Adipose-derived stem cell exosomes loaded with icariin alleviates rheumatoid arthritis by modulating macrophage polarization in rats

Rheumatoid arthritis (RA) is a chronic autoimmune disease marked by synovitis and cartilage destruction. The active compound, icariin (ICA), derived from the herb Epimedium, exhibits potent anti-inflammatory properties. However, its clinical utility is limited by its water insolubility, poor permeability, and low bioavailability. To address these challenges, we developed a multifunctional drug delivery system-adipose-derived stem cells-exosomes (ADSCs-EXO)-ICA to target active macrophages in synovial tissue and modulate macrophage polarization from M1 to M2. High-performance liquid chromatography analysis confirmed a 92.4 ± 0.008% loading efficiency for ADSCs-EXO-ICA. In vitro studies utilizing cellular immunofluorescence (IF) and flow cytometry demonstrated significant inhibition of M1 macrophage proliferation by ADSCs-EXO-ICA. Enzyme-linked immunosorbent assay, cellular transcriptomics, and real-time quantitative PCR indicated that ADSCs-EXO-ICA promotes an M1-to-M2 phenotypic transition by reducing glycolysis through the inhibition of the ERK/HIF-1α/GLUT1 pathway. In vivo, ADSCs-EXO-ICA effectively accumulated in the joints. Pharmacodynamic assessments revealed that ADSCs-EXO-ICA decreased cytokine levels and mitigated arthritis symptoms in collagen-induced arthritis (CIA) rats. Histological analysis and micro computed tomography confirmed that ADSCs-EXO-ICA markedly ameliorated synovitis and preserved cartilage. Further in vivo studies indicated that ADSCs-EXO-ICA suppresses arthritis by promoting an M1-to-M2 switch and suppressing glycolysis. Western blotting supported the therapeutic efficacy of ADSCs-EXO-ICA in RA, confirming its role in modulating macrophage function through energy metabolism regulation. Thus, this study not only introduces a drug delivery system that significantly enhances the anti-RA efficacy of ADSCs-EXO-ICA but also elucidates its mechanism of action in macrophage function inhibition.

Anti-inflammatory effects of icariin in the acute and chronic phases of the mouse pilocarpine model of epilepsy

Neuroinflammation mediated by microglia made a significant contribution in the pathophysiology of epilepsy. Icariin (ICA), a bioactive ingredient isolated from Epimedium, has been shown to present both antioxidant and anti-inflammatory properties. This study was to explore the potential therapeutic effects of icariin on mouse pilocarpine model of epilepsy and its underlying mechanisms in vivo and in vitro. To this end, we firstly measured the serum concentrations of the proinflammatory cytokines IL-1β and IL-6 from patients with temporal lobe epilepsy and found that patients with a higher seizure frequency showed correspondingly higher inflammatory reaction. Mouse pharmacokinetic study, transmembrane transportation assay, and cell viability assay collectively demonstrated that ICA was able to cross the blood-brain barrier and has good biocompatibility. The acute and chronic epilepsy models were next established in a pilocarpine mouse model of acquired epilepsy. Icariin has been identified that it could cross the blood-brain barrier and enter the hippocampus to exhibit therapeutic effects. ICA treatment dramatically promoted microglial polarization to the M2 phenotype in epilepsy mice both in the acute and chronic phases. Reduced release of M1-associated proinflammatory factors, such as IL-1β and IL-6, corroborates the altered glial cell polarization. Furthermore, ICA alleviated seizure intensity and mortality in acute phase epileptic mice. Models in the chronic group also showed improved general condition, cognition ability, and memory function after ICA treatment. Taken together, our research strongly suggested that icariin has the potential to treat epilepsy via inhibiting neuroinflammation by promoting microglial polarization to the M2 phenotype.

Liver protecting effects and molecular mechanisms of icariin and its metabolites

As a detoxification and metabolism organ, the liver plays a vital role in human health. However, an excessive consumption of drugs and toxins, exposure to pathogenic viruses, and unhealthy living habits can lead to liver damage, which may even develop into liver cirrhosis and liver cancer. Epimedium brevicornum Maxim. is a traditional Chinese medicine and dietary supplement in which the flavonoid icariin is a main functional component. Although the protective mechanisms of icariin and its metabolites against liver injury are not yet comprehensively understood, an increasing number of studies have confirmed their liver-protective and anticancer effects. Indeed, icaritin, one of the metabolites of icariin, is currently utilized as an active component of an anti-cancer drug. This paper presents a review of the molecular mechanisms through which icariin and its metabolites actively protect against the occurrence and development of liver injury, and, thus, provides a comprehensive reference for further research and their application in liver protection.

