Immunoregulatory and anti-HIV-1 enzyme activities of antioxidant components from lotus (Nelumbo nucifera Gaertn.) rhizome

Bioactive polysaccharides from lotus as potent food supplements: a review of their preparation, structures, biological features and application prospects

Lotus is a famous plant of the food and medicine continuum for millennia, which possesses unique nutritional and medicinal values. Polysaccharides are the main bioactive component of lotus and have been widely used as health nutritional supplements and therapeutic agents. However, the industrial production and application of lotus polysaccharides (LPs) are hindered by the lack of a deeper understanding of the structure-activity relationship (SAR), structural modification, applications, and safety of LPs. This review comprehensively comments on the extraction and purification methods and structural characteristics of LPs. The SARs, bioactivities, and mechanisms involved are further evaluated. The potential application and safety issues of LPs are discussed. This review provides valuable updated information and inspires deeper insights for the large scale development and application of LPs.

Fresh and Browned Lotus Root Extracts Promote Cholesterol Metabolism in FFA-Induced HepG2 Cells through Different Pathways

Browning of fresh-cut plants is mainly attributed to the enzymatic browning of phenolic compounds induced by polyphenol oxidase (PPO), producing browning products such as anthraquinones, flavanol oxides, and glycosides, which are usually considered to be non-toxic. Could browning bring any benefits on behalf of their bioactivity? Our previous study found that browned lotus root extracts (BLREs) could reduce the cholesterol level in obese mice as fresh lotus root extracts (FLREs) did. This study aimed to compare the mechanisms of FLRE and BLRE on cholesterol metabolism and verify whether the main component's monomer regulates cholesterol metabolism like the extracts do through in vitro experiments. Extracts and monomeric compounds are applied to HepG2 cells induced by free fatty acids (FFA). Extracellular total cholesterol (TC) and triglyceride (TG) levels were also detected. In addition, RT-PCR and Western blot were used to observe cholesterol metabolism-related gene and protein expression. The in vitro results showed that BLRE and FLRE could reduce TC and TG levels in HepG2 cells. In addition, BLRE suppressed the synthesis of cholesterol. Meanwhile, FLRE promoted the synthesis of bile acid (BA) as well as the clearance and efflux of cholesterol. Furthermore, the main monomers of BLRE also decreased cholesterol synthesis, which is the same as BLRE. In addition, the main monomers of FLRE promoted the synthesis of BAs, similar to FLRE. BLRE and FLRE promote cholesterol metabolism by different pathways.

LC-ESI-QTOF-MS/MS Characterization and Estimation of the Antioxidant Potential of Phenolic Compounds from Different Parts of the Lotus (Nelumbo nucifera) Seed and Rhizome

Edible lotus (Nelumbo nucifera G.) is widely consumed in Asian countries and treated as a functional food and traditional medicinal herb due to its abundant bioactive compounds. Lotus rhizome peels, rhizome knots, and seed embryos are important byproducts and processing waste of edible lotus (Nelumbo nucifera G.) with commercial significance. Nevertheless, the comprehensive phenolic profiling of different parts of lotus is still scarce. Thus, this study aimed to review the phenolic contents and antioxidant potential in lotus seeds (embryo and cotyledon) and rhizomes (peel, knot, and pulp) grown in Australia. In the phenolic content and antioxidant potential estimation assays by comparing to the corresponding reference standards, the lotus seed embryo exhibited the highest total phenolic content (10.77 ± 0.66 mg GAE/g_f.w.), total flavonoid content (1.61 ± 0.03 mg QE/g_f.w.), 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity (9.66 ± 0.10 mg AAE/g_f.w.), 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) scavenging activity (14.35 ± 0.20 mg AAE/g_f.w.), and total antioxidant capacity (6.46 ± 0.30 mg AAE/g), while the highest value of ferric ion reducing antioxidant power (FRAP) activity and total tannin content was present in the lotus rhizome knot (2.30 ± 0.13 mg AAE/g_f.w.). A total of 86 phenolic compounds were identified in five parts of lotus by liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry (LC-ESI-QTOF-MS/MS), including phenolic acids (20), flavonoids (51), lignans (3), stilbenes (2), and other polyphenols (10). The most phenolic compounds, reaching up to 68%, were present in the lotus seed embryo (59). Furthermore, the lotus rhizome peel and lotus seed embryo exhibit significantly higher contents of selected polyphenols than other lotus parts according to high-performance liquid chromatography (HPLC) quantification analysis. The results highlighted that byproducts and processing waste of edible lotus are rich sources of phenolic compounds, which may be good candidates for further exploitation and utilization in food, animal feeding, and pharmaceutical industries.

