Toxicological profile of the Hymenaea courbaril stem bark hydroalcoholic extract using in vitro bioassays and an alternative in vivo Caenorhabditis elegans model.

Hymenaea genus has been used in folk medicine in Brazil, but few studies investigated its toxicity profile. Thus, the aim of this study was to determine toxicological parameters of Hymenaea courbaril stem bark hydroalcoholic extract by utilizing three cell lines including murine macrophages (RAW 264.7), mouse fibroblast cells (L929) and human lung fibroblast (MRC-5), as well as Salmonella/microsome assay, and in vivo Caenorhabditis elegans model. The predominant detected phytoconstituents in the extract were coumarins, flavonoids, phenolics, tannins and saponins and by HPLC analysis, astilbin (AST) was found to be the main component. The DPPH assay demonstrated that H. courbaril hydroalcoholic extract exhibited potent antioxidant activity, with an IC50 of 3.12 µg/ml. The extract at concentrations of 400 and 800 µg/ml decreased cell viability 48 hr after treatment in L929 and MRC-5 cell lines. In the Raw 264.7 strain, just the highest concentration (800 µg/ml) lowered cell viability within 48 hr following exposure. The concentration of 100 µg/ml did not markedly affect cell viability in the trypan blue assay. In the alkaline comet assay the extract was found to be non-genotoxic. In the Ames test, the extract exhibited low mutagenic potential without metabolic activation, since only the highest concentrations produced an effect. H. courbaril extract only affected the survival of C. elegans at concentrations of 800 and 1600 µl/ml. These findings demonstrate that H. courbaril extract appears to exert low toxicity as evidenced in vitro and mutagenicity assays; however, the biological relevance of the response of C. elegans survival to safety assessments needs further studies.

Achyrocline satureioides as an adjuvant therapy for the management of mild viral respiratory infections in the context of COVID-19: Preliminary results of a randomized, placebo-controlled, and open-label clinical trial.

We evaluated the impact of an Achyrocline satureioides inflorescence infusion on the clinical outcomes of viral respiratory infections, including those caused by SARS-CoV-2, in a monocentric, randomized, open-label, placebo-controlled clinical trial. Patients with symptoms of viral respiratory infection, including suspected cases of COVID-19, were included and assigned to receive either A. satureioides (n = 57) or Malus domestica (n = 67) infusions twice a day for 14 days. All participants were included before the RT-PCR results, performed using a nasopharyngeal swab. The patients were further divided into subgroups according to real-time polymerase chain reaction results: SARS-CoV-2-positive and SARS-CoV-2-negative subgroups for statistical analyses. We assessed clinical outcomes, such as the latency to resolution of cough, dyspnea, fever, sore throat, chest pain, smell and taste dysfunctions, diarrhea, nausea, abdominal pain, and loss of appetite; hospitalization; and mortality with questionnaires and medical records. The subjects that received early A. satureioides infusion showed a significant reduction in the average number of days with respiratory and neurological symptoms compared with the control group (M. domestica infusion). We conclude that A. satureioides is a safe agent and, in combination with standard care, improves viral respiratory infection symptoms, especially those related to COVID-19.

The challenge of flavonoid/cyclodextrin complexation in a complex matrix of the quercetin, luteolin, and 3-O-methylquercetin.