Beneficial role of kaempferol and its derivatives from different plant sources on respiratory diseases in experimental models

Respiratory illnesses impose a significant health burden and cause deaths worldwide. Despite many advanced strategies to improve patient outcomes, they are often less effective. There is still considerable room for improvement in the treatment of various respiratory diseases. In recent years, alternative medicinal agents derived from food plants have shown better beneficial effects against a wide variety of disease models, including cancer. In this regard, kaempferol (KMF) and its derivatives are the most commonly found dietary flavonols. They have been found to exhibit protective effects on multiple chronic diseases like diabetes, fibrosis, and so on. A few recent articles have reviewed the pharmacological actions of KMF in cancer, central nervous system diseases, and chronic inflammatory diseases. However, there is no comprehensive review that exists regarding the beneficial effects of KMF and its derivatives on both malignant- and non-malignant respiratory diseases. Many experimental studies reveal that KMF and its derivatives are helpful in managing a wide range of respiratory diseases, including acute lung injury, fibrosis, asthma, cancer, and chronic obstructive pulmonary disease, and their underlying molecular mechanisms. In addition, we also discussed the chemistry and sources, the absorption, distribution, metabolism, excretion, and toxicity (ADMET) properties, methods to enhance bioavailability, as well as our perspective on future research with KMF and its derivatives.

Regulatory mechanism of icariin in cardiovascular and neurological diseases

Cardiovascular diseases (CVDs) and neurological diseases are widespread diseases with substantial rates of morbidity and mortality around the world. For the past few years, the preventive effects of Chinese herbal medicine on CVDs and neurological diseases have attracted a great deal of attention. Icariin (ICA), the main constituent of Epimedii Herba, is a flavonoid. It has been shown to provide neuroprotection, anti-tumor, anti-osteoporosis, and cardiovascular protection. The endothelial protection, anti-inflammatory, hypolipidemic, antioxidative stress, and anti-apoptosis properties of ICA can help stop the progression of CVDs and neurological diseases. Therefore, our review summarized the known mechanisms and related studies of ICA in the prevention and treatment of cardio-cerebrovascular diseases (CCVDs), to better understand its therapeutic potential.

Controlled released naringin-loaded liposome/sucrose acetate isobutyrate hybrid depot for osteogenesis in vitro and in vivo

Introduction: A common problem in bone tissue engineering is that the burst release of active osteogenic factors is not beneficial for osteogenesis. This study aimed to prepare naringin (Ng) liposomes to reduce the burst release of Ng and improve new bone formation. Methods: We synthesized Ng liposomes using the thin-film hydration method. Drug-encapsulation efficacy experiments were conducted using the ultracentrifugation technique. The morphology and size distributions of freezedried liposomes were determined by transmission electron microscopy and dynamic light scattering. The Ng liposomes and Ng-lipo/sucrose acetate isobutyrate (SAIB) depots were characterized using Fourier transform infrared spectroscopy and in vitro release studies. After implantation of the Ng-lipo/SAIB depots, in vitro osteoblast-liposome interactions and in vivo osteogenesis were tested. Results: The formulation of freeze-dried Ng liposomes via an optimized recipe yielded nanosized (136.9 nm) negatively charged particles with a high encapsulation efficiency (~76.3%). Their chemical structure did not change after adding SAIB to the Ng liposomes. The burst release was reduced dramatically from 74.4% to 23.7%. In vivo, after 8 weeks, the new bone formation rate in the calvarial defects of Sprague-Dawley rats receiving Ng-lipo/SAIB was 57% compared with 25.18% in the control group (p = .0003). Discussion: Our results suggested that Ng-lipo/SAIB hybrid depots could serve as candidate materials for drug delivery in bone regeneration applications.

