Inhibitors of nitric oxide production from the bark of Myrica rubra: structures of new biphenyl type diarylheptanoid glycosides and taraxerane type triterpene

Guidelines for Evaluating the Antioxidant Activity of Lignin via the 2,2-diphenyl-1-picrylhydrazyl (DPPH) Assay

The most widespread procedure to measure the antioxidant activity of lignin is via the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. So far, different experimental procedures (i. e., different solvent, time, etc.) have been used to implement the DPPH methodology without estimating the effect of such modifications on the experimental procedure. To overcome this issue, the impact of the solvent, the time, and the type of substrate on the evaluation of the antioxidant activity (AoA) of lignin via the DPPH assay was investigated in this work. We found that multiple different parameters affect the evaluation of the AoA of lignin: i) the stability of the DPPH radical and the lignin solubility in a given solvent; ii) the importance of reaching steady state (the effect of time); iii) the background noise associated with lignin absorbance at λ=515 nm (used to monitor the DPPH radical scavenging); iv) lignin structure; v) providing a normalized radical scavenging index (nRSI); vi) comparing nRSI vs. inhibition percentage (IP) values. Overall, our investigation allowed us to provide guidelines on how to perform the DPPH assay for a more reliable evaluation of lignin AoA.

Macrocyclic Compounds with Diverse Skeletons from the Roots of Myrica nana and Their Spasmolytic Activity

Six undescribed macrocyclic compounds, including diarylhexanoids (1 and 2), a diarylhexanoid glucoside (3), diarylheptanoids (4 and 5), and an aceroside (6), were isolated from the roots of Myrica nana Cheval., along with 11 known analogues (7-17). The structures were elucidated by spectroscopic analysis, as well as by calculated optical rotatory dispersion and derivatization reactions. Metabolites 1-3, with a rare macrocyclic diarylhexane skeleton, differ from the familiar macrocyclic diarylheptanoids. The spasmolytic activity of the isolated compounds was evaluated on acetylcholine-induced contraction of isolated rat ileum. All isolated compounds exhibited significant spasmolytic activities with an EC50 ranging from 1.4 to 5.1 μM. The spasmolytic mechanism of action of compound 1 could be related to the NO production, blockade of muscarinic receptors, K+ efflux, and cytosolic calcium reduction.

Cyclic diarylheptanoids from Myrica javanica: isolation, transformation, and bioactivity evaluation

Three cyclic diarylheptanoids, myricanol (1), myricanone (2), and porson (3), were isolated from Myrica javanica (Myricaceae). As a major component, myricanol (1) was obtained from dry powdered bark and twigs (up to 1.6%). Transformation of myricanol (1) afforded 5-prenylmyricanol (4) and 5-benzylmyricanol (5) in 84.5% and 65% yields, respectively. The bioactivities of the isolated cyclic diarylheptanoids and their derivatives were investigated to determine their cytotoxicity and DPPH (2,2-diphenyl-1-picrylhydrazyl) scavenging activities. The cytotoxicity assay against murine leukaemia P-388 cells demonstrated that compounds 4 and 5 showed an almost two-fold increase in the activity of their parent molecule (1), with an IC50 value of 12 µM. Furthermore, the free radical scavenging assay showed that myricanol (1) had the highest radical scavenging activity, revealing the importance of the free phenolic group (IC50 39.3 µM).

Myricitrin promotes osteogenesis and prevents ovariectomy bone mass loss via the PI3K/AKT signalling pathway

This study aimed to explore the effect of myricitrin on osteoblast differentiation in mice immortalised bone marrow mesenchymal stem cells (imBMSCs). Additionally, ovariectomy (OVX) mice were employed to examine the effect of myricitrin on bone trabecular loss in vivo. The effect of myricitrin on the proliferation of imBMSCs was evaluated using a cell counting kit-8 assay. Alizarin red staining, alkaline phosphatase staining were performed to elucidate osteogenesis. Furthermore, qRT-PCR and western blot determined the expression of osteo-specific genes and proteins. To screen for candidate targets, mRNA transcriptome genes were sequenced using bioinformatics analyses. Western blot and molecular docking analysis were used to examine target signalling markers. Moreover, rescue experiments were used to confirm the effect of myricitrin on the osteogenic differentiation of imBMSCs. OVX mice were also used to estimate the delay capability of myricitrin on bone trabecular loss in vivo using western blot, micro-CT, tartaric acid phosphatase (Trap) staining, haematoxylin and eosin staining, Masson staining and immunochemistry. In vitro, myricitrin significantly enhanced osteo-specific genes and protein expression and calcium deposition. Moreover, mRNA transcriptome gene sequencing and molecular docking analysis revealed that this enhancement was accompanied by an upregulation of the PI3K/AKT signalling pathway. Furthermore, copanlisib, a PI3K inhibitor, partially reversed the osteogenesis promotion induced by myricitrin. In vivo, western blot, micro-CT, hematoxylin and eosin staining, Masson staining, Trap staining and immunochemistry revealed that bone trabecular loss rate was significantly alleviated in the myricitrin low- and high-dose groups, with an increased expression of osteopontin, osteoprotegerin, p-PI3K and p-AKT compared to the OVX group. Myricitrin enhances imBMSC osteoblast differentiation and attenuate bone mass loss partly through the upregulation of the PI3K/AKT signalling pathway. Thus, myricitrin has therapeutic potential as an antiosteoporosis drug.

