George Pak-Heng Leung

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• PhD
• Professor (Associate) at The University of Hong Kong

Background Sclerostin (SOST) is traditionally regarded as an osteocyte-derived secreted glycoprotein that regulates bone mineralization. Recent studies reported that SOST is also released from non-skeletal sources, especially during inflammation. However, the cellular source and regulatory mechanisms governing SOST generation in inflammation remain...

The pharmacological effects of Amauroderma rugosum (AR), an edible mushroom found mainly in Southeast Asia, are not well studied, particularly its neuroprotective properties. This study investigated the neuroprotective effects of AR aqueous extract (ARW) in a d‐galactose‐induced accelerated aging mouse model and senescent SH‐SY5Y neuronal cells. Be...

There is little documentation currently on the pharmacological activity and therapeutic value of Amauroderma rugosum (AR). However, the antioxidant and anti-inflammatory effects of AR aqueous extracts on keratinocytes have been reported. This study has aimed to investigate whether the antioxidant and anti-inflammatory properties of AR are related t...

Medulla Tetrapanacis (MT) is a commonly used herbal ingredient in soup to promote lactation and management of mastitis among lactating mothers worldwide, particularly in Asian countries. However, scientific evidence to support its usage in the management of mastitis is limited. This study aimed to investigate the effects of MT water extract and its...

Benzo[a]pyrene (B[a]P) is known to inhibit neurodifferentiation and induce neurodegeneration. Agarwood or Aquilaria crassna (AC), a plant with health-promoting properties, may counteract the neurotoxic effects of B[a]P by promoting neuronal growth and survival. This study investigated the protective effect of AC leaf ethanolic extract (ACEE) on the...

Chronic kidney disease (CKD) presents a substantial global public health challenge, with high morbidity and mortality. CKD patients often experience dyslipidaemia and poor glycaemic control, further exacerbating inflammation and oxidative stress in the kidney. If left untreated, these metabolic symptoms can progress to end-stage renal disease, nece...

YH0618, a medicinal and edible formulation, has demonstrated the potential to alleviate doxorubicin-induced alopecia in animal studies and clinical trials. However, the mechanisms underlying its therapeutic effects remain unexplored. The objective of this study was to ascertain possible therapeutic targets of YH0618 in the treatment of doxorubicin-...

The pharmacological activity and medicinal significance of Amauroderma rugosum (AR) have rarely been documented. We examined the antioxidant and neuroprotective effects of AR on 6-hydroxydopamine (6-OHDA)-induced neurotoxicity in an SH-SY5Y human neuroblastoma cell model of Parkinson’s disease (PD) and explored the active ingredients responsible fo...

Nam Wah banana (Musa paradisiaca L.) is the most common banana cultivar in Thailand. Large amounts of its non-consumable byproducts are considered undervalued and thrown as waste. Exploring the potential utilization and application of banana byproducts for human benefit can add to their value and minimize the risk of threats. This study aimed to in...

Aquilaria crassna (AC) is a beneficial plant widely used to alleviate various health ailments. Nevertheless, the neuroprotection, antiaging, and xenobiotic detoxification against high benzo[a]pyrene induction have not been investigated. This study aimed to investigate the effects of ethanolic extract of AC leaves (ACEE) in vitro using SH-SY5Y cells...

COVID-19 pandemic, caused by the SARS-CoV-2 virus, is still affecting the entire world via the rapid emergence of new contagious variants. Vaccination remains the most effective prevention strategy for viral infection, yet not all countries have sufficient access to vaccines due to limitations in manufacturing and transportation. Thus, there is an...

Despite the acknowledged advantages of combined immunochemotherapy for tumor treatment, the high efficiency of co-delivery of these combined agents into the targeted tumor tissue is still challenging. Herein, based on a "three-birds-with-one-stone" strategy, a facile glycyrrhizic acid (GL)-lipid hybrid nanoplatform loading triptolide (TP/GLLNP) is...

Simple Summary The gut microbiome plays a crucial role in many aspects of canine health, such as metabolism, immune function, and even behavior. The canine gut microbiome is an important and emerging field of veterinary research, with promising potential in facilitating disease diagnosis and management. This first-of-its-kind study aims to characte...