Icariin: A Potential Alternative Against Osteoporosis

Osteoporosis is a metabolic skeletal disorder characterized by increased fragility and fracture risk as s result of reduced bone mineral density and microstructural destruction and caused a heavy burden on families and society. Current medicines, on the other hand, have some limitations, with side effects and doubts regarding long-term efficacy being highlighted. Studies seeking for natural constituents as potential treatment options therefore come into focus. Icariin is a phytochemical derived from a traditional Chinese medicine, Herba epimedium, that has been used to treat orthopedic disorders in ancient China for thousands of years, including osteoporosis, osteoarthritis, and fracture. Icariin belongs to a category of prenylated flavonoids and has been shown to help reduce osteoporosis bone loss while having relatively low side effects. Icariin's anti-osteoporosis properties manifest in a variety of ways, like promoting osteogenesis, suppressing osteoclastogenesis and bone resorption, regulating migration, proliferation, and differentiation of mesenchymal stem cells, enhancing angiogenesis, anti-inflammation, and antioxidation. These procedures entail a slew of critical signaling pathways, such as PPARγ, ERα/AKT/β-catenin, and MAPK. Therefore, icariin can be an applicable alternative to improve osteoporosis although the underlying mechanisms have yet to be fully understood. In this study, we searched using the terms “icariin” and “osteoporosis,” and included 64 articles meeting the inclusion criteria and reviewed the research of icariin in anti-osteoporosis over the last 10 years, and discussed new prospects for future study. Therefore, this review may provide some references for further studies.

Icariin: A Potential Neuroprotective Agent in Alzheimer's Disease and Parkinson's Disease

Alzheimer's disease (AD) and Parkinson's disease (PD) are the most common neurodegenerative diseases worldwide. They are characterized by the loss of neurons and synapses in special parts of the central nervous system (CNS). There is no definitive treatment for AD and PD, but extensive studies are underway to identify the effective drugs which can slow the progression of these diseases by affecting the factors involved in their pathophysiology (i.e., aggregated proteins, neuroinflammation, and oxidative stress). Icariin, a natural compound isolated from Epimedii herba, is known because of its anti-inflammatory and anti-oxidant properties. In this regard, there are numerous studies indicating its potential as a natural compound against the progression of CNS disorders, such as neurodegenerative diseases. Therefore, this review aims to re-examine findings on the pharmacologic effects of icariin on factors involved in the pathophysiology of AD and PD.

Anti-inflammatory and immunoregulatory effects of icariin and icaritin

Inflammation and immunity dysregulation have received widespread attention in recent years due to their occurrence in the pathophysiology of many conditions. In this regard, several pharmacological studies have been conducted aiming to evaluate the potential anti-inflammatory and immunomodulatory effects of phytochemicals. Epimedium, a traditional Chinese medicine, is often used as a tonic, aphrodisiac, and anti-rheumatic agent. Icariin (ICA) is the main active ingredient of Epimedium and is, once ingested, mainly metabolized into Icaritin (ICT). Data from in vitro and in vivo studies suggested that ICA and its metabolite (ICT) regulated the functions and activation of immune cells, modulated the release of inflammatory factors, and restored aberrant signaling pathways. ICA and ICT were also involved in anti-inflammatory and immune responses in several diseases, including multiple sclerosis, asthma, atherosclerosis, lupus nephritis, inflammatory bowel diseases, rheumatoid arthritis, and cancer. Yet, data showed that ICA and ICT exhibited similar but not identical pharmacokinetic properties. Therefore, based on their higher solubility and bioavailability, as well as trends indicating that single-ingredient compounds offer broader and safer therapeutic capabilities, ICA and ICT delivery systems and treatment represent interesting avenues with promising clinical applications. In this study, we reviewed the anti-inflammatory and immunomodulatory mechanisms, as well as the pharmacokinetic properties of ICA and its metabolite ICT.

