Novel benzopyran derivatives and their therapeutic applications: a patent review (2009–2016)

Introduction: The benzopyran derivatives present a wide variety of biological activity and behaviour. At the same time the benzopyran derivatives support their use as therapeutic agents for multiple diseases. Their structural characteristics correlated to physicochemical properties seem to define the extent of the biological activity.

Areas covered: This review summarizes new patents published on new benzopyran derivatives from 2009 to 2016.

Expert opinion: Many benzopyran derivatives have vivo/vitro biological responses. Their clinical evaluation will be critical to assess therapeutic utility. The compounds containing benzopyran moiety is well defined as lead compounds for design of new more promising molecules.     

Taurine reduces blue light-induced retinal neuronal cell apoptosis in vitro

Background: The massive uptake of organic compatible osmolytes is a self-protective response to multiple stressors.

Objective: This study aimed to determine the protective effects of the osmolyte taurine against blue light-induced apoptosis in retinal neuronal cells in vitro.

Methods: Real-time PCR was used to measure osmolyte transport. Radioimmunoassays were performed to measure osmolyte uptake. Cell Counting Kit-8 assays were conducted to measure cellular viability. Flow cytometry analysis was used to measure apoptosis.

Results: Compared with normotonic stress, hypertonic stress-induced uptake of osmolytes, including betaine, myoinositol, and taurine, into the retinal neuronal cells. Blue light increased osmolyte transporter mRNA expression together with osmolyte uptake. Furthermore, taurine significantly suppressed blue light-induced retinal neuronal cell apoptosis.

Conclusion: The compatible osmolyte taurine may have an important role in cell resistance to blue light and cell survival.     

Taurine prevents ultraviolet B induced apoptosis in retinal ganglion cells

Background: Compatible osmolytes accumulation is an active resistance response in retina under ultraviolet (UV) radiation and hypertonicity conditions.

Objective: The purpose of this research is to investigate the protective role of taurine on retina under UVB radiation.

Methods: Osmolytes transporters were measured by quantitative realtime PCR. Osmolytes uptake was estimated by radioimmunoassay. Cell viability was calculated by MTT assay. Cell apoptosis was measured by flow cytometry analysis.

Results: Hypertonicity accelerated osmolytes uptake into retinal ganglion cells (RGCs) including taurine, betadine, and myoinositol. UVB radiation increased osmolytes transporter expression and osmolytes uptake. In addition, osmolyte taurine remarkably prevented UVB radiation induced cell apoptosis in RGCs.

Conclusions: The effect of compatible osmolyte taurine on cell survival rate may play an important role in cell resistance and adaption to UVB exposure.     

Saffron and its derivatives,crocin, crocetin and safranal: a patent review

Introduction: Saffron and its main components have traditionally been used as pharmaceutical agents. Current experimental research projects have also exhibited their applications in a wide spectrum of disorder treatments.

Area covered: This review covers the demonstrated findings and patents on therapeutic/pharmaceutical properties of saffron and related derivatives, since 2000 to bold their outstanding merit on human health. An extensive literature review was performed in USP Patent, Patentscope, Espacenet and Google Patent in the field of CNS, cardiovascular, urogenital, dermatological and inflammatory disorders.

Expert opinion: The growing body of patents showed the value of saffron and the respective crucial components alone or in combination with the other raw materials, herbal extracts, to apply in various therapeutic/pharmaceutical areas. They could be engaged as an adjuvant treatment in phototherapy, cancer, cardiovascular and neurodegenerative diseases and hypoxia-induced dangerous conditions. However, the application of these components in the clinic has been limited to very few drugs yet. This might be due poor clinical trials data. According the human trend toward the use of plant-derived compounds instead of medicines derived from chemical substances, special attention must be focused to link the worth of saffron, herbal medicine of third millennium, from basic sciences to patients’ bed.     

Can apps and calendar methods predict ovulation with accuracy?

Objective: The accuracy of prediction of ovulation by cycle apps and published calendar methods was determined by comparing to true probability of ovulation.