Computational Insight into the Rope-Skipping Isomerization of Diarylether Cyclophanes

The restricted rotation of chemical bonds may lead to the formation of stable, conformationally chiral molecules. While the asymmetry in chiral molecules is generally observed in the presence of one or more stereocenters, asymmetry exhibited by conformational chirality in compounds lacking stereocenters, called atropisomerism, depends on structural and temperature factors that are still not fully understood. This atropisomerism is observed in natural diarylether heptanoids where the length of the intramolecular tether constrains the compounds to isolable enantiomers at room temperature. In this work, we examine the impact tether length has on the activation free energies to isomerization of a diarylether cyclophane substructure with a tether ranging from 6 to 14 carbons. Racemization activation energies are observed to decay from 48 kcal/mol for a 7-carbon tether to 9.2 kcal/mol for a 14-carbon tether. Synthetic efforts to experimentally test these constraints are also presented. This work will likely guide the design and synthesis of novel asymmetric cyclophanes that will be of interest in the catalysis community given the importance of atropisomeric ligands in the field of asymmetric catalysis.

Synthesis, Biological Evaluation and Molecular Docking Study of Cyclic Diarylheptanoids as Potential Anticancer Therapeutics

BACKGROUND

Cancer is one of the leading causes of mortality globally. To cope with cancer, it is necessary to develop anticancer drugs. Bioactive natural products, i.e. diarylheptanoids, have gained significant attention of researchers owing to their intriguing structures and potent biological activities. In this article, considering the development of anticancer drugs with enhanced selectivity towards cancerous cells, a series of Cyclic Diarylheptanoids (CDHs) are designed, synthesized and evaluated their biological activity.

OBJECTIVE

To establish an easy route for the synthesis of diarylheptanoids, and evaluate their antiproliferative, and topoisomerase-I & -IIα inhibitory activities, for developing potential anticancer drugs among CDHs.

METHODS

Diarylheptanoids were synthesized from reported linear diarylheptanoids using the classical Ullmann reaction. Antibacterial activity was evaluated by the filter paper disc diffusion method. Cell viability was assessed by measuring mitochondrial dehydrogenase activity with a Cell Counting Kit (CCK-8). Topoisomerases I and II (topo-I and -IIα) inhibitory activity was measured by the assessment of relaxation of supercoiled pBR322 plasmid DNA. IFD protocol of Schrodinger Maestro v11.1 was used to characterize the binding pattern of studied compounds with the ATPase domain of the human topo-IIα.

RESULTS

The synthesized CDHs were evaluated for their biological activities (antibacterial, antiproliferative, and topoisomerase-I & -IIα inhibitory activities, respectively). Leading to obtain a series of anticancer agents with the least inhibitory activities against different microbes, improving their selectivity for cancer cells. In brief, most of the synthesized CDHs had excellent antiproliferative activity against T47D (human breast cancer cell line). Pterocarine possessed the strongest activity (2i; IC50 = 0.63µM) against T47D. The cyclic diarylheptanoid 2b induced 30% inhibition of topoisomerase-IIα activity at 100μM compared with the reference of etoposide, which induced 72% inhibition. Among the tested compounds, galeon (2h) displayed very low activity against four bacterial strains. Compounds 2b, 2h, and 2i formed hydrogen bonds with Thr215, Asn91, Asn120, Ala167, Lys168 and Ile141 residues, which are important for binding of ligand compound to the ATPase binding site of topoisomerase IIα by acting as ATP competitive molecule validated by docking study. In silico Absorption, Distribution, Metabolism and Excretion (ADME) analysis revealed the predicted ADME parameters of the studied compounds which showed recommended values.

CONCLUSION

A series of CDHs were synthesized and evaluated for their antibacterial, antiproliferative, and topo-I & -IIα inhibitory activities. SARs study, molecular docking study and in silico ADME analysis were conducted. Five compounds exhibited excellent and selective antiproliferative activity against the human breast cancer cell line (T47D). Among them, a compound 2h showed topo-IIα activity by 30% at 100µM, which represented a moderate intensity of inhibition compared with etoposide. Three of them formed hydrogen bonds with Thr215, Asn91, Asn120, and Ala167 residues, which are considered as crucial residues for binding to the ATPase domain of topoisomerase IIα. According to in silico drug-likeness property analysis, three compounds are expected to show superiority over etoposide in case of absorption, distribution, metabolism and excretion.

Study on the Material Basis of Neuroprotection of Myrica rubra Bark

Background: Increasing attention has been given to the search for neuroprotective ingredients from natural plants. Myrica rubra bark (MRB) has been used in traditional oriental medicine for over thousand years and has potential neuroprotection. Methods and Results: Ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) was used to identify the compounds in MRB extract, and the MTT assay was performed to evaluate the neuroprotection of six major compounds from MRB against glutamate-induced damage in PC12 cells. The result displayed nineteen compounds were identified, and myricitrin and myricanol 11-sulfate were shown to have neuroprotection, which prevented cell apoptosis through alleviating oxidative stress by reducing the levels of reactive oxygen species and methane dicarboxylic aldehyde, as well as by enhancing the activities of superoxide dismutase. Conclusions: Several active compounds from MRB may offer neuroprotection and have the potential for the development of new drugs against central nervous system diseases.

Myricanol rescues dexamethasone-induced muscle dysfunction via a sirtuin 1-dependent mechanism

BACKGROUND

Muscle atrophy and weakness are adverse effects of high dose or the sustained usage of glucocorticoids. Loss of mitochondria and degradation of protein are highly correlated with muscle dysfunction. The deacetylase sirtuin 1 (SIRT1) plays a vital role in muscle remodelling. The current study was designed to identify myricanol as a SIRT1 activator, which could protect skeletal muscle against dexamethasone-induced wasting.