The complexation of herbal constituents with cyclodextrin has been a useful tool to improve their aqueous solubility. However, the simultaneous complexation of these compounds still lacks detailed studies. The present study investigated the multicomplexation of quercetin (QCT), luteolin (LUT), and 3-O-methylquercetin (3OMQ) with (2-hydroxypropyl)-ß-cyclodextrin (HPßCD), when they are simultaneously contained in a flavonoid-enriched fraction (FEF) of Achyrocline satureioides. The phase-solubility diagram revealed a linear correlation between the flavonoids solubility and the HPßCD concentration, demonstrating the formation of complexes with a 1:1 stoichiometric ratio, which was confirmed by ESI-MS. Negative ΔG0 values indicated that complexation was spontaneous. Flavonoids/HPßCD interactions were evidenced by FT-IR, DSC, SEM, and 1D and 2D NMR. The last one showed the formation of inclusion complexes by insertion of the B-ring of the flavonoids into the cavity of HPßCD. Unexpectedly, the FEF/HPßCD complex showed a radical scavenger potential lower than the FEF. The HPLC analysis revealed that the complex contained different flavonoid ratio than the fraction. Thus, the antioxidant capacity of the samples was demonstrated to be related to the ratio among the flavonoids, rather than to the total flavonoids. These new findings are very useful for developing herbal cyclodextrin-based products from A. satureioides or other herbal products.

Glioprotective Effect of Chitosan-Coated Rosmarinic Acid Nanoemulsions Against Lipopolysaccharide-Induced Inflammation and Oxidative Stress in Rat Astrocyte Primary Cultures.

Rosmarinic acid (RA) is a natural polyphenolic compound with a well-documented neuroprotective effect mainly associated with its anti-inflammatory and antioxidant activities. Recently, our research group developed and optimized chitosan-coated RA nanoemulsions (RA CNE) intended to be used for nasal delivery as a new potential neuroprotective therapy. In this sense, the present study aimed to evaluate the protective and/or therapeutic potential of RA CNE in inflammation/oxidative stress induced by LPS (1 µg mL-1) in rat astrocyte primary cultures. In summary, pre-treatment with RA CNE before exposure to LPS (protective protocol) reduced significantly the LPS-induced alterations in astrocyte cell viability, proliferation, and cell death by necrosis, which was not observed in therapeutic protocol. RA CNE protective protocol also enhanced anti-oxidative status by ~ 50% by decreasing oxygen reactive species production and nitric oxide levels and preventing total thiol content decrease. Finally, our results demonstrate the protective effect of RA CNE in migratory activation and GFAP expression of reactive astrocytes. Overall, our findings indicate for the first time the RA CNE glioprotective potential, associated with an increase in cell viability and proliferation, a preventive effect on cellular death by necrosis, migratory ability and hypertrophic reactive astrocytes, and the reparation of astrocyte redox state.

Box-Behnken Design for Extraction Optimization Followed by High Performance Countercurrent Chromatography: Production of a Flavonoid-enriched Fraction from Achyrocline Satureioides.

The biological properties of Achyrocline satureioides have been mostly ascribed to its major flavonoids quercetin (QCT), luteolin (LUT), and 3-O-methylquercetin (3OMQ). The present study aimed to optimize the extraction by dynamic maceration of the major phenolic compounds in order to obtain in a subsequent step a flavonoid-enriched fraction (FEF) using high performance countercurrent chromatography (HPCCC). A 3-level Box-Behnken design (BBD) was applied to maximize the extraction of the substances, using the plant : solvent ratio (X1 ), extraction time (X2 ), and ethanol concentration (X3 ) as factors. One-step HPCCC semipreparative separation with a solvent system composed of hexane : ethyl acetate : methanol : water (0.9 : 0.9 : 0.8 : 1.0, v/v) was employed to obtain the FEF. The second-order polynomial model was able to fit the experimental data adequately. The linear and quadratic terms of X3 were the most significant factors that affected all the responses. The positive linear term of X3 indicated a substantial increase in extraction yield, while the negative quadratic term showed a nonlinear tendency. Linear terms of X1 suggested a tendency to solvent saturation, except for QCT. The terms of X2 did not affect the responses substantially. The HPCCC method was found to be efficient and rapid for separating the FEF with 71% (w/w) flavonoid content. Overall, the developed extraction procedure coupled with HPCCC proved to be efficient for obtaining an enriched fraction with a very high content of flavonoids from A. satureioides.

Correction to: High lactobionic acid production by immobilized Zymomonas mobilis cells: a great step for large-scale process.

In the original publication, table captions were incorrectly published. The correct captions are given here.