Methods: A total of 949 volunteers collected urine samples for one entire menstrual cycle. Luteinizing hormone was measured to assign surge day, enabling probability of ovulation to be determined across different cycle lengths. Cycle-tracking apps were downloaded. As none provided their methodology, four published calendar-based methods were also examined: standard days, rhythm, alternative rhythm and simple calendar method. The volunteer ovulation data was applied to the app/calendar methods to determine their accuracy.

Results: Mean cycle length was 28 days (range: 23–35); 34% of women believed they had a 28-day cycle, but only 15% did. No LH surge was seen for 99 women. Most likely day of ovulation for a 28-day cycle was day 16 (21%). Accuracy of ovulation prediction was no better than 21% by the apps. The standard days and rhythm methods were most likely to predict ovulation (70% and 89%, respectively) but had very low accuracy.

Conclusions: Ovulation day varies considerably for any given menstrual cycle length, thus it is not possible for calendar/app methods that use cycle-length information alone to accurately predict the day of ovulation.

National Clinical Trial Code: NCT01577147. Registry website: www.clinicaltrials.gov.     

Lapachol and lapachone analogs: a journey of two decades of patent research(1997-2016)

Introduction: Lapachol (1), β-lapachone (2) and α-lapachone (3) are three well-studied natural products isolated from Tabebuia impetiginosa having most interesting chemodiversity and demonstrating diverse biological effects.

Areas covered: The current review summarizes the recent and past discovery of chemotherapeutic agents based on the compounds 1–3. This review presents an overview of patents filed over the past two decades (1997 to 2016) mostly relating to the anticancer effects of these lapachol and lapachone analogues.

Expert opinion: The large number of interesting patents published on the therapeutic potential of quinones 1–3 and their synthetic derivatives lends credence to the importance of these molecules. Moreover, these quinones demonstrated potent anticancer effects towards various cancer cell lines and chemical modification of these quinones have led to products displaying enhanced anticancer effects. It is noteworthy that the majority of patents published are on the anticancer effects of quinones 1–3 and their synthetic derivatives along with a limited number of additional biological effects. It is our opinion that in order to get lead compounds, there needs to be a greater focus on the elucidation of the precise mechanism of action of these compounds including SAR and in vivo studies.     

Ursolic acid derivatives for pharmaceutical use: a patent review (2012-2016)

Introduction: Ursolic acid (UA), belongs to a group of pentacyclic triterpenoids and is known to possess some very interesting biological properties. Protocols have been developed in order to synthesize bioactive UA analogs which have resulted in numerous ursolic acid analogs being synthesized during the period 2012–2016. Ursolic acid and its analogues can be employed to treat various cancers, inflammatory diseases, diabetes, Parkinson’s disease, Alzheimer’s disease, hepatitis B, hepatitis C and AIDS to mention but a few.

Areas covered: This review covers patents on therapeutic activities of ursolic acid (UA) and its synthetic derivatives published during the four year period 2012–2016. A discussion about structure-activity relationships (SAR) of these analogs is also included.

Expert opinion: Ursolic acid and its synthetic derivatives demonstrated excellent anticancer, antidiabetic, antiarrhythmic, anti-hyperlipidemic, antimicrobial, anti-hypercholesterolemic, and anti-cardiovascular properties. Additionally, various ursolic acid analogues have been synthesized through modification at positions C₂-OH, C₃-OH and C_17-CO₂H. It is noteworthy that the C-17 amide and amino analogs of UA possessed better anticancer activity compared to the parent compound (UA). Most importantly, UA has the potential to conjugate with other anticancer drugs or be transformed into its halo derivatives since this will greatly facilitate scientists to get lead compounds in cancer drug discovery.     

New insights in the metabolism of oxybutynin: evidence of N-oxidation of propargylamine moiety and rearrangement to enaminoketone

1. Oxybutynin hydrochloride is an antimuscarinic agent prescribed to patients with an overactive bladder (OAB) and symptoms of urinary urge incontinence. Oxybutynin undergoes pre-systemic metabolism, and the N-desethyloxybutynin (Oxy-DE), is reported to have similar anticholinergic effects.