Medulla Tetrapanacis (MT) is a commonly used herb to promote lactation and manage mastitis in lactating mothers. However, its anti-inflammatory and anti-bacterial effects are currently unknown. We hypothesized that MT water extract possesses anti-inflammatory and anti-bacterial effects by modulating macrophage polarization to reduce the release of...

Ergosterol is an important sterol commonly found in edible mushrooms, and it has important nutritional value and pharmacological activity. Ergosterol is a provitamin. It has been well established that edible mushrooms are an excellent food source of vitamin D2 because ergosterol is a precursor that is converted to vitamin D2 under ultraviolet radia...

Cancer metastasis remains the most common cause of death in breast cancer patients. Tumor-associated macrophages (TAMs) are a novel therapeutic target for the treatment of metastatic breast cancer. Despite the good anti-cancer activity of garcinone E (GE), there are no reports on its therapeutic effects on breast cancer metastasis. The objective of...

Asthma is a chronic inflammatory disease characterized by airway hypersensitivity and remodeling. The current treatments provide only short-term benefits and may have undesirable side effects; thus, alternative or supplementary therapy is needed. Because intracellular calcium (Ca2+) signaling plays an essential role in regulating the contractility...

Despite various therapeutic approaches, colorectal cancer is among the most fatal diseases globally. Hence, developing novel and more effective methods for colorectal cancer treatment is essential. Recently, reactive oxygen species (ROS)/JNK signaling pathway has been proposed as the potential target for the anticancer drug discovery. The present s...

Background: Breast cancer metastasis is leading cause of cancer death among women worldwide. Tumor-associated macrophages (TAMs) have been considered as potential targets for treating breast cancer metastasis because they promote tumor growth and development. Glycyrrhetinic acid (GA) is one of the most important phytochemicals of licorice which ha...

Ganoderma lucidum has long been used as a multi-purpose plant and functional food. The pharmacological properties of G. lucidum are primarily attributed to its polysaccharides and triterpenoids. Ganoderic and lucidenic acids are the two major triterpenoids groups in G. lucidum. Despite the discovery of 22 types of lucidenic acids, research on lucid...

Background As one of the most classic antineoplastic agents, doxorubicin (Dox) is extensively used to treat a wide range of cancers. Nevertheless, the clinical outcomes of Dox-based therapies are severely hampered due to the significant cardiotoxicity. Glycyrrhetinic acid (GA) is the major biologically active compound of licorice, one of the most w...

Keratinocytes form the physical barrier of the skin and play an important role in the inflammatory process. Amauroderma rugosum is an edible mushroom; however, its pharmacological properties have seldom been studied. Although the anti-inflammatory effect of the organic solvent extract of Amauroderma rugosum has been previously reported, it is not k...

Background Nucleoside transporters are crucial in regulating the functions of adenosine. This study investigated the contribution of equilibrative nucleoside transporter (ENT) type 4 to adenosine transport in cardiomyocytes under simulated ischemic conditions and whether the inhibition of ENT4 could protect cardiomyocytes against ischemia-reperfusi...

Ageing is a risk factor for many degenerative diseases. Cardiovascular diseases (CVDs) are usually big burdens for elderly, caregivers and the health system. During the aging process, normal functions of vascular cells and tissue progressively lost and eventually develop vascular diseases. Endothelial dysfunction, reduced bioavailability of endothe...

Angiogenesis, the formation of new capillaries from pre-existing vascular networks, plays an important role in many physiological and pathological processes. The use of pro-angiogenic agents has been proposed as an attractive approach for promoting wound healing and treating vascular insufficiency-related problems, such as ischemic heart disease an...

Clinical outcomes for doxorubicin (Dox) are limited by its cardiotoxicity but a combination of Dox and agents with cardioprotective activities is an effective strategy to improve its therapeutic outcome. Natural products provide abundant resources to search for novel cardioprotective agents. Ganoderma lucidum (GL) is the most well-known edible mush...

Amauroderma rugosum (AR) is a basidiomycete in the Ganodermataceae family that has been used traditionally to prevent epileptic attacks and constant crying in babies. However, AR has not been widely studied scientifically. In this review, we summarize the phytochemical components and pharmacological properties of AR that have been reported in the l...