Lotus (Nelumbo nucifera Gaertn.) and Its Bioactive Phytocopounds: A Tribute to Cancer Prevention and Intervention

Simple Summary

The plant Nelumbo nucifera (Gaertn.), commonly known as lotus, sacred lotus, Indian lotus, water lily, or Chinese water lily, is an aquatic perennial crop belonging to the family of Nelumbonaceae. N. nucifera has traditionally been used as an herbal medicine and functional food in many parts of Asia. It has been found that different parts of this plant consist of various bioactive phytocompounds. Within the past few decades, N. nucifera and its phytochemicals have been subjected to intense cancer research. In this review, we critically evaluate the potential of N. nucifera phytoconstituents in cancer prevention and therapy with related mechanisms of action.

Abstract

Cancer is one of the major leading causes of death worldwide. Accumulating evidence suggests a strong relationship between specific dietary habits and cancer development. In recent years, a food-based approach for cancer prevention and intervention has been gaining tremendous attention. Among diverse dietary and medicinal plants, lotus (Nelumbo nucifera Gaertn., family Nymphaeaceae), also known as Indian lotus, sacred lotus or Chinese water lily, has the ability to effectively combat this disease. Various parts of N. nucifera have been utilized as a vegetable as well as an herbal medicine for more than 2000 years in the Asian continent. The rhizome and seeds of N. nucifera represent the main edible parts. Different parts of N. nucifera have been traditionally used to manage different disorders, such as fever, inflammation, insomnia, nervous disorders, epilepsy, hypertension, cardiovascular diseases, obesity, and hyperlipidemia. It is believed that numerous bioactive components, including alkaloids, polyphenols, terpenoids, steroids, and glycosides, are responsible for its various biological and pharmacological activities, such as antioxidant, anti-inflammatory, immune-modulatory, antiviral, hepatoprotective, cardioprotective, and hypoglycemic activities. Nevertheless, there is no comprehensive review with an exclusive focus on the anticancer attributes of diverse phytochemicals from different parts of N. nucifera. In this review, we have analyzed the effects of N. nucifera extracts, fractions and pure compounds on various organ-specific cancer cells and tumor models to understand the cancer-preventive and therapeutic potential and underlying cellular and molecular mechanisms of action of this interesting medicinal and dietary plant. In addition, the bioavailability, pharmacokinetics, and possible toxicity of N. nucifera-derived phytochemicals, as well as current limitations, challenges and future research directions, are also presented.

Comprehensive characterization of lotus root polysaccharide-phenol complexes

To explore the effects of phenolic binding on the structure and activity of lotus root polysaccharides (LRPs), five LRP-phenol complexes containing catechin (61.22 mg/g), gallic acid (9.37 mg/g), ferulic acid (29.28 mg/g), chlorogenic acid (83.80 mg/g) or caffeic acid (14.80 mg/g) were prepared via noncovalent intermolecular interaction, respectively. The interaction was confirmed by the differences among LRPs, phenols and their complexes in ultraviolet-visible and Fourier-transform infrared spectra. The phenolic binding caused significant changes in the molecular weight (MW) distribution and aggregation behavior of LRPs, particularly their average MW (34.49 kDa) increased by 3.73-8.30 times. Compared to LRPs, the complexes all showed stronger antioxidant activities. Notably, the binding of catechin improved the macrophage-stimulating effect of LRPs, specifically promoting the NO production at normal condition and inhibiting the NO overproduction induced by lipopolysaccharide. The noncovalent interaction with phenolic compounds is a promising method for the structural and functional improvement of LRPs.