High lactobionic acid production by immobilized Zymomonas mobilis cells: a great step for large-scale process.

Lactobionic acid and sorbitol are produced from lactose and fructose in reactions catalyzed by glucose-fructose oxidoreductase and glucono-δ-lactonase, periplasmic enzymes present in Zymomonas mobilis cells. Considering the previously established laboratory-scale process parameters, the bioproduction of lactobionic acid was explored to enable the transfer of this technology to the productive sector. Aspects such as pH, temperature, reuse and storage conditions of Ca-alginate immobilized Z. mobilis cells, and large-scale bioconversion were assessed. Greatest catalyst performance was observed between pH range of 6.4 and 6.8 and from 39 to 43 °C. The immobilized biocatalyst was reused for twenty three 24-h batches preserving the enzymatic activity. The activity was maintained during biocatalyst storage for up to 120 days. Statistically similar results, approximately 510 mmol/L of lactobionic acid, were attained in bioconversion of 0.2 and 3.0 L, indicating the potential of this technique of lactobionic acid production to be scaled up to the industrial level.

A stability-indicating ultra-fast liquid chromatography method for the assay of the main flavonoids of Achyrocline satureioides (Marcela) in porcine skin layers and nanoemulsions.

INTRODUCTION: Achyrocline satureioides (marcela or macela) is a plant widely used in folk medicine in South America. Recently, there has been increasing interest for the development of skin care products containing A. satureoides extracts, due to its well-documented antioxidant, antiherpetic, and wound healing properties. OBJECTIVES: The present study aimed to develop and validate a yet unexplored stability-indicating and robust ultra-fast liquid chromatography (UFLC) method for the simultaneous quantification of the main flavonoids of A. satureioides in extracts, nanoemulsions, and porcine skin layers. MATERIAL AND METHODS: The chromatographic separation of flavonoids quercetin, luteolin, and 3-O-methylquercetin was performed on a Luna C18 analytical column (100 mm × 2.0 mm i.d.; particle size 2.5 µm) using isocratic elution with methanol/phosphoric acid 1% (48:52 v/v) with a flow rate of 0.3 mL/min at 40°C. RESULTS: The method was found to be specific, linear (R > 0.998), precise, accurate, and robust for all flavonoids assayed in A. satureioides extract, nanoemulsions, and porcine ear skin. A low matrix effect was noted for all complex matrices. The stability-indicating UFLC method was evaluated by submitting isolated flavonoids, a mixture of standards, and A. satureioides extract to acidic, alkaline, oxidative, UV-A/UV-C light, and thermal stress conditions. No peaks were found co-eluting with the flavonoids of interest in all matrices. The robustness of the method was confirmed using Plackett-Burman experimental design. CONCLUSION: The short run time (8 min) and reliability of the method could be useful for the determination of A. satureioides flavonoids in topical product development since extracts of this medicinal plant have been used to treat various skin disorders.

Semi-preparative isolation and purification of phenolic compounds from Achyrocline satureioides (Lam) D.C. by high-performance counter-current chromatography.