8-Prenylnaringenin tissue distribution and pharmacokinetics in mice and its binding to human serum albumin and cellular uptake in human embryonic kidney cells

8-Prenylnaringenin (8-PN), a hop flavonoid, is a promising food substance with health benefits. Compared with nonprenylated naringenin, 8-PN exhibits stronger estrogenic activity and prevents muscle atrophy. Moreover, 8-PN prevents hot flushes and bone loss. Considering that prenylation reportedly improves the bioavailability of flavonoids, we compared the parameters related to the bioavailability [pharmacokinetics and tissue distribution in C57/BL6 mice, binding affinity to human serum albumin (HSA), and cellular uptake in HEK293 cells] of 8-PN and its mother (non-prenylated) compound naringenin. C57/BL6 mice were fed an 8-PN or naringenin mixed diet for 22 days. The amount of 8-PN (nmol/g tissue) in the kidneys (16.8 ± 9.20), liver (14.8 ± 2.58), muscles (3.33 ± 0.60), lungs (2.07 ± 0.68), pancreas (1.80 ± 0.38), heart (1.71 ± 0.27), spleen (1.36 ± 0.29), and brain (0.31 ± 0.09) was higher than that of naringenin. A pharmacokinetic study in mice demonstrated that the C _max of 8-PN (50 mg/kg body weight) was lower than that of naringenin; however, the plasma concentration of 8-PN 8 h after ingestion was higher than that of naringenin. The binding affinity of 8-PN to HSA and cellular uptake in HEK293 cells were higher than those of naringenin. 8-PN bioavailability features assessed in mouse or human model experiments were obviously different from those of naringenin.

Traditional Chinese Medicine Compound-Loaded Materials in Bone Regeneration

Bone is a dynamic organ that has the ability to repair minor injuries via regeneration. However, large bone defects with limited regeneration are debilitating conditions in patients and cause a substantial clinical burden. Bone tissue engineering (BTE) is an alternative method that mainly involves three factors: scaffolds, biologically active factors, and cells with osteogenic potential. However, active factors such as bone morphogenetic protein-2 (BMP-2) are costly and show an unstable release. Previous studies have shown that compounds of traditional Chinese medicines (TCMs) can effectively promote regeneration of bone defects when administered locally and systemically. However, due to the low bioavailability of these compounds, many recent studies have combined TCM compounds with materials to enhance drug bioavailability and bone regeneration. Hence, the article comprehensively reviewed the local application of TCM compounds to the materials in the bone regeneration in vitro and in vivo. The compounds included icariin, naringin, quercetin, curcumin, berberine, resveratrol, ginsenosides, and salvianolic acids. These findings will contribute to the potential use of TCM compound-loaded materials in BTE.

Intradermal injection of icariin-HP-β-cyclodextrin improved traumatic brain injury via the trigeminal epineurium-brain dura pathway

The lower bioavailability after oral administration limited icariin applications in Central Nervous System. Icariin/HP-β-cyclodextrin (HP-β-CD) inclusion complex was prepared for acute severe opening traumatic brain injury (TBI) via facial intradermal(i.d.) in mystacial pad. After fluid percussion-induced TBI, icariin/HP-β-CD at 0.4 mg/kg i.d. preserved more neurons and oligodendrocytes than intranasal injection (i.n.) or intravenous injection via tail vein (i.v.) and decreased microglia and astrocyte activation. Icariin/HP-β-CD i.d. reduced apoptosis in cortical penumbra while i.n. and i.v. showed weak or no effects. Icariin/HP-β-CD i.d. reduced Evans blue leakage and altered CD34, ZO-1, Claudin-5 and beta-catenin expression after TBI. Moreover, icariin/HP-β-CD promoted human umbilical vein endothelial cells proliferation. Thus, Icariin/HP-β-CD i.d. improved TBI, including blood brain barrier opening. Fluorescein 5-isothiocyanate (FITC) and 3,3'-Dioctadecyloxacarbocyanine perchlorate (DiOC18(3)) mimic HP-β-CD and icariin respectively. FITC and DiOC18(3) were similarly delivered to trigeminal epineurium, perineurium and perivascular spaces or tissues, caudal dura mater and scattered in trigeminal fasciculus, indicating that icariin/HP-β-CD was delivered to brain via trigeminal nerve-dura mater-brain pathways. In sum, intradermal injection in mystacial pad might delivered icariin/HP-β-CD to brain and icariin/HP-β-CD improved acute severe opening TBI.

