Antioxidant,antimicrobial,and α-glucosidase inhibitory activities of saponin extracts from walnut(Juglans regia L.) leaves

Objective:To investigate the relationship between triterpenoid saponin content and antioxidant,antimicrobial,and α-glucosidase inhibitory activities of 70%ethanolic,butanolic,aqueous,supernate and precipitate extracts of Juglans regia leaves.Methods:Triterpenoid saponins of different Juglans regia leaf extracts were measured by the vanillin method.Antioxidant activity was evaluated against DPPH and ABTS free radicals.We also assessed α-glucosidase inhibitory and antimicrobial activities of the leaf extracts.Pearson’s correlation coefficient was evaluated to determine the correlation between the saponin content and biological activities.Results:The butanolic extract was most effective against DPPH with an IC50of 6.63μg/mL,while the aqueous extract showed the highest scavenging activity against ABTS free radical with an IC50of 42.27μg/mL.Pearson’s correlation analysis indicated a strong negative correlation (r=-0.956) between DPPH radical scavenging activity (IC50) and the saponin content in the samples examined.In addition,the aqueous extract showed the best α-glucosidase inhibitory activity compared with other extracts.All the extracts had fair antibacterial activity against Bacillus subtilis,Escherichia coli,and Klebsiella pneumoniae except for the aqueous extract.Conclusions:Juglans regia extracts show potent antioxidant,antimicrobial,and α-glucosidase inhibitory activities.There is a correlation between saponin levels in Juglans regia leaf extracts and the studied activities.However,additional research is required to establish these relationships by identifying the specific saponin molecules responsible for these activities and elucidating their mechanisms of action.

Evaluation of bioactive flavonoids in Citri Reticulatae Pericarpium from different regions and its association with antioxidant andα-glucosidase inhibitory activities

Background:To explore the differences of 14 batches of Citri Reticulatae Pericarpium from different regions.Methods:The main aim of this study was to develop a high-performance liquid chromatography method-photodiode array detection for determining the contents of five flavonoids and the chromatographic fingerprints of Citri Reticulatae Pericarpium from different regions.Theα-glucosidase inhibitory activities and antioxidant properties of Citri Reticulatae Pericarpium,based on free-radical scavenging assays against 1,1-diphenyl-2-picrylhydrazyl,2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid),and hydroxyl radicals,were estimated and compared.Results:Among the tested compounds,the content of hesperidin(13.386-68.235 mg/g)was the highest and that of hesperitin(0.045-0.277 mg/g)was the lowest.In comparing different sources of Citri Reticulatae Pericarpium,the contents of narirutin in Citri Reticulatae Pericarpium from Guangdong(0.824-0.851 mg/g)and Sichuan(1.069-1.204 mg/g)provinces of China were lower than in other provinces.In contrast,nobiletin(8.429-12.237 mg/g)and tangeretin(3.947-4.613 mg/g)were most abundant in Guangdong sources of Citri Reticulatae Pericarpium,followed by samples from Sichuan Province(nobiletin:6.761-7.658 mg/g;tangeretin:3.422-3.933 mg/g).Correlation analysis showed that nobiletin and tangeretin were the main contributors to the antioxidant capacity,and narirutin was the main active component inhibiting theα-glucosidase activity of Citri Reticulatae Pericarpium.Conclusion:This work revealed that the intrinsic quality of Citri Reticulatae Pericarpium was affected by different growing regions,which provides a scientific basis for controlling the quality of Citri Reticulatae Pericarpium and rationally developing and utilizing Citri Reticulatae Pericarpium.

Cucurbitane-Type Triterpene Glycosides from Momordica charantia and Their α-Glucosidase Inhibitory Activities

Ten cucurbitane-type triterpene glycosides,including five new compounds named charantosides H(1),J(2),K(3),momor-characoside A(4),goyaglycoside-l(5),and five known compounds(6-10),were isolated from the EtOAc extract of Momor-dica charantia fruits.The chemical structures of these compounds were identified by 1D and 2D NMR and HRESIMS spectroscopic analyses.Configurations of new compounds were determined by ROESY correlations and comparison of their 13C NMR data with literature reported values.All compounds were evaluated for their inhibition againstα-glucosidase,in which compounds 2,5,7,8,9 showed moderate inhibitory activities with IC50 values ranging from 28.40 to 63.26μM comparing with the positive control(acarbose,IC5087.65±6.51μM).

Antioxidant andα-glucosidase inhibitiory activity of Cercis chinensis flowers

Antioxidant andα-glucosidase inhibitiory active compounds of Cercis chinensis flowers were investigated with bio-assay guiding method.Ethyl acetate fraction(CLEa)and n-butanol fraction(CLBu)exhibited antioxidant andα-glucosidase inhibitiory activity in vitro,and the corresponding active fractions,EaFr.3,EaFr.5 and BuFr.1,exhibited higher antioxidant andα-glucosidase inhibitiory activity than those of other fractions.Eight compounds,ethyl gallate(1),stearic acid(2),docosanoic acid(3),5α-stigmast-9(11)-en-3β-ol(4),kaempferol-3-O-α-rhamnopyranoside(5),vanillic acid(6),fisetin(7),andβ-sitosterol(8),were isolated and identified from CLEa and CLBu.Ethyl gallate shown the highest antioxidant activity by scavenging DPPH radical and reducing ferric compared.Docosanoic acid and vanillic acid shown strongerα-glucosidase inhibitory activity than that of acarbose.