2. We revisited the oxidative metabolic fate of oxybutynin by liquid chromatography–tandem mass spectrometry analysis of incubations with rat and human liver fractions, and by measuring plasma and urine samples collected after oral administration of oxybutynin in rats. This investigation highlighted that not only N-deethylation but also N-oxidation participates in the clearance of oxybutynin after oral administration.

3. A new metabolic scheme for oxybutynin was delineated, identifying three distinct oxidative metabolic pathways: N-deethylation (Oxy-DE) followed by the oxidation of the secondary amine function to form the hydroxylamine (Oxy-HA), N-oxidation (Oxy-NO) followed by rearrangement of the tertiary propargylamine N-oxide moiety (Oxy-EK), and hydroxylation on the cyclohexyl ring.

4. The functional activity of Oxy-EK was investigated on the muscarinic receptors (M_1-3) demonstrating its lack of antimuscarinic activity.

5. Despite the presence of the α,β-unsaturated function, Oxy-EK does not react with glutathione indicating that in the clearance of oxybutynin no reactive and potentially toxic metabolites were formed.     

Cyclodextrins improving the physicochemical and pharmacological properties of antidepressant drugs: a patent review

Introduction: Depression is a serious mood disorder and is one of the most common mental illnesses. Despite the availability of several classes of antidepressants, a substantial percentage of patients are unresponsive to these drugs, which have a slow onset of action in addition to producing undesirable side effects. Some scientific evidence suggests that cyclodextrins (CDs) can improve the physicochemical and pharmacological profile of antidepressant drugs (ADDs). The purpose of this paper is to disclose current data technology prospects involving antidepressant drugs and cyclodextrins.

Areas covered: We conducted a patent review to evaluate the antidepressive activity of the compounds complexed in CDs, and we analyzed whether these complexes improved their physicochemical properties and pharmacological action. The present review used 8 specialized patent databases for patent research, using the term ‘cyclodextrin’ combined with ‘antidepressive agents’ and its related terms. We found 608 patents. In the end, considering the inclusion criteria, 27 patents reporting the benefits of complexation of ADDs with CDs were included.

Expert opinion: The use of CDs can be considered an important tool for the optimization of physicochemical and pharmacological properties of ADDs, such as stability, solubility and bioavailability.     

A review on phytochemical and pharmacological properties of Litsea coreana

Context: Litsea coreana H. Lév. (Lauraceae) is used as an ethnic herb or beverage in China. Substantial studies indicate that it contains a variety of compounds and shows diverse bioactivities with no toxicity.

Objective: This review analyzes and summarizes the ethnopharmacological applications, phytochemistry, and pharmacological activities and molecular mechanisms of L. coreana.

Methods: Related literature (from 1998 to 2016) was obtained and compiled via searching databases including Scopus, Web of Science, Google Scholar, CNKI and PubMed. Keywords (Litsea coreana, hawk tea, eagle tea and laoying cha) were used to select the articles.

Results: Studies indicate that L. coreana contains characteristic polysaccharides, polyphenols, essential oils, and numerious flavonoids, which exhibit remarkable bioactivities, such as hepatoprotection, hyperglycaemia, anti-inflammation, antioxidation and antibacterial, through multiple molecular mechanisms.

Conclusion: This paper provides a systematic review on the phytochemicals and pharmacological activities of L. coreana which should be useful for further study and application of this medicinal herb.     

Inhibitors of α-glucosidase and α-amylase from Cyperus rotundus

Context: A methanol extract of Cyperus rotundus L. (Cyperaceae) rhizomes showed inhibitory activity against α-glucosidase and α-amylase, two enzymes involve in carbohydrate digestion.

Objective: Identification of compounds from C. rotundus rhizomes responsible for the inhibition of α-glucosidase and α-amylase.