Comparative Analysis of Chemical Constituents in Different Parts of Lotus by UPLC and QToF-MS

Six parts of lotus (seeds, leaves, plumule, stamens, receptacles and rhizome nodes) are herbal medicines that are listed in the Chinese Pharmacopoeia. Their indications and functions have been confirmed by a long history of clinical practice. To fully understand the material basis of clinical applications, UPLC-QToF-MS combined with the UNIFI platform and multivariate statistical analysis was used in this study. As a result, a total of 171 compounds were detected and characterized from the six parts, and 23 robust biomarkers were discovered. The method can be used as a standard protocol for the direct identification and prediction of the six parts of lotus. Meanwhile, these discoveries are valuable for improving the quality control method of herbal medicines. Most importantly, this was the first time that alkaloids were detected in the stamen, and terpenoids were detected in the cored seed. The stamen is a noteworthy part because it contains the greatest diversity of flavonoids and terpenoids, but research on the stamen is rather limited.

Indian Medicinal Plants and Formulations and Their Potential Against COVID-19-Preclinical and Clinical Research

The cases of COVID-19 are still increasing day-by-day worldwide, even after a year of its first occurrence in Wuhan city of China. The spreading of SARS-CoV-2 infection is very fast and different from other SARS-CoV infections possibly due to structural differences in S proteins. The patients with severe diseases may die due to acute respiratory distress syndrome (ARDS) caused by systemic inflammatory reactions due to the excessive release of pro-inflammatory cytokines and chemokines by the immune effector cells. In India too, it is spreading very rapidly, although the case fatality rate is below 1.50% (https://www.statista.com), which is markedly less than in other countries, despite the dense population and minimal health infrastructure in rural areas. This may be due to the routine use of many immunomodulator medicinal plants and traditional AYUSH formulations by the Indian people. This communication reviews the AYUSH recommended formulations and their ingredients, routinely used medicinal plants and formulations by Indian population as well as other promising Indian medicinal plants, which can be tested against COVID-19. Special emphasis is placed on Indian medicinal plants reported for antiviral, immunomodulatory and anti-allergic/anti-inflammatory activities and they are categorized for prioritization in research on the basis of earlier reports. The traditional AYUSH medicines currently under clinical trials against COVID-19 are also discussed as well as furtherance of pre-clinical and clinical testing of the potential traditional medicines against COVID-19 and SARS-CoV-2. The results of the clinical studies on AYUSH drugs will guide the policymakers from the AYUSH systems of medicines to maneuver their policies for public health, provide information to the global scientific community and could form a platform for collaborative studies at national and global levels. It is thereby suggested that promising AYUSH formulations and Indian medicinal plants must be investigated on a priority basis to solve the current crisis.

Mutations of Glu560 within HIV-1 Envelope Glycoprotein N-terminal heptad repeat region contribute to resistance to peptide inhibitors of virus entry

Background

Peptides corresponding to N- and C-terminal heptad repeat regions (HR1 and HR2, respectively) of gp41 can inhibit HIV-1 infection in a dominant negative manner by interfering with refolding of the viral HR1 and HR2 to form a six-helix bundle (6HB) that induces fusion between viral and host cell membranes. Previously, we found that HIV-1 acquired the mutations of Glu560 (E560) in HR1 of envelope (Env) to escape peptide inhibitors. The present study aimed to elucidate the critical role of position 560 in the virus entry and potential resistance mechanisms.