METHODS

The dexamethasone-induced atrophy in C2C12 myotubes was evaluated by expression of myosin heavy chain, muscle atrophy F-box (atrogin-1), and muscle ring finger 1 (MuRF1), using western blots. The mitochondrial content and oxygen consumption were assessed by MitoTracker staining and extracellular flux analysis, respectively. Muscle dysfunction was established in male C57BL/6 mice (8-10 weeks old, n = 6) treated with a relatively high dose of dexamethasone (25 mg/kg body weight, i.p., 10 days). Body weight, grip strength, forced swimming capacity, muscle weight, and muscle histology were assessed. The expression of proteolysis-related, autophagy-related, apoptosis-related, and mitochondria-related proteins was analysed by western blots or immunoprecipitation.

RESULTS

Myricanol (10 μM) was found to rescue dexamethasone-induced muscle atrophy and dysfunction in C2C12 myotubes, indicated by increased expression of myosin heavy chain (0.33 ± 0.14 vs. 0.89 ± 0.21, *P < 0.05), decreased expression of atrogin-1 (2.31 ± 0.67 vs. 1.53 ± 0.25, *P < 0.05) and MuRF1 (1.55 ± 0.08 vs. 0.99 ± 0.12, **P < 0.01), and elevated ATP production (3.83 ± 0.46 vs. 5.84 ± 0.79 nM/mg protein, **P < 0.01), mitochondrial content (68.12 ± 10.07% vs. 116.38 ± 5.12%, *P < 0.05), and mitochondrial oxygen consumption (166.59 ± 22.89 vs. 223.77 ± 22.59 pmol/min, **P < 0.01). Myricanol directly binds and activates SIRT1, with binding energy of -5.87 kcal/mol. Through activating SIRT1 deacetylation, myricanol inhibits forkhead box O 3a transcriptional activity to reduce protein degradation, induces autophagy to enhance degraded protein clearance, and increases peroxisome proliferator-activated receptor γ coactivator-1α activity to promote mitochondrial biogenesis. In dexamethasone-induced muscle wasting C57BL/6 mice, 5 mg/kg myricanol treatment reduces the loss of muscle mass; the percentages of quadriceps and gastrocnemius muscle in myricanol-treated mice are 1.36 ± 0.02% and 0.87 ± 0.08%, respectively (cf. 1.18 ± 0.06% and 0.78 ± 0.05% in dexamethasone-treated mice, respectively). Myricanol also rescues dexamethasone-induced muscle weakness, indicated by improved grip strength (70.90 ± 4.59 vs. 120.58 ± 7.93 g, **P < 0.01) and prolonged swimming exhaustive time (48.80 ± 11.43 vs. 83.75 ± 15.19 s, **P < 0.01). Myricanol prevents dexamethasone-induced muscle atrophy and weakness by activating SIRT1, to reduce muscle protein degradation, enhance autophagy, and promote mitochondrial biogenesis and function in mice.

CONCLUSIONS

Myricanol ameliorates dexamethasone-induced skeletal muscle wasting by activating SIRT1, which might be developed as a therapeutic agent for treatment of muscle atrophy and weakness.

Protective effects of Myrica rubra flavonoids against hypoxia/reoxygenation-induced cardiomyocyte injury via the regulation of the PI3K/Akt/GSK3β pathway

Myrica rubra is well known for its delicious taste and high nutritional value. The present study investigated the potential protective effects and mechanisms of M. rubra flavonoids (MRF) extract on isoproterenol (ISO)-induced myocardial injury in rats and hypoxia/reoxygenation (H/R) injury in H9c2 cardiomyocytes. An in vivo study revealed that MRF decreased serum cardiac enzyme levels, ameliorated pathological heart alterations and increased the antioxidant potential. The in vitro investigation demonstrated that MRF inhibited cell death, reactive oxygen species (ROS) accumulation, mitochondrial membrane depolarization, apoptosis rate and caspase-3 activation and enhanced the Bcl-2/Bax ratio during H/R injury. These effects were accompanied by the phosphorylation of protein kinase B (Akt) and glycogen synthase kinase (GSK)-3β. Further mechanism studies demonstrated that LY294002, a specific inhibitor of phosphoinositide 3-kinase (PI3K), abolished the MRF-mediated cardioprotection against H/R-induced apoptosis and ROS overproduction. Collectively, these results suggested that MRF exerts cardioprotective effects by attenuating oxidative damage and cardiomyocyte apoptosis most likely via a PI3K/Akt/GSK3β-dependent mechanism.

Convergent total synthesis of (±) myricanol, a cyclic natural diarylheptanoid

Third total synthesis of the meta, meta-bridged diarylheptanoid: myricanol with remarkable anti-tau properties.

