Late-stage C-H amination of abietane diterpenoids

Water extract of medicinal ink (WEMI) attenuates lipopolysaccharide-induced NO production of Raw264.7 cells via downregulating JAK2/STAT3-mediated iNOS expression

ETHNOPHARMACOLOGICAL RELEVANCE

Medicinal ink is used as a traditional topical medicine for treating inflammatory diseases via detoxification, relieving pain, hemostasis, and reducing swelling. However, the effect of medicinal ink on the inhibition of inflammatory responses and the underlying molecular mechanism remain unclear.

AIM OF THE STUDY

The present study aimed to investigate the anti-inflammatory function of water extract of medical ink (WEMI) and elucidate its active mechanisms.

MATERIALS AND METHODS

Cell viability was assessed using crystal violet staining assay. Interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were detected by ELISA. Nitric oxide (NO) production was measured by Griess assay. The activation of inflammatory signaling molecules stimulated by lipopolysaccharide (LPS) was evaluated by assessing levels of inducible nitric oxide synthase (iNOS), phosphorylated Janus kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3) using Western blot assay.

RESULTS

Water extract of medical ink (WEMI) did not present cytotoxic effect on murine macrophage Raw264.7 cells. High dosage of WEMI slightly rescued LPS-suppressed cell viability of Raw264.7 cells. WEMI did not induce NO production or IL-6 secretion, though WEMI significantly induced secretion of TNF-α on Raw264.7 cells not stimulated with LPS. On the other hand, LPS effectively stimulated inflammation on Raw264.7 cells; however, WEMI dramatically reduced LPS-induced NO production. WEMI alleviated LPS-stimulated IL-6 secretion but did not affect the content of TNF-α. In addition, WEMI effectively reduced expression of iNOS by abolishing LPS-mediated phosphorylation of JAK2 and STAT3 but not TLR4-mediated NF-κB and MAPK molecules.

CONCLUSIONS

Our findings suggest that WEMI targets of the JAK2/STAT3-mediated iNOS expression play a key role in alleviating LPS-induced inflammatory responses in RAW264.7 macrophages. Therefore, medicinal ink may be a potential topical agent for treating fasciitis or synovitis via regulating the immune system.

sp3 -Rich Glycyrrhetinic Acid Analogues Using Late-Stage Functionalization as Potential Breast Tumor Regressing Agents

Late-stage functionalization (LSF) aids drug discovery efforts by introducing functional groups onto C-H bonds on pre-existing skeletons. We adopted the LSF strategy to synthesize analogues of the abundantly available triterpenoid, glycyrrhetinic acid (GA), by introducing aryl groups in the A-ring, expanding the A-ring and selectively activating one methyl group of the gem-dimethyl groups. Intriguingly, two compounds were found to preferentially accumulate in the mitochondrial compartment of MDA-MB-231 breast cancer cells, to cause depolarization of mitochondrial membrane potential and to induce antiproliferative and anti-invasive effects through enhanced mitochondrial superoxide production with parallel depletion of GSH levels. Furthermore, intraperitoneal administration of these two compounds, in comparison with GA, greatly regressed breast tumor growth and metastasis in a SCID mouse model bearing labeled MDA-MB-231 cells.

Late-stage trifluoromethylthiolation of benzylic C-H bonds

The benzylic positions in drugs are sites that readily react with cytochrome P450 oxidases via single-electron oxidation. New synthetic methodologies to incorporate a fluoroalkyl group at the benzylic site are continually being developed, and in this paper, we report a metal-free and site-selective organophotoredox-catalyzed trifluoromethylthiolation of benzylic C-H bonds for a wide variety of alkyl arenes and heteroarenes. The precise and predictive regioselectivity among various C(sp³)-H bonds originates from an inner-sphere benzylic radical initiation mechanism, and avoids the use of external oxidants or hydrogen atom abstractors. Its practicality stems from the trifluoromethylthiolation of a series of drugs and complex organic molecules, which is overwhelmingly selective for benzyl groups. This operationally simple protocol can provide a general and practical access to structurally diverse benzylic trifluoromethyl sulfides produced from ubiquitous benzylic C-H bonds. Large scale trifluoromethylthiolation can be achieved with continuous flow photoredox technology.

Fluoroalkylation of C-H bonds is a class of reaction highly sought after in medicinal chemistry. Here, the authors report a regioselective organophotoredox-catalyzed, trifluoromethylthiolation of benzylic C-H bonds for a wide variety of alkyl (hetero)arenes, and demonstrate its utility in continuous flow.