 11 showed inhibitory activities against LPS-induced nitric oxide (NO) production in RAW264.7 macrophages with the IC50 values of 72. 17 ± 4.74, 30.02 ± 2.03 and 28.34 ± 1.85 μM, respectively.

Monoterpenoids from the root bark of Acanthopanax gracilistylus and their inhibitory effects on neutrophil elastase, 5-lipoxygenase, andcyclooxygenase-2 in vitro

Twenty-four monoterpenoids, including three previously undescribed compounds (1-3), were isolated from the root bark of Acanthopanax gracilistylus W. W. Smith (Acanthopanacis Cortex). Their structures were unambiguously established based on spectroscopic analysis (HR-ESIMS, IR, 1D, and 2D NMR), and the absolute configurations of 1-3 were elucidated by comparing their experimental and calculated electronic circular dichroism spectra. In addition, the structure of 8 was confirmed by single-crystal X-ray diffraction. The inhibitory activities of 1-24 against neutrophil elastase, 5-lipoxygenase, and cyclooxygenase-2 (COX-2) were studied in vitro for the first time, and the results showed that compound 24 possessed a significant inhibitory effect on COX-2 with an IC50 value of 1.53 ± 0.10 μΜ. This research first reported the presence of monoterpenoids in Acanthopanacis Cortex, including one monoterpenoid 2 with an unusual 4/5 bicyclic lactone system, and compounds 4 and 5 have never been reported in nature.

Monoterpenoid derivatives from Hyssopus cuspidatus Boriss. and their bioactivities

Six undescribed monoterpenoids, together with twelve known compounds were isolated and identified from Hyssopus cuspidatus Boriss. Their structures were established by spectroscopic analysis, and the absolute configurations were established by ECD calculations and single-crystal X-ray diffraction crystallography. The isolated compounds were tested for their anti-inflammatory, antibacterial and antitumor activities. Most of the compounds showed potent anti-inflammatory activities. Among them, 3β-hydroxy-7,8-dihydro-β-ionone (8), oleanolic acid (17) and acetylpleamolic acid (18) showed strong anti-inflammatory activity against IL-6 and TNF-α in lipopolysaccharide (LPS) stimulated RAW 264.7 cells. Several compounds showed moderate inhibitory activities against Staphylococcus aureus, Candida albicans, and Escherichia coli. And (4S)-p-menth-l-ene-7,8-diol 8-O-β-D-glucopyranoside (16) showed antitumor activities against MCF-8 and HT-29 cell lines with IC₅₀ values of 93.39 ± 3.69 and 71.89 ± 2.94 μM, respectively. Oleanolic acid (17) showed moderate antitumor activity against HT-29 cell lines with an IC₅₀ value of 52.62 ± 1.63 μM. In this study, the discovery of anti-inflammatory, antibacterial and antitumor components from H. cuspidatus could benefit further development and utilization of this plant.

Carboxylesterase inhibitors from clinically available medicines and their impact on drug metabolism

Mammalian carboxylesterases (CES), the key members of the serine hydrolase superfamily, hydrolyze a wide range of endogenous substances and xenobiotics bearing ester or amide bond(s). In humans, most of identified CES are segregated into the CES1A and CES2A subfamilies. Strong inhibition on human CES (including hCES1A and hCES2A) may modulate pharmacokinetic profiles of CES-substrate drugs, thereby changing the pharmacological and toxicological responses of these drugs. This review covered recent advances in discovery of hCES inhibitors from clinically available medications, as well as their impact on CES-associated drug metabolism. Three comprehensive lists of hCES inhibitors deriving from clinically available medications including therapeutic drugs, pharmaceutical excipients and herbal medicines, alongside with their inhibition potentials and inhibition parameters, are summarized. Furthermore, the potential risks of hCES inhibitors to trigger drug/herb-drug interactions (DDIs/HDIs) and future concerns in this field are highlighted. Potent hCES inhibitors may trigger clinically relevant DDIs/HDIs, especially when these inhibitors are co-administrated with CES substrate-drugs with very narrow therapeutic windows. All data and knowledge presented here provide key information for the clinicians to assess the risks of clinically available hCES inhibitors on drug metabolism. In future, more practical and highly specific substrates for hCES1A/hCES2A should be developed and used for studies on CES-mediated DDIs/HDIs both in vitro and in vivo.

Classification-based strategies to simplify complex traditional Chinese medicine (TCM) researches through liquid chromatography-mass spectrometry in the last decade (2011-2020): Theory, technical route and difficulty

The difficulty of traditional Chinese medicine (TCM) researches lies in the complexity of components, metabolites, and bioactivities. For a long time, there has been a lack of connections among the three parts, which is not conducive to the systematic elucidation of TCM effectiveness. To overcome this problem, a classification-based methodology for simplifying TCM researches was refined from literature in the past 10 years (2011-2020). The theoretical basis of this methodology is set theory, and its core concept is classification. Its starting point is that "although TCM may contain hundreds of compounds, the vast majority of these compounds are structurally similar". The methodology is composed by research strategies for components, metabolites and bioactivities of TCM, which are the three main parts of the review. Technical route, key steps and difficulty are introduced in each part. Two perspectives are highlighted in this review: set theory is a theoretical basis for all strategies from a conceptual perspective, and liquid chromatography-mass spectrometry (LC-MS) is a common tool for all strategies from a technical perspective. The significance of these strategies is to simplify complex TCM researches, integrate isolated TCM researches, and build a bridge between traditional medicines and modern medicines. Potential research hotspots in the future, such as discovery of bioactive ingredients from TCM metabolites, are also discussed. The classification-based methodology is a summary of research experience in the past 10 years. We believe it will definitely provide support and reference for the following TCM researches.

Paeonone A, a novel nonanortriterpenoid from the roots of Paeonia lactiflora

Paeonone A (1), a unique nonanortriterpenoid, and a new octanortriterpenoid, paeonone B (2), were isolated from the roots of Paeonia lactiflora, together with a known analogue, palbinone (3). Paeonone A (1) is the first example of naturally occurring nonanortriterpenoid with a diketo acid group. Extensive NMR and HRESIMS experiments were applied to identify the structures of 1 and 2, and their absolute configurations were solved by single-crystal X-ray diffraction and ECD data. Biological properties of 1-3 were explored against pancreatic lipase and cancer cell lines.