A NIR fluorescent probe for fatty acid amide hydrolase bioimaging and its application in development of inhibitors

Fluorescence-Based Enzyme Activity Assay: Ascertaining the Activity and Inhibition of Endocannabinoid Hydrolytic Enzymes

The endocannabinoid system, known for its regulatory role in various physiological processes, relies on the activities of several hydrolytic enzymes, such as fatty acid amide hydrolase (FAAH), N-acylethanolamine-hydrolyzing acid amidase (NAAA), monoacylglycerol lipase (MAGL), and α/β-hydrolase domains 6 (ABHD6) and 12 (ABHD12), to maintain homeostasis. Accurate measurement of these enzymes' activities is crucial for understanding their function and for the development of potential therapeutic agents. Fluorometric assays, which offer high sensitivity, specificity, and real-time monitoring capabilities, have become essential tools in enzymatic studies. This review provides a comprehensive overview of the principles behind these assays, the various substrates and fluorophores used, and advances in assay techniques used not only for the determination of the kinetic mechanisms of enzyme reactions but also for setting up kinetic assays for the high-throughput screening of each critical enzyme involved in endocannabinoid degradation. Through this comprehensive review, we aim to highlight the strengths and limitations of current fluorometric assays and suggest future directions for improving the measurement of enzyme activity in the endocannabinoid system.

Endocannabinoid Hydrolase Inhibitors: Potential Novel Anxiolytic Drugs

Over the past decade, the idea of targeting the endocannabinoid system to treat anxiety disorders has received increasing attention. Previous studies focused more on developing cannabinoid receptor agonists or supplementing exogenous cannabinoids, which are prone to various adverse effects due to their strong pharmacological activity and poor receptor selectivity, limiting their application in clinical research. Endocannabinoid hydrolase inhibitors are considered to be the most promising development strategies for the treatment of anxiety disorders. More recent efforts have emphasized that inhibition of two major endogenous cannabinoid hydrolases, monoacylglycerol lipase (MAGL) and fatty acid amide hydrolase (FAAH), indirectly activates cannabinoid receptors by increasing endogenous cannabinoid levels in the synaptic gap, circumventing receptor desensitization resulting from direct enhancement of endogenous cannabinoid signaling. In this review, we comprehensively summarize the anxiolytic effects of MAGL and FAAH inhibitors and their potential pharmacological mechanisms, highlight reported novel inhibitors or natural products, and provide an outlook on future directions in this field.

Piperine: Chemistry and Biology

Piperine is a plant-derived promising piperamide candidate isolated from the black pepper (Piper nigrum L.). In the last few years, this natural botanical product and its derivatives have aroused much attention for their comprehensive biological activities, including not only medical but also agricultural bioactivities. In order to achieve sustainable development and improve survival conditions, looking for environmentally friendly pesticides with low toxicity and residue is an extremely urgent challenge. Fortunately, plant-derived pesticides are rising like a shining star, guiding us in the direction of development in pesticidal research. In the present review, the recent progress in the biological activities, mechanisms of action, and structural modifications of piperine and its derivatives from 2020 to 2023 are summarized. The structure-activity relationships were analyzed in order to pave the way for future development and utilization of piperine and its derivatives as potent drugs and pesticides for improving the local economic development.

Nor-triterpenoids from the fruiting bodies of Ganoderma lucidum and their inhibitory activity against FAAH

Two new nor-triterpenoids ganodrenol A (1), B (2), and a new natural product ganodrenol C (3), along with three known nor-triterpenoids (4-6) were isolated from the fruiting bodies of Ganoderma lucidum. The chemical structures of these isolates were determined by 1 D and 2 D NMR, HRESIMS, and X-ray crystallography analysis. The inhibitory effects of isolated triterpenoids (1-6) against FAAH were evaluated by an in vitro assay, and compound 4 showed an inhibition rate of 70.27%. In addition, the cytotoxic effect of compounds (1-6) was evaluated against LOVO, MCF-7, and RAW264.7 cells, which displayed no significant cytotoxicity.

Lanostane triterpenoids from Ganoderma lucidum and their inhibitory effects against FAAH

Ganoderma lucidum is a famous edible and medicinal fungus. Through a bioactive phytochemical investigation of the ethanolic extracts of the fruiting bodies of G. lucidum, twenty-nine triterpenoids, including eleven previously undescribed triterpenoids, were isolated and characterized based on spectroscopic data. The inhibitory effects of all the triterpenes against fatty acid amide hydrolase (FAAH) were found to be in the range of 30-60% at 100 μM. Methyl ganoderate A displayed the strongest inhibitory activity (61%) against FAAH. Furthermore, all compounds displayed no cytotoxicity against LOVO and MCF-7 human cancer cells. Hence, our present study provides information about G. lucidum as a functional food or pharmaceutical supplement for the treatment of neuroinflammation.

Triterpenoids from the fruiting bodies of Ganoderma lucidum and their inhibitory activity against FAAH

Seventeen triterpenoids including four new lanostane triterpenoids (1-3 and 5) were isolated from the fruiting bodies of Ganoderma lucidum by various chromatographic techniques. Their chemical structures were determined by extensive spectroscopic data, including 1D-NMR, 2D-NMR, and HRESIMS. In addition, the spectral data of compound 4 was reported for the first time. In an in vitro bioassay, most isolated triterpenoids could inhibit the hydrolysis activity of fatty acid amide hydrolase (FAAH). Furthermore, there is no cytotoxicity observed for these isolated triterpenoids. Therefore, G. lucidum showed the potential application for anti-neuroinflammation and more FAAH inhibitors may be explored from G. lucidum.