Royleanone Derivatives From Plectranthus spp. as a Novel Class of P-Glycoprotein Inhibitors.

Cancer is among the leading causes of death worldwide. One of the most challenging obstacles in cancer treatment is multidrug resistance (MDR). Overexpression of P-glycoprotein (P-gp) is associated with MDR. The growing incidence of cancer and the development of MDR drive the search for novel and more effective anticancer drugs to overcome the MDR problem. Royleanones are natural bioactive compounds frequently found in Plectranthus spp. The cytotoxic diterpene 6,7-dehydroroyleanone (1) is the main component of the P. madagascariensis (Pers.) Benth. essential oil, while 7α-acetoxy-6ß-hydroxyroyleanone (2) can be isolated from acetonic extracts of P. grandidentatus Gürke. The reactivity of the natural royleanones 1 and 2 was explored to obtain a small library of new P-gp inhibitors. Four new derivatives (6,7-dehydro-12-O-tert-butyl-carbonate-royleanone (20), 6,7-dehydro-12-O-methylroyleanone (21), 6,7-dehydro-12-O-benzoylroyleanone (22), and 7α-acetoxy-6ß-hydroxy-12-O-benzoylroyleanone (23) were obtained as pure with overall modest to excellent yields (21-97%). P-gp inhibition potential of the derivatives 20-23 was evaluated in human non-small cell lung carcinoma NCI-H460 and its MDR counterpart NCI-H460/R with the P-gp overexpression, through MTT assay. Previously prepared diterpene 7α-acetoxy-6ß-benzoyloxy-12-O-(4-chloro)benzoylroyleanone (4), has also been tested. The P-gp inhibiting effects of compounds 1-4 were also assessed through a Rhodamine 123 accumulation assay. Derivatives 4 and 23 have significant P-gp inhibitory potential. Regarding stability and P-gp inhibition potential, results suggest that the formation of benzoyl esters is a more convenient approach for future derivatives with enhanced effect on the cell viability decrease. Compound 4 presented higher anti-P-gp potential than the natural diterpenes 1, 2, and 3, with comparable inhibitory potential to Dexverapamil. Moreover, derivative 4 showed the ability to sensitize the resistant NCI-H460/R cells to doxorubicin.

Artemia species: An Important Tool to Screen General Toxicity Samples.

Medicinal plants are a good source of novel therapeutic drugs, due to the phytochemicals present. Artemia, commonly known as brine shrimp, is a tiny halophilic invertebrate belonging to class Crustacean, which plays an important role in saline aquatic and marine eco-systems. Besides its usage in aquaculture, it is also highly valued for its application in toxicity detection and it is used in areas such as Ecology, Physiology, Ecotoxicology, Aquaculture and Genetics. Furthermore, Artemia based lethality assay (brine shrimp lethality assay, BSLA) is rapid, convenient and low cost. Presently, brine shrimp lethality assays are enormously employed in research and applied toxicology. It has been used in the study of natural products as a preliminary toxicity assay to screen a large number of extracts and compounds for drug discovery in medicinal plants. The aim of this review paper is to collect, organize, select and discuss the existing knowledge about the different uses of Artemia salina as a bench-top bioassay for the discovery and purification of bioactive natural products.

Parvifloron D from Plectranthusstrigosus: Cytotoxicity Screening of Plectranthus spp. Extracts.