Natural bioactive molecules: An alternative approach to the treatment and control of glioblastoma multiforme

Glioblastoma multiforme is one of the most deadly malignant tumors, with more than 10,000 cases recorded annually in the United States. Various clinical analyses and studies show that certain chronic diseases, including cancer, interact between cell-reactive radicals rise and pathogenesis. Reactive oxygen and nitrogenous sources include endogenous (physiological processes), and exogenous sources contain reactive oxygen and nitrogen (xenobiotic interaction). The cellular oxidation/reduction shifts to oxidative stress when the regulation mechanisms of antioxidants are surpassed, and this raises the ability to damage cellular lipids, proteins, and nucleic acids. OBJECTIVE: This review is focused on how phytochemicals play crucial role against glioblastoma multiforme and to combat these, bioactive molecules and their derivatives are either used alone, in combination with anticancer drugs or as nanomedicine formulations for better cancer theranostics over the conventional approach. CONCLUSION: Bioactive molecules found in seeds, vegetables, and fruits have antioxidant, anti-inflammatory, and anticancer properties that may help cancer survivors feel better throughout chemotherapy or treatment. However, incorporating them into the nanocarrier-based drug delivery for the treatment of GBMs, which could be a promising therapeutic strategy for this tumor entity, increasing targeting effectiveness, increasing bioavailability, and reducing side effects with this target-specificity, drug internalization into cells is significantly improved, and off-target organ aggregation is reduced.

Nanocarriers in the Enhancement of Therapeutic Efficacy of Natural Drugs

Abstract Since time immemorial, plant derived natural products have been used for the treatment of various human diseases before the intervention of modern medicine. The basis of modern medicine is still being inspired from traditional medicine and therapies. However, despite their tremendous therapeutic potential, these natural drugs often have poor bioavailability, metabolic instability, and aqueous insolubility. These factors greatly impede a natural drug’s commercialization potential as a mainstream medicine. Therefore, the development of nanocarrier drug delivery systems is indispensable in overcoming the various constraints of the bottlenecks which occur with natural drugs. Of particular interest in this review are four plant materials endogenous to China with the common names of barrenwort or horny goat weed (Epimedium), Shu Di Huang (Rehmannia glutinosa, RG), ginseng (Panax ginseng), and Dong Quai or female ginseng (Angelica sinensis, AS), each having been scientifically investigated for a wide range of therapeutic uses as has been originally discovered from the long history of traditional usage and anecdotal information by local population groups in Asia. The integration of natural drugs from the East and nanocarrier drug delivery systems developed from the West is paving the way towards further accurate and efficient medicine therapy. We further discuss the potential benefits of these plants and the enhancement of their therapeutic efficacy by nanotechnology intervention.

Bioactive Icariin/β-CD-IC/Bacterial Cellulose with Enhanced Biomedical Potential

A "super" bioactive antibacterial hydrogel, Icariin-β-CD-inclusion complex/Bacterial cellulose and an equally capable counterpart Icariin-Bacterial cellulose (ICBC) were successfully produced with excellent antioxidant properties. The highly porous hydrogels demonstrated very high fluid/liquid absorption capability and were functionally active as Fourier Transform Infrared Spectrometer (FTIR) test confirmed the existence of abundant hydroxyls (-OH stretching), carboxylic acids (-CH₂/C-O stretching), Alkyne/nitrile (C≡C/C≡N stretching with triple bonds) and phenol (C-H/N-O symmetric stretching) functional groups. Scanning electron microscope (SEM) and X-ray diffraction (XRD) tests confirmed a successful β-CD-inclusion complexation with Icariin with a great potential for sustained and controlled drug release. In vitro drug release test results indicated a systemic and controlled release of the drug (Icariin) from the internal cavities of the β-CD inclusion complex incorporated inside the BC matrix with high Icariin (drug) release rates. Impressive inactivation rates against Gram-negative bacteria Escherichia coli ATCC 8099 and gram-positive bacteria Staphylococcus aureus ATCC 6538; >99.19% and >98.89% respectively were recorded, as the materials proved to be non-toxic on L929 cells in the in vitro cytotoxicity test results. The materials with promising versatile multipurpose administration of Icariin for wound dressing (as wound dressers), can also be executed as implants for tissue regeneration, as well as face-mask for cosmetic purposes.

An injectable liposome for sustained release of icariin to the treatment of acute blunt muscle injury

OBJECTIVES

Icariin, extracted from Epimedium, is a kind of flavonoid and possesses osteogenesis and antioxidant. This study aimed to evaluate the therapeutic effects of icariin liposome on acute blunt skeletal muscle injury in rats.