INTRODUCTION: Phenolic compounds present in Achyrocline satureioides are known to have therapeutic benefits like antioxidant, anti-inflammatory, and antitumour properties. The main polyphenols present in the plant are quercetin (QCT), luteolin (LUT), 3-O-methylquercetin (3OMQ), and achyrobichalcone (ACB). However, the effective isolation and purification of these compounds from A. satureioides inflorescences are not an easy task. OBJECTIVE: To develop an efficient high-performance counter-current chromatography (HPCCC) method for quick separation and purification of naturally occurring phenolic compounds from the extract of A. satureioides. METHODOLOGY: A two-step HPCCC semi-preparative isolation method was developed using a solvent system composed of n-hexane/ethyl acetate/methanol/water (0.8:1.0:0.8:1.0) and dichloromethane/methanol/water (3.5:3.5:2.5). RESULTS: The HPCCC method was used to obtain two fractions. The first fraction (F1 ) contained high levels of ACB, among other constituents, while the second fraction (F2 ) contained mostly QCT, LUT, and 3OMQ. Besides the high ACB content, F1 contained three other flavonoid-aglycones (kaempferol, 97.3%; isokaempferide, 92.4%; and 3,3'-di-O-methylquercetin, 95.2%) identified by an ultra-performance liquid chromatography system coupled to a quadrupole time-of-flight with high-definition mass spectrometry (UPLC-QTOF/HDMS) and nuclear magnetic resonance (NMR) analysis. Purity levels of ACB, 3OMQ, QCT, and LUT were 98.0, 97.0, 97.5, and 90.2%, respectively. CONCLUSION: This is the first time that high purity ACB and six other flavonoids were obtained from A. satureioides inflorescences by HPCCC. These excellent results reveal the potential and versatility of HPCCC as a technique to produce different types of products from this plant species on a semi-preparative scale: enriched fractions, new metabolites, or high purity compounds.

Solid Dispersion of Kaempferol: Formulation Development, Characterization, and Oral Bioavailability Assessment.

Kaempferol (KPF), an important flavonoid, has been reported to exert antioxidant, anti-inflammatory, and anticancer activity. However, this compound has low water solubility and hence poor oral bioavailability. This work aims to prepare a solid dispersion (SD) of KPF using Poloxamer 407 in order to improve the water solubility, dissolution rate, and pharmacokinetic properties KPF. After optimization, SDs were prepared at a 1:5 weight ratio of KPF:carrier using the solvent method (SDSM) and melting method (SDMM). Formulations were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD) analysis, differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). The solubility in water of carried-KPF was about 4000-fold greater than that of free KPF. Compared with free KPF or the physical mixture, solid dispersions significantly increased the extent of drug release (approximately 100% within 120 min) and the dissolution rate. Furthermore, after oral administration of SDMM in rats, the area under the curve (AUC) and the peak plasma concentration (Cmax) of KPF from SDMM were twofold greater than those of free KPF (p < 0.05). In conclusion, SD with Poloxamer 407 is a feasible pharmacotechnical strategy to ameliorate the dissolution and bioavailability of KPF.

Compatibility study of rosmarinic acid with excipients used in pharmaceutical solid dosage forms using thermal and non-thermal techniques.

Rosmarinic acid (RA) is a phenolic compound that presents well-documented anti-inflammatory, antioxidant and antitumor activities, and based on its pharmacological potential and poor bioavailability, several solid dosage forms have been developed to RA delivery. Therefore, in literature, there are no reports about RA compatibility with excipients. In this regard, the aim of the present study was to evaluate, for the first time, the compatibility of RA with excipients commonly used in solid dosage forms at a 1:1 (RA:excipient) ratio using differential scanning calorimetry (DSC), thermogravimetry (TG), Fourier-transform infrared (FTIR), solid-state nuclear magnetic resonance (ssNMR), and isothermal stress testing (IST) coupled with liquid chromatography (LC). The excipients selected were hydroxypropyl methylcellulose (HPMC), microcrystalline cellulose (MCC), lactose monohydrate (LAC), polyvinylpyrrolidone (PVP), talc (TALC), croscarmellose sodium (CCS), and magnesium stearate (MgSTE). According to DSC results, physical interactions were found between RA and HPMC, LAC, CCS, and MgSTE. The TG analyses confirmed the physical interactions and suggested chemical incompatibility. FTIR revealed physical interaction of RA with TALC and MgSTE and the ssNMR confirmed the physical interaction showed by FTIR and excluded the presence of chemical incompatibility. By IST, the greatest loss of RA content was found to CCS and MgSTE (>15%), demonstrating chemical incompatibilities with RA. High temperatures used in DSC and TG analyses could be responsible for incompatibilities in binary mixtures (BMs) with HPMC and LAC, while temperature above 25 °C and presence of water were factors that promote incompatibilities in BMs with CCS and MgSTE. Overall results demonstrate that RA was compatible with MCC and PVP.