Diarylheptanoid Glycosides of Morella salicifolia Bark

A methanolic extract of Morella salicifolia bark was fractionated by various chromatographic techniques yielding six previously unknown cyclic diarylheptanoids, namely, 7-hydroxymyricanol 5-O-β-d-glucopyranoside (1), juglanin B 3-O-β-d-glucopyranoside (2), 16-hydroxyjuglanin B 17-O-β-d-glucopyranoside (3), myricanone 5-O-β-d-gluco-pranosyl-(1→6)-β-d-glucopyranoside (4), neomyricanone 5-O-β-d-glucopranosyl-(1→6)-β-d-glucopyranoside (5), and myricanone 17-O-α-l-arabino-furanosyl-(1→6)-β-d-glucopyranoside (6), respectively, together with 10 known cyclic diarylheptanoids. The structural diversity of the diarylheptanoid pattern in M. salicifolia resulted from varying glycosidation at C-3, C-5, and C-17 as well as from substitution at C-11 with hydroxy, carbonyl or sulfate groups, respectively. Structure elucidation of the isolated compounds was achieved on the basis of one- and two-dimensional nuclear magnetic resonance (NMR) as well as high-resolution electrospray ionisation mass spectrometry (HR-ESI-MS) analyses. The absolute configuration of the glycosides was confirmed after hydrolysis and synthesis of O-(S)-methyl butyrated (SMB) sugar derivatives by comparison of their ¹H-NMR data with those of reference sugars. Additionally, absolute configuration of diarylheptanoid aglycones at C-11 was determined by electronic circular dichroism (ECD) spectra simulation and comparison with experimental CD spectra after hydrolysis.

Characterization of diarylheptanoids: An emerging class of bioactive natural products

Diarylheptanoids are a class of secondary plant metabolites with a wide variety of bioactivity. Research on their phytochemistry and phytoanalysis is rapidly growing and the number of identified structures bearing the aryl-C₇-aryl skeleton is at present approaching 500. Historically, the yellow pigment curcumin has been characterized as the first diarylheptanoid and the extensive research on naturally occurring analogues is still ongoing. In this review, studies dealing with the characterization of linear and cyclic derivatives are discussed from the phytoanalytical point of view. Isolation, fractionation and purification strategies from natural sources along with their chromatographic behavior and structural characteristics are discussed. The role of various techniques used for the extraction (such as Soxhlet extraction, sonication, maceration/percolation, microwave-assisted extraction, supercritical carbon dioxide extraction); isolation (liquid-liquid extraction, column chromatographic techniques, preparative thin-layer and high-performance liquid chromatography, centrifugal partition chromatography, counter-current chromatography); separation (thin-layer chromatography, high-performance liquid chromatography, gas chromatography, capillary electrophoresis) and structural characterization (UV/Vis spectroscopy, infrared spectroscopy, X-ray crystallography, mass spectrometry, nuclear magnetic resonance spectroscopy and circular dichroism spectroscopy) are critically reviewed.

Study on Chemical Profile and Neuroprotective Activity of Myrica rubra Leaf Extract

The chemical profile of Myrica rubra (a native species in China) leaf extract was investigated by UPLC-PDA-HRMS, and the neuroprotective activity of two characteristic constituents, myricanol and myricetrin, was evaluated with N2a cells using H₂O₂-inducedoxidative challenge through a series of methods, e.g., MTT assay, ROS assay and [Ca2+]i assay. Among the 188 constituents detected in the extract of Myrica rubra leaf, 116 were identified definitely or tentatively by the comprehensive utilization of precise molecular weight and abundant multistage fragmentation information obtained by quadrupole orbitrap mass spectrometry. In addition, 14 potential new compounds were reported for the first time. This work established an example for the research of microconstituents in a complex analyte and revealed that suppression of H₂O₂-induced cytotoxicity in N2a cells was achieved by the pretreatment with myricanol. The evidence suggested myricanol may potentially serve as a remedy for prevention and therapy of neurodegenerative diseases induced by oxidative stress.

Hypolipidemic effects of Myrica rubra extracts and main compounds in C57BL/6j mice

The present study evaluated the antihyperlipidemic activity of myricetin, myricetrin, the alcohol fraction (AF) and the ethyl acetate fraction (EF) obtained from the bark of Myrica rubra (MR) in high-fat and high-cholesterol (HFHC) induced hyperlipidemic C57BL/6j mice. Mice were treated with myricetin, myricetrin, AF and EF with a dose of 130 mg per kg per day for 35 days. After treatment, serum parameters including total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), total bile acids (TBA), etc., were examined. The results revealed that EF showed the highest weight lowering activity (P < 0.01). All tested samples decreased the levels of the TC, TG, LDL-C, TBA and LPS (lipopolysaccharide) content in the serum of mice to different extents. Liver fat deposition was significantly reduced after myricetin, myricetrin, AF and EF therapy (P < 0.01). Additionally, the cell size of epididymal adipose tissue was also decreased in myricetin, AF and EF groups (P < 0.05). The antihyperlipidemic activity of these samples may be attributed to the inhibition of lipid synthesis via suppressing the expression of HMGCR (3-hydroxy-3-methylglutaryl coenzyme A reductase) and ACC1 (acetyl-CoA carboxylase), promoting the metabolism and excretion of lipids via up-regulating the expression of SREBP2 (sterol regulatory element binding proteins), LDLR (low density lipoprotein receptor), UCP2 (uncoupling protein 2) and CYP7A1 (cholesterol 7α-hydroxylase). These results may provide a powerful foundation for seeking and utilizing Myrica rubra bio-active compounds for the treatment of hyperlipidemia and cardiovascular diseases.

