Innovative Microemulsion Loaded with Unusual Dimeric Flavonoids from Fridericia platyphylla (Cham.) L.G. Lohmann Roots

Fridericia platyphylla (Cham.) L.G. Lohmann is a species native to the Brazilian cerrado, with promising bioactivity. The organic fraction of the roots is rich in unusual dimeric flavonoids, reported as potential candidates for cancer treatment. The exploration of these flavonoids is very important, considering their diverse biological activities and the need for innovative therapeutic options. This work aimed to develop and characterize a microemulsion loaded with a non-polar fraction (DCM). The constituents were chosen, and the pseudo-ternary diagram was constructed to determine the region of microemulsion formation. The microemulsions blank (ME), with 3% (ME3) and 5% (ME5) of fraction DCM, were characterized in terms of droplet size, zeta potential, and polydispersity index. Both MEs showed particle sizes <100 nm; only ME3 exhibited better values for polydispersity index and zeta potential and was therefore selected for further study. The organoleptic and physicochemical characteristics were evaluated, revealing limpidity and transparency typical of these microstructures, physiologically acceptable pH, refractive index of 1.42±0.01, and density of 1.017 g/cm3±0.01. The stability tests showed good stability profiles even after exposure to extreme thermal conditions, with minimal changes in pH and the content of the incorporated fraction. The in vitro release study demonstrated that ME3 enabled the controlled release of the fraction, with a cumulative amount released over 60% within 6 h. Furthermore, fraction DCM and ME3 exhibited no toxicity in Tenebrio molitor larvae. The developed microemulsion exhibited excellent properties, so this study represents the first successful attempt to develop a formulation that incorporates the dimeric flavonoid fraction.

Flavonoid brachydin B decreases viability, proliferation, and migration in human metastatic prostate (DU145) cells grown in 2D and 3D culture models

Brachydin B (BrB) is a unique dimeric flavonoid extracted from Fridericia platyphylla (Cham.) LG Lohmann with different biological activities. However, the antitumoral potential of this flavonoid is unclear. In our study, we evaluated the effects of the BrB flavonoid on cell viability (MTT, resazurin, and lactate dehydrogenase assays), proliferation (protein dosage and clonogenic assay), and migration/invasion (3D ECM gel, wound-healing, and transwell assays) of metastatic prostate (DU145) cells cultured both as traditional 2D monolayers and 3D tumor spheroids in vitro. The results showed that the BrB flavonoid promotes cytotoxic effects from ≥1.50 μM after 24 h of treatment in DU145 cells in monolayers. In 3D prostate tumor spheroids, BrB also induced cytotoxic effects at higher concentrations after longer treatment (48, 72, and 168 h). Furthermore, BrB treatment is associated with reduced DU145 clonogenicity in 2D cultures, as well as decreased area/volume of 3D tumor spheroids. Finally, BrB (6 μM) reduced cell migration/invasion in 2D monolayers and promoted antimigratory effects in DU145 tumor spheroids (≥30 μM). In conclusion, the antitumoral and antimigratory effects observed in DU145 cells cultured in 2D and 3D models are promising results for future studies with BrB using in vivo models and confirm this molecule as a candidate for metastatic prostate cancer therapy.

Chemical characterization of Brazilian savannah Byrsonima species (muricis) and their impact on genomic instability and chemopreventive effects

The identification of new drugs with few or no adverse effects is of great interest worldwide. In cancer therapy, natural products have been used as chemopreventive and chemotherapeutic agents. Plants from the Brazilian savannah belonging to the Byrsonima genus are popularly known as muricis and have attracted much attention due to their various pharmacological activities. However, there are currently no data on these plants concerning their use as chemopreventive or chemotherapeutic agents in human cell lines. The present study assessed the potential of B. correifolia, B. verbascifolia, B. crassifolia, and B. intermedia extracts as natural alternatives in the prevention and/or treatment of cancer. The chemical constituents present in each extract were analyzed by electrospray ionization-mass spectrometry (ESI-MSN). The mutagenic/antimutagenic (micronucleus assay), genotoxic/antigenotoxic (comet assay), apoptotic/necrotic (acridine orange/ethidium bromide uptake), and oxidative/antioxidative (CM-H₂DCFDA) effects of the extracts and their influence on gene expression (RTqPCR) were investigated in nonmetabolizing gastric (MNP01) and metabolizing hepatocarcinoma (HepG2) epithelial cells to evaluate the effects of metabolism on the biological activities of the extracts. The genotoxicity, mutagenicity, and apoptotic effects observed in HepG2 cells with B. correifolia and B. verbascifolia extracts are probably associated with the presence of proanthocyanidins and amentoflavone. In MNP01 cells, none of the four extracts showed mutagenic effects. B. crassifolia and B. intermedia extracts exhibited strong antimutagenicity and enhanced detoxification in HepG2 cells and antioxidant capacities in both types of cells, possibly due to the presence of gallic and quinic acids, which possess chemopreventive properties. This study identifies for the first time B. correifolia and B. verbascifolia extracts as potential agents against hepatocarcinoma and B. crassifolia and B. intermedia extracts as putative chemopreventive agents.

