Cytotoxic and genotoxic butanolides and lignans from Aiouea trinervis

Chemistry and Bioactivity of the Genus Persea - A Review

This review provides the first comprehensive appraisal of bioactive compounds and their biological activities in Persea species from 1950 to 2023. Relevant articles from reputable databases, including PubMed, Web of Science, Science Direct and Google Scholar were collected, leading to the isolation of about 141 metabolite compounds, mainly flavonoids, terpenoids, fatty alcohols, lignoids, and γ-lactone derivatives. These compounds exhibit diverse biological activities, including insecticidal, antifeedant, nematicidal, antibacterial, antifungal, antiviral, cytotoxic, anti-inflammatory, and antioxidant properties. The review emphasizes the significant chemical and pharmacological potential of different Persea species, encouraging further research in various fields and medicine. Valuable insights into potential applications of Persea plants are provided.

Cinnamomum Species: Bridging Phytochemistry Knowledge, Pharmacological Properties and Toxicological Safety for Health Benefits

The genus Cinnamomum includes a number of plant species largely used as food, food additives and spices for a long time. Different traditional healing systems have used these plants as herbal remedies to cure diverse ailments. The aim of this comprehensive and updated review is to summarize the biodiversity of the genus Cinnamomum, its bioactive compounds, the mechanisms that underlie the pharmacological activities and molecular targets and toxicological safety. All the data in this review have been collected from databases and recent scientific literature including Web of Science, PubMed, ScienceDirect etc. The results showed that the bioactive compounds of Cinnamomum species possess antimicrobial, antidiabetic, antioxidant, anti-inflammatory, anticancer and neuroprotective effects. The preclinical (in vitro/in vivo) studies provided the possible molecular mechanisms of these action. As a novelty, recent clinical studies and toxicological data described in this paper support and confirm the pharmacological importance of the genus Cinnamomum. In conclusion, the obtained results from preclinical studies and clinical trials, as well as reduced side effects provide insights into future research of new drugs based on extracts and bioactive compounds from Cinnamomum plants.

Antitrypanosomal butanolides from Aiouea trinervis

In a search for new antitrypanosomal agents in the Brazilian flora, the ethanol extract of the xylopodium from Aiouea trinervis (Lauraceae) exhibited in vitro activity against the epimastigote forms of Trypanosoma cruzi, the etiological agent of Chagas disease. Bioassay-guided chromatographic fractionation of the ethanol extract afforded three butanolides, isoobtusilactone A (1), epilitsenolide C2 (2), and epilitsenolide C1 (3). Butanolides 1 and 3 were more active against T. cruzi epimastigotes than the reference drug benznidazole (by 8.9-fold and 3.2-fold, respectively), while 2 proved inactive. Compounds 1 and 3 showed low cytotoxicity in mammalian Vero cells (CC50> 156 μmol L-1) and high selectivity index (SI) values for epimastigotes (SI = 56.8 and 28.6, respectively), and 1 was more selective than benznidazole (SI = 46.5). Butanolide 1 at 24 μmol L-1 also led to cell cycle alterations in epimastigote forms, and inhibited the growth of amastigote cells in more than 70 %. In silico ADMET properties of 1 were also analyzed and predicted favorable drug-like characteristics. This butanolide also complied with Lipinski's rule of five and was not predicted as interference compound (PAINS). This is the first report on the isolation of these bioactive butanolides under the guidance of in vitro trypanocidal activity against T. cruzi.