Results

The Glu560Lys/Asp/Gly (E560K/D/G) mutations in HR1 of gp41 that are selected under the pressure of N- and C-peptide inhibitors modified its molecular interactions with HR2 to change 6HB stability and peptide inhibitor binding. E560K mutation increased 6HB thermostability and resulted in resistance to N peptide inhibitors, but E560G or E560D as compensatory mutations destabilized the 6HB to reduce inhibitor binding and resulted in increased resistance to C peptide inhibitor, T20. Significantly, the neutralizing activities of all mutants to soluble CD4 and broadly neutralizing antibodies targeting membrane proximal external region, 2F5 and 4E10 were improved, indicating the mutations of E560 could regulate Env conformations through cross interactions with gp120 or gp41. The molecular modeling analysis of E560K/D/G mutants suggested that position 560 might interact with the residues within two potentially flexible topological layer 1 and layer 2 in the gp120 inner domain to apparently affect the CD4 utilization. The E560K/D/G mutations changed its interactions with Gln650 (Q650) in HR2 to contribute to the resistance of peptide inhibitors.

Conclusions

These findings identify the contributions of mutations of E560K/D/G in the highly conserved gp41 and highlight Env’s high degree of plasticity for virus entry and inhibitor design.

Lotus Flavonoids and Phenolic Acids: Health Promotion and Safe Consumption Dosages

Nelumbo nucifera Gaertn., also known as the sacred lotus, is extensively cultivated in Southeast Asia, primarily for food and as an herbal medicine. This article reviews studies published between 1995 and 2017, on flavonoid and phenolic acid profiles and contents of 154 different cultivars of lotus. So far, some 12 phenolic acids and 89 to 90 flavonoids (47 flavonols, 25 to 26 flavons, 8 flavan-3-ols, 4 flavanons, and 5 anthocyanins) have been isolated from different parts of the lotus plant, including its leaves (whole leaf, leaf pulp, leaf vein, and leaf stalk), seeds (seedpod, epicarp, coat, kernel, and embryo), and flowers (stamen, petal, pistil, and stalk), although not all of them have been quantified. Factors affecting flavonoids and phenolic acid profiles, including types of tissues and extracting factors, are discussed in this review, in order to maximize the application of the lotus and its polyphenols in the food industry. Health promotion activities, attributed to the presence of flavonoids and phenolic acids, are described along with toxicology studies, illustrating appropriate usage and safe consumption dosages of lotus extracts. This review also presents the controversies and discusses the research gaps that limit our ability to obtain a thorough understanding of the bioactivities of lotus extracts.

Fingerprint profiling of polysaccharides from different parts of lotus root varieties

Thirty-nine polysaccharides isolated from different parts of 13 lotus root varieties were characterized with fingerprint and chemometrics analyses to explore their similarity and diversity. The physicochemical features of lotus root polysaccharides (LRPs) were found to be the following: LRPs contained mainly polysaccharides (5.94 kDa) and polysaccharide-protein complexes (11.57 kDa and 5.30 kDa); their carbohydrates were composed of mannose, rhamnose, glucuronic acid, galacturonic acid, glucose, galactose and arabinose approximately in the molar ratio of 0.19 : 0.14 : 0.08 : 0.17 : 6.49 : 1.00 : 0.16; and node LRPs possessed more binding proteins and uronic acids than both flesh and peel LRPs. Their fingerprints based on Fourier-transform infrared spectroscopy, pre-column derivatization high-performance liquid chromatography and high performance size-exclusion chromatography all exhibited relatively high similarities, contributing to the common figerprint models which could be utilized as references for the identification of LPRs. In addition, the fingerprint characteristics associated with the between-group variability of LRPs in the score plots derived from multivariate analytical models might indicate which variety or part of lotus root they were isolated from. Therefore, multi-fingerprinting techniques have the potential to be applied to the identification and quality control of LRPs.

Thirty-nine polysaccharides isolated from lotus roots were characterized with fingerprint and chemometrics analyses to explore their similarity and diversity.

