Bio-Prospecting of Crude Leaf Extracts from Thirteen Plants of Brazilian Cerrado Biome on Human Glioma Cell Lines.

(1) Background: Malignant gliomas are aggressive tumors characterized by fast cellular growth and highly invasive properties. Despite all biological and clinical advances in therapy, the standard treatment remains essentially palliative. Therefore, searching for alternative therapies that minimize adverse symptoms and improve glioblastoma patients' outcomes is imperative. Natural products represent an essential source in the discovery of such new drugs. Plants from the cerrado biome have been receiving increased attention due to the presence of secondary metabolites with significant therapeutic potential. (2) Aim: This study provides data on the cytotoxic potential of 13 leaf extracts obtained from plants of 5 families (Anacardiaceae, Annonaceae, Fabaceae, Melastomataceae e Siparunaceae) found in the Brazilian cerrado biome on a panel of 5 glioma cell lines and one normal astrocyte. (3) Methods: The effect of crude extracts on cell viability was evaluated by MTS assay. Mass spectrometry (ESI FT-ICR MS) was performed to identify the secondary metabolites classes presented in the crude extracts and partitions. (4) Results: Our results revealed the cytotoxic potential of Melastomataceae species Miconia cuspidata, Miconia albicans, and Miconia chamissois. Additionally, comparing the four partitions obtained from M. chamissois crude extract indicates that the chloroform partition had the greatest cytotoxic activity against the glioma cell lines. The partitions also showed a mean IC50 close to chemotherapy, temozolomide; nevertheless, lower toxicity against normal astrocytes. Analysis of secondary metabolites classes presented in these crude extracts and partitions indicates the presence of phenolic compounds. (5) Conclusions: These findings highlight M. chamissois chloroform partition as a promising component and may guide the search for the development of additional new anticancer therapies.

Bioprospecting of Natural Compounds from Brazilian Cerrado Biome Plants in Human Cervical Cancer Cell Lines.

Cervical cancer is the third most common in Brazilian women. The chemotherapy used for the treatment of this disease can cause many side effects; then, to overcome this problem, new treatment options are necessary. Natural compounds represent one of the most promising sources for the development of new drugs. In this study, 13 different species of 6 families from the Brazilian Cerrado vegetation biome were screened against human cervical cancer cell lines (CCC). Some of these species were also evaluated in one normal keratinocyte cell line (HaCaT). The effect of crude extracts on cell viability was evaluated by a colorimetric method (MTS assay). Extracts from Annona crassiflora, Miconia albicans, Miconia chamissois, Stryphnodendron adstringens, Tapirira guianensis, Xylopia aromatica, and Achyrocline alata showed half-maximal inhibitory concentration (IC50) values < 30 µg/mL for at least one CCC. A. crassiflora and S. adstringens extracts were selective for CCC. Mass spectrometry (Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometer (ESI FT-ICR MS)) of A. crassiflora identified fatty acids and flavonols as secondary compounds. One of the A. crassiflora fractions, 7C24 (from chloroform partition), increased H2AX phosphorylation (suggesting DNA damage), PARP cleavage, and cell cycle arrest in CCC. Kaempferol-3-O-rhamnoside and oleic acid were bioactive molecules identified in 7C24 fraction. These findings emphasize the importance of investigating bioactive molecules from natural sources for developing new anti-cancer drugs.

Antiproliferative Flavanoid Dimers Isolated from Brazilian Red Propolis.

Herein reported are results of the chemical and biological investigation of red propolis collected at the Brazilian Northeast coastline. New propolones A-D (1-4), with a 3-{3-[(2-phenylbenzofuran-3-yl)methyl]phenyl}chromane skeleton; propolonones A-C (5-7), with a 3-[3-(3-benzylbenzofuran-2-yl)phenyl]chromane skeleton; and propolol A (8), with a 6-(3-benzylbenzofuran-2-yl)-3-phenylchromane skeleton, were isolated as constituents of Brazilian red propolis by cytotoxicity-guided assays and structurally identified by analysis of their spectroscopic data. Propolone B (2) and propolonone A (5) display significant cytotoxic activities against an ovarian cancer cell line expressing a multiple drug resistance phenotype when compared with doxorubicin.

Hexane partition from Annona crassiflora Mart. promotes cytotoxity and apoptosis on human cervical cancer cell lines.