Repellent and Feeding Deterrent Activities of Butanolides and Lignans Isolated from Cinnamomum camphora against Tribolium castaneum

Three lignans (1–3) and three butanolides (4–6) were isolated from the lipophilic extract of the Cinnamomum camphora stem bark. The six compounds were identified as (-)-sesamin (1), 9α-hydroxysesamin (2), 9β-hydroxysesamin (3), obtusilactone A (4), isoobtusilactone A (IOA, 5), and isomahubanolide (6) from their spectroscopic data. Four (1, 2 and 5, 6) of them were evaluated for their repellent and feeding deterrent activities against Tribolium castaneum. In this work, the three butanolides (4–6) were confirmed to exist in C. camphora for the first time. Results of bioassays indicated that (-)-sesamin (1), IOA (5), and isomahubanolide (6) displayed certain repellent activities against T. castaneum at 78.63, 15.73, and 3.15 μg/cm2 at 2 h after exposure. Among the three compounds, (-)-sesamin (1) and IOA (5) exerted stronger effects and maintained longer duration of repellency. Furthermore, IOA (5) and isomahubanolide (6) showed good feeding deterrent activity against T. castaneum. IOA (5) was still potently active at low concentrations with the feeding deterrence index (FDI) ranging from 42.85% to 50.66% at 15–1500 ppm. This work provides some evidence for explaining antiinsect properties of the nonvolatile fraction of the C. camphora stem bark and helps promote the development and comprehensive utilization of this tree species.

Cytotoxic lignans from Cryptocarya impressinervia

Chemical investigation of the twigs of Cryptocarya impressinervia yielded 23 known compounds including 8 lignans, 3 phenylpropionates, 1 xanthone, 3 flavonoids, 1 phenylpropanoid, 1 substitued phenol, 1 triterpenoid, 3 sterols and 2 aliphatic compounds. All the compounds was isolated from C. impressinervia for the first time. 9,9'-O-Di-feruloyl-(-)-secoisolariciresinol (1) displayed significant cytotoxic activities on five human cancer cell lines (HL-60, SMMC-7721, A-549, MCF-7 and SW-480), with IC₅₀ values of 3.58, 4.55, 6.39, 5.09 and 4.80 μM, respectively. Rhusemialin A (2) showed significant activity against HL-60 with IC₅₀ of 3.69 μM. Dihydrosinapyl ferulate (3) displayed moderate cytotoxic activities against five tested human cancer cell lines. To the best of our knowledge, this is the first report on the constituents of C. impressinervia and cytotoxic activities of compounds 1-3 on the tested cancer cell lines.

Cytotoxic and Apoptotic Activity of Majoranolide from Mezilaurus crassiramea on HL-60 Leukemia Cells

Majoranolide, a butanolide isolated from the nonpolar fraction of an ethanol extract of Mezilaurus crassiramea (Lauraceae) fruits, is being reported for the first time in this genus and the third time in plants. Structurally identified from 1D and 2D NMR and HRESIMS data, majoranolide proved cytotoxic against cancer cells—MCF-7 and MDA-MB-231 (breast), HT-29 (colon), PC-3 (prostate), 786-0 (renal), and HL-60 (leukemia)—inhibiting growth in HL-60 cells (GI₅₀ = 0.21 μM) and exhibiting higher selectivity for this line than for nonneoplastic NIH/3T3 murine fibroblasts. Effects on the cell cycle, caspase-3 activation, and plasma membrane integrity were evaluated by flow cytometry. Expression of genes related to apoptotic pathways (BAX, BCL2, BIRC5, and CASP8) was investigated using RT-qPCR. At 50 μM, majoranolide induced cell cycle arrest at G1 in 24 h increased the sub-G1 population in 48 h and increased caspase-3 activation in a time-dependent manner. The compound upregulated BAX and CASP8 transcription (proapoptotic genes) and downregulated BIRC5 (antiapoptotic). Loss of plasma membrane integrity in 30% of cells occurred at 48 h, but not at 24 h, characterizing gradual, programmed death. The results suggest that majoranolide cytotoxicity involves apoptosis induction in HL-60 cells, although other mechanisms may contribute to this cell death.