The Plectranthus genus is commonly used in traditional medicine due to its potential to treat several illnesses, including bacterial infections and cancer. As such, aiming to screen the antibacterial and cytotoxic activities of extracts, sixteen selected Plectranthus species with medicinal potential were studied. In total, 31 extracts obtained from 16 Plectranthus spp. were tested for their antibacterial and anticancer properties. Well diffusion method was used for preliminary antibacterial screening. The minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) values of the five most active acetonic extracts (P. aliciae, P. japonicus, P. madagascariensis var. "Lynne", P. stylesii, and P. strigosus) were determined. After preliminary toxicity evaluation on Artemia salina L., their cytotoxic properties were assessed on three human cancer cell lines (HCT116, MCF-7, and H460). These were also selected for mechanism of resistance studies (on NCI-H460/R and DLD1-TxR cells). An identified compound-parvifloron D-was tested in a pair of sensitive and MDR-Multidrug resistance cancer cells (NCI-H460 and NCI-H460/R) and in normal bronchial fibroblasts MRC-5. The chemical composition of the most active extract was studied through high performance liquid chromatography with a diode array detector (HPLC-DAD/UV) and liquid chromatography-mass spectrometry (LC-MS). Overall, P. strigosus acetonic extract showed the strongest antimicrobial and cytotoxic potential that could be explained by the presence of parvifloron D, a highly cytotoxic diterpene. This study provides valuable information on the use of the Plectranthus genus as a source of bioactive compounds, namely P. strigosus with the potential active ingredient the parvifloron D.

Design of Finasteride-Loaded Nanoparticles for Potential Treatment of Alopecia.

BACKGROUND/AIMS: Androgenetic alopecia is an extremely common dermatological disorder affecting both men and women. Oral finasteride (FNS), a synthetic 4-aza-3-oxosteroid compound with poor aqueous solubility, blocks the peripheral conversion of testosterone to dihydrotestosterone (DHT) in a significant reduction in DHT concentration, achieving satisfactory results in alopecia treatment. However, its oral intake generally causes severe side effects. Considering that there is currently no scientifically proven treatment, new drug delivery systems able to improve alopecia therapy are urgently required. METHODS: In this study, polymeric nanoparticles have been proposed as a new carrier for topical delivery of FNS in hair follicles. RESULTS AND CONCLUSIONS: Polymeric nanoparticles, prepared by using a modified method of the emulsification/solvent diffusion, showed a mean particle size around 300 nm, which may be sufficient for reaching the dermis and hair follicles and negative zeta potential values. Scanning electron microscope measurements showed that all the polymeric nanoparticles exhibited a spherical shape and a smooth surface regardless of their composition. A high encapsulation efficiency was achieved for FNS (79.49 ± 0.47%). In vitro release assays in physiological conditions demonstrated that nanoparticles yielded a prolonged release of FNS for 3 h. Skin assays through an in vitro permeation study demonstrated that nanoparticles had low levels of penetration of FNS, improving its time residence onto the skin. All excipients used in nanoparticle composition and in 3 different vehicles were safe. These results suggest that the proposed novel formulation presents several good characteristics indicating its suitability for dermal delivery of FNS for alopecia treatment.

Bioproduction of gold nanoparticles for photothermal therapy.

BACKGROUND: Photothermal response of plasmonic nanomaterials can be utilized for a number of therapeutic applications such as the ablation of solid tumors. METHODS & RESULTS: Gold nanoparticles were prepared using different methods. After optimization, we applied an aqueous plant extract as the reducing and capping agent of gold and maximized the near-infrared absorption (650-900 nm). Resultant nanoparticles showed good biocompatibility when tested in vitro in human keratinocytes and yeast Saccharomyces cerevisiae. Gold nanoparticles were easily activated by controlled temperature with an ultrasonic water bath and application of a pulsed laser. CONCLUSION: These gold nanoparticles can be synthesized with reproducibility, modified with seemingly limitless chemical functional groups, with adequate controlled optical properties for laser phototherapy of tumors and targeted drug delivery.

Unsaponifiable matter from oil of green coffee beans: cosmetic properties and safety evaluation.