Recent Breakthroughs in the Antioxidant and Anti-Inflammatory Effects of Morella and Myrica Species

Oxidative stress is one of the risk factors for the development of several chronic diseases, such as diabetes, cancer, cardiovascular and neurodegenerative diseases. Antioxidants are therefore highly sought and can be seen as a type of preventive medicine against several diseases. Myrica and Morella genus (Myricaceae) are taxonomically very close and their species are trees or shrubs with edible fruits that exhibit relevant uses in traditional medicine, for instance in Chinese or Japanese folk medicine they are used to treat diarrhea, digestive problems, headache, burns and skin diseases. Nearly 36 compounds were isolated from different morphological parts of Myrica and/or Morella species and their antioxidant and anti-inflammatory activities evaluated. Thirteen of these compounds exhibit greater effects than the positive controls used. Adenodimerin A was the most active compound reported (in a 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay EC50= 7.9 ± 0.3 µM). These results are just one aspect of the antioxidant and anti-inflammatory evaluations reported regarding Myrica and Morella species, so a comprehensive overview on the current status, highlighting the antioxidant health promoting effect of these species, their key antioxidant compounds as well as the compounds with protective effects against oxidative stress related diseases such as inflammation, is relevant.

Myricanol induces apoptotic cell death and anti-tumor activity in non-small cell lung carcinoma in vivo

This study explored the inhibiting effect and mechanism of myricanol on lung adenocarcinoma A549 xenografts in nude mice. Forty nude mice with subcutaneous A549 xenografts were randomly divided into five groups: high-dose myricanol (40 mg/kg body weight) group; middle-dose myricanol (20 mg/kg body weight) group; low-dose myricanol (10 mg/kg body weight) group; polyethylene glycol 400 vehicle group (1 mL/kg); and tumor model group. Nude mice were sacrificed after 14 days of treatment and the tumor inhibition rate (TIR, %) was then calculated. The relative mRNA expression levels of Bax, Bcl-2, VEGF, HIF-1α, and survivin in the tumor tissues were determined by real-time PCR. TUNEL assay was applied to determine cellular apoptosis, while IHC test was performed to detect the protein expression levels of Bax, Bcl-2, VEGF, HIF-1α, and survivin. The TIR of the three myricanol-treated groups ranged from 14.9% to 38.5%. The IHC results showed that the protein expression of Bcl-2, VEGF, HIF-1α, and survivin were consistently downregulated, whereas that of Bax was upregulated after myricanol treatment. Myricanol also significantly upregulated the mRNA expression of Bax and downregulated that of Bcl-2, VEGF, HIF-1α, and survivin in a dose-dependent manner (p < 0.05 to 0.001). These results are consistent with those of IHC. The TUNEL assay results indicated that apoptotic-positive cells significantly increased in the myricanol-treated tumor tissues compared with the cells of the vehicle control group (p < 0.01 to 0.001). These data suggest that myricanol could significantly decelerate tumor growth in vivo by inducing apoptosis.

A twist of nature – the significance of atropisomers in biological systems

This review encompasses the synthesis and identification of recently detected natural atropisomers with potential therapeutic activity.

Growth-inhibiting and apoptosis-inducing activities of Myricanol from the bark of Myrica rubra in human lung adenocarcinoma A549 cells

Myrica rubra (Lour.) Sieb. Et Zucc. is a myricaceae Myrica plant. It is a subtropical fruit tree in China and other Asian countries. The bark of M. rubra is used in Chinese folk medicine because of its antibacterial, antioxidant, anti-inflammatory, and anticancer activities. However, the mechanisms underlying such activities remain unclear. This study investigated whether or not Myricanol extracted from M. rubra bark elicits anti-cancer effects on human lung adenocarcinoma A549 cells by inducing apoptosis in vivo. Myricanol was extracted from M. rubra bark through system solvent extraction and silica gel layer column separation. The results of tritiated thymidine assay, colony formation assay, and flow cytometry indicated that Myricanol inhibited the growth of A549 cells. The effects of Myricanol on the expression of key apoptosis-related genes in A549 cells were evaluated by quantitative PCR and Western blot analyses. Myricanol significantly inhibited the growth of A549 cells in a dose-dependent manner, with a half maximal inhibitory concentration of 4.85 μg/ml. Myricanol significantly decreased colony formation and induced A549 cell apoptosis. Myricanol upregulated the expression of Caspase-3, Caspase-9, Bax, and p21 and downregulated the expression of Bcl-2 at the mRNA and protein levels. These changes were associated with apoptosis. Based on these results, we propose that Myricanol elicits growth inhibitory and cytotoxic effects on lung cancer cells. Therefore, Myricanol may be a clinical candidate for the prevention and treatment of lung cancer.

Biological evaluation of secondary metabolites from the roots of Myrica adenophora

Bioassay-guided fractionation of the roots of Myrica adenophora led to isolation of 24 known compounds and hitherto unknown compounds, including three A-type proanthocyanidins [adenodimerins A-C], two esters of sucrose [myricadenins A and B ], and the phenolic glycoside 6'-O-galloyl orbicularin. Spectroscopic analyses were used to determine their structures. Adenodimerin A, myricananin C, and myricetin showed strong 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities, with SC50 values of 7.9, 16.3, and 15.9 μM, respectively. Adenodimerin A, myricanone, myricananin C, (-)-myricanol, myricanol 11-O-β-D-glucopyranoside, and myricetin showed stronger 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) radical scavenging activities than the positive control, with SC50 values of 7.5, 19.6, 12.0, 22.3, 19.6, and 15.6 μM, respectively. 5-Deoxymyricanone, porson, 12-hydroxymyricanone (-)-myricanol, and (+)-galeon exhibited anti-tubercular activity against Mycobacterium tuberculosis H37Rv in vitro and MICs values of 25.8, 40.0, 35.8, 30.0, and 15.0 μg/mL, respectively. Myricadenin A, myricanone, myricananin C, and (-)-myricanol exhibited anti-inflammatory activities in the iNOS assay with EC50 values of 18.1, 1.00, 13.0, and 7.5 μM, respectively.