Effect of Meloxicam on the Proliferation and Apoptosis of the Raji Cell Line: an In Vitro Study

Meloxicam, a nonsteroidal anti-inflammatory drug, inhibits the production of PGE2 by blocking Cox-2 activity. Specific inhibition of Cox-2 can be useful in cancer therapy by apoptosis stimulation. The objective of the research was to study the effect of meloxicam on the proliferation and apoptosis of Raji cell lines. Burkitt lymphoma (BL) cells (Raji ATCC CCL-86) were treated with various concentrations of meloxicam for 24 hours. The proliferation of the cells was evaluated by using an MTT assay. Cell apoptosis was assessed using flow cytometry, and SEM was performed to observe the morphological changes of the cells. Results showed that meloxicam affected Raji cell proliferation as well as cell apoptosis. The percentage of viable cells was decreased significantly after being treated with meloxicam (p < 0.05). Apoptotic cell percentage was higher in the groups treated with meloxicam compared to the control group (p < 0.05). SEM showed morphological changes in the Raji cells after treatment with meloxicam, showing apoptotic characteristics. These findings suggest that meloxicam has anticancer properties by inhibiting Raji cell proliferation and inducing Raji cell apoptosis in vitro. A combination of meloxicam with chemotherapy agents may improve the outcome of BL treatment.

Anticancer activities of Brachydin C in human prostate tumor cells (DU145) grown in 2D and 3D models: stimulation of cell death and downregulation of metalloproteinases in spheroids

Brachydin C (BrC) has demonstrated in vitro cytotoxic and antiproliferative effects in prostate cancer cells. In the present study, we compare the anticancer effects of BrC in DU145 cells grown in common bidimensional cultures (2D) and multicellular tumor spheroids (MCTS), often denominated 3D in vitro models, that can better mimic the microenvironment of tissues. BrC IC₅₀ values obtained in the resazurin assay after 24 h of treatment were 47.31 μM (2D) and 229.8 μM (3D) and these cytotoxic effects were time dependent only in 3D. BrC (5 to 60 μM) interfered with the growth of MCTS and reduced cell viability after 11 days of treatment, a result that is not attributable to oxidative stress evaluated using the CM-H₂ DCFDA probe. BrC (6.0 μM) impaired horizontal (wound healing) and vertical cell migration and invasion (transwell assay) in 2D and BrC (5.0 to 60 μM) in 3D (ECM Gel®). BrC modulated the expression of genes BIRC5, TNF-α, CASP3, NKX3.1, MMP9, MMP11, CDH1, and ITGAM and downregulated proteins CASP7, BAX, and TNF-α in western blotting analysis. In conclusion, BrC stimulated cell death and decreased epithelial-mesenchymal transition. Furthermore, DU145 MCTS displayed higher resistance to BrC- induced cell death than 2D cultures, a difference that should be considered in future approaches in prostatic cancer studies.

Unusual dimeric flavonoids (brachydins) induce ultrastructural membrane alterations associated with antitumor activity in cancer cell lines