Materials and methods: Compounds were identified by a phytochemical investigation using combined chromatographic and spectroscopic methods. α-glucosidase and α-amylase inhibitory activities were evaluated by in vitro enzyme inhibition assays.

Results: A new (2RS,3SR)-3,4′,5,6,7,8-hexahydroxyflavane (1), together with three known stilbene dimers cassigarol E (2), scirpusin A (3) and B (4) were isolated. Compound 2 inhibited both α-glucosidase and α-amylase activities while the flavane 1 only showed effect on α-amylase, and compounds 3 and 4 were active on α-glucosidase. All four compounds showed significant 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity.

Discussion: The inhibitory activities against α-amylase and α-glucosidase of the C. rotundus rhizomes were reported for the first time. Stilbene dimers are considered as potent inhibitors of α-glucosidase and promising antihyperglycemic agents.

Conclusion: The isolated compounds may contribute to the antidiabetic property of C. rotundus.     

Influence of route of administration/drug formulation and other factors on adherence to treatment in rheumatoid arthritis (pain related) and dyslipidemia (non-pain related)

Objectives: A comprehensive review was performed to investigate the effect of route of administration on medication adherence and persistence in rheumatoid arthritis (RA) and to compare adherence/persistence with oral medications between RA and a non-painful disease (dyslipidemia).

Research design and methods: Comprehensive database searches were performed to identify studies investigating medication adherence and/or persistence in adults with RA receiving conventional synthetic or biologic agents. Similar searches were performed for studies of patients with dyslipidemia receiving statins. Studies had to be published after 1998 in English and involve ≥6 months’ follow up.

Main outcome measures: Adherence and persistence were compared between the different routes of drug administration in RA, and between the two diseases for oral medications.

Results: A total of 35 and 28 papers underwent data extraction for RA and dyslipidemia, respectively. Within the constraints of the analysis, adherence and persistence rates appeared broadly similar for the different routes of drug administration in RA. Adherence to oral medications was also broadly similar across the two diseases, but persistence was lower in dyslipidemia. Poor adherence has clinical consequences in both diseases: greater disease activity and risk of flare in RA, and increased serum cholesterol levels and risk of heart and cerebrovascular disease in dyslipidemia. Over 1–3 years, poor adherence to biologic RA medications led to increased resource use and medical costs but lower total direct costs due to reduced biologic drug costs. Conversely, poor adherence to dyslipidemia medications resulted in increased total direct costs. In both diseases, adherence improved with patient education/support.

Conclusions: The route of drug administration and the symptomatic (pain) nature of the disease do not appear to be dominant factors for drug adherence or persistence in RA.

Limitation: The wide range of adherence and persistence values and definitions across studies made comparisons between drug formulations and diseases difficult.     

Linezolid-induced lactic acidosis: the thin line between bacterial and mitochondrial ribosomes

Introduction: Linezolid inhibits bacterial growth by targeting bacterial ribosomes and by interfering with bacterial protein synthesis. Lactic acidosis is a rare, but potentially lethal, side effect of linezolid.

Areas covered: The pathogenesis of linezolid-induced lactic acidosis is reviewed with special emphasis on aspects relevant to the recognition, prevention and treatment of the syndrome.

Expert opinion: Linezolid-induced lactic acidosis reflects the untoward interaction between the drug and mitochondrial ribosomes. The inhibition of mitochondrial protein synthesis diminishes the respiratory chain enzyme content and thus limits aerobic energy production. As a result, anaerobic glycolysis and lactate generation accelerate independently from tissue hypoxia.

In the absence of any confirmatory test, linezolid-induced lactic acidosis should be suspected only after exclusion of other, more common, causes of lactic acidosis such as hypoxemia, anemia or low cardiac output. Normal-to-high whole-body oxygen delivery, high venous oxygen saturation and lack of response to interventions that effectively increase tissue oxygen provision all suggest a primary defect in oxygen use at the mitochondrial level.

During prolonged therapy with linezolid, blood drug and lactate levels should be regularly monitored. The current standard-of-care treatment of linezolid-induced lactic acidosis consists of drug withdrawal to reverse mitochondrial intoxication and intercurrent life support.     

