Antibiotic Coordination Frameworks against Antibiotic Resistance: How to Involve Students through Experimental Practices in the Search for Solutions to Public Health Problems.

For decades, multiple varieties of antibiotics have been successfully used for therapeutic purposes. Nevertheless, antibiotic resistance is currently one of the major threats to global health. This work presents an innovative laboratory practice carried out in an inorganic medicinal chemistry course within the Degrees of Pharmacy and Biochemistry for undergraduate students. This experiment includes three classes of 2 h each. The first class consisted of the mechanochemical synthesis of an antibiotic coordination framework (ACF) using a known antibiotic (nalidixic acid) and zinc as the ligand. The prepared Zn-nalidixic acid ACF (Zn-ACF) was obtained in up to 82% yield with high purity. On the second day, the synthesized Zn-ACF was characterized by Fourier-transform infrared spectroscopy (FTIR) and powder X-ray diffraction (PXRD). Finally, during the last class, the antimicrobial activity was tested against Escherichia coli by the well diffusion method. The students verified the higher antimicrobial activity of Zn-ACF compared to nalidixic acid, proving that small changes in the chemical structure can result in great biological differences. In the end, the students presented their results in a poster format, encouraging the development of their soft skills and scientific results communication and dissemination. In the future, it is expected that such a laboratory experiment at the interface between medicinal chemistry, microbiology, analytical techniques, public health, and pharmacology will lead to the development and implementation of some service-learning practices and will serve as a model to look at for other courses and institutions.

Anticancer diterpenes of African natural products: Mechanistic pathways and preclinical developments.

BACKGROUND: The African continent is home to five biodiversity hotspots, boasting an immense wealth of medicinal flora, fungi and marine life. Diterpenes extracted from such natural products have compelling cytotoxic activities that warrant further exploration for the drug market, particularly in cancer therapy, where mortality rates remain elevated worldwide. PURPOSE: To demonstrate the potential of African natural products on the global stage for cancer therapy development and provide an in-depth analysis of the current literature on the activity of cancer cytotoxic diterpenes from African natural sources (to our knowledge, the first of its kind); not only to reveal the most promising candidates for clinical development, but to demonstrate the importance of preserving the threatened ecosystems of Africa. METHODS: A comprehensive search by means of the PRISMA strategy was conducted using electronic databases, namely Web of Science, PubMed, Google Scholar and ScienceDirect. The search terms employed were 'diterpene & mechanism & cancer' and 'diterpene & clinical & cancer'. The selection process involved assessing titles in English, Portuguese and Spanish, adhering to predefined eligibility criteria. The timeframe for inclusion spanned from 2010 to 2023, resulting in 218 relevant papers. Chemical structures were visualized using ChemDraw 21.0, PubChem was utilized to search for CID numbers. RESULTS: Despite being one of the richest biodiverse zones in the world, African natural products are proportionally underreported compared to Asian countries or otherwise. The diterpenes andrographolide (Andrographis paniculata), forskolin (Coleus forskohlii), ent-kauranes from Isodon spp., euphosorophane A (Euphorbia sororia), cafestol & kahweol (Coffea spp.), macrocylic jolkinol D derivatives (Euphorbia piscatoria) and cyathane erinacine A (Hericium erinaceus) illustrated the most encouraging data for further cancer therapy exploration and development. CONCLUSIONS: Diterpenes from African natural products have the potential to be economically significant active pharmaceutical and medicinal ingredients, specifically focussed on anticancer therapeutics.

Biological Activity of 6,7-Dehydroxyroyleanone and Derivatives Obtained from Plectranthus aliciae (Codd) A.J.Paton.