The lignan, (-)-sesamin reveals cytotoxicity toward cancer cells: pharmacogenomic determination of genes associated with sensitivity or resistance

(-)-Sesamin is a lignan present in sesam oil and a number of medicinal plants. It exerts various pharmacological effects, such as prevention of hyperlipidemia, hypertension, and carcinogenesis. Moreover, (-)-sesamin has chemopreventive and anticancer activity in vitro and in vivo. Multidrug resistance (MDR) of tumors leads to fatal treatment outcome in many patients and novel drugs able to kill multidrug-resistant cells are urgently needed. P-glycoprotein (MDR1/ABCB1) is the best known ATP-binding cassette (ABC) drug transporter mediating MDR. ABCB5 is a close relative to ABCB1, which also mediates MDR. We found that the mRNA expressions of ABCB1 and ABCB5 were not related to the 50% inhibition concentrations (IC50) for (-)-sesamin in a panel of 55 cell lines of the National Cancer Institute, USA. Furthermore, (-)-sesamin inhibited ABCB1- or ABCB5-overexpressing cells with similar efficacy than their drug-sensitive parental counterparts. In addition to ABC transporter-mediated MDR, we attempted to identify other molecular determinants of (-)-sesamin resistance. For this reason, we performed COMPARE and hierarchical cluster analyses of the transcriptome-wide microarray-based mRNA expression of the NCI cell panel. Twenty-three genes were identified, whose mRNA expression correlated with the IC50 values for (-)-sesamin. These genes code for proteins of different biological functions, i.e. ribosomal proteins, components of the mitochondrial respiratory chain, proteins involved in RNA metabolism, protein biosynthesis, or glucose and fatty acid metabolism. Subjecting this set of genes to cluster analysis showed that the cell lines were assembled in the resulting dendrogram according to their responsiveness to (-)-sesamin. In conclusion, (-)-sesamin is not involved in MDR mediated by ABCB1 or ABCB5 and may be valuable to bypass chemoresistance of refractory tumors. The microarray expression profile, which predicted sensitivity or resistance of tumor cells to (-)-sesamin consisted of genes, which do not belong to the classical resistance mechanisms to established anticancer drugs.

Obtusilactone A and (-)-sesamin induce apoptosis in human lung cancer cells by inhibiting mitochondrial Lon protease and activating DNA damage checkpoints

Several compounds from Cinnamomum kotoense show anticancer activities. However, the detailed mechanisms of most compounds from C. kotoense remain unknown. In this study, we investigated the anticancer activity of obtusilactone A (OA) and (-)-sesamin in lung cancer. Our results show that human Lon is upregulated in non-small-cell lung cancer (NSCLC) cell lines, and downregulation of Lon triggers caspase-3 mediated apoptosis. Through enzyme-based screening, we identified two small-molecule compounds, obtusilactone A (OA) and (-)-sesamin from C. kotoense, as potent Lon protease inhibitors. Obtusilactone A and (-)-sesamin interact with Ser855 and Lys898 residues in the active site of the Lon protease according to molecular docking analysis. Thus, we suggest that cancer cytotoxicity of the compounds is partly due to the inhibitory effects on Lon protease. In addition, the compounds are able to cause DNA double-strand breaks and activate checkpoints. Treatment with OA and (-)-sesamin induced p53-independent DNA damage responses in NSCLC cells, including G(1) /S checkpoint activation and apoptosis, as evidenced by phosphorylation of checkpoint proteins (H2AX, Nbs1, and Chk2), caspase-3 cleavage, and sub-G(1) accumulation. In conclusion, OA and (-)-sesamin act as both inhibitors of human mitochondrial Lon protease and DNA damage agents to activate the DNA damage checkpoints as well induce apoptosis in NSCLC cells. These dual functions open a bright avenue to develop more selective chemotherapy agents to overcome chemoresistance and sensitize cancer cells to other chemotherapeutics.

Sesamin Induces Human Leukemic Cell Apoptosis via Mitochondrial and Endoplasmic Reticulum Stress Pathways

Background

Sesamin is a purified compounds extracted from the seeds of Sesamum orientale Linn., which contains antioxidant and anticancer activities. The objective of this study was to identify the mechanistic effect of sesamin on human leukemic HL-60, U937 and Molt-4 cell apoptosis.

