Lindera cyclopentenedione intermediates from the roots of Lindera aggregata

Neuroprotective lindenane sesquiterpenoids from the roots of Lindera aggregata (Sims) Kosterm

Eleven previously undescribed lindenane sesquiterpenoids, lindaggrols A-K (1-11), were isolated from the roots of Lindera aggregata (Sims) Kosterm, together with five known ones. Their structures were elucidated by HR-ESI-MS, NMR, and single-crystal X-ray diffraction analyses. Lindaggrol A (1) is an undescribed rearranged dinor-lindenane with an unprecedented 3/5/5 tricyclic scaffold. All isolated compounds were assayed for their neuroprotective effects against erastin-induced ferroptosis in HT-22 cells. Among them, 3, 12 and 14 exhibited significant neuroprotective activities with EC50 values ranging from 1.4 to 8.7 μM.

Traditional uses, phytochemistry, pharmacology, processing methods and quality control of Lindera aggregata (Sims) Kosterm: A critical review

ETHNOPHARMACOLOGICAL RELEVANCE

Dried root tubers of L.aggregata have been widely used in Chinese herbal medicine for thousands of years to promote qi, relieve pain, warm kidney, and disperse cold.

AIM OF THE STUDY

This review aims to assess the research progress of L.aggregata, to comprehensively understand its development status, to point out the shortcomings of the existing researches, and to provide reference for further research on L.aggregata.

MATERIALS AND METHODS

By searching various databases for literatures on "Lindera aggregata", "Linderae Radix" and "Lindera strychnifolia", as well as relevant textbooks and digital documents, an overall and critical review of the subject was conducted.

RESULTS

Through phytochemical studies on different parts of L.aggregata, about 260 compounds were isolated, including flavonoids, alkaloids, terpenes, volatile oils, and other compounds. A large number of in vivo and in vitro studies have shown that L.aggregata has a plethora of pharmacological effects such as anti-cancer, anti-arthritis, anti-bacterial, anti-oxidation, anti-diabetic nephropathy, hepatoprotective, lipid-lowering effect and so on.

CONCLUSION

While the pharmacological effects of L.aggregata have been confirmed, most studies only use simple in vitro cell lines or animal disease models to evaluate their pharmacological activities. Therefore, future research should be conducted in a more comprehensive clinical manner. Further pharmacological research is also necessary to fully clarify the action mechanism of L.aggregata. It is also interesting to note that L.aggregata is often used to treat frequent urination in ancient times, but its molecular basis and mechanism of action are still unclear, and systematic studies are lacking. In terms of quality control, the source of L.aggregata is single, mostly wild, and the main medicinal part of L.aggregata is the tuber, while the yield of straight root is large. Therefore, further attention should be paid to the rapid propagation technology of L.aggregata and whether straight root can be included in medicinal use. It is also worth thinking whether sulfur-fumigation is necessary for preserving L.aggregata. As vinegar-processing is a common processing method for L. aggregata, the mechanism of such processing method remains to be investigated. In addition, in-depth research on the pharmacokinetics and long-term toxicity of L.aggregata is necessary to ensure its efficacy and safety.

Rare 7,9'-dinorlignans with neuroprotective activity from the roots of Lindera aggregata (Sims) Kosterm

Linderagatins C-F (1-4), the first examples of naturally occurring diaryltetrahydrofuran-type 7,9'-dinorlignans, were characterized from the roots of Lindera aggregata (Sims) Kosterm. The structures of these dinorlignans were elucidated by extensive spectroscopic analysis. The absolute configurations were determined based on calculated and experimental ECD data. A biosynthetic pathway for these dinorlignans was hypothetically proposed. Compounds 2 and 3 showed significant neuroprotective effects on erastin-induced ferroptosis in HT-22 cells with EC50 values of 23.4 and 21.8 μM, respectively.

Unlocking mild-condition benzene ring contraction using nonheme diiron N-oxygenase

Benzene ring contractions are useful yet rare reactions that offer a convenient synthetic route to various valuable chemicals. However, the traditional methods of benzene contraction rely on noble-metal catalysts under extreme conditions with poor efficiency and uncontrollable selectivity. Mild-condition contractions of the benzene ring are rarely reported. This study presents a one-step, one-pot benzene ring contraction reaction mediated by an engineered nonheme diiron N-oxygenase. Using various aniline substrates as amine sources, the enzyme causes the phloroglucinol-benzene-ring contraction to afford a series of 4-cyclopentene-1,3-dione structures. A reaction detail study reveals that the nonheme diiron N-oxygenase first oxidizes the aromatic amine to a nitroso intermediate, which then attacks the phloroglucinol anion and causes benzene ring contraction. Besides, we have identified two potent antitumor compounds from the ring-contracted products.