Equilibrative nucleoside transporters (ENTs) play a vital role in nucleotide synthesis, regulation of adenosine function and chemotherapy. Current inhibitors of ENTs are mostly ENT1-selective. Our previous study has demonstrated that 4-((4-(2-fluorophenyl)piperazin-1-yl)methyl)-6-imino-N-(naphthalen-2-yl)-1,3,5-triazin-2-amine (FPMINT) is a novel i...

Background Accumulating evidence suggest that behavioral sensitization is involved in the process of drug addiction. Zebrafish are sensitive to a variety of addictive drugs and are thus suitable for the study of behavioral sensitization. However, in contrast to mature rodent models of behavioral sensitization, how this phenomenon manifests in aquat...

Background: The anti-cancer activity of andrographolide (Andro) has been extensively demonstrated in recent years. It is supposed that modifying the chemical structure of Andro can improve its efficacy and reduce its toxicity. Purpose: In this study, the anti-cancer effect of a 14β-(2′-chlorophenoxy) derivative of andrographolide known as AGS-30 wa...

Narirutin is one of the most common flavanones found in citrus fruits. The vascular effects of its analogues naringenin and naringin have been reported but its effects on the cardiovascular system are largely unknown. In this study, relaxation effect of narirutin and its mechanisms of action were investigated by measuring isometric tension in rat m...

Aging is a major risk factor for many diseases, including cardiovascular diseases, neurological disorders, cancer and diabetes mellitus. Oxidative stress plays a key role in the aging process. Amauroderma rugosum is an edible mushroom that has rarely been studied. The aims of this study were to compare the major chemical constituents and to investi...

Amauroderma rugosum (AR) is a dietary mushroom in the Ganodermataceae family whose pharmacological activity and medicinal value have rarely been reported. In this study, the antioxidant capacity and neuroprotective effects of AR were investigated. The aqueous extract of AR was confirmed to contain phenolic compounds, polysaccharides, and triterpene...

Objective: Although the α2-adrenoceptor receptor (α2-AR) agonist dexmedetomidine causes coronary vasoconstriction, activation of endothelial α2-ARs is known to induce vascular relaxation. Here, we used functional studies and molecular techniques to explore the involvement of different α2-AR subtypes (α2A-AR, α2B-AR α2C-AR) in the effects of dexmede...

Background Therapeutic regimens of breast cancer treatment are increasingly inclined to adopt combination strategy based on the broad spectrum antitumor effect of doxorubicin (Dox). Currently, combination therapy comprises of conventional anti-cancer drugs and angiogenesis inhibitors have been corroborated as an effective approach in cancer treatme...

To avoid the narrow therapeutic window and take advantage of the anticancer efficacy of triptolide (TP), a major active component of Tripterygium wilfordii Hook.F., a novel thermo-responsive nano-micelle hydrogel was fabricated in present study for the sustained release of TP in breast tumor tissue. Briefly, the amphiphilic poloxamer 188-g-poly (N-...

Colorectal cancer (CRC) is the leading cause of cancer lethality worldwide, inflicting a heavy burden on society. Unfortunately, the complex nature of CRC pathogenesis renders current chemotherapies and targeted therapies unsatisfactory. Conventional medicine generally concentrates on the killing of tumor cells by inducing cell death or activation...

The clinical application of triptolide (TPL) in tumor therapy has been greatly limited by its toxicity and inefficient delivery. Herein, a localized and sustained-release thermo-sensitive hydrogel was developed for the intra-tumor administration of TPL. Based on the amphiphilic structure of poly (N-isopropylacrylamide-co-acrylic acid)-g-F68 copolym...

A new aromatic glycoside (1) and a new natural product, neolignan (2), along with twenty-three known compounds (3-25), were isolated from the thorns of Gleditsia sinensis. According to the spectroscopic analyses (IR, UV, HRESIMS, NMR and ECD), the structures of isolates were elucidated. Herein, compounds 4, 6-8, 10-13, 15, 16, 18, 20, 23 were isola...

Equilibrative nucleoside transporters (ENTs) are the proteins responsible for transporting nucleosides across cell membrane. The role of ENT 1 in cardioprotection has been reported but the biological functions of ENT 2 remains unclear. To study the functions of ENT 2, pharmacological approach using selective ENT 2 inhibitors is an option but such i...

