Quinone derivatives from the rhizomes of Acorus gramineus and their biological activities

Potential of natural products in inflammation: biological activities, structure-activity relationships, and mechanistic targets

A balance between the development and suppression of inflammation can always be found in the body. When this balance is disturbed, a strong inflammatory response can damage the body. It sometimes is necessary to use drugs with a significant anti-inflammatory effect, such as nonsteroidal anti-inflammatory drugs and steroid hormones, to control inflammation in the body. However, the existing anti-inflammatory drugs have many adverse effects, which can be deadly in severe cases, making research into new safer and more effective anti-inflammatory drugs necessary. Currently, numerous types of natural products with anti-inflammatory activity and distinct structural features are available, and these natural products have great potential for the development of novel anti-inflammatory drugs. This review summarizes 260 natural products and their derivatives with anti-inflammatory activities in the last two decades, classified by their active ingredients, and focuses on their structure-activity relationships in anti-inflammation to lay the foundation for subsequent new drug development. We also elucidate the mechanisms and pathways of natural products that exert anti-inflammatory effects via network pharmacology predictions, providing direction for identifying subsequent targets of anti-inflammatory natural products.

Thermal and (Thermo-Reversible) Photochemical Cycloisomerization of 1H-2-Benzo[c]oxocins: From Synthetic Applications to the Development of a New T-Type Molecular Photoswitch

A novel T-type molecular photoswitch based on the reversible cyclization of 1H-2-benzo[c]oxocins to dihydro-4H-cyclobuta[c]isochromenes has been developed. The switching mechanism involves a light-triggered ring-contraction of 8-membered 1H-2-benzo[c]oxocins to 4,6-fused O-heterocyclic dihydro-4H-cyclobuta[c]isochromene ring systems, with reversion back to the 1H-2-benzo[c]oxocin state accessible through heating. Both processes are unidirectional and proceed with good efficiency, with switching properties─including reversibility and half-life time─easily adjusted via structural functionalization. Our new molecular-switching platform exhibits independence from solvent polarity, originating from its neutral-charge switching mechanism, a property highly sought-after for biological applications. The photoinduced ring-contraction involves a [2+2] conjugated-diene cyclization that obeys the Woodward-Hoffmann rules. In contrast, the reverse process initiates via a thermal ring-opening (T > 60 °C) to produce the original 8-membered 1H-2-benzo[c]oxocins, which is thermally forbidden according to the Woodward-Hoffmann rules. The thermal ring-opening is likely to proceed via an ortho-quinodimethane (o-QDM) intermediate, and the corresponding switching mechanisms are supported by experimental observations and density functional theory calculations. Other transformations of 1H-2-benzo[c]oxocins were found upon altering reaction conditions: prolonged heating of the 1H-2-benzo[c]oxocins at a significantly elevated temperature (72 h at 120 °C), with the resulting dihydronaphthalenes formed via the o-QDM intermediate. These reactions also proceed with good chemoselectivities, providing new synthetic protocols for motifs found in several bioactive molecules, but are otherwise difficult to access.

Catalytic Synthesis of 1H-2-Benzoxocins: Cobalt(III)-Carbene Radical Approach to 8-Membered Heterocyclic Enol Ethers

The metallo-radical activation of ortho-allylcarbonyl-aryl N-arylsulfonylhydrazones with the paramagnetic cobalt(II) porphyrin catalyst [CoII(TPP)] (TPP = tetraphenylporphyrin) provides an efficient and powerful method for the synthesis of novel 8-membered heterocyclic enol ethers. The synthetic protocol is versatile and practical and enables the synthesis of a wide range of unique 1H-2-benzoxocins in high yields. The catalytic cyclization reactions proceed with excellent chemoselectivities, have a high functional group tolerance, and provide several opportunities for the synthesis of new bioactive compounds. The reactions are shown to proceed via cobalt(III)-carbene radical intermediates, which are involved in intramolecular hydrogen transfer (HAT) from the allylic position to the carbene radical, followed by a near-barrierless radical rebound step in the coordination sphere of cobalt. The proposed mechanism is supported by experimental observations, density functional theory (DFT) calculations, and spin trapping experiments.

Efficacy and Safety of Wei Bi Mei, a Chinese Herb Compound, as an Alternative to Bismuth for Eradication of Helicobacter pylori

Bismuth-containing quadruple therapy has been recommended as the first line of treatment in areas of high clarithromycin or metronidazole resistance. However, safety concerns of bismuth agents have long been raised. We first assessed the efficacy and safety of Wei Bi Mei granules, which are bismuth compounds consisting of three synthetic drugs and five medicinal herbs, compared to bismuth aluminate and colloidal bismuth subcitrate (CBS) in H. pylori-infected mouse model. We then used atomic fluorescence spectroscopy and autometallography to measure the accumulation of three bismuth agents in the brain, heart, liver, and kidneys in adult Sprague-Dawley rats. We also evaluated the safety of bismuth agents by conducting clinical biochemistry tests in blood samples of experimental animals. Wei Bi Mei granules exhibited the highest efficacy of anti-H. pylori activity and yielded the lowest bismuth accumulation when compared to CBS and bismuth aluminate. Our findings show that Wei Bi Mei granules are a safe Chinese medicinal herb with potent anti-H. pylori activity and can be considered as an alternative to current bismuth compounds. Thus, Wei Bi Mei granules merit further evaluation, particularly with regard to efficacy and safety when they are combined with other H. pylori eradication medications in the clinical setting.