The Plectranthus genus (Lamiaceae) is known to be rich in abietane diterpenes. The bioactive 6,7-dehydroxyroyleanone (DHR, 1) was previously isolated from Plectranthus madagascariensis var. madagascariensis and var. aliciae. This study aimed to explore the occurrence of DHR, 1, in P. aliciae and the potential bioactivities of new semisynthetic derivatives from DHR, 1. Several extraction methods were evaluated, and the hydrodistillation, using a Clevenger apparatus, afforded the highest yield (77.8 mg/g of 1 in the essential oil). Three new acyl derivatives (2-4) were successfully prepared from 1 (yields of 86-95%). Compounds 1-4 showed antioxidant activity, antibacterial effects, potent cytotoxic activity against several cell lines, and enhanced anti-inflammatory activity that surpassed dexamethasone (positive control). These findings encourage further exploration of derivatives 2-4 for potential mechanisms of antitumoral, antioxidant, and anti-inflammatory capabilities, studying both safety and efficacy.

Dehydroroyleanone as a Building Block for a Drug Delivery Platform Based on Self-Assembled Nanoparticles: Structural Studies and Chemical Modification.

6,7-Dehydroroyleanone (DHR) is a caspase-induced cytotoxic abietane diterpene, frequently found on Plectranthus spp. A pharmaceutical formulation consisting of a DHR-squalene conjugate was synthesized and analyzed by different techniques such as scanning electron microscopy (SEM). The facile production of the dispersion of DHR-squalene conjugate nanoparticles in phosphate buffer (pH 7.4) suggests that this nanodelivery platform may be an effective system to improve the solubility and bioavailability of DHR, so that therapeutical systemic levels may be achieved.

Parvifloron D-based potential therapy for glioblastoma: Inducing apoptosis via the mitochondria dependent pathway.

Glioblastoma (GB) is the most malignant and frequent primary tumor of the central nervous system. The lack of diagnostic tools and the poor prognosis associated with this tumor type leads to restricted and limited options of treatment, namely surgical resection and radio-chemotherapy. However, despite these treatments, in almost all cases, patients experience relapse, leading to survival rates shorter than 5 years (∼15-18 months after diagnosis). Novel therapeutic approaches are urgently required (either by discovering new medicines or by repurposing drugs) to surpass the limitations of conventional treatments and improve patients' survival rate and quality of life. In the present work, we investigated the antitumor potential of parvifloron D (ParvD), a drug lead of natural origin, in a GB cell line panel. This natural drug lead induced G2/M cell cycle arrest and apoptosis via activation of the intrinsic mitochondria-dependent pathway. Moreover, the necessary doses of ParvD to induce pronounced inhibitory effects were substantially lower than that of temozolomide (TMZ, first-line treatment) required to promote comparable effects. Therefore, ParvD may have the potential to overcome the resistance related to TMZ and contribute to the pursuit of hopeful treatments based on ParvD as a drug lead for future chemotherapeutics.

Lethality Bioassay using Artemia salina L.

Natural products have been used since ancient times to produce medicines. Nowadays, there are plenty of chemotherapeutic drugs obtained from natural sources and used against a plethora of diseases. Unfortunately, most of these compounds often display systemic toxicity and adverse effects. In order to better evaluate the tolerability of selected potentially bioactive samples, brine shrimp (Artemia salina) is generally used as a model in lethality studies. The A. salina test is based on the ability of the studied bioactive compounds to kill the microcrustaceans in their larval stage (nauplii). This method represents a convenient starting point for cytotoxicity studies, as well as for the general toxicity screening of synthetic, semisynthetic, and natural products. It can be considered a simple, quick, and low-cost assay, compared to many other assays (in vitro cells or yeast strains, zebrafish, rodents) generally suitable for the aforementioned purposes; moreover, it can be easily performed even without any specific training. Overall, A. salina assay represents a useful tool for the preliminary toxicity evaluation of selected compounds and the bio-guided fractionation of natural product extracts.

Phytochemical Study and Antiglioblastoma Activity Assessment of Plectranthus hadiensis (Forssk.) Schweinf. ex Sprenger var. hadiensis Stems.