Controlling self-renewal and lineage differentiation of stem cells (SCs) is critical for SC therapy in regenerative medicine. Multiple signal pathways such as Wnt, TGF-β and BMP are involved in modulating proliferation or specific differentiation of different types of SCs. Dietary phytochemicals, the major source of new drugs, are found to stimulat...

In parallel with the prevalence metabolic syndrome, nonalcoholic fatty liver disease (NAFLD) has become the most common chronic liver disease in most countries. It features a constellation of simple steatosis, nonalcoholic steatohepatitis (NASH), fibrosis, cirrhosis, and even hepatocellular carcinoma. There are no approved drugs for effective manag...

Introduction The Chinese medicine formulation, tumour‐shrinking decoction (TSD, FM1523), which consists of 15 natural medicines, is used for uterine fibroids (UFs) therapy and possesses excellent clinical therapeutic effect. Objective To develop a sensitive and validated analytical method for the simultaneous quantification of four crucial bioacti...

People with the genetic disease cystic fibrosis (CF) often carry a deletion mutation ∆F508 on the gene encoding the CF transmembrane conductance regulator (CFTR) Cl⁻ channel. This mutation greatly reduces the CFTR maturation process and slows the channel opening rate. Here, we investigate whether residues near F508 contribute to these defects in ∆F...

Alzheimer's disease (AD) is the most common cause of dementia in the elderly, characterized by progressive cognitive dysfunction. Aquaporin 9 (AQP9) is an aquaglyceroporin membrane channel shown biophysically to conduct water, glycerol, and other small solutes. In our study, we reported for the first time an age-associated decrease of AQP9 mRNA and...

Worldwide, colorectal cancer (CRC) is a deleterious disease causing millions of death annually. 5-Fluorouracil (5-FU) is a first-line chemotherapy for CRC, but chemoresistance and gastrointestinal mucositis limit its efficacy. Polyphenol-rich foods are increasingly popular due to their potential beneficial role in cancer. Ellagitannins is a group o...

Upon searching the Chinese Pharmacopoeia, it is found that 97 herbs belong to the large intestine meridians among which 23 of them are traditionally used for intestine‐related cancer treatment. Pomegranate peel, in particular, is used to treat diarrhea, dysentery, and bloody stool which are similar to symptoms of colorectal cancer and intestinal mu...

Background: Andrographolide is the major bioactive component isolated from Andrographis paniculata. Its pharmacological activities, such as anti-cancer, anti-angiogenic and anti-inflammatory effects have been demonstrated. However, its poor bioavailability and limited efficacy pose difficulties for its therapeutic development. Recently, a new andro...

Background Ilexsaponin A1 is the major bioactive ingredient of Ilex pubescens Hook. et Arn. This plant has been conventionally used in Traditional Chinese Medicine for the treatment of cardiovascular diseases including stroke, coronary arterial disease, and peripheral vascular diseases. Purpose To investigate the pro-angiogenic effect of Ilexsapon...

5-Fluorouracil (5-FU) is a commonly used chemotherapeutic agent for breast cancer. However, its use often leads to drug resistance and mucositis. This study aimed to investigate whether proanthocyanidins from Ficus virens possessed anti-breast cancer and anti-mucositis activities. The results showed that the cytotoxic effects of the proanthocyanidi...

Sichuan pepper, a well-known traditional Chinese spice, is popularly used in Chinese cuisine. In this study, the antioxidant activities of Sichuan pepper water extract (SP) were evaluated both chemically [in 2,2-diphenyl-1-(2,4,6-trinitrophenyl) hydrazyl (DPPH) assay] and biologically [in 2,2′-azobis-(2-amidinopropane) (AAPH)-induced haemolysis ass...

Hemorrhagic stroke occurs when a weakened vessel ruptures and bleeds into the surrounding brain, leading to high rates of death and disability worldwide. A series of complex pathophysiological cascades contribute to the risk of hemorrhagic stroke, and no therapies have proven effective to prevent hemorrhagic stroke. Stabilization of vascular integr...

Breast cancer is the most frequently diagnosed cancer and cause of cancer death in women worldwide. Current treatments often result in systematic toxicity and drug resistance. Combinational use of non-toxic phytochemicals with chemotherapy agents to enhance the efficacy and reduce toxicity would be one promising approach. In this study, bioactive p...