Methods

The cytotoxicity was performed by 3-(4,5-dimethyl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Reactive oxygen species was measured by employing 2', 7'-dichlorodihydrofluorescein diacetate and flow cytometry. The mitochondrial transmembrane potential was determined by 3,3'-dihexyloxacarbocyanine iodide and flow cytometer. Caspase-3 and -8 activities were detected by using fluorogenic DEVD-AMC and IETD-AMC substrates, respectively. The protein expression of cytochrome c and GADD153, an endoplasmic reticulum (ER) stress protein, was illustrated by immunoblot.

Results

Sesamin was cytotoxic to HL-60 > U937 > Molt-4 > PBMCs and caused the three cell lines to die with the morphology of apoptotic character, i.e., condensed nuclei and apoptotic bodies. It produced reactive oxygen species in all cell lines, with a decrease in mitochondrial transmembrane potential. The caspase-3 activity was increased in sesamin-induced HL-60 cell apoptosis whereas casase-8 activity did not alter. Cytochrome c release was not increased. The expression of GADD153 was increased time dependently, indicating the involvement of ER stress pathway in HL-60 cells.

Conclusions

Sesamin-induced human leukemic cell apoptosis was via oxidative stress, the mitochondrial and ER stress pathways.

Chemical constituents of the bark of Machilus wangchiana and their biological activities

Eleven new metabolites, butanolides 1-6, lignan derivatives 7-9, sesquiterpene 10, and 3',4'-seco-flavane derivative 11, have been isolated from an ethanol extract of Machilus wangchiana. Twenty known compounds, including ginkgolides A and B (16 and 17), were also isolated. Their structures and absolute configurations were determined by spectroscopic and chemical methods. Compounds 7, 8a, 8b, 9, 11, (+)-guaiacin (12), meso-dihydroguaiaretic acid (13), and hamabiwalactone A (15) showed potent in vitro activities against the release of beta-glucuronidase in rat polymorphonuclear leukocytes (PMNs) induced by platelet-activating factor (PAF), with 42.5-75.6% inhibition at 10(-5) M. Compounds 8, 8a, 8b, 9, and 11 reduced dl-galactosamine (GalN)-induced hepatocyte (WB-F344 cells) damage with 39.4 +/- 6.3% to 53.6 +/- 3.5% inhibition at 10(-4) M. Isomahubannolide-23 (14) was cytotoxic against human stomach cancer (BGC-823) and ovarian cancer (A2780) cell lines, with IC(50) values of 0.13 and 2.66 muM, respectively.

Anticancer activity of isoobtusilactone A from Cinnamomum kotoense: involvement of apoptosis, cell-cycle dysregulation, mitochondria regulation, and reactive oxygen species

In this study, we investigate the anticancer effect of isoobtusilactone A (IOA), a constituent isolated from the leaves of Cinnamomum kotoense, on human non-small cell lung cancer (NSCLC) A549 cells. IOA was found to induce the arrest of G2-M phase, induce apoptosis, increase sub-G1, and inhibit the growth of these cells. Further investigation revealed that IOA's blockade of the cell cycle was associated with increased levels of p21/WAF1, p27 (kip1), and p53. In addition, IOA triggered the mitochondrial apoptotic pathway, as indicated by an increase in Bax/Bcl-2 ratios, resulting in a loss of mitochondrial membrane potential, release of cytochrome c, activation of caspase-9 and caspase-3, and cleavage of PARP. We also found the generation of reactive oxygen species (ROS) to be a critical mediator in IOA-induced inhibition of A549 cell growth. In antioxidant and NO inhibitor studies, we found that by pretreating A549 cells with either N-acetylcystenine (NAC), catalase, mannitol, dexamethasone, trolox, or L-NAME we could significantly decrease IOA production of ROS. Moreover, using NAC to block ROS, we could significantly suppress IOA-induced antiproliferation, antimigration, and anti-invasion. Finally, we found that IOA inhibited the migration and invasion of A549 cell migration and invasion. Taken together, these results suggest that IOA has anticancer effects on A549 cells.