Glioblastoma (GB) is the most malignant form of primary astrocytoma, accounting for more than 60% of all brain tumors in adults. Nowadays, due to the development of multidrug resistance causing relapses to the current treatments and the development of severe side effects resulting in reduced survival rates, new therapeutic approaches are needed. The genus Plectranthus belongs to the Lamiaceae family and is known to be rich in abietane-type diterpenes, which possess antitumor activity. Specifically, P. hadiensis (Forssk.) Schweinf. ex Sprenger has been documented for the use against brain tumors. Therefore, the aim of this work was to perform the bioguided isolation of compounds from the acetonic extract of P. hadiensis stems and to investigate the in vitro antiglioblastoma activity of the extract and its isolated constituents. After extraction, six fractions were obtained from the acetonic extract of P. hadiensis stems. In a preliminary biological screening, the fractions V and III showed the highest antioxidant and antimicrobial activities. None of the fractions were toxic in the Artemia salina assay. We obtained different abietane-type diterpenes such as 7α-acetoxy-6ß-hydroxyroyleanone (Roy) and 6ß,7ß-dihydroxyroyleanone (DiRoy), which was also in agreement with the HPLC-DAD profile of the extract. Furthermore, the antiproliferative activity was assessed in a glioma tumor cell line panel by the Alamar blue assay. After 48 h treatment, Roy exerted strong antiproliferative/cytotoxic effects against tumor cells with low IC50 values among the different cell lines. Finally, we synthesized a new fluorescence derivative in this study to evaluate the biodistribution of Roy. The uptake of BODIPY-7α-acetoxy-6ß-hydroxyroyleanone by GB cells was associated with increased intracellular fluorescence, supporting the antiproliferative effects of Roy. In conclusion, Roy is a promising natural compound that may serve as a lead compound for further derivatization to develop future therapeutic strategies against GB.

C20-nor-Abietane and Three Abietane Diterpenoids from Plectranthus mutabilis Leaves as P-Glycoprotein Modulators.

In this study, a bioguided fractionation of Plectranthus mutabilis extract was performed by chromatographic methods. It yielded one new nor-abietane diterpene, mutabilol (1), and three known abietanes, coleon-U-quinone (2), 8α,9α-epoxycoleon-U-quinone (3), and coleon U (4). The abietane diterpenoid 5 was also tentatively identified using HPLC-MS/MS. Moreover, the extract profile and quantification of each isolated compound were determined by HPLC-DAD. Compound 4 was the major compound in the extract. Compounds 2-4 were found to be selective toward cancer cell lines and were able to inhibit P-glycoprotein (P-gp) activity in NCI-H460/R cells at longer exposure of 72 h and consequently revert doxorubicin (DOX) resistance in subsequent combined treatment. None of the compounds influenced the P-gp expression in NCI-H460/R cells, while the extract significantly increased it.

Plectranthus ecklonii Benth: A Comprehensive Review Into its Phytochemistry and Exerted Biological Activities.

