Positive Control Quercetin Research Articles

Chemical Constituents from a Mangrove-Derived Actinobacteria Isoptericola chiayiensis BCRC 16888 and Evaluation of Their Anti-NO Activity.

Cultivation of the actinobacteria strain Isoptericola chiayiensis, a mangrove-derived actinobacteria that was isolated from a mangrove soil collected in Chiayi County, resulted in the isolation of one new 2-furanone derivative, isopterfuranone (1), one new sesquiterpenoid, isopterchiayione (2), one new benzenoid derivative, isopterinoid (3), five new flavonoids, chiayiflavans A-E (4-8), and 4 metabolites isolated for the first time from nature source, methyl 3-(4-methyl-2,5-dioxopyrrolidin-3-yl)propanoate (9), 3-ethyl-4-methylpyrrolidine-2,5-dione (10), chiayiensol (11) and chiayiensic acid (12). Their structures were determined through in-depth spectroscopic and mass-spectrometric analyses. Most of the isolates showed potent inhibitory effects on NO production in LPS-stimulated RAW 264.7 murine macrophages cells with IC50 values ranging from 9.36 to 40.02 μM. Of these isolates, 4 and 5 showed NO inhibitory activity with IC50 values of 17.14 and 9.36 μM, stronger than the positive control quercetin (IC50 =36.95 μM). This is the first report on flavan metabolites from the genus Isoptericola.

Triterpene Acids from Mesona procumbens Exert Anti-inflammatory Effects on LPS-Stimulated Murine Macrophages by Regulating the MAPK Signaling Pathway.

Five new triterpene acids, mesonaic acids A-C (1-3), 2α,3α,19α-trihydroxy-24-nor-4(23),12-oleanadien-28-oic acid (4), and 3α,19α,22α-trihydroxy-2-oxo-12-ursen-28-oic acid (5), and 10 known triterpene acid compounds (6-15) were isolated from a methanolic extract of Mesona procumbens. Triterpenes 1-3 possess unusual hexacyclic skeletons with a 13α,27-cyclopropane ring. Regarding their anti-inflammatory activity, compounds 1-3, 6, and 7 inhibited NO production with EC50 values lower than 15 μM, which were better than that of the positive control quercetin. Compounds 1-3, 6, and 7 markedly decreased levels of the inducible iNOS and COX-2 proteins in macrophages by inhibiting the activation of NF-κB through interference with the MAPK signaling pathway. Based on these data, compounds 1-3, 6, and 7 have great potential as NO inhibitors.

Dibenzocyclooctadiene lignans from Artemisia sieversiana and their anti-inflammatory activities.

Two previously undescribed dibenzocyclooctadiene lignans, named sieverlignans D-E (1-2), as well as eight known ones (3-10), were isolated from the aerial parts of Artemisia sieversiana. Their structures were elucidated from extensive spectroscopic analysis, including HRMS, NMR and electronic circular dichroism (ECD) experiments. This study is the first to report dibenzocyclooctadiene lignans in the genus Artemisia and this plant. All the compounds were evaluated for their anti-neuroinflammatory activities on the lipopolysaccharides (LPS)-induced nitric oxide production in BV-2 murine microglial cells. Compounds 1 and 6 exhibited the moderate activities with their IC50 values of 47.7 and 21.9μM, compared to a positive control quercetin with the IC50 value of 16.0μM.

Chemical Constituents and their Antioxidant, Anti-Inflammatory and Anti-Acetylcholinesterase Activities from Pholidota cantonensis.