Isoobtusilactone A induces both caspase-dependent and -independent apoptosis in Hep G2 cells

Isoobtusilactone A, a constituent isolated from the leaves of Cinnamomum kotoense, has been demonstrated by us earlier to be an agent capable of inducing apoptotic cell death of Hep G2 cells. In order to clarify if caspases alone were the sole mediator for eliciting this apoptotic process, a broad caspases inhibitor, Z-VAD.fmk, was utilized to explore this possibility. Interestingly, although Z-VAD.fmk was demonstrated to be capable of completely inhibiting isoobtusilactone A-induced oligonucleosomal DNA fragmentation, yet it could only prevent limited amount of cells from becoming apoptosis-prone. These data implied that some other mechanism(s) might be involved. Thus, the involvement of apoptosis-inducing factor (AIF), a mediator arbitrating caspase-independent apoptosis, in isoobtusilactone A-induced apoptotic process was examined. These findings indicated that isoobtusilactone A could elicit the nuclear translocation of AIF that accompanied the occurrence of large-scale DNA fragmentation. Reduction of AIF expression by AIF-siRNA transfection suppressed large-scale DNA fragmentation. Interestingly, inhibition of AIF expression by AIF-siRNA could not prevent isoobtusilactone A-induced oligonucleosomal DNA fragmentation. In the same vein, when the cells were simultaneously combined pretreatment with AIF-siRNA and Z-VAD.fmk, both large-scale DNA and oligonucleosomal DNA fragmentations could nearly be prevented. Taken together, these findings suggested that isoobtusilactone A-induced apoptotic cell death was mediated via both caspase-dependent and -independent pathways.

Isoobtusilactone A-induced apoptosis in human hepatoma Hep G2 cells is mediated via increased NADPH oxidase-derived reactive oxygen species (ROS) production and the mitochondria-associated apoptotic mechanisms

Chemoprevention by the use of naturally occurring substances is becoming a promising strategy to prevent cancer. In this study, the effects of isoobtusilactone A, a novel constituent isolated from the leaves of Cinnamomum kotoense, on the proliferation of human hepatoma Hep G2 cells were studied. Under our experimental conditions, isoobtusilactone A was found to elicit a concentration-dependent growth impediment (IC(50)=37.5 microM). The demise of these cells induced by isoobtusilactone A was apoptotic in nature, exhibiting a concentration-dependent increase in sub-G(1) fraction and DNA fragmentation. Subcellular fractionation analysis further revealed that Bax translocation to mitochondria resulted in a rapid release of cytochrome c, followed by activation of caspase 3 and PARP cleavage, and finally cell death. Isoobtusilactone A-treated cells also displayed transient increase of ROS during the earlier stage of the experiment, followed by the disruption of mitochondrial transmembrane potential (DeltaPsi(m)). The presence of a ROS scavenger (N-acetyl-L-cysteine) and an inhibitor of NADPH oxidase (diphenyleneiodonium chloride) blocked ROS production and the subsequent apoptotic cell death. In addition, in order to investigate the acute toxicity of isoobtusilactone A, groups of 5-6-week old Sprague-Dawley rats were subjected to oral administration of 350, or 700 mg/kg bw isoobtusilactone A four times each week for two weeks. There was no significant difference between control animals and treated animals with respect to the body weight gain, the body weight ratio of liver, spleen and kidney, haematological and clinical chemistry parameters. Taken together, our data suggest that ROS generated through the activation of NADPH oxidase plays an essential role in apoptosis induced by isoobtusilactone A, and the dosages of isoobtusilactone A tested in this study did not cause animal toxicity.