The medicinal and pharmaceutical importance of Dendrobium species

Plants of the Dendrobium genus, one of the largest in the Orchidaceae, manifest a diversity of medicinal effects encompassing antiangiogenic, immunomodulating, antidiabetic, cataractogenesis-inhibiting, neuroprotective, hepatoprotective, anti-inflammatory, antiplatelet aggregation, antifungal, antibacterial, antiherpetic, antimalarial, aquaporin-5 stimulating, and hemagglutininating activities and also exert beneficial actions on colonic health and alleviate symptoms of hyperthyroidism. The active principles include a wide range of proteinaceous and non-proteinaceous molecules. This mini-review discusses the latest advances in what is known about the medicinal and pharmaceutical properties of members of the Dendrobium genus and explores how biotechnology can serve as a conduit to mass propagate valuable germplasm for sustainable exploration for the pharmaceutical industry.

Cytotoxic, Antitumor and Immunomodulatory Effects of the Water-Soluble Polysaccharides from Lotus (Nelumbo nucifera Gaertn.) Seeds

Lotus is an edible and medicinal plant, and the extracts from its different parts exhibit various bioactivities. In the present study, the hot water-soluble polysaccharides from lotus seeds (LSPS) were evaluated for their cancer cell cytotoxicity, immunomodulatory and antitumor activities. LSPS showed significant inhibitory effects on the mouse gastric cancer MFC cells, human liver cancer HuH-7 cells and mouse hepatocarcinoma H22 cells. The animal studies showed that LSPS inhibited tumor growth in H22 tumor-bearing mice with the highest inhibition rate of 45.36%, which is comparable to that induced by cyclophosphamide (30 mg/kg) treatment (50.79%). The concentrations of white blood cells were significantly reduced in cyclophosphamide-treated groups (p < 0.01), while LSPS showed much fewer side effects according to the hematology analysis. LSPS improved the immune response in H22 tumor-bearing mice by enhancing the spleen and thymus indexes, and increasing the levels of serum cytokines including tumor necrosis factor-α and interleukin-2. Moreover, LSPS also showed in vivo antioxidant activity by increasing superoxide dismutase activity, thus reducing the malondialdehyde level in the liver tissue. These results suggested that LSPS can be used as an antitumor and immunomodulatory agent.

Phenolic Profiles and Antioxidant Activity of Lotus Root Varieties

Lotus root attracts increasing attention mainly because of its phenolic compounds known as natural antioxidants. Its thirteen varieties were systematically analyzed on the content, distribution, composition and antioxidant activity of phenolic compounds for a better understanding of this aquatic vegetable. The respective mean contents of total phenolics in their flesh, peel and nodes were 1.81, 4.30 and 7.35 mg gallic acid equivalents (GAE)/g fresh weight (FW), and those of total flavonoids were 3.35, 7.69 and 15.58 mg rutin equivalents/g FW. The phenolic composition determined by a high-performance liquid chromatography method varied significantly among varieties and parts. The phenolics of flesh were mainly composed of gallocatechin and catechin; those of peel and node were mainly composed of gallocatechin, gallic acid, catechin and epicatechin. The antioxidant activities of phenolic extracts in increasing order were flesh, peel and node; their mean concentrations for 50% inhibition of 2,2-diphenyl-1-picrylhydrazyl radical were 46.00, 26.43 and 21.72 µg GAE/mL, and their mean values representing ferric reducing antioxidant power were 75.91, 87.66 and 100.43 µg Trolox equivalents/100 µg GAE, respectively. “Zoumayang”, “Baheou”, “No. 5 elian” and “Guixi Fuou” were the hierarchically clustered varieties with relatively higher phenolic content and stronger antioxidant activity as compared with the others. Especially, their nodes and peels are promising sources of antioxidants for human nutrition.