Notwithstanding the advances in molecular target-based drugs, chemotherapy remains the most common cancer treatment, despite its high toxicity. Consequently, effective anticancer therapies with fewer adverse effects are needed. Therefore, this study aimed to determine the anticancer activity of the dichloromethane fraction (DCMF) isolated from Arrabidae brachypoda roots, whose components are three unusual dimeric flavonoids. The toxicity of DCMF was investigated in breast (MCF-7), prostate (DU145), and cervical (HeLa) tumor cells, as well as non-tumor cells (PNT2), using sulforhodamine B (cell viability), Comet (genotoxicity), clonogenicity (reproductive capacity) and wound healing (cell migration) assays, and atomic force microscopy (AFM) for ultrastructural cell membrane alterations. Molecular docking revealed affinity between albumin and each rare flavonoid, supporting the impact of fetal bovine serum in DCMF antitumor activity. The IC₅₀ values for MCF7, HeLa, and DU145 were 2.77, 2.46, and 2.51 µg/mL, respectively, and 4.08 µg/mL for PNT2. DCFM was not genotoxic to tumor or normal cells when exposed to twice the IC₅₀ for up to 24 h, but it inhibited tumor cell migration and reproduction compared to normal cells. Additionally, AFM revealed alterations in the ultrastructure of tumor nuclear membrane surfaces, with a positive correlation between DCMF concentration and tumor cell roughness. Finally, we found a negative correlation between roughness and the ability of DCMF-treated tumor cells to migrate and form colonies with more than 50 cells. These findings suggest that DCFM acts by causing ultrastructural changes in tumor cell membranes while having fewer toxicological effects on normal cells.

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.

Aglycone flavonoid brachydin A shows selective cytotoxicity and antitumoral activity in human metastatic prostate (DU145) cancer cells

In prostate cancer, flavonoids possess a wide variety of anticancer effects, focused on the antioxidant/pro-oxidant activity, inactivation of the androgen receptor, cell cycle arrest, apoptosis induction, metastasis inhibition, among others. This current research investigated the antitumoral in vitro activity of Brachydin A (BrA), a dimeric flavonoid isolated from Fridericia platyphylla, in human castration-resistant prostate cancer DU145. It was compared BrA selective effects in tumor prostate DU145 cells with non-tumor prostate epithelial PNT2 cells. Cell viability experiments (resazurin, neutral red, MTT, and LDH release assays) showed that BrA was sevenfold more cytotoxic to tumor cells than non-tumor prostate cells, with IC₅₀ values of 77.7 µM and 10.7 µM for PNT2 and DU145 cells, respectively. Furthermore, BrA induced necrosis and apoptosis (triple fluorescence staining assay) without interfering with oxidative stress (CM-H₂DCFDA) in DU145 cells. Also, BrA (15.36 µM) reduced cell proliferation on clonogenic assay (DU145 cells) but no change in cell number and protein content was observed when cell growth curve assay was used. Wound healing and transwell assays were used for checking the effects of BrA on cell migration and invasion, and BrA impaired these processes in PNT2 (wound healing) and DU145 cells (transwell). Our results inspire further studies to test BrA as a novel chemotherapeutic drug and to evaluate its effects on drug-resistant metastatic cancer cells.

Selective anticancer effects of Serjania marginata Casar. extract in gastric cells are mediated by antioxidant response

Gastric cancer is the fifth most common malignancy worldwide. Serjania marginata Casar. (SM) displays anti-inflammatory properties and has been used to treat gastrointestinal disorders. In the current study, we examined whether the hydroethanolic extract of SM leaves exerted cytotoxic, mutagenic, and protective effects in non-tumor gastric epithelium cells (MNP01) and gastric adenocarcinoma cells (ACP02) in vitro and analyzed whether its action was selective. Initially, cell viability (MTT assay), cell cycle kinetics (flow cytometry), and cell proliferation (total protein content) were analyzed. In addition, genomic instability (cytokinesis-block micronucleus cytome assay), anti/pro-oxidant status (CM-H₂ DCFDA probe), and transcriptional expression (RT-qPCR) of genes related to cell cycle, cell death, and antioxidant defense were also evaluated. The SM extract was cytotoxic toward MNP01 and ACP02 cells at concentrations greater than 300 and 100 μg·ml^-1 , respectively, and decreased protein content only toward ACP02 cells at 200 μg ml^-1 . In ACP02 cells, the SM extract at 100 μg·ml^-1 associated with doxorubicin (DXR; 0.2 μg ml^-1 ) clearly promoted cell cycle arrest at the G2/M phase. The extract alone was not mutagenic to either cell type and reversed DXR-induced DNA damage and H₂ O₂ -induced oxidative stress in MNP01 cells. The gene expression experiments showed that SM hydroethanolic extract exerts an antioxidant response via NFE2L2 activation in non-tumor gastric cells, and cell cycle arrest (G2/M) in ACP02 gastric cancer cells via the TP53 pathway. The selective action of SM indicates that it is a promising therapeutic agent to treat gastric diseases and merits further studies.