Cervical cancer is the third most commonly diagnosed tumor type and the fourth cause of cancer-related death in females. Therapeutic options for cervical cancer patients remain very limited. Annona crassiflora Mart. is used in traditional medicine as antimicrobial and antineoplastic agent. However, little is known about its antitumoral properties. In this study the antineoplastic effect of crude extract and derived partitions from A. crassiflora Mart in cervical cancer cell lines was evaluated. The crude extract significantly alters cell viability of cervical cancer cell lines as well as proliferation and migration, and induces cell death in SiHa cells. Yet, the combination of the crude extract with cisplatin leads to antagonistic effect. Importantly, the hexane partition derived from the crude extract presented cytotoxic effect both in vitro and in vivo, and initiates cell responses, such as DNA damage (H2AX activity), apoptosis via intrinsic pathway (cleavage of caspase-9, caspase-3, poly (ADP-ribose) polymerase (PARP) and mitochondrial membrane depolarization) and decreased p21 expression by ubiquitin proteasome pathway. Concluding, this work shows that hexane partition triggers several biological responses such as DNA damage and apoptosis, by intrinsic pathways, and was also able to promote a direct decrease in tumor perimeter in vivo providing a basis for further investigation on its antineoplastic activity on cervical cancer.

Biocatalytic Synthesis of Flavonoid Esters by Lipases and Their Biological Benefits.

Several studies have described important biological activities of flavonoids such as coronary heart disease prevention, hepatoprotective, anti-inflammatory and anticancer activities, enzyme inhibition activity, and antibacterial, antifungal, and antiviral activities. Flavonoids show promising activity as natural plant-based antioxidants due to their antioxidant and free radical scavenging properties. However, their primary applications as antioxidants in the pharmaceutical, cosmetic, and food industries are limited because of their moderately hydrophilic nature. Enzymatic acylation of natural polyphenols with fatty acids or other acyl donors has been suggested for improving the lipophilic nature of the glycosylated flavonoids. This approach increases flavonoid solubility and stability in lipophilic systems. Acylation of flavonoids with different acyl donors may also introduce beneficial properties to the molecule, such as penetration through the cell membrane and improved antioxidant, antimicrobial, anti-inflammatory, antiproliferative, cytogenetic, and enzyme inhibition activities. Chemical methods for the synthesis of flavonoid esters lead to the formation of side products and the simultaneous decomposition of the flavonoids due to harsh reaction conditions. In contrast, biocatalytic acylation of flavonoids by lipases offers advantages associated to the wide availability of these enzymes, their low cost, chemo-, regio-, and enantioselectivity, mild condition processing and non-requirement of cofactors. This article is focused on the recent development of lipase-catalyzed synthesis of flavonoid esters and the impact of the acylation reaction on their biological activities.

Artemisia annua L.: evidence of sesquiterpene lactones' fraction antinociceptive activity.

BACKGROUND: Artemisia annua L. has been used for many centuries in Chinese traditional medicine. Artemisinin, the active principle was first isolated and identified in the 1970s becoming the global back bone to the fight against malaria. Our research group previously developed an economic and ecological friendly process to obtain this compound. In the pursuit to also exploit the residue generated throughout the process we further evaluated the pharmacological potential of that extract. METHODS: The alcoholic crude extract after artemisinin precipitation maintained an enriched sesquiterpene lactones content with residue artemisinin (1.72%) and deoxyartemisinin (0.31%), used as chemical markers for this sample. This study evaluated the pharmacological potential of the enriched sesquiterpene lactone fraction (Lac-FR) on different nociceptive and inflammatory experimental animal models. Previous findings on the biological properties of lactones obtained from natural products permitted us to explore the antinociceptive activities of these compounds based on in vivo chemical-induced behavioral assays. RESULTS: The enriched sesquiterpene lactone fraction (Lac-FR) was administrated by intraperitoneal injection producing a relevant reduction in the reaction time of the animals in both phases of the formalin test, significantly reduced the sensitivity to mechanical allodynia stimulus, reduced the paw edema caused by carrageenan injection and promoted high antinociceptive activity in tail flick model suggesting relationship with the opioid system. Further studies are being undertaken to elucidate the active components involved with the antinociceptive activity as well as evaluation of synergy effect that is seen by combination of substances that is greater than would be expected from consideration of individual contributions. CONCLUSION: For the first time, results presented herein provided consistent data to support the potential use of these lactones for pain relief as revealed by chemical-induced nociception assays in mice.