A study of effects of peptide fragments of bovine and human lactoferrins on activities of three key HIV-1 enzymes

The intent of this study was to examine human and bovine lactoferrin fragments including lactoferrin (1-11), lactoferricin and lactoferrampin, all of which did not demonstrate hemolytic activity toward rabbit erythrocytes at 1 mM concentration, for possible inhibitory effects on the activities of HIV-1 reverse transcriptase, protease and integrase. The data showed that human lactoferricin was the most potent in inhibiting HIV-1 reverse transcriptase (IC50 =2 μM). Bovine lactoferricin (IC50 = 10 μM) and bovine lactoferrampin (IC50 = 150 μM) were less potent. Human lactoferrampin and human and bovine lactoferrin (1-11) at 1 mM concentration did not exhibit any inhibitory effect on HIV-1 reverse transcriptase. All peptides showed only a slight inhibitory effect (from slightly below 2% to 6% inhibition) on HIV-1 protease. Human lactoferrampin and bovine lactoferrampin showed obvious inhibitory effect on HIV-1 integrase at 37 μM and 18.5 μM, respectively. The HIV-1 integrase inhibitory activity of human lactoferrampin and bovine lactoferrampin was dose-dependent. The other peptides were devoid of HIV-1 integrase inhibitory activity. Thus, it is concluded that some lactoferrin fragments exert an inhibitory action on HIV-1 reverse transcriptase and HIV-1 integrase.

Escalating chronic kidney diseases of multi-factorial origin in Sri Lanka: causes, solutions, and recommendations

During the last two decades, Sri Lanka, located close to the equator, has experienced an escalating incidence of chronic kidney disease (CKD) of unknown aetiology (CKDue) in dry zonal areas. Similar incidences of unusual CKDs have been reported in the dry zonal, agricultural areas of several other equatorial countries. In Sri Lanka, the incidence of CKDue is highest in the North Central Province (NCP), where approximately 45 % of the country's paddy fields are located. However, in recent years, the disease has spread into areas adjacent to as well as distant from the NCP. The cause of CKD in Sri Lanka is unknown, and may likely due to interactions of different potential agents; thus, CKD is of multi-factorial origin (CKD-mfo). These factors include, the negative effects from overuse of agrochemicals. Nevertheless, the potential interactions and synergism between probable agents have not been studied. This systematic review discusses the proposed hypotheses and causes of CKD-mfo in Sri Lanka, and ways to decrease the incidence of this disease and to eradicate it, and provide some recommendations. During the past decade, a number of groups have investigated this disorder using different methodologies and reported various correlations, but failed to find a cause. Research has focussed on the contamination of water with heavy metals, agrochemicals, hard water, algae, ionicity, climate change, and so forth. Nevertheless, the levels of any of the pollutants or conditions reported in water in NPC are inconsistent not correlated with the prevalence of the disease, and are too low to be the sole cause of CKD-mfo. Meanwhile, several nephrotoxins prevalent in the region, including medications, leptospirosis, toxic herbs, illicit alcohol, locally grown tobacco, and petrochemicals, as well as the effects of changed habits occured over the past four decades have not been studied to date. Taken together, the geographical distribution and overall findings indicate that combinations of factors and/or their interactions are likely to precipitate CKD-mfo, which kills more than 5,000 people annually in Sri Lanka; most victims are middle-aged male farmers. Much anecdotal evidence from this region suggests that consumption of contaminated water is the most likely source of this deadly disease. Although the aetiology is unknown, prevention of this "environmentally acquired" disease seems relatively straightforward. Solutions include (a) preventing environmental pollution, (b) stopping the irresponsible use and decreasing the usage of agrochemicals, and encouraging the use of environmentally friendly agricultural methods, (c) taking proper precautions when using agrochemicals and safe disposal of their containers, (d) changing the risky behaviour of farmers and educating them to preserve the environment, and (e) providing clean potable water to all affected regions. Implementing a well-coordinated, in-depth, region-wide, broad-based research study together with a long-term effective surveillance programme across the country is essential to curbing this disease. Unless firm actions are taken promptly, more than three million healthy people in the country, live in agricultural regions, are at risk for contracting CKD-mfo and succumb to premature deaths, which are preventable.