METHODS

Icariin liposome was prepared by the thin-film dispersion method. After muscle injury, the corresponding treatment measures were given every day for two weeks. Recovery and mechanism of muscle injury were evaluated by QRT-PCR, HE, immunohistochemistry, malondialdehyde, superoxide dismutase and serological tests.

KEY FINDINGS

The particle size, polydispersity index, zeta potential, encapsulation efficiency and drug loading of icariin liposomes were 171.37 ± 38.23 nm, 0.27 ± 0.01, -5.59 ± 1.36 mV, 78.15 ± 2.04% and 15.62%, respectively. The QRT-PCR showed that icariin liposome significantly promoted the expression of MHCIIB and vimentin. Through HE, immunohistochemistry, ELISA and serological tests, we found that icariin liposome effectively promoted desmin expression, reduced collagen I expression and inhibited the production of pro-inflammatory factors, including TNF-α and IL-6. Icariin liposome therapy significantly reduced the level of malondialdehyde and increased the activity of superoxide dismutase.

CONCLUSIONS

Icariin liposome has excellent therapeutic effects on acute blunt muscle injury in rats by improving immunity, repairing cytoskeleton and cellular integrity, anti-inflammation, anti-fibrosis and antioxidant stress.

Pharmacological effects of icariin

Icariin (ICA) is a principal active component from traditional Chinese medicine Epimedium grandiflorum. To explain its traditional medical usages by modern science, a variety of pharmacological effects have been studied for ICA. In this review, we summarized the pharmacokinetics of ICA as well as its pharmacological mechanisms in neurodegenerative disease, cardiovascular disease, anti-osteoporosis, anti-inflammation, anti-oxidative stress, anti-depression and anti-tumors.

Icariin and Its Metabolites as Potential Protective Phytochemicals Against Alzheimer's Disease

Alzheimer’s disease (AD) is a neurodegenerative disorder affecting more than 35 million people worldwide. As the prevalence of AD is dramatically rising, there is an earnest need for the identification of effective therapies. Available drug treatments only target the symptoms and do not halt the progression of this disorder; thus, the use of natural compounds has been proposed as an alternative intervention strategy. Icariin, a prenylated flavonoid, has several therapeutic effects, including osteoporosis prevention, sexual dysfunction amelioration, immune system modulation, and improvement of cardiovascular function. Substantial studies indicate that icariin may be beneficial to AD by reducing the production of extracellular amyloid plaques and intracellular neurofibrillary tangles and inhibiting phosphodiesterase-5 activity. Moreover, increasing evidence has indicated that icariin exerts a protective role in AD also by limiting inflammation, oxidative stress and reducing potential risk factors for AD such as atherosclerosis. This mini-review discusses the multiple potential mechanisms of action of icariin on the pathobiology of AD including explanation regarding its bioavailability, metabolism and pharmacokinetic.

Improved Pharmacokinetics of Icariin (ICA) within Formulation of PEG-PLLA/PDLA-PNIPAM Polymeric Micelles

Icariin (ICA) is a major flavonoid that contains the active compound Epimedii Folium. However, ICA’s pharmacokinetic characteristics remain unsatisfactory due to its low bioavailability, and hence limited drugability. In order to improve its pharmacokinetics and achieve prolonged blood circulation time, a novel polymeric micelle, made of the self-assembled micelle between poly (ethylene glycol)-poly (_L-lactic acid) (PEG-PLLA) and poly (_D-lactic acid)-poly(N-isopropylacrylamide) (PDLA-PNIPAM), was designed to encapsulate ICA. Our experimental results showed that this polymeric micelle formulation of ICA exhibited uniform nano-size distribution and high stability within 48 h. The new formulation also allowed sustained ICA release in an in vitro drug release study. Furthermore, in vivo experiments revealed that ICA bioavailability in the PEG-PLLA/PDLA-PNIPAM polymeric micelle formulation was significantly higher compared to ICA alone, or ICA in the traditional Pluronic F127 micelle formulation. Finally, we show that metabolite analysis confirmed that ICA within the PEG-PLLA/PDLA-PNIPAM polymeric micelle formulation provided better drug protection, reduced drug metabolites production, and decreased undesired first-pass effects. Overall, these data show that ICA within PEG-PLLA/PDLA-PNIPAM polymeric micelle formulation exhibit advantages, in terms of improved physicochemical properties, sustained release of ICA in vitro, and improved bioavailability of ICA in vivo, which represent a feasible approach for improving the drugability of pharmaceutical small molecules with low bioavailability or poor stability.