Ethnopharmacological Relevance: Plectranthus genus (Lamiaceae family) contain several species with acknowledged ethnopharmacological uses, such as, for gastrointestinal and respiratory-related problems, due to their anti-inflammatory, antibacterial and antifungal properties. The bioactivity of isolated medicinal compounds from this genus justifies the increased interest in recent times for species of Plectranthus, placing them in the spotlight for natural product drug development. Aim of the study: To the best of our knowledge, this is the first review on the biological activities of Plectranthus ecklonii Benth. As such, the aim of this review was three-fold: 1) to summarize the chemical compounds isolated from P. ecklonii; 2) to collate the biological activities and mechanisms of action of these compounds from in vitro studies; and 3) to evaluate the documented uses and potential applications of this species, in order to postulate on the direction of pharmaceutical uses of this species. Materials and methods: An extensive database retrieval was performed using the electronic databases Web of Science, PubMed, Google Scholar and ScienceDirect. The search criteria consisted of the keywords "Plectranthus ecklonii", "Plectranthus ecklonii + review", "Plectranthus ecklonii + diterpenes" or "Plectranthus ecklonii + abietanes", "ecklonii + parviflorone D", searched individually and as combinations. Eligibility criteria were set out and titles in English, Portuguese and Spanish were reviewed, with all references included dating from 1970 to 2021. A total of 169 papers were selected and included. Chemical structures were drawn using ChemDraw 20.0, CID numbers were searched in PubChem and the PRISMA diagram was created using PowerPoint 2012. Results: To date, a total of 28 compounds have been isolated from P. ecklonii, including diterpenes, triterpenes, flavonoids, and hydroxycinnamic acids. Most focused on the antimicrobial action of its constituents, although compounds have demonstrated other bioactivities, namely antioxidant, anti-inflammatory and antitumor. The most recent studies emphasize the diterpenoids, particularly parviflorone D, with the help of nanotechnology. Conclusions: The widespread ethnobotanical and traditional uses of P. ecklonii can be scientifically justified by a range of biological activities, demonstrated by isolated secondary metabolites. These bioactivities showcase the potential of this species in the development of economically important active pharmaceutical ingredients, particularly in anticancer therapy.

Self-Assembly Nanoparticles of Natural Bioactive Abietane Diterpenes.

Different approaches have been reported to enhance penetration of small drugs through physiological barriers; among them is the self-assembly drug conjugates preparation that shows to be a promising approach to improve activity and penetration, as well as to reduce side effects. In recent years, the use of drug-conjugates, usually obtained by covalent coupling of a drug with biocompatible lipid moieties to form nanoparticles, has gained considerable attention. Natural products isolated from plants have been a successful source of potential drug leads with unique structural diversity. In the present work three molecules derived from natural products were employed as lead molecules for the synthesis of self-assembled nanoparticles. The first molecule is the cytotoxic royleanone 7α-acetoxy-6ß-hydroxyroyleanone (Roy, 1) that has been isolated from hairy coleus (Plectranthus hadiensis (Forssk.) Schweinf). ex Sprenger leaves in a large amount. This royleanone, its hemisynthetic derivative 7α-acetoxy-6ß-hydroxy-12-benzoyloxyroyleanone (12BzRoy, 2) and 6,7-dehydroroyleanone (DHR, 3), isolated from the essential oil of thicket coleus (P. madagascariensis (Pers.) Benth.) were employed in this study. The royleanones were conjugated with squalene (sq), oleic acid (OA), and/or 1-bromododecane (BD) self-assembly inducers. Roy-OA, DHR-sq, and 12BzRoy-sq conjugates were successfully synthesized and characterized. The cytotoxic effect of DHR-sq was previously assessed on three human cell lines: NCI-H460 (IC50 74.0 ± 2.2 µM), NCI-H460/R (IC50 147.3 ± 3.7 µM), and MRC-5 (IC50 127.3 ± 7.3 µM), and in this work Roy-OA NPs was assayed against Vero-E6 cells at different concentrations (0.05, 0.1, and 0.2 mg/mL). The cytotoxicity of DHR-sq NPs was lower when compared with DHR alone in these cell lines: NCI-H460 (IC50 10.3 ± 0.5 µM), NCI-H460/R (IC50 10.6 ± 0.4 µM), and MRC-5 (IC5016.9 ± 0.5 µM). The same results were observed with Roy-OA NPs against Vero-E6 cells as was found to be less cytotoxic than Roy alone in all the concentrations tested. From the obtained DLS results, 12BzRoy-sq assemblies were not in the nano range, although Roy-OA NP assemblies show a promising size (509.33 nm), Pdl (0.249), zeta potential (-46.2 mV), and spherical morphology from SEM. In addition, these NPs had a low release of Roy at physiological pH 7.4 after 24 h. These results suggest the nano assemblies can act as prodrugs for the release of cytotoxic lead molecules.