Biological activities of extracts from Chinese bayberry (Myrica rubra Sieb. et Zucc.): a review

Chinese bayberry (Myrica rubra Sieb. et Zucc.) is a subtropical fruit tree native to China and other Asian countries, and culture of this Myricaceae plant has been recorded in Chinese history for more than 2000 years. Bayberry fruit is delicious with attractive color, flavor, and high economic value. Compared with other berries, bayberry fruit is a rich source of cyanidin-3-glucoside (C3G, e.g., 64.8 mg/100 g fresh weight in 'Biqi' cultivar), which accounts for at least 85 % of the anthocyanins in the fruit. Bayberry is also a plant with high medicinal value since different organs have been used historically as folk medicines. Research efforts suggest bayberry extracts contain antioxidants that exhibit bioactivities counteracting inflammation, allergens, diabetes, cancer, bacterial infection, diarrhea and other health issues. Bayberry compounds have been isolated and characterized to provide a better understanding of the chemical mechanisms underlying the biological activities of bayberry extracts and to elaborate the structure-activity relationships. As the identification of compounds progresses, studies investigating the in vivo metabolism and bioavailability as well as potential toxicity of bayberry extracts in animal models are receiving more attention. In addition, breeding and genetic studies of bayberry with high accumulation of health-benefiting compounds may provide new insight for the bayberry research and industry. This review is focused on the main medicinal properties reported and the possible pharmaceutically active compounds identified in different bayberry extracts.

Diarylheptanoid sulfates and related compounds from Myrica rubra bark

Three new diarylheptanoids, myricanol 11-sulfate (1), juglanin B 11-sulfate (2), and myricanone 5-O-(6'-O-galloyl)glucoside (3), were isolated from the bark of Myrica rubra. Compounds 1 and 2 were characterized as diarylheptanoid sulfates on the basis of spectroscopic analyses. The antioxidative activities of the fractionated extracts and isolated compounds were estimated by the oxygen radical absorbance capacity (ORAC) and superoxide dismutase (SOD)-like activity assays. The major isolate, myricitrin (4), displayed a high ORAC value and moderate SOD-like activity (13,198 μmol TE (Trolox equivalent)/g and IC₅₀ 127.5 μg/mL, respectively), which might explain the potent antioxidative activity of this material.

Biological activities of phenolic compounds isolated from galls of Terminalia chebula Retz. (Combretaceae)

The aqueous extract of galls from Terminalia chebula Retz. (Combretaceae) was fractionated on Diaion and refractionated on octadecyl silica column. Six phenolic compounds were isolated and identified as gallic acid (1), punicalagin (2), isoterchebulin (3), 1,3,6-tri-O-galloyl-β-D-glucopyranose (4), chebulagic acid (5) and chebulinic acid (6). All of the compounds showed stronger 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and melanin inhibitory activities than ascorbic acid, butylated hydroxytoluene, α-tocopherol, arbutin and kojic acid, the reference compounds. Gallic acid (1) exhibited inhibitory activity against nitric oxide production in lipopolysaccharide-activated macrophages. However, all isolated compounds exhibited less activity than the reference compounds in mushroom tyrosinase inhibition and human tumour cytotoxicity assays. This study has demonstrated that the phenolic compounds isolated from galls of T. chebula might contribute significantly due to their antioxidant and whitening activities.

Naturally Occurring Diarylheptanoids

Diarylheptanoids, natural products with a 1,7-diphenylheptane structural skeleton, are mainly distributed in the roots, rhizomes and bark of Alpinia, Zingiber, Curcuma and Alnus species. They have become of interest in natural product research over the past twenty years because of their remarkable anticancer, anti-emetic, estrogenic, antimicrobial and antioxidant activity. This paper compiles all 307 naturally occurring diarylheptanoids from 46 plants as reported in 137 references with their distributions, physiological activities and 13C-NMR spectral data.

Three new cyclic diarylheptanoids and other phenolic compounds from the bark of Myrica rubra and their melanogenesis inhibitory and radical scavenging activities

Ten cyclic diarylheptanoids (1-10), including three new compounds: myricanone 5-O-alpha-L-arabinofuranosyl-(1-->6)-beta-D-glucopyranoside (7), myricanone 17-O-beta-D-(6'-O-galloyl)-glucopyranoside (8), and 16-methoxy acerogenin B 9-O-beta-D-apiofuranosyl-(1-->6)-beta-D-glucopyranoside (10), along with two flavonoids (11, 12), were isolated from the extracts of Myrica rubra (Myricaceae) bark. The structures of new compounds were determined on the basis of spectroscopic methods. On evaluation of compounds 1-12 against the melanogenesis in the B16 melanoma cells, six compounds, 3, 5, 7, 8, 10, and 12, exhibited inhibitory effects with 30-56% reduction of melanin content at 25 microg/mL with no or very weak toxicity to the cells (82-103% of cell viability at 25 microg/mL). In addition, upon evaluation of compounds 1-12 against the scavenging activities of free radicals [against the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical], seven compounds, 1, 3, 5, 6, 8, 11, and 12, showed potent scavenging activity [IC(50) 2-21 microM (0.6-7.3 microg/mL)].