An outline for the pharmacological effect of icariin in the nervous system

Icariin is a major active component of the traditional herb Epimedium, also known as Horny Goat Weed. It has been extensively studied throughout the past several years and is known to exert anti-oxidative, anti-neuroinflammatory, and anti-apoptotic effects. It is now being considered as a potential therapeutic agent for a wide variety of disorders, ranging from neoplasm to cardiovascular disease. More recent studies have shown that icariin exhibits potential preventive and/or therapeutic effects in the nervous system. For example, icariin can prevent the production of amyloid β (1-42) and inhibit the expression of amyloid precursor protein (APP) and β-site APP cleaving enzyme 1 (BACE-1) in animal models of Alzheimer's disease (AD). Icariin has been shown to mitigate pro-inflammatory responses of microglia in culture and in animal models of cerebral ischemia, depression, Parkinson's disease (PD), and multiple sclerosis (MS). Icariin also prevents the neurotoxicity induced by hydrogen peroxide (H₂O₂), endoplasmic reticulum (ER) stress, ibotenic acid, and homocysteine. In addition, icariin is implicated in facilitating learning and memory in both normal aging animals and disease models. To date, we still have no consolidated source of knowledge about the pharmacological effects of icariin in the nervous system, though its roles in other tissues have been reviewed in recent years. Here, we summarize the pharmacological development of icariin as well as its possible mechanisms in prevention and/or therapy of disorders afflicting the nervous system in hope of expanding the knowledge about the preventive and/or therapeutic effect of icariin in brain disorders.

Prenylation enhances the biological activity of dietary flavonoids by altering their bioavailability

Flavonoids are distributed across the plant kingdom and have attracted substantial attention owing to their potential benefits for human health. Several studies have demonstrated that flavonoids prenylation enhances various biological activities, suggesting an attractive tool for developing functional foods. This review provides an overview of the current knowledge on how prenylation influences the biological activity and bioavailability of flavonoids. The enhancement effect of prenylation on the biological activities of dietary flavonoids in mammals was demonstrated by comparing the effect of 8-prenyl naringenin (8PN) with that of parent naringenin in the prevention of disuse muscle atrophy in mice. This enhancement results from higher muscular accumulation of 8PN than naringenin. As to bioavailability, despite the lower absorption of 8-prenyl quercetin (8PQ) compared with quercetin, higher 8PQ accumulation was found in the liver and kidney. These data imply that prenylation interferes with the elimination of flavonoids from tissues.

Icariin combined with snailase shows improved intestinal hydrolysis and absorption in osteoporosis rats

Icariin has a significant anti-osteoporotic activity, but its clinical application is limited due to a poor oral bioavailability especially under pathological conditions like osteoporosis. Based on the intestinal absorption and metabolism characteristics of icariin in the osteoporosis rats, a kind of simple enteric capsules containing icariin and snailase was designed to overcome this issue in this study. Snailase was secleted as the most efficient exogenous hydrolase of icariin and the related hydrolysis reaction parameters were optimized in the artificial intestinal liquid. Moreover, the hydrolysates of icariin were proved more effective in promoting the rat calvarial osteoblast proliferation than icariin by the MTT assay. Therefore, snailase and icariin were packed into the enteric-coated capsules at an appropriate mass ratio of 1:1 to prepare the icariin loaded enteric-coated capsules (IECs), and then the in vitro release and in vivo pharmacokinetic behavior of IECs was evaluated. Icariin was almost completely hydrolyzed within 4h and approximately 89% of the total flavonoid had been released from IECs at 0.75h in the release medium, which met the requirement of the Chinese Pharmacopoeia on enteric preparations and the Weibull function model. The pharmacokinetic data showed IECs could significantly improved the integrated oral bioavailability of icariin by 50% compared to the IP (icariin without the snailase) in the ovariectomized rats, but no obvious difference was observed in the sham rats. The aforementioned results suggested that such a strategy of icariin combined with the snailase held a great potential in promoting the intestinal hydrolysis and absorption of icariin in the osteoporosis status, providing new research ideas for the active ingredients of traditional Chinese medicine with similar properties.