Total synthesis of (+)-trans-trikentrin†A.

Several syntheses have already been reported for cis-trikentrins and herbindoles, which are indole alkaloids unsubstituted at the C2 and C3 positions that bear a trans-1,3-dimethylcyclopentyl unit. Herein, we describe the first asymmetric and stereoselective synthesis of the more challenging trans-trikentrin A as its naturally occurring isomer. Different approaches were investigated and the strategy of choice was a combination of an enzymatic kinetic resolution and a thallium(III)-mediated ring contraction. The antiproliferative activities of the natural product and related intermediates have been tested against human tumor cell lines, leading to the discovery of new compounds with potent antitumor activity.

Populene D analogues: design, concise synthesis and antiproliferative activity.

An efficient and concise synthesis of nine populene D analogues was performed using an iodine-catalyzed Prins cyclization as the key transformation. The antiproliferative activity of these new pyrans against several cancer cell lines was then investigated. Among them, an isochromene with moderate activity (mean logGI(50) = 0.91) was found. Additionally, compounds with selectivity toward the tumor cell lines NCI-ADR/RES, OVCAR-3, and HT29 were discovered.

Phytochemical Analysis of the Fruit Pulp Extracts from Annona crassiflora Mart. and Evaluation of Their Antioxidant and Antiproliferative Activities.

Annona crassiflora Mart., the marolo fruit of the Cerrado biome, is one of the most frequently consumed species from the Brazilian Midwest. This study aimed to evaluate the chemical composition and the antioxidant and cytotoxic properties of the fruit pulp of A. crassiflora collected at Chapada das Mesas, Maranhão, Brazil. The volatile concentrate was identified as mainly ethyl octanoate, ethyl hexanoate, and methyl octanoate. From the ethanol (LFP-E) and ethyl acetate (LFP-A) extracts were identified phenolic acids (p-coumaric, gallic, quinic, and ferulic), flavones and derivatives (apigenin, epicatechin, 2'-5-dimethoxyflavone, 3',7-dimethoxy-3-hydroxyflavone, kaempferol-3-O-glucoside and 3-O-rutinoside, quercetin-3-O-glucoside, procyanidin B2, and rutin), aporphine alkaloids (xylopine, stephagine, and romucosine), and acetogenin (annonacin). For the LFP-E and LFP-A extracts, the total phenolic compound values were 15.89 and 33.16 mg GAE/g, the flavonoid compound content values were 2.53 and 70.55 mg QE/g, the DPPH radical scavenging activity showed EC50 values of 182.54 and 57.80 µg/mL, and the ABTS radical activity showed TEAC values of 94.66 and 192.61 µM TE/g. The LFP-E extract showed significant cytotoxicity and cell selectivity for the U251-glioma strain, presenting a GI50 value of 21.34 µg/mL, which is close to doxorubicin (11.68 µg/mL), the standard chemotherapeutic drug. The marolo fruit seems to be a promising source for developing innovative and healthy products for the food industry.

Antiproliferative Activity of Two Unusual Dimeric Flavonoids, Brachydin E and Brachydin F, Isolated from Fridericia platyphylla (Cham.) L.G.Lohmann: In Vitro and Molecular Docking Evaluation.

Despite the breakthrough in the development of anticancer therapies, plant-derived chemotherapeutics continue to be the basis of treatment for most types of cancers. Fridericia platyphylla is a shrub found in Brazilian cerrado biome which has cytotoxic, anti-inflammatory, and analgesic properties. The aim of this study was to investigate the antiproliferative potential of the crude hydroethanolic extract, subfraction (containing 59.3% of unusual dimeric flavonoids Brachydin E and 40.7% Brachydin F), as well as Brachydin E and Brachydin F isolated from F. platyphylla roots. The cytotoxic activity was evaluated in glioblastoma, lung, prostate, and colorectal human tumor cell lines. The crude hydroethanolic extract did not present cytotoxic activity, but its subfraction presented lower IC50 values for glioblastoma (U-251) and prostate adenocarcinoma (PC-3) cell lines. Brachydins E and F significantly reduced cell viability, proliferation, and clonogenic potential of PC-3, inducing them to the process of regulated cell death. In silico studies have indicated nuclear receptors as targets for Brachydins E and F, and molecular docking has pointed out their binding into glucocorticoid receptor (GR) ligand pocket. Targeting GR pathway has been described as a therapeutic strategy, especially for prostate cancer. These results suggest that Brachydin E and Brachydin F are promising compounds to be further explored for their antitumor effects.