Alzheimer's disease (AD) has the third highest health expenditures after heart disease and cancer. It has emerged as a serious global health issue. The discovery of new drugs to prevent and treat AD is of utmost importance. Pholidota cantonensis is an edible medicinal plant consumed in China. It is widely used in traditional Chinese medicine to treat various diseases. P. cantonensis has been reported to have antioxidant, anti-inflammatory, antitumor and antibacterial activities. Among these properties, its potent antioxidant activity has attracted our attention, since oxidative stress is one of the important pathological mechanisms involved in AD. This study aimed to isolate the compounds from the active extract and evaluate their bioactivities. Fifteen compounds, including one new compound, were obtained. The isolates were tested for 2,2'-diphenyl-1-picrylhydrazyl (DPPH)/2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activities, anti-acetylcholinesterase (anti-AChE) activities and inhibitory effects on nitrogen monoxide (NO) release in the BV-2 cells. Compounds 1, 2, 4, 6, 8, and 13-15 exhibited two kinds of AD-associated bioactivities. More importantly, compound 13 showed more potent NO inhibitory activity (IC50 = 0.72 ± 0.08μM) than the positive control quercetin (IC50 = 12.94 ± 0.08μM). Compound 13 also had a higher inhibitory rate (99.59 ± 0.43%) on AChE than that of the positive control galantamine (78.32 ± 1.16%) at the concentrate of 50μg/mL. Our studies provide new insights into this plant in terms of its potential in the development of new multi-target anti-Alzheimer's disease (anti-AD) drugs.

Flavonoids with anti-inflammatory activities from Daphne giraldii

The stem and root barks of Daphne giraldii Nitsche, also known as “Zushima”, is a traditional Chinese medicine with a long history of treating a variety of diseases such as rheumatism arthralgia, quadriplegia, headache, stomachache, waistache, and bruises. Chromatographic fractionation of the EtOH extracts of “Zushima” has led to the isolation of 26 flavonoids, including ten flavonols (1, 2, and 4–11), one flavone (12), two dihydroflavones (13 and 14), a dihydroflavonol (15), six flavans (3 and 16–20), three chalcones (21–23), and three 1,3-diarylpropanes (24–26). Daphgiflavones A−C (1–3) were new flavonoids. Their structures were elucidated by spectroscopic analysis. All compounds were evaluated for anti-inflammatory properties by testing their inhibitory activities against nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated murine RAW264.7 macrophages. Compounds 8, 11, 21, and 23 exhibited significant inhibition on NO production with IC50 values ranging from 2.26 to 6.88 μM, being more active than the positive control quercetin (IC50: 14.16 μM).

Nitric Oxide Production Inhibitory Eudesmane-Type Sesquiterpenoids from Artemisia argyi.

Six new eudesmane-type sesquiterpene derivatives, artemargyinins A-F were isolated from the leaves of Artemisia argyi. Their structures were elucidated based on the extensive analysis of spectroscopic data. Artemargyinins A-F feature a lactone ring-opening eudesmane-type sesquiterpene with an isoprenoid group at C(8). All compounds were tested for their inhibitory effects on lipopolysaccharide-induced nitric oxide (NO) production in RAW264.7 macrophages. Artemargyinins A-F showed more potent NO production inhibitory activity with IC50 values ranging from 7.66±0.53 to 61.19±2.54 μM than the positive control quercetin (IC50 =74.34±1.39 μM). Among them, artemargyinins C and D exhibited strong inhibitory activity with IC50 values of 8.08±0.21 and 7.66±0.53 μM, respectively.

Two new ditetrahydrofuran lignans from Artemisia sieversiana

Two new ditetrahydrofuran lignans, named sieverlignans A and B (1 and 2), together with six known ones (3–8), were isolated from the aerial parts of Artemisia sieversiana. Their structures were established on the basis of spectroscopic analysis including HRMS, NMR spectra and circular dichroism experiments. All the compounds were evaluated for their anti-neuroinflammatory effects on the lipopolysaccharides (LPS)-induced nitric oxide production in BV-2 murine microglial cells. Compound 2 exhibited the significant activity with its IC50 value of 11.9 ± 0.8 μM, respectively, compared to a positive control quercetin with its IC50 value of 16.0 ± 1.1 μM.

