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Several disease-modifying osteoarthritis (OA) drugs have emerged, but none have been approved for clinical use due to their systemic side effects, short half-life, and rapid clearance from the joints. Nordihydroguaiaretic acid (NDGA), a reactive oxygen species (ROS) scavenger and autophagy inducer, could be a potential treatment for OA. In this report, we show for the first time that sustained delivery of NDGA through polymeric microparticles maintains therapeutic concentrations of drug in the joint and ameliorates post-traumatic OA (PTOA) in a mouse model. In vitro treatment of oxidatively stressed primary chondrocytes from OA patients using NDGA-loaded poly(lactic- co -glycolic acid) (PLGA) microparticles (NDGA-MP) inhibited 15-lipoxygenase, induced autophagy, prevented chondrosenescence, and sustained matrix production. In vivo intra-articular delivery of NDGA-MP was non-toxic and had prolonged retention time (up to 35 days) in murine knee joints. Intra-articular therapy using NDGA-MP effectively reduced cartilage damage and reduced pain in the surgery-induced PTOA mouse model. Our studies open new avenues to modulate the immune environment and treat post-traumatic OA using ROS quenchers and autophagy inducers.

The coronavirus infectious disease 2019 (COVID-19) is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and has been spreading rapidly worldwide, creating a pandemic. This article describes the evaluation of the antiviral activity of nordihydroguaiaretic acid (NDGA), a molecule found in Creosote bush ( Larrea tridentata ) leaves, against SARS-CoV-2 in vitro. A 35 µM concentration of NDGA was not toxic to Vero cells and exhibited a remarkable inhibitory effect on the SARS-CoV-2 cytopathic effect, viral plaque formation, RNA replication, and expression of the SARS-CoV-2 spike glycoprotein. The 50% effective concentration for NDGA was as low as 16.97 µM. Our results show that NDGA could be a promising therapeutic candidate against SARS-CoV-2.

In this study, we demonstrate that Raman microscopy combined with computational analysis is a useful approach to discriminating accurately between brain tumor bio-specimens and to identifying structural changes in glioblastoma (GBM) bio-signatures after nordihydroguaiaretic acid (NDGA) administration. NDGA phenolic lignan was selected as a potential therapeutic agent because of its reported beneficial effects in alleviating and inhibiting the formation of multi-organ malignant tumors. The current analysis of NDGA's impact on GBM human cells demonstrates a reduction in the quantity of altered protein content and of reactive oxygen species (ROS)-damaged phenylalanine; results that correlate with the ROS scavenger and anti-oxidant properties of NDGA. A novel outcome presented here is the use of phenylalanine as a biomarker for differentiating between samples and assessing drug efficacy. Treatment with a low NDGA dose shows a decline in abnormal lipid-protein metabolism, which is inferred by the formation of lipid droplets and a decrease in altered protein content. A very high dose results in cell structural and membrane damage that favors transformed protein overexpression. The information gained through this work is of substantial value for understanding NDGA's beneficial as well as detrimental bio-effects as a potential therapeutic drug for brain cancer.

Acute lung injury (ALI) is a continuum of pulmonary changes caused by various lung insults. Previously, we synthesized a series of nordihydroguaiaretic acid analogs; of these, compound 3a exhibited excellent antioxidant capacity in a murine model of middle cerebral artery occlusion. However, it remains unclear whether compound 3a can modulate lipopolysaccharide (LPS)-induced ALI. ALI was induced via tracheal LPS administration, and the pathological changes were assessed. The level of inflammation was verified by immunofluorescence and immunohistochemical analyses. Apoptosis was measured by terminal deoxynucleotidyl transferase dUTP nick-end labeling assays and Western blotting. Changes in the levels of mitogen-activated protein kinase (MAPK)/nuclear factor-κB (NF-κB) pathway proteins were assessed by immunofluorescence assays and Western blotting. In vitro, RAW 264.7 cells were treated with compound 3a prior to LPS challenge, and the intracellular level of inflammation was assessed by quantitative PCR (qPCR). Relevant proteins were detected via immunofluorescence assays and Western blotting. Mice developed extensive lung inflammation by 24 h after LPS challenge. Histological examination revealed signs typical of ALI. Preadministration of compound 3a markedly ameliorated the histopathological changes and reduced fluid exudation into the alveolar space. Compound 3a also greatly reduced the levels of inflammation and apoptosis both in vivo and in vitro. Moreover, compound 3a markedly reduced phosphorylation of MAPK/NF-κB pathway-related proteins and p65 translocation, consistent with the in vitro observations. In summary, administration of compound 3a prior to LPS suppressed ALI via inhibition of the MAPK/NF-κB pathway., (Copyright © 2022. Published by Elsevier B.V.)

Fingolimod (FTY720) inhibits Ca 2+ -permeable, Mg 2+ -sensitive channels called transient receptor potential melastatin 7 (TRPM7), but its effects on Ca 2+ paradox (CP) - induced myocardial damage has not been evaluated. We studied the effect of FTY720 on CP-induced myocardial damage and used other TRPM7 channel inhibitors nordihydroguaiaretic acid (NDGA) and Mg 2+ to test if any effect of FTY720 was via TRPM7 inhibition. Langendorff-perfused Wistar rat hearts were treated with FTY720 or NDGA and subjected to a CP protocol consisting of Ca 2+ depletion followed by Ca 2+ repletion. Hearts of rats pre-treated with MgSO 4 were also subjected to CP. Hemodynamic parameters were measured using an intraventricular balloon, and myocardial infarct size was quantified using triphenyltetrazolium chloride stain. TRPM7 proteins in ventricular tissue were detected using immunoblot analysis. FTY720, but not NDGA, decreased CP-induced infarct size. Both FTY720 and NDGA minimized the CP-induced elevation of left ventricular end-diastolic pressure, but only FTY720 ultimately improved ventricular developed pressure. Mg 2+ pre-treatment had no effect on CP-induced infarct size, nor hemodynamic parameters during CP, nor the level of TRPM7 protein expression in ventricular tissue. Overall, FTY720 attenuated CP-induced myocardial damage, with potential therapeutic implications on Ca 2+ -mediated cardiotoxicity; however, the cardioprotective mechanism of FTY720 seems to be unrelated to TRPM7 channel modulation.