Visible light catalyzed reaction of α-bromochalcones with chalcones: direct access to the urundeuvine scaffold

The α-keto vinyl radicals generated from α-bromochalcones under visible light photoredox catalyzed conditions were trapped by chalcones.

Synthetic studies en route to the first total synthesis of a naturally occurring quinone from Acorus gramineus, iso-merrilliaquinone, iso-magnoshinin and 2-epi-3,4-dihydro magnoshinin

An elegant Diels–Alder based approach has been demonstrated for the first racemic total synthesis of gramineusquinone B, iso-merrilliaquinone, iso-magnoshinin and 2-epi-3,4-dihydro magnoshinin.

Antioxidant Lignans and Neolignans from Acorus tatarinowii

Eleven new lignans and neolignans, named acortatarinowins G-N (1-8), including three pairs of enantiomers (1a/1b-3a/3b) and five optically pure lignans and neolignans (4-8), along with five known analogs (9-14), were isolated from the rhizomes of Acorus tatarinowii Schott. Compounds 1-3 were successfully separated by chiral HPLC to afford 1a/1b-3a/3b. The planar structures of 1-8 were elucidated by extensive spectroscopic analyses including HRESIMS and NMR. Their absolute configurations were determined by analyses of single-crystal X-ray diffraction and a modified Mosher's method, assisted by experimental and calculated electronic circular dichroism (ECD) data. Compounds 1a and 1b were rare 7,8'-epoxy-8,7'-oxyneolignane. Compounds 1-8 were evaluated for their antioxidant activities using 2,2-diphenyl-1-picrylhydrazyl (DPPH) reducing antioxidant power assay. Compound 6, exhibiting strong DPPH radical scavenging capacity with IC50 value of 16.4 ± 0.22 μg/mL, could interpret the herbal traditional usage.

(±)-Acortatarinowins A-F, Norlignan, Neolignan, and Lignan Enantiomers from Acorus tatarinowii

Three pairs of new 8-O-4'-type dinorneolignan enantiomers, (±)-acortatarinowins A-C (1a/1b-3a/3b), a pair of new 8-O-4'-type (4a/4b) and a pair of rare C7-C8'-type (5a/5b) neolignan enantiomers, (±)-acortatarinowins D and E, and a pair of new furofuran-type lignan enantiomers, (±)-acortatarinowin F (6a/6b), along with two pairs of known lignan enantiomers (7a/7b and 8a/8b), were obtained from the rhizomes of Acorus tatarinowii. The separation of 1-8 by chiral HPLC using a Daicel IC column led to the isolation of eight pairs of enantiomers, 1a/1b-8a/8b, which had variable enantiomeric excess (ee) values of approximately 66, 71, 63, 60, 0, 38, 48, and 75%, respectively. The structures were elucidated by extensive spectroscopic and chemical methods, and their absolute configurations were determined by a combined analysis of single-crystal X-ray diffraction and a modified Mosher's method, assisted by experimental and calculated electronic circular dichroism data. Among them, compounds 1a, 3a, 6b, 8a, and 8b showed weak inhibitory activities against NO production in activated macrophages with IC50 values ranging from 23.3 to 38.0 μM, respectively.

Acorus Linnaeus: a review of traditional uses, phytochemistry and neuropharmacology

Acorus Linnaeus is a herb used in many ancient medicinal systems. Phytochemical and neuropharmacological studies have revealed that many beneficial compounds possessed anticonvulsant, antiepileptic, neuroprotective, memory enhancing, and sedative properties.

(−) and (+)-Merrilliaquinone, a pair of new quinone enantiomers from Illicium merrillianum and their distinctive effect on human hepatoma and hepatic cells

Two new quinone enantiomers (−) and (+)-merrilliaquinone (1a, 1b) were isolated from Illicium merrillianum, 1b exhibited a selective cytotoxicity between human hepatoma cell lines and normal human hepatic cells, while 1a didn't have such activity.

Qualitative and quantitative analysis of the major constituents in Acorus tatarinowii Schott by HPLC/ESI-QTOF-MS/MS

Acorus tatarinowii Schott (ATS) is a well-known traditional Chinese medicine (TCM) for the treatment of epilepsy, amnesia and insomnia. In this study, a methodology utilizing high-performance liquid chromatography (HPLC) coupled with electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-QTOF-MS/MS) was established for the separation and structural identification of the major chemical constituents in ATS for the first time. Overall, 46 major constituents including flavonoid glycosides, phenylpropane derivatives, amides and lignans were identified or tentatively characterized. Seven major constituents, including four phenylpropane derivatives and three lignans, were further quantified as marker substances, which showed good linearity within the test ranges. These results indicated that the developed quantitative method was linear, sensitive, and precise for quality control of ATS.