CONTEXT: Unsaponifiable matter (UM), a fraction of green coffee oil (GCO) contains functional compounds responsible for desirable cosmetic properties such as UV-B absorption. OBJECTIVES: To evaluate oil content and sun protection factor (SPF) variability of the two most important species of coffee and, the toxic and cytotoxic effects, as well as cosmetic properties, including antioxidant and antimicrobial activities of UM obtained from green Coffea arabica seed oil. MATERIALS AND METHODS: The safety and potential cosmetic properties of UM extracted from green coffee oil (GCO) were evaluated by the brine shrimp viability and the MTT cytotoxicity assays. The SPF and antioxidant activity were evaluated using in vitro methods. RESULTS: Relevant cytotoxicity was found against keratinocytes for concentrations ≥25 µg/mL and in the brine shrimp assay (LC50 24 µg/mL). Antimicrobial and antioxidant activities (IC50 1448 µg/mL) were low in UM but SPF was 10 times higher than in GCO. CONCLUSION: UM is a novel potential UV-B absorbent but its use as a cosmetic ingredient should be better considered due to the considerable cytotoxicity shown in the experimental conditions described.

Polymeric nanoparticles modified with fatty acids encapsulating betamethasone for anti-inflammatory treatment.

Topical glucocorticosteroids were incorporated into nanocarrier-based formulations, to overcome side effects of conventional formulations and to achieve maximum skin deposition. Nanoparticulate carriers have the potential to prolong the anti-inflammatory effect and provide higher local concentration of drugs, offering a better solution for treating dermatological conditions and improving patient compliance. Nanoparticles were formulated with poly-ϵ-caprolactone as the polymeric core along with stearic acid as the fatty acid, for incorporation of betamethasone-21-acetate. Oleic acid was applied as the coating fatty acid. Improvement of the drug efficacy, and reduction in drug degradation with time in the encapsulated form was examined, while administering it locally through controlled release. Nanoparticles were spherical with mean size of 300 nm and negatively charged surface. Encapsulation efficiency was 90%. Physicochemical stability in aqueous media of the empty and loaded nanoparticles was evaluated for six months. Drug degradation was reduced compared to free drug, after encapsulation into nanoparticles, avoiding the potency decline and promoting a controlled drug release over one month. Fourier transform infrared spectroscopy and thermal analysis confirmed drug entrapment, while cytotoxicity studies performed in vitro on human keratinocytes, Saccharomyces cerevisiae models and Artemia salina, showed a dose-response relationship for nanoparticles and free drug. In all models, drug loaded nanoparticles had a greater inhibitory effect. Nanoparticles increased drug permeation into lipid membranes in vitro. Preliminary safety and permeation studies conducted on rats, showed betamethasone-21-acetate in serum after 48 h application of a gel containing nanoparticles. No skin reactions were observed. In conclusion, the developed nanoparticles may be applied as topical treatment, after encapsulation of betamethasone-21-acetate, as nanoparticles promote prolonged drug release, increase drug stability in aqueous media, reducing drug degradation, and increase drug permeability through lipid membranes.

Design of polymeric nanoparticles and its applications as drug delivery systems for acne treatment.

OBJECTIVE: The aim of this study was to evaluate a formulation made of poly(lactide-co-glycolide) (PLGA) nanoparticles containing azelaic acid for potential acne treatment. METHODS: Azelaic acid-loaded PLGA nanoparticles were prepared by spontaneous emulsification processes using poloxamer 188 as stabilizer. Several manufacturing parameters such as stirring rate, concentration of stabilizer and different recovery methods were investigated. Nanoparticles were evaluated in terms of size, zeta potential, encapsulation efficiency, release kinetics and permeation kinetics in vitro. Furthermore, in vitro toxicological studies were performed in Saccharomyces cerevisiae model. RESULTS: The results showed that by adjusting some formulation conditions it was possible to obtain nanoparticles with high loading and a controlled drug release. Freeze-dried recovery altered the nanoparticles structure by enhancing porous structures and mannitol was required to control the mean particle size. The centrifugation recovery was found to be the best approach to nanoparticles recovery. Similar toxicity profiles were observed for both drug-free and azelaic acid-loaded nanoparticles, with concentration-dependent decreases in cell viability. CONCLUSION: These results indicate a potential formulation for controlled release delivery of azelaic acid to the follicular unit.