Box Jellyfish (Cnidaria, Cubozoa) Extract Increases Neuron's Connection: A Possible Neuroprotector Effect.

Neurodegenerative diseases are one of the major causes of death worldwide, characterized by neurite atrophy, neuron apoptosis, and synapse loss. No effective treatment has been indicated for such diseases so far, and the search for new drugs is being increased in the last years. Animal venoms' secretion/venom can be an alternative for the discovery of new molecules, which could be the prototype for a new treatment. Here, we present the biochemical characterization and activity of the extract from the box jellyfish Chiropsalmus quadrumanus (Cq) on neurites. The Cq methanolic extract was obtained and incubated to human SH-SY5Y neurons, and neurite parameters were evaluated. The extract was tested in other cell types to check its cytotoxicity and was submitted to biochemical analysis by mass spectrometry in order to check its composition. We could verify that the Cq extract increased neurite outgrowth length and branching junctions, amplifying the contact between SH-SY5Y neurons, without affecting cell body and viability. The extract action was selective for neurons, as it did not cause any effects on other cell types, such as tumor line, nontumor line, and red blood cells. Moreover, mass spectrometry analysis revealed that there are no proteins but several low molecular mass compounds and peptides. Three peptides, characterized as cryptides, and 14 low molecular mass compounds were found to be related to cytoskeleton reorganization, cell membrane expansion, and antioxidant/neuroprotective activity, which act together to increase neuritogenesis. After this evaluation, we conclude that the Cq extract is a promising tool for neuronal connection recovery, an essential condition for the treatment of neurodegenerative diseases.

Investigation of U-251 cell death triggered by flavonoid luteolin: towards a better understanding on its anticancer property against glioblastomas.

Recently, many studies have reported the anticancer properties of flavonoid luteolin against a variety of tumors, but there is still a lack in the description of its mechanism of action. In attempt to better contribute to the literature, we evaluated the antiproliferative activity of luteolin extracted by Fridericia platyphylla in a panel of tumor cell lines representative of six different tissues. Luteolin presented antiproliferative activity for all the assessed tumor cell lines, being glioblastoma the most sensitive one. This compound was able to inhibit U-251 cells migration and tumorigenesis. Besides, luteolin leads U-251 tumor cells to apoptosis death by depolarisation of the mitochondrial membrane, ERK proteins phosphorylation, cleavage of PARP and Caspase 9, further inducing DNA damage by H2AX phosphorylation, which had not yet been described for glioblastomas. Altogether, our results reaffirm luteolin as a potential therapeutic drug.

Characterization of a refinement of the "pylorus ligation" model of rat gastric ulceration resulting in "no pain" and a more specific pharmacological response.

INTRODUCTION: The pharmacological assessment of the factors for gastric protection of a test substance should involve experimental models that can determine the involvement of cytoprotective factors, as well as their influence on the secretion of hydrochloric acid. The original protocol of pylorus ligation in rats proposed by Shay et al. in 1945, still in use today, provides a latency time of 240 min without considering the effect of postoperative pain in the mechanisms of peptic ulcer. This paper proposes a modification of this experimental protocol by eliminating the pain throughout the postoperative period, as a refinement of the test with consequent improvement of the pharmacological response. METHODS: Adult male Wistar/Uni rats underwent surgical ligation of the pylorus and were kept anesthetized throughout the experimental period (4h) in contrast to the other experimental groups that followed the original protocol proposed by Shay et al., 1945. RESULTS: We were able to determine effective doses for a positive control, as well as of a variety of secretagogues in the new experimental protocol proposed. DISCUSSION: The suppression of post-surgical pain, through the use of anesthesia throughout the experimental period, brought several benefits for the study of gastric acid secretion, rendering a more homogeneous pharmacologic response in non-inbred animals, thus being an effective experimental procedure.