Metabolomic Determination of Specialized Metabolites Using Liquid Chromatography-Tandem Mass Spectrometry in the Traditional Chinese Medicines Astragali Radix and Hedysari Radix

The Traditional Chinese Medicines (TCMs) Astragali Radix (AR) derived from Astragalus membranaceus (Fisch.) Bge. var. mongholicus (Bge.) Hsiao and A. membranaceus (Fisch.) Bge., and Hedysari Radix (HR) derived from Hedysarum polybotrys Hand.-Mazz. (family Leguminosae) are well-known for increasing the tonic effects on “Qi.” A better insight into the specialized (secondary) metabolites is essential to understand the effects of TCM; however, such metabolites remain largely unknown. Here, we performed a metabolomics-based analysis using liquid chromatography-tandem mass spectrometry in 3 plant tissues—periderm, phloem, and xylem—to identify potential bioactive metabolites. Multivariate statistical analysis revealed 29 metabolites showing a significant difference between groups and 10 biomarker candidates of AR and HR. An anti-inflammatory assay showed that the xylem of both AR and HR and the phloem of HR showed higher anti-inflammatory activity than the positive control quercetin in terms of nitric oxide inhibition.

Synergistic activity of extracts of three South African alien invasive weeds combined with conventional antibiotics against selected opportunistic pathogens

Plants are known to play a major role in the treatment of microbial infections, as they contain important bioactive components that may act in synergism with conventional antibiotics, which are presently under threat of microbial resistance. Synergistic activity between dichloromethane, acetone, 70% ethanol, 50% methanol and hot water extracts of three southern African alien invasive plant species, namely Chromolaena odorata, Gomphrena celosioides and Tithonia rotundifolia and gentamicin, streptomycin, rifampicin and amphotericin B was studied using the checkerboard method. Antioxidant activity of the extracts was determined using the quantitative 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) decolourisation methods. The anti-inflammatory activity was determined with the 15-lipoxygenase enzyme assay. Synergistic to additive effects were observed among all tested extracts in combination with the conventional antibiotics against most of the tested strains. This was evident when the extracts were combined with gentamicin or amphotericin B against Klebsiella pneumoniae, Enterococcus faecalis, Salmonella Typhimurium, Cryptococcus neoformans and Candida albicans. The extracts of C. odorata had the best antioxidant activity in the ABTS assay with the 70% ethanol extract showing a minimum inhibitory concentration (IC50) of 1.960 μg/mL, better than that of vitamin C (IC50 = 2.027 μg/mL). The dichloromethane extract of T. rotundifolia displayed promising radical scavenging activity in the DPPH assay with an IC50 of 16.231 μg/mL. Most of the extracts of C. odorata (except the acetone extract) had anti-inflammatory activity better than that of the positive control quercetin (IC50 = 24.601 μg/mL). Results from this study indicate that extracts of these weedy plant species contain bioactive compounds that may act in synergy with conventional antibiotics in the fight against resistant microbial strains. Additionally they may reduce oxidative stress and inflammation.

Extracts of Two Relatively Safe South African Alien Weeds have Synergistic Activity with Conventional Antibiotics against some Urinary Tract Pathogens

Plants have potential to play a role in the treatment of urinary tract infections, as they contain important bioactive components. These bioactive components may act in synergism with conventional antibiotics which are presently under threat of microbial resistance. They also play a key role in the reduction of oxidative stress. Synergistic activity of dichloromethane, acetone, 70% ethanol, 50% methanol and hot water extracts of the southern African alien weeds Chromolaena odorata and Tithonia rotundifolia combined with gentamicin and amphotericin B was studied using the checkerboard method. Antioxidant activity of the extracts was determined using the quantitative 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging and 2,2′‐azinobis‐(3‐ethylbenzothiazoline‐6‐sulfonic acid) (ABTS) decolorisation methods. The anti‐inflammatory activity was determined through the 15‐lipoxygense enzyme assay. Toxicity screening of the extracts was carried out against Vero monkey kidney, human carcinoma Caco‐2 and human liver C3A cell lines using a colorimetric assay. Synergistic to additive effects were observed among all tested extracts in combination with the conventional antibiotics against all tested strains which are Escherichia coli, Enterococcus faecalis, Klebsiella pneumoniae, Salmonella Typhimurium, Aspergillus fumigatus and Candida albicans. Although the extracts of both plant species had antioxidant activity, the extracts of C. odorata displayed better activity in the ABTS assay with the 70% ethanol extract showing a 50% inhibitory concentration (IC50) of 1.96 μg/mL, better than that of vitamin C (IC50 = 2.027 μg/mL). The dichloromethane extract of T. rotundifolia had better radical scavenging activity in the DPPH assay with an IC50 of 16.231 μg/mL. All the extracts of C. odorata had anti‐inflammatory activity better than that of the positive control quercetin (IC50 = 24.601 μg/mL) except for the acetone extract which was slightly higher (IC50 = 26.098) than the positive control. Lethal concentrations (LC50) of the extracts against Vero, Caco‐2 and C3A cells ranged from 0.78 to 0.96mg/mL, 0.198 to 0.32mg/mL and 0.67 to 0.88 mg/mL respectively, indicating that the extracts are relatively safe in vitro. Results from this study indicate that the extracts of these weedy plant species contain comparatively non‐cytotoxic bioactive compounds that may act in synergy with conventional antibiotics in the treatment of urinary tract infections. Additionally they may reduce oxidative stress and inflammation. Further studies to determine the active component(s) of these weed plants are ongoing.Support or Funding InformationNo fundingThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