Guarana (Paullinia cupana Mart.) prevents ß-amyloid aggregation, generation of advanced glycation-end products (AGEs), and acrolein-induced cytotoxicity on human neuronal-like cells.

Advanced glycation end-products (AGEs) are considered potent molecules capable of promoting neuronal cell death and participating in the development of neurodegenerative disorders such as Alzheimer's disease (AD). Previous studies have shown that AGEs exacerbate ß-amyloid (Aß) aggregation and AGE-related cross-links are also detected in senile plaques. Acrolein (ACR) is an α, ß-unsaturated aldehyde found in the environment and thermally processed foods, which can additionally be generated through endogenous metabolism. The role of ACR in AD is widely accepted in the literature. Guarana (Paullinia cupana Mart.) is popularly consumed by the population in Brazil, mainly for its stimulant activity. In the present study, we showed that guarana (10, 100, and 1000 µg/mL) is able to prevent protein glycation, ß-amyloid aggregation, in vitro methylglyoxal, glyoxal, and ACR (20 µM)-induced toxicity on neuronal-like cells (SH-SY5Y). Since these are considered typical AD pathological hallmarks, we propose that guarana may deserve further research as a potential therapeutic agent in such a neurodegenerative disease.

Pharmacological evaluation of a traditional Brazilian medicinal plant, Monteverdia ilicifolia. Part I - Preclinical safety study.

ETHNOPHARMACOLOGICAL RELEVANCE: Monteverdia ilicifolia (Maytenus ilicifolia, Celastraceae), known as "espinheira-santa", has been widely used in Brazil to manage mainly gastrointestinal diseases. This species has been listed in the Brazilian Pharmacopeia and in the National List of Essential Medicines (RENAME). Considering that clinical studies about M. ilicifolia are rare, our group has been performing a broader project designed to evaluate the efficacy of M. ilicifolia capsules in a clinical trial, for this reason, approaches to provide safety to those patients are relevant. AIM OF THE STUDY: We aimed to investigate the potential pharmacokinetic interaction and hepatotoxicity and intestinal toxicity of an aqueous extract of M. ilicifolia and its main phytocompounds, catequin, epicatequin, and quercetin. METHODS AND MATERIALS: Slices of liver and intestine of Wistar rats were incubated with different concentrations of M. ilicifolia extract or isolated compounds (catechin, epicatechin and quercetin). Commercial kits were used to evaluate enzyme activities of CYP2D6 and CYP3A4 isoforms, as well as cell viability (MTT) assay and intracellular enzymes leakage, specifically lactate dehydrogenase (LDH), alkaline phosphatase (AP), aspartate aminotransferase (AST), alanine aminotransferase (ALT) were studied. RESULTS: Incubation with M. ilicifolia extract, catechin, epicatechin and quercetin did not affect significantly any evaluated parameter in intestines. The intracellular enzymes leakages, CYP2D6, LDH and AST, were increased with M. ilicifolia extract and quercetin in liver slices. CONCLUSIONS: Our in vitro findings highlighted, for the first time, the potential hepatotoxicity induced by an aqueous extract of M. ilicifolia, consequently this species and its products should be avoided in liver diseases, supporting that studies of safety must be performed including in the context of traditional medicinal plants.

Achyrocline satureioides review: From the pharmacochemical diversity to the technological development of products.

Achyrocline satureioides (Lam.) DC (Asteraceae) is a native species of the southeastern subtropical and temperate region of South America, popularly known as "marcela" or "macela". This species is recognized, in traditional medicine, by diverse biological activities such as digestive, antispasmodic, anti-inflammatory, antiviral, sedative, hepatoprotective, among others. Some of these activities have been related to the presence of phenolic compounds, including flavonoids, phenolic acids, terpenoids in the essential oils, coumarins and phloroglucinol derivatives reported to the species. The approaches on the technological development of phytopharmaceutical products of this species provided relevant advances in the optimization of the extraction and product obtention, especially spray-dried powders, hydrogels, ointments, granules, films, nanoemulsions and nanocapsules. The most relevant biological activities described for the extracts or derivative products from A. satureioides were antioxidant, neuroprotective, antidiabetic, antiobesity, antimicrobial, anticancer effects, and obstructive sleep apnea syndrome. The scientific and technological findings reported for the species, in conjunction with its traditional use and cultivation, reveal the high potential of the species for diverse industrial applications.