Structures of new phenylbutanoids and nitric oxide production inhibitors from the rhizomes of Zingiber cassumunar

The methanolic (MeOH) extract from the rhizomes of Zingiber cassumunar showed nitric oxide (NO) production inhibitory effects induced by lipopolysaccharide (LPS) in mouse peritoneal macrophages. From the MeOH extract, six new phenylbutanoids, phlains I-VI, were isolated together with 16 known constituents. The structures of new phenylbutanoids were determined on the basis of physicochemical and chemical evidence. In addition, the inhibitory effects of the principal constituents on the NO production were examined. Among them, phlain III (IC50=24 microM), (E)-1-(3,4-dimethoxyphenyl)buta-1,3-diene (69 microM), (E)-1-(2,4,5-trimethoxyphenyl)buta-1,3-diene (83 microM), and cassumunaquinone 1 (47 microM) were found to show the inhibitory effects.

Absolute stereostructures of olibanumols A, B, C, H, I, and J from olibanum, gum-resin of Boswellia carterii, and inhibitors of nitric oxide production in lipopolysaccharide-activated mouse peritoneal macrophages

Three new monoterpenes, olibanumols A (1), B (2), and C (3), and three new triterpenes, olibanumols H (4), I (5), and J (6), were isolated from olibanum, the exuded gum-resin from Boswellia carterii BIRDW. Their structures including the absolute configuration were determined by chemical and physicochemical evidence. Among the constituents, olibanumols A (1), H (4), and I (5), and isofouquierol (12) exhibited nitric oxide production inhibitory activity in lipopolysaccharide-activated mouse peritoneal macrophages.

Myricarborin A and n-Butyl-α-L-rhamnopyranoside, Two Novel Compounds from the Bark of Myrica Rubra

From the bark of Chinese Myrica rubra (Myricaceae) two novel compounds, myricarborin A and n-butyl-α-L-rhamnopyranoside, have been isolated along with (+)- S- myricanol, (-)- R- myricanol 5- O-β-D-(6′-O-galloyl)-glucopyanoside and n-butyl-β-D-fructopyranoside. The structures of the novel compounds were determined by spectroscopic methods.

Bioactive constituents from chinese natural medicines. XXIV. Hypoglycemic effects of Sinocrassula indica in sugar-loaded rats and genetically diabetic KK-A(y) mice and structures of new acylated flavonol glycosides, sinocrassosides A(1), A(2), B(1), and B(2)

The methanolic extract from the whole plant of Sinocrassula indica (Crassulaceae) was found to inhibit the increase in serum glucose levels in oral administration of sucrose and glucose in rats at a dose of 250 mg/kg (p.o.). However, the extract did not inhibit the increase in serum glucose levels after intraperitoneal administration of glucose in these animals but did partly inhibit the gastric emptying. On the other hand, this extract significantly inhibited the increase in serum glucose levels after administration for 2 weeks in KK-A(y) mice, a genetically type II diabetic mice, at a dose of 250 mg/kg/d (p.o.) without significant changes of the weights of body, liver, and visceral fat. From the extract, four new acylated flavonol glycosides, sinocrassosides A(1), A(2), B(1), and B(2), were isolated together with 11 flavonoids and 2 megastigmanes. The absolute stereostructures of the four new compounds were elucidated on the basis of chemical and physicochemical evidence.

Bioactive constituents from Chinese natural medicines. XXIII. Absolute structures of new megastigmane glycosides, sedumosides A(4), A(5), A(6), H, and I, and hepatoprotective megastigmanes from Sedum sarmentosum

The methanol-eluted fraction of the hot water extract from the whole plant of Sedum sarmentosum (Crassulaceae) was found to show hepatoprotective effect on D-galactosamine-induced cytotoxicity in primary cultured mouse hepatocytes. From the active fraction, five new megastigmane glycosides, sedumosides A(4), A(5), A(6), H, and I, were isolated together with 22 megastigmane constituents. Their absolute stereostructures were elucidated on the basis of chemical and physicochemical evidence. Among them, sedumoside F(1) (IC(50)=47 microM), (3S,5R,6S,9R)-megastigmane-3,9-diol (61 microM), and myrsinionosides A (52 microM) and D (62 microM) were found to show the strong hepatoprotective activity.

Diarylheptanoids from Alnus hirsuta inhibit the NF-kB activation and NO and TNF-alpha production

Six diarylheptanoids (1-6) from the stem bark of Alnus hirsuta were investigated for their inhibitory activity against LPS-induced NF-kB activation and NO and TNF-alpha production. Among them, compounds 2, 3, and 6 displayed inhibitory activity against NF-kB activation and NO and TNF-alpha production with IC50 values of 9.2-9.9 microM, 18.2-19.3 microM, and 22.3-23.7 microM, respectively, in RAW264.7 cells. Three active compounds had no significant cytotoxicity in RAW264.7 cells at their effective concentrations. This is the first report of NF-kB-inhibitory activity of these compounds and supports the pharmacological use of A. hirsuta, which has been employed as a herbal medicine for the treatment of inflammatory diseases.