Escalating chronic kidney diseases of multi-factorial origin in Sri Lanka: causes, solutions, and recommendations

During the last two decades, Sri Lanka, located close to the equator, has experienced an escalating incidence of chronic kidney disease (CKD) of unknown aetiology (CKDue) in dry zonal areas. Similar incidences of unusual CKDs have been reported in the dry zonal, agricultural areas of several other equatorial countries. In Sri Lanka, the incidence of CKDue is highest in the North Central Province (NCP), where approximately 45 % of the country's paddy fields are located. However, in recent years, the disease has spread into areas adjacent to as well as distant from the NCP. The cause of CKD in Sri Lanka is unknown, and may likely due to interactions of different potential agents; thus, CKD is of multi-factorial origin (CKD-mfo). These factors include, the negative effects from overuse of agrochemicals. Nevertheless, the potential interactions and synergism between probable agents have not been studied. This systematic review discusses the proposed hypotheses and causes of CKD-mfo in Sri Lanka, and ways to decrease the incidence of this disease and to eradicate it, and provide some recommendations. During the past decade, a number of groups have investigated this disorder using different methodologies and reported various correlations, but failed to find a cause. Research has focussed on the contamination of water with heavy metals, agrochemicals, hard water, algae, ionicity, climate change, and so forth. Nevertheless, the levels of any of the pollutants or conditions reported in water in NPC are inconsistent not correlated with the prevalence of the disease, and are too low to be the sole cause of CKD-mfo. Meanwhile, several nephrotoxins prevalent in the region, including medications, leptospirosis, toxic herbs, illicit alcohol, locally grown tobacco, and petrochemicals, as well as the effects of changed habits occured over the past four decades have not been studied to date. Taken together, the geographical distribution and overall findings indicate that combinations of factors and/or their interactions are likely to precipitate CKD-mfo, which kills more than 5,000 people annually in Sri Lanka; most victims are middle-aged male farmers. Much anecdotal evidence from this region suggests that consumption of contaminated water is the most likely source of this deadly disease. Although the aetiology is unknown, prevention of this "environmentally acquired" disease seems relatively straightforward. Solutions include (a) preventing environmental pollution, (b) stopping the irresponsible use and decreasing the usage of agrochemicals, and encouraging the use of environmentally friendly agricultural methods, (c) taking proper precautions when using agrochemicals and safe disposal of their containers, (d) changing the risky behaviour of farmers and educating them to preserve the environment, and (e) providing clean potable water to all affected regions. Implementing a well-coordinated, in-depth, region-wide, broad-based research study together with a long-term effective surveillance programme across the country is essential to curbing this disease. Unless firm actions are taken promptly, more than three million healthy people in the country, live in agricultural regions, are at risk for contracting CKD-mfo and succumb to premature deaths, which are preventable.

First report on isolation of methyl gallate with antioxidant, anti-HIV-1 and HIV-1 enzyme inhibitory activities from a mushroom (Pholiota adiposa)