A review on the chemical constituents and pharmacological efficacies of Lindera aggregata (Sims) Kosterm

Lindera aggregata (Sims) Kosterm. (L. aggregata), which belongs to the genus Lindera in the family Lauraceae, is widely distributed in Asia and the temperate, tropical regions of North America. Its roots and leaves have been used for thousands of years as traditional Chinese medicine and/or functional food. To further explore its underlying nutritional value, this review provided a comprehensive insight into chemical constituents and pharmacological effects on L. aggregata. The phytochemical investigation of different parts of L. aggregata led to the identification of up to 349 components belonging to sesquiterpenoids, alkaloids, flavonoids, essential oils, and other compounds. Among them, sesquiterpenoids, flavonoids, and alkaloids are assessed as representative active ingredients of L. aggregata. A wide variety of pharmacological effects of L. aggregata, such as anti-hyperlipidemic, anti-tumor, anti-inflammatory, analgesic, and anti-oxidant, have been proved in vitro and in vivo. In summary, this review aims to provide a scientific basis and reference for further research and utilization of L. aggregata and lay the foundation for developing functional foods with potential active ingredients for the prevention and management of related diseases.

Effects of Compounds Isolated from Lindera erythrocarpa on Anti-Inflammatory and Anti-Neuroinflammatory Action in BV2 Microglia and RAW264.7 Macrophage

Lindera erythrocarpa contains various constituents such as cyclopentenedione-, flavonoid-, and chalcone-type components. In this study, a novel bi-linderone derivative and 17 known compounds were isolated from the leaves of L. erythrocarpa by using various chromatographic methods. The structures of the components were determined from nuclear magnetic resonance and mass spectrometry data. All isolated compounds were tested for anti-inflammatory and anti-neuroinflammatory activities in lipopolysaccharide (LPS)-induced BV2 and RAW264.7 cells. Some of these compounds showed anti-inflammatory effects by inhibiting the nitric oxide (NO) produced by LPS. In particular, linderaspirone A (16), bi-linderone (17) and novel compound demethoxy-bi-linderone (18) showed significant inhibitory effects on the production of prostaglandin E2 (PGE₂), tumor necrosis factor-α, and interleukin-6. The three compounds also inhibited the expression of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2), which are pro-inflammatory proteins, and the activation of nuclear factor κB (NF-κB). Therefore, linderaspirone A (16), bi-linderone (17), and demethoxy-bi-linderone (18) isolated from the leaves of L. erythrocarpa have therapeutic potential in neuroinflammatory diseases.

Linderanoids A-O, dimeric sesquiterpenoids from the roots of Lindera aggregata (Sims) Kosterm

Fifteen undescribed dimeric sesquiterpenoids, linderanoids A-O along with one known lindenane-type sesquiterpenoid dimer, lindenaneolide F, were isolated and identified from the roots of Lindera aggregata. Their structures and absolute configurations were elucidated using spectroscopy and electronic circular dichroism (ECD) analysis. All the isolated compounds were screened for transforming growth factor (TGF)-β inhibitory activity, and the results showed that linderanoid E significantly inhibited the TGF- β induced smad2 phosphorylation at a concentration of 25 μM.

Nostotrebin 6 Related Cyclopentenediones and δ-Lactones with Broad Activity Spectrum Isolated from the Cultivation Medium of the Cyanobacterium Nostoc sp. CBT1153

Cyanobacteria are an interesting source of biologically active natural products, especially chemically diverse and potent protease inhibitors. On our search for inhibitors of the trypanosomal cysteine protease rhodesain, we identified the homodimeric cyclopentenedione (CPD) nostotrebin 6 (1) and new related monomeric, dimeric, and higher oligomeric compounds as the active substances in the medium extract of Nostoc sp. CBT1153. The oligomeric compounds are composed of two core monomeric structures, a trisubstituted CPD or a trisubstituted unsaturated δ-lactone. Nostotrebin 6 thus far has been the only known cyanobacterial CPD. It has been found to be active in a broad variety of assays, indicating that it might be a pan-assay interference compound (PAIN). Thus, we compared the antibacterial and cytotoxic activities as well as the rhodesain inhibition of selected compounds. Because a compound with a δ-lactone instead of a CPD core structure was equally active as nostotrebin 6, the bioactivities of these compounds seem to be based on the phenolic substructures rather than the CPD moiety. While the dimers were roughly equally potent, the monomer displayed slightly weaker activity, suggesting that the compounds show unspecific activity depending upon the number of free phenolic hydroxy groups per molecule.