Sexual enhancement products for sale online: raising awareness of the psychoactive effects of yohimbine, maca, horny goat weed, and Ginkgo biloba

INTRODUCTION

The use of unlicensed food and herbal supplements to enhance sexual functions is drastically increasing. This phenomenon, combined with the availability of these products over the Internet, represents a challenge from a clinical and a public health perspective.

METHODS

A comprehensive multilingual assessment of websites, drug fora, and other online resources was carried out between February and July 2013 with exploratory qualitative searches including 203 websites. Additional searches were conducted using the Global Public Health Intelligence Network (GPHIN). Once the active constitutes of the products were identified, a comprehensive literature search was carried out using PsycInfo and PubMed.

RESULTS

The most common sexual enhancement products available on the Internet were identified. Their active ingredients included yohimbine, maca, horny goat weed and Ginkgo biloba. These four substances were reported with the occurrence of adverse events and the induction of psychological symptoms, such as mood changes, anxiety, and hallucinations as well as addictive behaviours.

CONCLUSIONS

Uncontrolled availability of sexual enhancement products that contain potentially harmful substances is a major public health concern. The possible impact on population health, particularly among subjects with psychiatric disorders, usually at risk for sexual dysfunction, may be significant. This new trend needs to be extensively studied and monitored.

Improved oral bioavailability of breviscapine via a Pluronic P85-modified liposomal delivery system

Objectives

Breviscapine, a hydrophobic drug used for treating cardiovascular disease, was encapsulated in liposomes to improve its pharmaceutical characteristics. This study describes a novel liposome composition approach to specifically inhibit the P-glycoprotein efflux system.

Methods

Breviscapine-loaded Pluronic P85-coated liposomes were prepared by the thin film hydration technique. The particle size, zeta potential and encapsulation efficiency of the formulations were characterized. In-vitro drug release and permeability of Caco-2 cells were investigated. In-vitro characteristics and pharmacokinetics of the liposomes were evaluated in rat studies.

Key findings

The Pluronic P85-modified liposomes dispersed individually and had an approximate diameter of 118.8 ± 4.9 nm and a zeta potential of −35.4 ± 1.5 mV. Encapsulation efficiency was more than 90%. The use of the P85-coated liposomes resulted in significantly (P < 0.05) increased absorption of breviscapine in Caco-2 cells and in 5.6-fold enhancement in its oral bioavailability in rats.

Conclusion

The P85-modified liposomes for the oral delivery of breviscapine were prepared using l-α-phosphatidylcholine (soy-hydrogenated) and cholesterol with a narrow size distribution. This method seems to effectively enhance the bioavailability of breviscapine in rats.

Stabilization of distearoylphosphatidylcholine lamellar phases in propylene glycol using cholesterol

Phospholipid vesicles (liposomes) formed in pharmaceutically acceptable nonaqueous polar solvents such as propylene glycol are of interest in drug delivery because of their ability to improve the bioavailability of drugs with poor aqueous solubility. We have demonstrated a stabilizing effect of cholesterol on lamellar phases formed by dispersion of distearoylphosphatidylcholine (DSPC) in water/propylene glycol (PG) solutions with glycol concentrations ranging from 0 to 100%. The stability of the dispersions was assessed by determining the effect of propylene glycol concentration on structural parameters of the lamellar phases using a complementary combination of X-ray and neutron scattering techniques at 25 °C and in the case of X-ray scattering at 65 °C. Significantly, although stable lamellar phases (and liposomes) were formed in all PG solutions at 25 °C, the association of the glycol with the liposomes' lamellar structures led to the formation of interdigitated phases, which were not thermostable at 65 °C. With the addition of equimolar quantities of cholesterol to the dispersions of DSPC, stable lamellar dispersions (and indeed liposomes) were formed in all propylene glycol solutions at 25 °C, with the significant lateral phase separation of the bilayer components only detectable in propylene glycol concentrations above 60% (w/w). We propose that the stability of lamellar phases of the cholesterol-containing liposomes formed in propylene glycol concentrations of up to 60% (w/w) represent potentially very valuable drug delivery vehicles for a variety of routes of administration.