Preliminary Biological Activity Screening of Plectranthus spp. Extracts for the Search of Anticancer Lead Molecules.

Plectranthus species (Lamiaceae) have been employed in traditional medicine and this is now validated by the presence of bioactive abietane-type diterpenoids. Herein, sixteen Plectranthus acetonic extracts were prepared by ultrasound-assisted extraction and their biological activity was screened. The antimicrobial activity of each extract was screened against yeasts, and Gram-positive and Gram-negative bacteria. The P. hadiensis and P. mutabilis extracts possessed significant activity against Staphylococcus aureus and Candida albicans (microdilution method). Moreover, all extracts showed antioxidant activity using the DPPH method, with P. hadiensis and P. mutabilis extracts having the highest scavenging activities. Selected by the Artemia salina model, P. hadiensis and P.ciliatus possessed low micromolar anti-proliferative activities in human colon, breast, and lung cancer cell lines. Furthermore, the most bioactive extract of P. hadiensis leaves and the known abietane diterpene, 7α-acetoxy-6ß-hydroxyroyleanone isolated from this plant, were tested against the aggressive type triple negative breast cancer (MDA-MB-231S). P. hadiensis extract reduced the viability of MDA-MB-231S cancer cell line cells, showing an IC50 value of 25.6 µg/mL. The IC50 value of 7α-acetoxy-6ß-hydroxyroyleanone was 5.5 µM (2.15 µg/mL), suggesting that this lead molecule is a potential starting tool for the development of anti-cancer drugs.

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.

Zoopharmacology: A Way to Discover New Cancer Treatments.

Zoopharmacognosy is the multidisciplinary approach of the self-medication behavior of many kinds of animals. Recent studies showed the presence of antitumoral secondary metabolites in some of the plants employed by animals and their use for the same therapeutic purposes in humans. Other related and sometimes confused term is Zootherapy, which consists on the employment of animal parts and/or their by-products such as toxins, venoms, etc., to treat different human ailments. Therefore, the aim of this work is to provide a brief insight for the use of Zoopharmacology (comprising Zoopharmacognosy and Zootherapy) as new paths to discover drugs studying animal behavior and/or using compounds derived from animals. This work is focused on the approaches related to cancer, in order to propose a new promising line of research to overcome multidrug resistance (MDR). This novel subject will encourage the use of new alternative prospective ways to find new medicines.

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.

Cytotoxic Activity of Royleanone Diterpenes from Plectranthus madagascariensis Benth.

Cytotoxicity screenings have identified Plectranthus plants as potential sources of antitumor lead compounds. In this work, several extracts from Plectranthus madagascariensis were prepared using different solvents (acetone, methanol, and supercritical CO2) and extraction techniques (maceration, ultrasound-assisted, and supercritical fluid extraction), and their chemical composition was detailed using high-performance liquid chromatography with a diode array detector. The cytotoxic activity of the major compounds identified, namely, rosmarinic acid (1) and abietane diterpenes 7α,6ß-dihydroxyroyleanone (2), 7α-formyloxy-6ß-hydroxyroyleanone (3), 7α-acetoxy-6ß-hydroxyroyleanone (4), and coleon U (5), was evaluated in a battery of human cancer cell lines, including breast (MDA-MB-231, MCF-7), colon (HCT116), and lung (NCI-H460, NCI-H460/R) cancer, and also in healthy lung (MCR-5) cells. Royleanone (3) was isolated for the first time from P. madagascariensis, and its full spectroscopic characterization (proton and carbon nuclear magnetic resonance) was accomplished. A high selectivity for lung cancer cells was observed for royleanones (2, 4) with selectivity indexes of 4.3 and 3.2, respectively. The observed results combined with literature data allowed the establishment of important structure-activity relationships for substituted royleanone abietanes, such as the requirement for an electron-donating group at positions 6 and/or 7 in the abietane skeleton, and an improved cytotoxic effect for substituents with log P values between 2 and 5.

