Asian Pacific Journal of Tropical Biomedicine

141-147

Authors: Clarice C.V. Moura, Rafaela S dos Santos, Lucienir P Duarte, Giovane Galdino

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.

155-163

Authors: Amaresh Mishra, Yamini Pathak, Anuj Kumar, Surabhi Kirti Mishra, Vishwas Tripathi

Objective: To explore natural compounds as potential inhibitors against main protease (Mpro) 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 Mpro. 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 Mpro of SARS-CoV-2 based on docking analysis. During MD simulations, all four natural compounds bound to Mpro 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 Mpro protein. Conclusions: Guggulsterone is a potential inhibitor of COVID- 19 main protease Mpro. Further in vitro and pre-clinical studies are needed.

174-182

Authors: Ummi Maryam Zulfin, Ave Rahman, Mila Hanifa, Rohmad Yudi Utomo, Sari Haryanti, Edy Meiyanto

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.