Background As a bioactive composite extracted from American cockroach, Xinmailong injection (XML) is used for the treatment of congestive heart failure (CHF) in China. Clinical data has provided evidence that XML has positive inotropic properties. The objective of this study was to assess the mechanisms involved in the therapeutical effect of XML o...

The aim of this study is to investigate the anti-angiogenic properties of andrographolide derivatives AGP-26a (12β-isomer), AGP-26b (12α-isomer) and AGP-26 (4 : 1 mixture of AGP-26a and AGP-26b) in vitro and in vivo. Human umbilical vein endothelial cells (HUVECs) and the Tg(fli-1a:EGFP)y1 zebrafish model were used to identify the anti-angiogenic a...

The prevalence of cognitive impairment and dementia caused by cerebrovascular disease is likely to increase with the global aging population. Vascular contributions to cognitive impairment and dementia (VCID) is a wide spectrum term used to include a diverse heterogeneous group of cognitive syndromes with vascular factors regardless of the cause of...

Calycosin and formononetin are two structurally similar isoflavonoids that have been shown to induce vasodilation in aorta and conduit arteries, but study of their actions on endothelial functions is lacking. Here, we demonstrated that both isoflavonoids relaxed rat mesenteric resistance arteries in a concentration-dependent manner, which was reduc...

Background This study reported a comprehensive approach (comparing the extraction yields, chemical profiles, antioxidant properties and CYP450-inhibitory effects) to evaluated the effectiveness of various extraction methods [microwave-assisted extraction using water (MAE-W), heat reflux extraction using water (HRE-W), ultrasonic extraction using 70...

Background and purpose: Vascular inflammation is a major factor contributing to the development of vascular diseases. The aim of this study was to investigate the role of α3-containing nicotinic acetylcholine receptors subtype (α3-nAChRs) in vascular inflammation. Experimental approach: Vascular inflammation was studied in the apolipoprotein E k...

Equilibrative nucleoside transporters (ENTs) play a crucial role in the transport of nucleoside and nucleoside analogues, which are important for nucleotide synthesis and chemotherapy. In addition, ENTs regulate extracellular adenosine levels in the vicinity of its receptors and hence influence adenosine-related functions. The clinical applications...

Formononetin is an isoflavone that has been shown to display estrogenic properties and induce angiogenesis activities. However, the interrelationship between the estrogenic properties and angiogenesis activities of formononetin are not well defined. In the present study, docking and enzymatic assay demonstrated that formononetin displayed direct bi...

In this study, we evaluated the anabolic effect and the underlying cellular mechanisms involved of vitamin K2 (10nM) and 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3) (10nM), alone and in combination, on primary osteoblasts harvested from the iliac crests of C57BL/KsJ lean (+/+) and obese/diabetic (db/db) mice. A lower alkaline phosphatase (ALP) activity...

Icaritin, a prenylflavonoid isolated from Herbal Epimedii, is well known for its osteoplastic and anti-tumour activities. Here, we examined the cardioprotective actions of icaritin on cardiac H9c2 cells under oxidative stress conditions induced by treatment with tert-butylhydroperoxide (t-BHP). Icaritin at a concentration range between 1 and 4 μM e...

We previously reported a novel danshensu analogue known as ADTM, which exhibited strong protective effects against oxidative stress-induced cellular injury and acute ischemic myocardial infarct in rat; however, the exact protein target of ADTM has not been fully characterized. In the present study, a biotin-conjugated ADTM analogue (BAA) was employ...

Oleanolic acid (OA) is a natural triterpenoid with anticancer property, but its hydrophobic nature and poor aqueous solubility pose challenges in pharmaceutical formulation development. The present study aimed at developing OA-loaded mPEG-PLGA or mPEG-PLA nanoparticles (NPs) to improve the delivery of OA. The NPs were prepared by nanoprecipitation...

The use of abacavir has been linked with increased cardiovascular risk in patients with human immunodeficiency virus infection; however, the mechanism involved remains unclear. We hypothesize that abacavir may impair endothelial function. In addition, based on the structural similarity between abacavir and adenosine, we propose that abacavir may af...