Treatment options and considerations for hypertensive patients to prevent dementia

Introduction: Dementia is a worldwide health concern, which leads to loss of autonomy. To date no curative treatment is available so focus on modifiable risk factors is of particular interest. Hypertension, particularly midlife high blood pressure, has been associated with an increased risk for cognitive decline and dementia including vascular dementia (VAD) and Alzheimer disease (AD). In this context, antihypertensive treatments might have a preventive effect.

The objective of this review was to examine the relationship between antihypertensive therapy and cognitive decline or dementia.

Areas covered: A literature search was conducted using PUBMED and the COCHRANE LIBRARY for publications from 1990 onwards mentioning cognitive decline, AD, Vad, mixed dementia, vascular cognitive impairment, hypertension and antihypertensive therapy. Thirty-nine relevant publications including 20 longitudinal studies, 10 randomized-controlled trials and 9 meta-analyses were taken into account.

Expert opinion: Most observational studies have suggested a potential preventive effect of antihypertensive therapies on cognitive decline and dementia, particularly calcium channel blockers and renin-angiotensin system blockers. Randomized clinical trials and meta-analyses provided more conflicting results potentially due to methodological issues.

In conclusion, antihypertensive therapies may reduce cognitive decline and incidence of dementia. Further randomized clinical trials conducted in populations at higher risk of cognitive decline, with longer periods of follow-up and cognition as the primary outcome are still needed.     

Decreased viability and proliferation of CHANG conjunctival epithelial cells after contact with ultraviolet light-irradiated pollen

Context: Contact with pollen is the major reason for the development of allergic symptoms on the ocular surface leading to a significant increase of allergic diseases worldwide. Environmental changes such as increased ultraviolet (UV) radiation and air pollution are discussed as contributory causes for this increase.

Objective: We investigated the effect of UV light on the histamine content of pollen and examined if an irradiation of pollen affects the viability and proliferation of conjunctival cells.

Materials and methods: Alder (Alnus glutinosa) and hazel (Corylus avellana) pollen were irradiated for different time periods with sunlight, UV-A or UV-B light and the histamine content was analysed and compared with non-irradiated pollen. Conjunctival epithelial cells (CHANG cells) were exposed to irradiated and non-irradiated pollen followed by an assessment of cell viability with the colorimetric MTS test and the impedance-based measurement of cell proliferation using the xCELLigence real-time analysis system.

Results: UV light irradiation increased the histamine level of alder and hazel pollen in a dose-dependent manner. CHANG cells treated with irradiated pollen induced a statistically significant higher decrease of cell viability than treatment with non-irradiated pollen.

Discussion and conclusions: Our results indicate that UV light is able to alter pollen thus making them more harmful for conjunctival cells.     

Frequency and costs of pulmonary exacerbations in patients with cystic fibrosis in the United States

Background: Information is limited regarding the cost of pulmonary exacerbations (PEx) among patients with cystic fibrosis in the United States.

Methods: To examine PEx costs, medical chart data were linked to insurance claims for patients aged ≥6 years who had commercial coverage from a large US health insurer affiliated with Optum during 2008–2013. A PEx was categorized as an episode requiring newly started (1) oral antibiotics (PEx-O) or (2) intravenous (IV) antibiotics and/or inpatient stay (PEx-IV).

Results: Among 241 patients, 88.0% had ≥1 PEx (2.9/year) of any type, and 48.1% had ≥1 PEx-IV. Prior PEx-IV was the strongest risk factor for subsequent PEx-IV. The mean cost per episode was $12,784 for PEx of any type and $36,319 for PEx-IV. Patients with worse lung function were more likely to experience a PEx and incurred higher annual PEx-related costs.

Limitations: This was an observational study using a convenience sample of patients with commercial coverage from a large US health insurer whose medical charts were available for abstraction. Results of the study may not be generalizable to individuals with Medicaid coverage and other types of insurance, or to the uninsured.