The challenge of improving pterostilbene (PTS) solubility for solid and semi-solid dosage forms: The obtention of binary and ternary systems.

Pterostilbene (PTS) is a drug candidate with low water solubility and poor bioavailability. On the other hand, drug:cyclodextrins complexes frequently provide bulk powders with low drug concentrations, which is crucial for obtention solid or semi-solid pharmaceutical dosage forms. In order to determine the optimal conditions for enhancing the solubility of PTS:BCD (ß-cyclodextrin) complex, a Box-Behnken design was performed. Although the optimal conditions have been applied, low complexation efficiency (0.127) and the bulk powder remained. A PTS:BCD:HPMC (HPMC, hydroxypropyl methylcellulose) ternary system was developed to overcome this limitation, comparing two media, water and a mixture of ethanol-water. When ethanol was used as a co-solvent, the PTS:BCD:HPMC ternary system (freeze-dried) contained 116.65 ± 1.40 mg/g of PTS. This value was 3.4-fold higher than the PTS content observed when the same ternary system was obtained in aqueous media (34.8 mg/g) and 2.8-fold higher than the PTS content observed for PTS:BCD complex (freeze-dried) obtained using ethanol as a co-solvent. Dissolution tests revealed that after 120 min, in a buffer with a pH value of 1.2, only 43% of PTS dissolved. In contrast, 80% and 90% of PTS were dissolved from the PTS:BCD complex and PTS:BCD:HPMC ternary system, respectively. Moreover, the dissolution was fast in a buffer with a pH value of 6.8. PTS:BCD complex reached the maximum PTS dissolution at 75 min and PTS:BCD:HPMC at 45 min. In summary, the results of this study demonstrated, for the first time, that low-bulk powders with a high content of PTS can be obtained from PTS:BCD:HPMC ternary systems using ethanol as a co-solvent. This new finding offers a valuable alternative for producing solid or semi-solid formulations containing highly soluble PTS.

Cyclodextrin-Based Delivery Systems and Hydroxycinnamic Acids: Interactions and Effects on Crucial Parameters Influencing Oral Bioavailability-A Review.

Hydroxycinnamic acids (HCAs) are a subclass of phenolic acids presenting caffeic acid (CA), chlorogenic acid (CGA), coumaric acid (COA) isomers, ferulic acid (FA), and rosmarinic acid (RA) as the major representants, being broadly distributed into vegetal species and showing a range of biological potentials. Due to the low oral bioavailability of the HCAs, the development of delivery systems to promote better administration by the oral route is demanding. Among the systems, cyclodextrin (CD)-based delivery systems emerge as an important technology to solve this issue. Regarding these aspects, in this review, CD-based delivery systems containing HCAs are displayed, described, and discussed concerning the degree of interaction and their effects on crucial parameters that affect the oral bioavailability of HCAs.

Effect of Hydrogel Containing Achyrocline satureioides (Asteraceae) Extract-Loaded Nanoemulsions on Wound Healing Activity.