Background and purpose: Kaempferol, a plant flavonoid present in normal human diet, can modulate vasomotor tone. The present study aimed to elucidate the signalling pathway through which this flavonoid enhanced relaxation of vascular smooth muscle. Experimental approach: The effect of kaempferol on the relaxation of porcine coronary arteries to...

Pulmonary delivery of siRNA has considerable therapeutic potential for treating viral respiratory infectious diseases including influenza. By introducing siRNA that targets the conserved region of viral genes encoding nucleocapsid protein (NP), viral mRNAs can be degraded and viral replication can be inhibited in mammalian cells. To enable siRNA to...

Hypothyroidism impairs endothelium-dependent dilatations, while hyperthyroidism augments the production of endothelial nitric oxide. Thus, experiments were designed to determine if thyroid hormone causes endothelium-dependent responses, or alleviates diabetic endothelial dysfunction. Isometric tension was measured in rings with or without endotheli...

The cardioprotective effects of adenosine and adenosine receptor agonists have been studied extensively. However, their therapeutic outcomes in ischemic heart disease are limited by systemic side effects such as hypotension, bradycardia and sedation. Equilibrative nucleoside transporter (ENT) inhibitors may be an alternative. By reducing the uptake...

The role of Kdr (VEGFR-2/Flk-1) in vascular formation has been well described, but the role of Flt1 (VEGFR-1) is not well studied and is generally considered as a decoy receptor for trapping VEGF.Methods The effects of VEGFR1/2 kinase inhibitor (VRI) and calycosin on Flt1 tyrosine kinase (TK) activity were evaluated by molecular docking, enzymatic...

Baicalein is one of the major flavonoids found in the root of Scutellaria baicalensis Georgi. Previous studies suggest that baicalein displays protective effect on experimental cardiac models in vitro and in vivo. However, the mode of action remains unclear. Here we showed that baicalein conferred cardioprotective effect against oxidative stress-in...

In ischemic disorders such as chronic wounds and myocardial ischemia, there is inadequate tissue perfusion due to vascular insufficiency. Besides, it has been observed that prolonged use of anti-angiogenic agents in cancer therapy produces cardiovascular toxicity caused by impaired vessel integrity and regeneration. In the present study, we used VE...

Ergothioneine is a thiourea derivative of histidine found in food, especially mushrooms. Experiments in cell-free systems and chemical assays identified this compound as a powerful antioxidant. Experiments were designed to test the ability of endothelial cells to take up ergothioneine and hence benefit from protection against oxidative stress. RT-P...

The objective of this study was to investigate the 14,15-epoxyeicosatrienoic acid (14,15-EET)-induced vasodilatations as well as the underlying signaling pathways in rat mesenteric arteries from young, adult and old normotensive (WKY) and hypertensive rats. Protein expressions for prostaglandin EP1-4 receptors, large conductance Ca(2+)-activated K(...

Poster Presentation - Theme 5: Healthy Aging: no. 5.05 The Symposium program's website is located at http://www.med.hku.hk/rps18/poster_presentation_sessions.php?theme=5

This study investigated the mechanism of the cytotoxic effect of emodin, an active anthraquinone, on human lung adenocarcinoma A549 cells. In vitro growth inhibition and suppression on colony forming were used to evaluate the effects of emodin on A549 cells. Emodin’s ability in changing the expressions of apoptosis-related genes was studied by real...

Panax notoginseng saponins (PNS) are major active constituents of P. notoginseng. This study investigated the mechanisms of the hypocholesterolaemic and atheroscleroprotective effects of PNS. It was found that treatment of PNS (30 or 100 mg/kg/day, p.o.) could significantly reduce elevated serum total cholesterol, triacylglycerol, low-density lipop...

Consumption of functional foods for managing plasma cholesterol level has gained acceptance globally. The hypocholesterolaemic and vascular protective effects of the dried fruit of Crataegus pinnatifida, hawthorn (Shan Zha), were investigated in rats fed with normal diet, high cholesterol diet (HCD) or HCD plus Shan Zha 80% ethanolic extract treatm...

Statins (3-hydroxy-3-methyl-glutaryl coenzyme A (HMG-CoA) reductase inhibitors) consumption provides beneficial effects on cardiovascular systems. However, effects of statins on vascular KATP channel gatings are unknown. Pig left anterior descending coronary artery and human left internal mammary artery were isolated and endothelium-denuded for ten...