Comparison Study of Different Extracts of Plectranthus madagascariensis, P. neochilus and the Rare P. porcatus (Lamiaceae): Chemical Characterization, Antioxidant, Antimicrobial and Cytotoxic Activities.

Medicinal plants of the Plectranthus genus (Lamiaceae) are known for their ethnopharmacological relevance, mainly against infectious, dermatologic and gastrointestinal pathologies. Three Plectranthus species originated from South Africa, namely P. madagascariensis, P. neochilus and the rare P. porcatus were hereby screened for their antimicrobial and cytotoxic activities related with their known and/or potential ethnomedicinal uses. Twenty-six extracts were prepared by the combination of extraction methods (infusion, decoction, microwave-assisted, ultrasound-assisted, maceration and supercritical fluid extraction) with different polarity solvents (water, methanol, acetone and supercritical CO2). The comparison study of these extracts was elucidated through the corresponding chemical characterization and cytotoxic activity data. Therefore, the acetone extract from P. madagascariensis prepared by ultrasound extraction method revealed potent antibacterial activity against Gram-positive bacteria (1.95 < minimum inhibitory concentration (MIC) < 7.81 µg/mL), including a methicillin-resistant Staphylococcus aureus (MRSA) strain. Additionally, acetone extracts from both P. madagascariensis and P. neochilus exhibited relevant antibacterial activity against Gram-negative Klebsiella pneumonia (0.48 < MIC < 3.91 µg/mL), validating the traditional uses of such plants as anti-infectious agents. All methanolic extracts showed potent antioxidant effects at 100 µg/mL measured as their radical scavenging activity (60.8-89.0%) in the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The P. madagascariensis extract obtained by maceration in acetone showed moderate cytotoxic effects in the MDA-MB-231 cell line (triple negative human breast carcinoma). The extract concentration that caused a 50% inhibition in cell viability (IC50) was 64.52 µg/mL. All extracts in this comparative study were profiled by high-performance liquid chromatography-HPLC with a diode-array detector-DAD (HPLC-DAD) and the main known bioactive components were identified in each extract, which included polyphenols (caffeic 1, chlorogenic 2 and rosmarinic 3 acids), abietane diterpenes (7α-acetoxy-6ß-hydroxyroyleanone 4 and coleon U 5) and flavone glycosides (rutin 6 and naringin 7).

Family medicine physicians' perception and attitudes of herbal substances use in greater Lisbon region.

BACKGROUND: Previous works showed patients preference for herbal substances (HS) although they also highlighted a discrepancy with physicians' adherence to HS and its recommendation. HYPOTHESIS/PURPOSE: This study aimed to assess physician's perception and attitudes concerning the use of HS for their patients in a Family Medicine approach. STUDY DESIGN: Observational cross-sectional exploratory study. METHODS: A questionnaire survey was applied to National Health System physicians; 113 questionnaires were distributed in the Greater Lisbon region. RESULTS: 80 valid questionnaires were received. The age of participants ranges from 29 to 64 with mean age of M ±â€¯SD:51.9 ±â€¯10.0 years, mostly women (71.4%). Of these, 61.5% were unaware of traditional herbal medicinal products' (THMP) legal recognition and 67.3% of the difference between THMP and well-established use medicines. Absence of accordance between use and knowledge of herbal medicines (HM)/herbal products (HP) (p = 0.025) can be related to lack of Phytotherapy knowledge perception based on the nonexistence of specific training reported by 94.0% of physicians. Through factor analysis, three dimensions were obtained: Factor1, ``Use''; Factor2, ``Autonomy''; Factor3 ``Effort''. The overall Cronbach's α was 0.77, and 0.82 for Factor1. The evidence of use/prescription, has a correlation with ``Use'' (p < 0.0001), willingness to prescribe (p < 0.0001) and self-medication (p < 0.0001). There is a correlation (r = 0.605, p < 0.0001) between HS recommendation and self-medication. There were differences in use, perception and attitudes among Personalized-Health-Care Units and Family-Health Units physicians in relation to Factor1: p = 0.007 and Factor2: p = 0.021, age (p = 0.001), years of Medical career (p = 0.002), HM use (p = 0.014) and information about alternatives (p = 0.03). Physicians who answered correctly to the question on silymarin had higher scores in factor1 than those who did not: 1.76 vs. 1.25 (p = 0.019). CONCLUSION: Low adherence to HS and little use of HM/HP were confirmed, highlighting the need for specific knowledge in Phytotherapy and its regulatory framework. This knowledge will enable the evaluation of herb-drug interactions and HM/HP adverse effects by the physicians thus justifying the integration of programmatic contents about HS in Medical Education.