Bioactive constituents from Chinese natural medicines. XX. Inhibitors of antigen-induced degranulation in RBL-2H3 cells from the seeds of Psoralea corylifolia

The ethyl acetate-soluble fraction of the methanolic extract from the seeds of Psoralea corylifolia was found to inhibit the release of beta-hexosaminidase, as a marker of antigen-IgE-induced degranulation in RBL-2H3 cells. Sixteen constituents were isolated from the ethyl acetate-soluble fraction and several constituents, Delta(1),3-hydroxybakuchiol (IC(50) = 49 microM), Delta(3),2-hydroxybakuchiol (69 microM, bavachin (58 microM), and psoralidin (ca. 100 microM), showed inhibitory activities against the antigen-induced degranulation.

Bioactive Constituents from Chinese Natural Medicines. XXII. Absolute Structures of New Megastigmane Glycosides, Sedumosides E1, E2, E3, F1, F2, and G, from Sedum sarmentosum (Crassulaceae)

Six new megastigmane glycosides, sedumosides E1, E2, E3, F1, F2, and G, were isolated from the whole plant of Sedum sarmentosum (Crassulaceae). The structures of new constituents including the absolute configuration were elucidated on the basis of chemical and physicochemical evidence.

Phenylethanoid oligoglycosides and acylated oligosugars with vasorelaxant activity from Cistanche tubulosa

The methanolic extract from the dried stems of Cistanche tubulosa (Schrenk) R. Wight was found to show an inhibitory effect on contractions induced by noradrenaline in isolated rat aortic strips. From the extract, new phenylethanoid oligoglycoside constituents, kankanosides F and G, and an acylated oligosugar, kankanose, were isolated together with 14 known compounds. The structures of these new compounds were determined on the basis of their chemical and physicochemical evidence. In addition, principal constituents, kankanoside F, kankanose, echinacoside, acteoside, and cistanoside F, showed vasorelaxant activity, and several structural requirements for the activity were clarified.

Monoterpene constituents from Cistanche tubulosa--chemical structures of kankanosides A-E and kankanol-

Four new iridoid glycosides, kankanosides A (1), B (2), C (3), and D (4), a chlorinated iridoid, kankanol (5), and an acyclic monoterpene glycoside, kankanoside E (6), were isolated from the methanolic extract of dried stems of Cistanche tubulosa (SCHRENK) R. WIGHT (Orobanchaceae) together with 16 known compounds. The structures of these new compounds (1-6) were determined on the basis of the chemical and physicochemical evidence.

Bioactive constituents from Chinese natural medicines. XVII. constituents with radical scavenging effect and new glucosyloxybenzyl 2-isobutylmalates from Gymnadenia conopsea

The methanol-eluted fraction of the methanolic extract from the tubers of Gymnadenia conopsea was found to show radical scavenging activities for DPPH and super oxide anion (.O2-) radicals. Three new glucosyloxybenzyl 2-isobutylmalates, gymnosides VIII, IX, and X, were isolated from this natural medicine together with 58 known constituents. The stereostructures of gymnosides were elucidated on the basis of chemical and physicochemical evidence. In addition, the phenanthrene and dihydrostilbene constituents showed radical scavenging activities and suggested the following structural requirements on radical scavenging activities; a) phenanthrenes: 1) dihydrogenation at the 9,10-positions enhances the activities, 2) the 1 or 3-p-hydroxybenzyl group enhances the activities; b) dihydrostilbenes: 1) methylation of the 3'-position reduces the activities, 2) the 2- and/or 6-p-hydroxybenzyl groups enhance the activities.

Suppression of inducible nitric oxide synthase expression by yakuchinones and their analogues

Analogues of yakuchinones were synthesized as inhibitors of nitric oxide production in lipopolysaccharide-activated macrophage cell line, RAW 264.7 cells. We prepared stronger inhibitors than the original natural molecules, yakuchinones A and B reported from Alpinia oxyphylla. From the limited structural activity relation study of analogues, we concluded that the optimal length of linker between two aryl groups and the presence of enone moiety in the linker were identified as essential for the activity. The IC50 value of the most potent structure was 0.92 microM. The active analogues suppressed the expression of inducible nitric oxide synthase protein and mRNA.

Human ACAT-1 and ACAT-2 inhibitory activities of pentacyclic triterpenes from the leaves of Lycopus lucidus TURCZ

Acyl-CoA: cholesterol acyltransferase (ACAT) catalyzes the acylation of cholesterol to cholesteryl ester with long chain fatty acids and ACAT inhibition is a useful strategy for treating hypercholesterolemia or atherosclerosis. Pentacyclic triterpenes, ursolic acid (1), oleanolic acid (2), and betulinic acid (3) were isolated from the methanol extracts of the leaves of Lycopus lucidus TURCZ. by bioassay-guided fractionation. The structures of compounds 1-3 were elucidated by their spectroscopic data analysis. Among them, betulinic acid (3) exhibited more potent human ACAT-1 and ACAT-2 inhibitory activities with IC(50) values of 16.2+/-0.6 and 28.8+/-1.3 microM, respectively.

Structures of New Flavonoids, Erycibenins D, E, and F, and NO Production Inhibitors from Erycibe expansa Originating in Thailand

A new flavanol, erycibenin D, and two new flavans, erycibenins E and F, were isolated from the stems of Erycibe expansa originating in Thailand. The structures of new flavonoids were elucidated on the basis of chemical and physicochemical evidence. In addition, the inhibitory activities of the isolated constituents from E. expansa on lipopolysaccharide-activated nitric oxide production in mouse peritoneal macrophages were examined. Among the principal constituents, two isoflavones, clycosin (IC50 = 13 microM) and erythrinin B (18 microM), and two rotenoids, deguelin (26 microM) and rotenone (27 microM), were found to show potent inhibitory activity.