New coumarins and monoterpene galloylglycoside from the stem bark of Sapium baccatum

Sapium baccatum has been traditionally used as therapeutic remedies. To support its medicinal benefits, our current phytochemical investigation attempted to further discover novel bioactive compounds from S. baccatum. Eight new phenolic compounds, namely, seven coumarins (1–7) and one monoterpene galloylglycoside (8), together with 23 (9–31) known compounds were isolated. Their structures were determined by extensive spectroscopic methods and comparison with literatures. The three pairs of enantiomers of 1, 2 and 7 were confirmed on the basis of HPLC chiral analysis, electronic circular dichroism data and optical rotations. Two coumarins (1–2) were proven to be artifacts through HPLC analysis. The inhibitory effects on TNF-α secretion were examined biologically in LPS-induced BV2 microglia cells and all of the tested compounds exhibited significant inhibitory activity, especially new compound 1 possessed stronger inhibitory effects compared to the positive control quercetin. In addition, compounds 14 and 15 showed weak antifungal activity against Candida albicans SC5314 with MIC values both at 64 μg/mL. The results laid a solid foundation for additional research on S.baccatum related to its anti-inflammatory and antifungal medicinal value.

A New Lipoxygenase Inhibitory Flavonoid from the Kino of Eucalyptus citriodora

A new lipoxygenase inhibitory flavonoid, 8-[1-(p-hydroxyphenyl)ethyl]rhamnocitrin (1), together with four known compounds, cinnamic acid (2), p-coumaric acid (3), caffeic acid (4), and gallic acid (5), was isolated from the kino of Eucalyptus citriodora, and their structures were elucidated on the basis of spectroscopic methods including 2D NMR spectra. These compounds were tested for inhibitory activity against 15-lipoxygenase. Compound 1 showed stronger inhibitory activity (IC50 27.6 ± 0.7 μM) than the positive control quercetin (IC50 37.5 ± 0.8 μM).

Anti-inflammatory and antioxidant properties of leaf extracts of eleven South African medicinal plants used traditionally to treat inflammation