Anticancer properties of the abietane diterpene 6,7-dehydroroyleanone obtained by optimized extraction.

AIM: 6,7-dehydroroyleanone (DHR) is a cytotoxic abietane present in the essential oil of Plectranthus madagascariensis. METHODS/RESULTS: Different extraction parameters were tested, and its extraction optimization was accomplished with a Clevenger apparatus-based hydrodistillation. After isolation, its effect on microtubules, P-glycoprotein and caspases was assessed on several cell lines and the compound was coupled with hybrid nanoparticles. The results show that DHR does not interfere with microtubule formation, but evades the resistance mechanisms of P-glycoprotein. Strong activation of caspases-3 and -9 indicates that DHR is able to induce apoptosis by triggering the intrinsic cell death pathway. Moreover, the assembly of DHR with hybrid nanoparticles was able to potentiate the effect of DHR in cancer cells. CONCLUSION: DHR seems to be a promising starting material with anticancer properties to further be explored.

Anticancer Hybrid Combinations: Mechanisms of Action, Implications and Future Perspectives.

The exponential growth of cancer cases worldwide together with recent advances concerning the pathophysiological mechanisms of the disease at the molecular level led to a paradigm shift in chemotherapy, from monotherapy to targeted drug combination regimens. However, adverse effects and the emergence of multidrug resistance (MDR) limit the effectiveness of these therapies. In this context, hybrid combinations mixing anticancer drugs and bioactive phytochemical components from medicinal plants, or even plant extracts, that can act synergistically on multiple targets and signaling pathways represent a promising approach with the potential to expand the current therapeutic arsenal. This review aims to provide a synopsis on anticancer hybrid combinations based on their multi-target mechanisms and synergistic effects from an extensive literature search focusing mainly on publications from the last ten years. In most of these combinations, the phytochemical component was shown to enhance the anticancer activity of the chemotherapeutic agent and to sensitize chemoresistant tumors in several types of cancer. Hybrid combinations, due to synergistic interactions, are also associated with less severe adverse events since lower doses can be used to achieve the same therapeutic effect. Further preclinical and clinical studies are needed, as well as the development of an adequate regulatory framework, before hybrid combination therapy can be translated into clinical practice.

Naturally Occurring Plectranthus-derived Diterpenes with Antitumoral Activities.

The study of natural sources such as plants, microorganisms and marine organisms has developed interest among the scientific community in recent years for their extensive and diverse chemical composition and consequent biological potential. The search for antitumor compounds is among the lead causes that justify phytochemical studies. Although some natural products have served as FDA approved chemotherapeutic agents, there is still a demand for the search of compounds with those characteristics. The Plectranthus genus has long been used in traditional medicine, and scientific studies have already proven its undeniable value as a source of bioactive compounds. Diterpenes are the most prominent biologically active group of secondary metabolites present in this genus. In particular, abietane diterpenes have long been studied for their biological activities, namely their anti-tumoral potential. In this review, abietane diterpenes isolated from Plectranthus genus with antiproliferative, antitumoral or cytotoxic potential are reported. In addition, a correlation between this subclass of diterpenes with their mechanisms of cell death has been discussed.