Effects of intrathecal and intracerebroventricular microinjection of kaempferol on pain: possible mechanisms of action

Effects of Natural Product-Derived Compounds on Inflammatory Pain via Regulation of Microglial Activation

Inflammatory pain is a type of pain caused by tissue damage associated with inflammation and is characterized by hypersensitivity to pain and neuroinflammation in the spinal cord. Neuroinflammation is significantly increased by various neurotransmitters and cytokines that are expressed in activated primary afferent neurons, and it plays a pivotal role in the development of inflammatory pain. The activation of microglia and elevated levels of pro-inflammatory cytokines are the hallmark features of neuroinflammation. During the development of neuroinflammation, various intracellular signaling pathways are activated or inhibited in microglia, leading to the regulation of inflammatory proteins and cytokines. Numerous attempts have been conducted to alleviate inflammatory pain by inhibiting microglial activation. Natural products and their compounds have gained attention as potential candidates for suppressing inflammatory pain due to verified safety through centuries of use. Many studies have also shown that natural product-derived compounds have the potential to suppress microglial activation and alleviate inflammatory pain. Herein, we review the literature on inflammatory mediators and intracellular signaling involved in microglial activation in inflammatory pain, as well as natural product-derived compounds that have been found to suppress microglial activation. This review suggests that natural product-derived compounds have the potential to alleviate inflammatory pain through the suppression of microglial activation.

Endogenous opiates and behavior: 2021

This paper is the forty-fourth consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2021 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides and receptors as well as effects of opioid/opiate agonizts and antagonists. The review is subdivided into the following specific topics: molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (1), the roles of these opioid peptides and receptors in pain and analgesia in animals (2) and humans (3), opioid-sensitive and opioid-insensitive effects of nonopioid analgesics (4), opioid peptide and receptor involvement in tolerance and dependence (5), stress and social status (6), learning and memory (7), eating and drinking (8), drug abuse and alcohol (9), sexual activity and hormones, pregnancy, development and endocrinology (10), mental illness and mood (11), seizures and neurologic disorders (12), electrical-related activity and neurophysiology (13), general activity and locomotion (14), gastrointestinal, renal and hepatic functions (15), cardiovascular responses (16), respiration and thermoregulation (17), and immunological responses (18).

Utilizing network pharmacological analysis to investigate the key targets and mechanisms of kaempferol against oxaliplatin-induced neurotoxicity

This study investigated the pharmacological mechanism of kaempferol in the treatment of oxaliplatin-induced neuropathic pain by network pharmacological method and cells experiment. The kaempferol and disease target genes were obtained from several databases, including TCMSP, SwissTargetPrediction, GeneCards, and CTD. Then, the common target genes of drugs and diseases were obtained using Venny online tools. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) functional analyses were carried out to obtain the enriched molecular pathways associated with the kaempferol and disease. Finally, we constructed a neuropathic pain cell experiment to confirm the findings. 138 intersection targets were identified between targets of kaempferol and oxaliplatin-induced neurotoxicity. Enrichment analyses revealed that the IL-17 signaling pathway was associated with the therapeutic effects of kaempferol. Kaempferol down-regulated the mRNA expression levels of TNF-α, IL-6, and CCL2 in oxaliplatin-treated astrocytes. Our findings showed that kaempferol alleviated oxaliplatin-induced neurotoxicity via regulation of inflammation-related genes.

Polysaccharides from Tetrastigma hemsleyanum Diels et Gilg: optimum extraction, monosaccharide compositions, and antioxidant activity

The optimization of extraction of Tetrastigma hemsleyanum Diels et Gilg polysaccharides (THP) using ultrasonic with enzyme method and its monosaccharide compositions and antioxidant activity were investigated in this work. Single-factor experiments and response surface methodology (RSM) were performed to optimize conditions for extraction, and the independent variables were (X_A) dosage of cellulase, (X_B) extraction time, (X_C) ultrasonic power, and (X_D) ratio of water to the material. The extraction rate of THP was increased effectively under the optimum conditions, and the maximum (4.692 ± 0.059%) was well-matched the predicted value from RSM. THP was consisted of mannose, glucuronic acid, rhamnose, galacturonic acid, glucose, galactose, and arabinose, while glucose was the dominant (26.749 ± 0.634%). According to the total antioxidant capacity assay with the FRAP method, DPPH, and hydroxyl radical scavenging assay, THP showed strong antioxidant activity with a dose-dependent behavior. The results indicated that THP has the potential to be a novel antioxidant and could expand its application in food and medicine.