Ethnopharmacological relevanceInflammation is a complex mechanism employed by the body to promote healing and restoration to normal function in the event of injury. Eleven plant species were selected in this study based on their use in traditional medicine against inflammation in South Africa. MethodsHexane, acetone, ethanol, methanol and water extracts of the powdered plants were prepared and a total of fifty-five extracts were tested for their anti-inflammatory and antioxidant activities. The anti-inflammatory activity of extracts was evaluated via the 15-lipoxygenase (15-LOX) inhibitory and the nitric oxide (NO) inhibition assays using lipopolysaccharide (LPS)-activated RAW 264.7 murine macrophages. Total flavonoid and total phenolic contents were determined. The antioxidant activity of the extracts was performed using radical scavenging DPPH (2, 2-diphenyl-1-picrylhydrazyl) and electron reducing ABTS (2, 2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) assays. ResultsThe hexane extract of Typha capensis (TC) had good lipoxygenase inhibitory activity with IC50 of 4.65 µg/mL, significantly (p < 0.05) higher than that of the positive control quercetin (IC50 = 24.60). The same extract also had good nitric oxide inhibitory activity with 86% NO inhibition and cell viability of 97% at 50 µg/mL. The TC acetone extract had the best antioxidant activity with IC50 of 7.11 and 1.91 µg/mL respectively in the DPPH and ABTS assays. Following fractionation of the TC plant material, the ethyl acetate fraction had interesting antioxidant activity and the methanol/water (35%) and hexane fractions had good 15-LOX inhibitory activity. The antioxidant and anti-inflammatory activities therefore resided in both polar and more non-polar fractions. ConclusionThe acetone extract of Typha capensis and its fractions had good anti-inflammatory and antioxidant activities, supporting the medicinal use of this species against inflammation. Other species including Ficus elastica, Carpobrotus edulis, Cotyledon orbiculata and Senna italica also had good activity worthy of further investigation.

Acridone alkaloids from the rhizomes of Luvunga scandens (Roxb.) Buch. Ham.

The ethyl acetate extract of the rhizomes of Luvunga scandens (Roxb.) Buch. - Ham. ex Wight & Arn (Rutaceae) delivered one new acridone alkaloid named Luvungaside A (1) together with three known acridone alkaloids, namely 1,3-dihydroxy-2-methoxy-10-methyl-9-acridone (2), arborinine (3) and 1-hydroxy-3-methoxy-10-methyl-9-acridone (4). Compounds were reported for the first time from the species L. scandens applying various chromatography methods. Chemical structures were elucidated by IR, UV, HR-ESI-MS, NMR 1D & 2D experiments and comparison with the literature. The cytotoxicity and hepatoprotective activity of compounds 1–4 in human hepatoma cell line HepG2 was measured by MTT assay. At 10–100 μM, compounds expressed significant hepatoprotective effect with prevention percentage ranging from 81.1% to 194.3%, compared to the positive control quercetin displaying 49.0%.

Traditional medicines used by Q’eqchi’ Maya to treat diabetic symptoms and their antiglycation potential

Ethnopharmacological relevanceBecause of the recent increase in type 2 diabetes and the need for complementary treatments in remote communities in many parts of the world, we undertook a study of treatments for diabetic symptoms used by traditional Q’eqchi’ Maya healers of Belize. We used quantitative ethnobotany to rank culturally important taxa and subsequent pharmacological and phytochemical studies to assess bioactivity. Materials and methodsAntidiabetic plants identified in field interviews with traditional healers were ranked by syndromic importance value (SIV) based on 15 symptoms of diabetes. Species ranked with high SIV were tested in an assay relevant to many diabetes complications, the advanced glycation endproduct (AGE) inhibition assay. Active principles were identified by phytochemical analysis and bioassay. ResultsWe collected over 70 plant species having a promising SIV score. The plants represented a broad range of neotropical taxa. Selected Q’eqchi’ antidiabetic plants with high SIV were collected in bulk and tested in the advanced glycation endproduct (AGE) inhibition assay. All plant extracts showed AGE inhibition and the half maximal inhibitory concentration (IC50) ranged from 40.8 to 733 µg/mL, while the most active species was Tynanthus guatemalensis Donn (Bignoniaceae). A linear regression showed a significant relationship between 1/ IC50 and SIV. Phytochemical analysis revealed the presence of verbascoside, as a major component and active principle of the T guatemalensis which had an IC50 = 5.1 µg/mL, comparable to the positive control quercetin. ConclusionThe results reveal a rich botanical tradition of antidiabetic symptom treatments among the Q’eqchi’. Study of highly ranked plants revealed their activity in AGE inhibition correlated with SIV. T. guatemalensis was identified as a promising species for further evaluation and local use.