Conclusions: Most patients experience ≥1 PEx annually, and nearly half require IV antibiotics and/or inpatient stay at considerable cost.     

Optimization of the extraction conditions and quantification by RP-LC analysis of three alkaloids in Zanthoxylum nitidum roots

Context: A classic traditional Chinese medicine, Zanthoxylum nitidum (Roxb.) DC. widely used in China, exhibits anticancer, anti-inflammatory and antianalgesic activities. Alkaloids are one of the main bioactive components. It is urgent to develop a simple and reliable method to determine the main alkaloids in Z. nitidum roots.

Objective: To determine the three alkaloids in Z. nitidum roots, a reversed-phase liquid chromatographic (RP-LC) method combined with an optimum extraction condition was established.

Materials and methods: A method involving four-factor-three-level orthogonal array design including the extracting solvent and the RP-LC condition was assayed. Twenty batches were collected from different areas of the Guangxi Province at different harvesting times. The determined alkaloids were nitidine chloride (NC, 1), ethoxychelerythrine (2) and liriodenine (3). The stable mobile phase was a C₁₈ packing, and the mobile phase was acetonitril-aqueous phosphoric acid-triethylamine-buffer solution.

Results: The optimum extraction and detection conditions have been determined in the process of quantification of Z. nitidum root alkaloids. The three alkaloids were detected simultaneously in the 20 batches of samples. The results clearly showed that alkaloid concentrations differed significantly among Z. nitidum collected from various collection areas.

Discussion and conclusion: We have established an optimum extraction and detection conditions in the process of quantification the three alkaloids in Z. nitidum roots. From this research, the most influenced factor on Z. nitidum roots was the collecting location, and the next factor was the harvesting time. The collecting location and the harvesting time should be considered as the high-quality medicinal herbs factors.     

Melphalan hydrochloride for the treatment of multiple myeloma

Introduction: Multiple myeloma (MM) is an incurable disease characterized by clonal plasma cell proliferation and overproduction of monoclonal paraprotein, hypercalcemia, renal failure, anemia, osteolytic bone lesions, and infections.

Melphalan, a nitrogen mustard, is an alkylating agent synthesized in 1953, and it has been used in multiple myeloma therapy for fifty years. Although novel agents have been introduced in the past few decades improving prognosis of the disease, melphalan still maintains a crucial role in the treatment of MM acting both as cytotoxic agent through damage to DNA, and as immunostimulatory drug by inhibiting Interleukin-6, as well as interaction with dendritic cells, and immunogenic effects in tumor microenvironment.

Areas covered: This review focuses on available data about melphalan pharmacology and its role in clinical practice.

Expert opinion: Melphalan remains crucial in therapy of multiple myeloma because of its good manageability, safety profile, efficacy, and economic sustainability. These characteristics make it pivotal also for new regimens in combination with novel agents.     

A patent review of two fruitful decades (1997-2016) of Isocoumarin research

Introduction: Isocoumarins comprise a six-membered oxygen heterocycle (α-pyranone) along with one aromatic ring and are known to possess interesting biological properties. During the last two decade (1997–2016), isocoumarin chemistry has attracted attention due to its biological and pharmaceutical effects viz., anticancer, anti-diabetic, antibacterial, antimalarial, and fungicidal effects.

Areas covered: This review covers the patents on the therapeutic activities of natural and synthetic isocoumarins over the last two decades (1997–2016). Moreover a number of international patents related to natural and synthetic isocoumarins along with their biological effects will be presented and discussed. Although a large number of patents have been published during the period of the review, the aim of this review is to focus on those important patents specifically related to microbial diseases, cancer, malaria, and diabetes.

Expert opinion: Isocoumarin and its synthetic analogs display a wide range of important pharmaceutical properties. Furthermore, isocoumarins have the potential to conjugate with other anticancer drugs which will synergistically increase the delivery and thus anticancer effects. Moreover, in order to get lead compounds, scientists should focus on the synthesis of halo and functionalized heterocyclic ring containing derivatives of isocoumarins as more potent drugs.