p-synephrine induces transcriptional changes via the cAMP/PKA pathway but not cytotoxicity or mutagenicity in human gastrointestinal cells

p-Synephrine (SN) is an alkaloid added to thermogenic formulations for weight loss that is predominantly absorbed in the human gastrointestinal tract (GI). As the adverse effects of SN on GI cells remain unclear, the aim of present study was to examine whether SN affected cell viability, cell cycle kinetics, genomic stability, redox status, and expression of cAMP/PKA pathway genes related to metabolism/energy homeostasis in stomach mucosa (MNP01) and colon adenocarcinoma (Caco-2) human cells. p-Synephrine at 25-5000 μM was not cytotoxic to both cell lines. At 2-200 μM, SN increased the formation of reactive oxygen species (ROS) but also enhanced levels of antioxidant defense molecules glutathione (GSH) and catalase (CAT) activity, which may account for the absence of cytotoxicity/mutagenicity in both cell lines. SN induced expression of the cAMP/PKA pathway genes ADCY3 and MAPK1 in MNP01 cells and MAPK1, GNAS, PRKACA, and PRKAR2A in Caco-2 cells, as well as modulated the transcription of genes related to cell proliferation (JUN; AKT1) and inflammation (RELA; TNF) in both cell lines. Therefore, the improved antioxidant state mitigated pro-oxidative effects attributed to SN. Evidence indicates that SN does not appear to exhibit adverse potential but modulated the cAMP/PKA pathway in human GI cell lines.

Characterization of the invitro cytotoxic effects of brachydins isolated from Fridericia platyphylla in a prostate cancer cell line

Brachydins (Br) A, B, and C are flavonoids extracted from Fridericia platyphylla (Cham.) L.G. Lohmann roots (synonym Arrabidaea brachypoda), whose extract previously exhibited cytotoxic and antitumor activity. In vitro cell culture of human prostate tumor cell line (PC-3) was used to determine cell viability as evidenced by MTT, neutral red, and LDH release using nine concentrations (0.24 to 30.72 µM) of each brachydin. A triple-fluorescent staining assay assessed the mechanism resulting in cell death. Genomic instability and protein expression were evaluated using comet assay and western blot analysis, respectively. The pro-oxidant status was analyzed using the5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate (CM-H₂DCFDA) probe. The IC₅₀ values for brachydins BrA, BrB, and BrC were 23.41, 4.28, and 4.44 µM, respectively, and all compounds induced apoptosis and necrosis. BrB and BrC increased p21 levels indicating a possible G1 cell cycle arrest. BrA (6 µM) and BrB (3.84 µM) decreased phospho-AKT (AKT serine/threonine kinase) expression, which also influenced cell cycle and proliferation. BrA, BrB, and BrC elevated cleaved PARP (poly (ADP-ribose) polymerase), a protein related to DNA repair and induction of apoptotic processes. Therefore, this study determined the IC₅₀ values of brachydins in the PC-3 cell line as well as the influence on cell proliferation and cell death processes, such as apoptosis and necrosis, indicating the proteins involved in these processes.

ABBREVIATIONS

ANOVA: Analysis of Variance; BrA: Brachydin A; BrB: Brachydin B; BrC: Brachydin C; CGEN: Genetic Heritage Management Council; CID: Compound identification number; CM-H₂DCFDA, 5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate, acetyl ester; CO₂: Carbon dioxide; DMSO: Dimethyl sulfoxide; DNA: Deoxyribonucleic acid; DTT: Dithiothreitol; DXR: Doxorubicin; ECL: Chemiluminescence; EDTA: Ethylenediaminetetraacetic acid; FBS: Fetal bovine serum; H₂O₂: Hydrogen peroxide; HRMS: High-Resolution Mass Spectrometry; IC50: Half maximal inhibitory concentration; LDH: Lactate dehydrogenase; MTT, 3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide; Na3VO4: Sodium Orthovanadate; NaOH: Sodium hydroxide; NCBI: National Center for Biotechnology Information; NMR: Nuclear Magnetic Resonance; PBS: Phosphate buffer saline; PCR: Polymerase chain reaction; PSMF: Phenylmethylsulfonyl fluoride; RPMI: Roswell Park Memorial Institute Medium; SDS-PAGE: Sodium Dodecyl Sulfate-Polyacrylamide gel electrophoresis; STR: Short tandem repeat; TBS-T: Tris-buffered saline and Polysorbate 20; UPHLC: Ultra-Performance Liquid Chromatography.