Three new lignanamides from the root of Lycium chinense with anti-inflammatory activity

Three new lignanamides, that is, a new lignanamide (1), and a pair of enantiomers (2a and 2b) were isolated from the EtOAc-soluble fraction of an EtOH extract of the root of Lycium chinense. The structures of these new compounds, including their absolute configuration, were established on the basis of HR-ESI-MS, NMR spectroscopic data and quantum chemical ECD calculations. Compound 2a showed significant anti-inflammatory activity in LPS-induced RAW 264.7 macrophages with the IC50 value of 10.77 ± 2.14 μM, comparing to that of positive control quercetin (17.21 ± 0.50 μM).

Antibacterial activity of Azadirachta indica, Pongamia pinnata, Psidium guajava and Mangifera indica and their mechanism of action against Streptococcus mutans

Background: Curative plants have reportedly been used to make chewing sticks/toothbrushes intended for the treatment of oral diseases. Objective: The in vitro antibacterial activities of Azadirachta indica, Pongamia pinnata, Psidium guajava, and Mangifera indica were evaluated against Streptococcus mutans, along with the cytotoxicity and antioxidant and synergistic potentials. The effect of M. indica on the expression of crucial virulence genes spaP and gtfB of S. mutans was determined. Materials and Methods: The antibacterial activity was determined using a modified microdilution method. The antioxidant potential was evaluated using diphenyl picrylhydrazyl (DPPH), Griess reagent, and nitroblue tetrazolium calorimetric assays. The synergistic activity was investigated using a modified checkerboard method, while the cytotoxicity was determined according to a cell proliferation 2,3-Bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide salt assay. Reverse transcription was the chosen method for determining the difference in expression of the spaP and gtfB genes after treatment with the plant sample. Results: M. indica and A. indica had the highest antibacterial activity at concentrations of 0.3 mg/ml and 6.25 mg/ml, respectively. A. indica had the best free radical scavenging of DPPH, exhibiting 50% inhibition at 28.72 μg/ml; while M. indica showed better superoxide scavenging potential than the positive control quercetin. Both M. indica and A. indica had adequate activity against the nitric oxide-free radical (12.87 and 18.89 μg/ml, respectively). M. indica selectively reduced the expression of the gtfB gene, indicating a mechanism involving Glucotranferases, specifically targeting bacterial attachment. Conclusion: The overall good antibacterial activity of M. indica correlated with the general good antioxidant capacity, while showing a potentially unique mechanism of bacterial inhibition, targeting virulence gene expression. Abbreviations used: AA: Ascorbic acid; BHI: Brain–heart infusion; CHX: Chlorhexidine; DPPH: Diphenyl picrylhydrazyl; DMSO: Dimethlysulfoxide; NBT: Nitroblue tetrazolium; NO: Nitric oxide; XTT: 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5 -carboxanilide salt.

Antibacterial activity of Azadirachta indica, Pongamia pinnata, Psidium guajava, and Mangifera indica and their mechanism of action against Streptococcus mutans

Background:Curative plants have reportedly been used to make chewing sticks/toothbrushes intended for the treatment of oral diseases.Objective:The in vitro antibacterial activities of Azadirachta indica, Pongamia pinnata, Psidium guajava, and Mangifera indica were evaluated against Streptococcus mutans, along with the cytotoxicity and antioxidant and synergistic potentials. The effect of M. indica on the expression of crucial virulence genes spaP and gtfB of S. mutans was determined.Materials and Methods:The antibacterial activity was determined using a modified microdilution method. The antioxidant potential was evaluated using diphenyl picrylhydrazyl (DPPH), Griess reagent, and nitroblue tetrazolium calorimetric assays. The synergistic activity was investigated using a modified checkerboard method, while the cytotoxicity was determined according to a cell proliferation 2,3-Bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide salt assay. Reverse transcription was the chosen method for determining the difference in expression of the spaP and gtfB genes after treatment with the plant sample.Results:M. indica and A. indica had the highest antibacterial activity at concentrations of 0.3 mg/ml and 6.25 mg/ml, respectively. A. indica had the best free radical scavenging of DPPH, exhibiting 50% inhibition at 28.72 μg/ml; while M. indica showed better superoxide scavenging potential than the positive control quercetin. Both M. indica and A. indica had adequate activity against the nitric oxide-free radical (12.87 and 18.89 μg/ml, respectively). M. indica selectively reduced the expression of the gtfB gene, indicating a mechanism involving Glucotranferases, specifically targeting bacterial attachment.SUMMARY Mangifera indica and Azadirachta indica had very good antibacterial activity against Streptococcus mutans and moderate toxicity against Vero cellsM. indica had the best antioxidant capacity overallM. indica reduced the expression of gtfB gene at 0.5 mg/ml. Abbreviations used: AA: Ascorbic acid; BHI: Brain–heart infusion; CHX: Chlorhexidine; DPPH: Diphenyl picrylhydrazyl; DMSO: Dimethlysulfoxide; NBT: Nitroblue tetrazolium; NO: Nitric oxide;

