Objective: To investigate the antinociceptive effect of tingenone on inflammatory pain, as well as and the involvement of the cannabinoid receptors type 2 (CB₂) and spinal microglia in this process. Methods: Male Swiss mice were subjected to inflammatory pain induced by intraplantar injection of carrageenan. The nociceptive threshold was measured by von Frey filaments test. Tingenone was administered orally 60 min before carrageenan injection. To evaluate the involvement of CB₂ receptor, endocannabinoids, and microglia, AM630 (a CB₂ receptor antagonist), MAFP (an inhibitor of an enzyme that hydrolyses endocannabinoids), and minocycline (a microglial inhibitor) were given intrathecally 20 min before tingenone administration. In addition, an immunofluorescence assay was used to evaluate CB₂ receptor and CD11B (a microglial marker) expression in the spinal cord dorsal horn. Results: Tingenone significantly reduced carrageenan-induced hyperalgesia, which was reversed by pretreatment with AM630. MAFP and minocycline potentiated and prolonged the tingenone- induced antinociception. CD11B expression was increased in the spinal cord dorsal horn of mice with inflammatory pain pretreated with tingenone, which was reduced by AM630, MAFP, and minocycline. Conclusions: CB₂ receptors and endocannabinoids participate in the tingenone-induced antinociception which may involve the inhibition of microglia at spinal level.

Objective: To explore the therapeutic role of morin against L-arginine-induced acute pancreatitis in rats. Methods: The group 1 received two intraperitoneal injections of normal saline, and groups 2-4 were given two intraperitoneal injections of L-arginine (250 mg/100 g body weight) at 1 h interval to induce acute pancreatitis. Subsequently, group 2 received no further treatment while groups 3 and 4 were treated with morin (30 mg/kg) and diclofenac sodium (30 mg/kg), respectively. Blood glucose and serum levels of insulin, α-amylase, malondialdehyde, myeloperoxidase, alanine aminotransferase, aspartate aminotransferase and cholesterol were measured. Moreover, histopathological study was carried out to investigate the effect of morin treatment on physiology of the pancreas. Results: L-arginine significantly altered the level of blood glucose and serum levels of insulin, α-amylase, malondialdehyde, myeloperoxidase, alanine aminotransferase, aspartate aminotransferase and cholesterol. Treatment with morin or diclofenac sodium significantly improved the levels of these biomarkers. Furthermore, morin showed more significant effect than diclofenac sodium. Histopathological analysis verified that morin protected the pancreas from deleterious effects of L-arginine. Conclusions: Morin plays a protective role against L-arginine- induced acute pancreatitis via reducing lipid peroxidation and tissue inflammation, and attenuating acute pancreatitis-associated alteration in insulin secretion and glucose metabolism.

Objective: To explore natural compounds as potential inhibitors against main protease (M^pro) of SARS-CoV-2. Methods: In the current study, systematic molecular docking analysis was conducted using AutoDock 4.2 to determine the binding affinities and interactions between natural compounds and M^pro. Selected natural compounds were further validated using a combination of molecular dynamic (MD) simulations and molecular mechanic Poisson-Boltzmann surface area (MM/PBSA) free energy calculations. Results: Out of twenty natural compounds, four natural metabolites namely, amentoflavone, guggulsterone, puerarin, and piperine were found to have strong interaction with M^pro of SARS-CoV-2 based on docking analysis. During MD simulations, all four natural compounds bound to M^pro at 50 ns and MM/G/P/BSA free energy calculations showed that all four shortlisted ligands had stable and favorable energies with strong binding to M^pro protein. Conclusions: Guggulsterone is a potential inhibitor of COVID- 19 main protease M^pro. Further in vitro and pre-clinical studies are needed.

Objective: To determine the effect of Lentinula edodes extract on ultraviolet (UV) A and UVB-induced changes in matrix metalloproteinase (MMP) and type I procollagen expression using human immortalized HaCaT keratinocytes. Methods: Lentinula edodes ethanol extract (LEE) was obtained by extraction with 80% ethanol for 4 h at 80 °C. Effect of LEE on UV-induced alteration on the expression and production of MMPs and type I procollagen in keratinocytes was investigated using ELISA, RT-PCR, and Western blotting assay. To determine the underlying mechanism of LEE-mediated effects, mitogen-activated protein kinase (MAPK) and activator protein 1 signaling pathways were analysed by Western blotting assay. Results: LEE significantly inhibited the expression of MMP-1 and MMP-9 and increased the expression of type I procollagen in UVA and UVB-irradiated HaCaT keratinocytes. The phosphorylation levels of p38 were significantly inhibited by LEE whereas it did not affect c-Jun N-terminal kinase and extracellular signal-regulated kinase phosphorylation. Suppression of p38 phosphorylation was also accompanied by downregulation of UVA and UVB-induced increase in c-Fos. Conclusions: LEE effectively inhibits the expression of MMP-1 and MMP-9 and increases type I procollagen production through the p38 MAPK/c-Fos signaling pathway in UVA and UVB-irradiated HaCaT keratinocytes. This findings suggest that Lentinula edodes may be developed as a cosmetic material to suppress UV exposuremediated skin aging.

Objective: To determine the effect of rice bran extract (RBE) in combination with doxorubicin on 4T1 triple-negative breast cancer cells and NIH-3T3 cells. Methods: RBE was obtained by maceration with n-hexane. The phytochemical profile of RBE was observed using highperformance liquid chromatography. Cytotoxic effect of RBE was evaluated through MTT assay. In addition, flow cytometry was used for cell cycle and apoptosis analysis. Cellular senescence was observed using SA-β-Gal assay and intracellular reactive oxygen species (ROS) levels were evaluated using DCFDA staining. The pro-oxidant property of RBE was also evaluated through 1-chloro- 2,4-dinitrobenzene spectrophotometry and molecular docking. Results: RBE was obtained with a yield of 18.42% w/w and contained tocotrienols as the major compound. RBE exerted no cytotoxic effect on 4T1 and NIH-3T3 cells. However, RBE in combination with doxorubicin decreased 4T1 cell viability synergistically (combination index<0.9) and induced apoptosis and senescence on 4T1 cells. RBE significantly decreased senescence in doxorubicin-treated NIH-3T3 cells. Additionally, RBE did not increase ROS levels in doxorubicin-treated 4T1 cells. Meanwhile, the combination of RBE and doxorubicin reduced ROS levels in NIH-3T3 cells. RBE significantly reduced glutathione-S-transferase activity and alpha-tocotrienol interacted with glutathione-S- transferase in the glutathione binding site. Conclusions: Rice bran may be used as a co-chemotherapeutic agent to improve the therapeutic effectiveness of doxorubicin while protecting against the cellular senescence effects of doxorubicin on healthy cells.