In this study, a compound with antioxidant and anti-HIV activities designated as HEB was first isolated from the edible mushroom Pholiota adiposa by extraction with ethanol and ethyl acetate. HEB was then purified by high performance liquid chromatography (HPLC) and identified to be methyl gallate (C8H8O5, 184.1 Da) based on data from its mass spectrum (MS) and nuclear magnetic resonance (NMR) spectrum. HEB displayed strong antioxidant potency in inhibiting, at 1.36 mM concentration, erythrocyte hemolysis and scavenging DPPH radicals and superoxide anion (O2(-)) by 82.4%, 85.6% and 71.4%, respectively. Besides exhibiting a low cytotoxicity, compound HEB demonstrated significant anti-HIV activity in that it inhibited HIV-1 replication in TZM-BL cells infected by pseudovirus with an IC50 value of 11.9 μM. Further study disclosed that HEB inhibited the viral entry process and activities of key enzymes essential for the HIV-1 life cycle. HEB inhibited HIV-1 reverse transcriptase and integrase activities with an IC50 value of 80.1 μM and 228.5 μM, respectively, and at 10 mM concentration inhibited HIV-1 protease activity by 17.1% which was higher than that achieved by the positive control pepstatin A. Interestingly, this study first revealed that H2O2 stimulation not only activated cell oxidative stress responses, but also accelerated HIV-1 long terminal repeat (LTR) promotion in TZM-BL cells, which was significantly reduced by HEB from 18.2% to about 2%. It implied a direct relationship between the antioxidant and anti-HIV activities of the natural active constituent HEB. Nuclear transcription factor kappa B (NF-κB) signal pathways plays an important role in oxidative stress responses. Meanwhile, there is κB target sequence in HIV promoter LTR which is significant for virus replication and gene expression. In this study, Western Blot assay showed that HEB could inhibit the activation of NF-κB signal pathway stimulated by H2O2 in mouse spleen cells through suppressing NF-κB (p65) translocation into nucleus and NF-kappa-B inhibitor (IκB) degradation in cytoplasm. In summary, the antioxidant HEB from P. adiposa could inhibit HIV-1 replication through multiple target sites. The data suggest that natural antioxidant compounds might have a potential for treatment of AIDS.

Anti-HIV-1 integrase activity of Mimusops elengi leaf extracts

CONTEXT

Integrase (IN) is one of the three human immunodeficiency virus type 1 (HIV-1) enzymes that, together with a reverse transcriptase and protease, allow the virus to reproduce itself after infecting the host cells. Any new knowledge on inhibitors of this enzyme could provide essential clues for the development of anti-HIV drugs.

OBJECTIVE

To evaluate the anti-HIV-1 IN activity of some Thai medicinal plant extracts, and to isolate the active compounds from the extract that possessed the strongest anti-HIV-1 IN activity.

MATERIALS AND METHODS

Ethanol extracts of eight Thai medicinal plants (10-100 µg/mL) were evaluated for their inhibitory effect against HIV-1 IN. An extract of Mimusops elengi L. (Sapotaceae) leaves that possessed the strongest anti-HIV-1 IN activity was fractionated to isolate the active compounds by an anti-HIV-1 IN assay-guided isolation process.

RESULTS AND DISCUSSION

The leaf extract from M. elengi had the strongest anti-HIV-1 IN activity with an IC₅₀ value of 62.1 µg/mL. A bioassay-guided isolation of the active compounds from M. elengi leaf extract resulted in the isolation of active compounds, identified as a mixture of gallocatechin and epigallocatechin. This mixture of gallocatechin and epigallocatechin showed satisfactory anti-HIV-1 IN activity with an IC₅₀ value of 35.0 µM. A flavanol glycoside, mearnsitrin was also isolated but was inactive at a concentration of 100 µM.

Effects of adenosine extract from Pholiota adiposa (Fr.) quel on mRNA expressions of superoxide dismutase and immunomodulatory cytokines

Pholiota adiposa is a kind of edible mushroom which has long been known for its health care applications. To reveal the exact mechanism of its protective functions in humans, in this study we isolated and identified the active compound PB3 of P. adiposa for the first time by a combination of chromatography techniques, including NKA macroporous resin and Sephadex G-15. PB3, with molecular mass of 267.2 Da and molecular formula of C₁₀H₁₃N₅O₄ discovered by mass spectrum (MS) was identified to be adenosine. Mice were injected intraperitoneally with purified fraction PB3. Seven days after injection, we found a 1.5-fold increase of IL10 at the mRNA level, while a down regulated expression of IL-2, IL-6 and IFN-γ to 49.0%, 56.9% and 73.4%, respectively, was detected in spleen by real-time quantitative PCR. What’s more, SOD expression level was significantly increased by 1.6-fold compared to control. Fraction PB3 displayed anti-inflammatory potency and heightened SOD activity on the transcriptional level, which could be considered of further pharmaceutical or medication value.