Comparative molecular docking studies of lupeol and lupenone isolated from Pueraria lobata that inhibits BACE1: Probable remedies for Alzheimer's disease.

To discover lead lupane triterpenoid's potential isolated from Pueraria lobata roots against β-site amyloid precursor protein cleaving enzyme 1 (BACE1), which serve as a rate limiting step in amyloid beta (Aβ) production altering the course of Alzheimer's disease. In addition, enzyme kinetics study and molecular docking were conducted to establish the inhibition type and structure activity relationship. A systematic study of 70% ethanolic P. lobata root extract was employed to identify its BACE1 inhibitory potential. Further, BACE1 inhibitory potential of two lupane terpenoids, yielded from ethanolic extract, was assessed. In order to determine their inhibition mode, Lineweaver-Burk plots and Michaelis-Menten model for BACE1 was performed. AutoDock 4.2 program in addition determined the molecular interaction of BACE1 with isolated terpenoids. Considering the inhibitory potential of 70% ethanolic extract of P. lobata against BACE1 (IC50=80.35μg/mL), lupeol and lupenone were subsequently isolated and exhibited notable or moderate BACE1 inhibitory activity with IC50 values of 5.12 and 62.98μmol/L, respectively, as compared to the positive control quercetin (IC50=21.28μmol/L). The enzyme kinetics study enabled us to identify both compounds as competitive inhibitors, where lupeol displayed a very potent inhibition against BACE1 with low inhibition constant (Ki) value of 1.43μmol/L, signifying greater binding affinity. In order to understand the binding mechanism and structure-activity relationship of two triterpene-based BACE1 inhibitors, we employed computer aided docking studies which evidently revealed that hydroxyl group of lupeol formed two hydrogen bonds with the ASP32 (catalytic aspartic residue) and SER35 residues of BACE1 with the binding energy of (-8.2kcal/mol), while the ketone group of lupenone did not form any hydrogen bonds with BACE1 giving evidence for less binding affinity. These results in turn have predicted the dependence of the inhibitory activity in the presence of hydroxyl group which has provided a new basis for BACE1 blockade. Our results have successfully explored the molecular mechanism of lupane triterpenoids via BACE1 inhibition, suggesting that lupeol in particular could be utilized as a useful therapeutic and preventive agent to mitigate Alzheimer's disease.

In vitro anti-inflammatory activities of blacklip abalone (Haliotis rubra) in RAW 264.7 macrophages

ABSTRACTAbalone (Haliotis sp) has been used as a traditional functional food for many years by different cultures believing that consumption provides health benefits. We investigated the anti-inflammatory activity from blacklip abalone visceral waste. An extract was prepared from the viscera using digestion with the food grade proteases papain and bromelain followed by anion exchange chromatography (AEC). The anti-inflammatory potential of the extract and AEC fractions were investigated in comparison to a plant-derived positive control (quercetin) through the inhibition of lipopolysaccharide-stimulated nitric oxide production in RAW 264.7 monocytes. Significant anti-inflammatory activity was observed in response to the abalone extract and the unbound AEC material over a concentration (based on collagen) range of 12–96 µg/mL. Overall, results indicated that blacklip abalone extract has anti-inflammatory activity in vitro, warranting further investigation into the bioactive constituents that may be potential anti-inflammatory therapeutics.