Achyrocline satureioides (Lam.) DC extract-loaded nanoemulsions have demonstrated potential for wound healing, with promising effects on keratinocyte proliferation. We carried out the first in vivo investigation of the wound healing activity of a hydrogel containing A. satureioides extract-loaded nanoemulsions. We prepared hydrogels by adding the gelling agent (Carbopol® Ultrez) to extract-loaded nanoemulsions (~250 nm in diameter) obtained by spontaneous emulsification. The final flavonoid content in formulation was close to 1 mg/mL, as estimated by ultra-fast liquid chromatography. Permeation/retention studies using porcine ear skin showed that flavonoids reached deeper layers of pig ear skin when it was damaged (up to 3.2 µg/cm² in the dermis), but did not reach the Franz-type diffusion cell receptor fluid. For healing activity, we performed a dorsal wound model using Wistar rats, evaluating the lesion size, anti-inflammatory markers, oxidative damage, and histology. We found that extract-loaded formulations promoted wound healing by increasing angiogenesis by ~20%, reducing inflammation (tumor necrosis factor α) by ~35%, decreasing lipid damage, and improving the re-epithelialization process in lesions. In addition, there was an increase in the number of blood vessels and hair follicles for wounds treated with the formulation compared with the controls. Our findings indicate that the proposed formulation could be promising in the search for better quality healing and tissue reconstruction.

Daidzein/cyclodextrin/hydrophilic polymer ternary systems.

OBJECTIVE: To evaluate the effect of different cyclodextrins (ß-cyclodextrin [ß-CD], methyl-ß-cyclodextrin [Mß-CD], or hydroxypropyl-ß-cyclodextrin [HPß-CD]) and/or hydrophilic polymers (carboxymethylcellulose, hydroxypropylmethylcellulose [HPMC], polyethyleneglycol, or polyvinylpyrrolidone [PVP]) on daidzein solubility in water. MATERIALS AND METHODS: The corresponding associations were characterized in aqueous media using phase-solubility studies. The morphology of daidzein/cyclodextrin freeze-dried complexes was characterized using scanning electron microscopy, and their spatial configuration was proposed by means of nuclear magnetic resonance spectroscopy. RESULTS AND DISCUSSION: In the presence of 6 mM of cyclodextrins, the solubility of daidzein in water was significantly enhanced: 5.7-fold (ß-CD), 7.2-fold (Mß-CD), and 9.4-fold (HPß-CD). The analysis of the three solid complexes proved that the formation of inclusion complexes occurred through the insertion of the B and C rings of daidzein molecule into the cyclodextrins cavity. The association of daidzein/cyclodextrin complexes to the hydrophilic polymers HPMC or PVP (1%, w/w) was able to improve the solubility of daidzein even further. CONCLUSION: The highest solubilizing effect was obtained for daidzein/HPß-CD/PVP ternary system (12.7-fold).

3-O-Methylquercetin from Achyrocline satureioides-cytotoxic activity against A375-derived human melanoma cell lines and its incorporation into cyclodextrins-hydrogels for topical administration.

3-O-Methylquercetin (3OMQ), a natural 3-O-methylflavonoid, was isolated from Achyrocline satureioides and purified using the high-performance counter current chromatography (HPCCC) on a semi-preparative scale. High-purity 3OMQ (98%) was obtained with excellent recovery (81.8% (w/w)) and good yield (190 mg/100 g of plant). Isolated 3OMQ was evaluated against the A375 human amelanotic melanoma cancer cell line and A375-derived with different degrees of aggressiveness (A375-A7, A375-G10, and A375-PCDNA3). The results showed that 3OMQ reduced the cell viability of all strains, demonstrating time- and dose-dependent responses. 3OMQ was used to obtain hydrogels for the topical treatment of melanoma. Thus, 3OMQ was incorporated into hypromellose hydrogels with/without different cyclodextrins (CDs). The 3OMQ formulations showed permeation/retention in all skin layers, namely stratum corneum, epidermis, and dermis. A significant amount of 3OMQ was found in the replication site of the melanoma cells (epidermis and dermis). Altogether, these results demonstrate that 3OMQ can be isolated from Achyrocline satureioides by HPCCC on a semi-preparative scale and exhibit cytotoxic activity against melanoma cells. Its incorporation into an HPMC hydrogel containing HP-ß-CD yielded a formulation with excellent technological and biopharmaceutical characteristics for evaluating the topical management of melanoma.