Bioactive constituents from the leaves of Quercus phillyraeoides A.Gray for-glucosidase inhibitor activity with concurrent antioxidant activity

Severalα-glucosidase inhibitory constituents were isolated from the methanolic extract of the leaves of Quercus phillyraeoides A.Gray(Q.phillyraeoides)using a bioassay-guided fractionation technique.Further separation and purification of the methanol-soluble fraction led to the isolation of constituents with moderate and strong inhibitory activities againstα-glucosidase:α-sitosterol-d-glucoside(1)and condensed tannin fractions(2,3,4,5,and 6).Compound 1 and fractions 2-6 had inhibitory concentration(IC50)values againstm-glucosidase from Saccharomyces cerevisiae of 118.8,2.79,2.78,3.10,2.60,and 3.14μg/mL,respectively,while quercetin as the standard had an IC50 value of 4.80mg/mL.Furthermore,the significant antioxidant activities were evaluated using several assays,such as the DPPH radical scavenging,hydrogen peroxide radical scavenging,reducing power,andβ-carotene-linoleate bleaching assays,and the results suggested that the isolated constituents showed their possible application for treating the hyperglycemia-induced oxidative stress.The results of the present study showed the potential of Q.phillyraeoides as a rich source of natural antidiabetic medicine.

A Pair of New Spirocyclic Alkaloid Enantiomers with TrxR Inhibitory Activities Were Isolated from Marine-Derived Aspergillus ruber TX-M4-1

One new spirocyclic alkaloid,5-isopentenyl-cryptoechinuline D(1),along with 11 known compounds(2–12),were iso-lated from a marine fungus Aspergillus ruber TX-M4-1.The structures of compounds 1–12 were elucidated by spectroscopic evi-dences.Compound 1 was initially isolated as an enantiomer,and further separation of 1 by chiral HPLC afforded a pair of enantio-mers,including(-)-5-isopentenyl-cryptoechinuline D(1a)and(+)-5-isopentenyl-cryptoechinuline D(1b).Their absolute configura-tions were elucidated by ECD spectroscopic data.Compounds 1a,5 and 10 could inhibit thioredoxin reductase(TrxR)activity with IC50 values of 6.2,36.3 and 18.6μmol L^(-1),respectively.Surface plasmon resonance(SPR)study also demonsrated the interactions between compounds 6,8 and Niemann-Pick C1 Like 1(NPC1L1)respectively,which indicate that compounds 6 and 8 are potential NPC1L1 inhibitors.

QSAR Studies on the Inhibitory Activityof Levofloxacin-thiadiazole HDACi Conjugates to Histone Deacetylases

A molecular electronegativity distance vector(M)based on 13 atomic types has been used to describe the structures of 19 conjugates(LHCc)of levofloxacin-thiadiazole HDAC inhibitor(HDACi)and related inhibitory activities(pH,i=1,2,6)of LHCc against histone deacetylases(HDACs,such as HDAC1,HDAC2 and HDAC6).The quantitative structure-activity relationships(QSAR)were established by using leaps-and-bounds regression analysis for the inhibitory activities(pH)of 19 above compounds to HDAC1,HDAC2 and HDAC6 along with M.The correlation coefficients(R~2)and the leave-one-out(LOO)cross validation Rfor the pH,pHand pHmodels were 0.976 and 0.949;0.985 and 0.977;0.976 and 0.932,respectively.The QSAR models had favorable correlations,as well as robustness and good prediction capability by R~2,F,R~2,A,Fand Vtests.Validated by using 3876 training sets,the models have good external prediction ability.The results indicate that the molecular structural units:–CH–(g=1,2),–NH,–OH,=O,–O–and–S–are the main factors which can affect the inhibitory activity of pH,pHas well as pHbioactivities of these compounds directly.Accordingly,the main interactions between HDACs inhibitor and HDACs are hydrophobic interaction,hydrogen bond,and coordination with Znto form compounds,which is consistent with the results in reports.

Moving fast, thinking fast:The relations of physical activity levels and bouts to neuroelectric indices of inhibitory control in preadolescents

Background:Structured vigorous physical activity(VPA)can improve cognitive control in children,but studies relating daily physical activity(PA)to cognitive control have yielded conflicting findings.While objectively measured daily PA summarizes all occurrences of PA within a registered period,a minimum duration of continuous PA is required for registration of a PA bout.Because brief bouts of high-intensity PA can account for a large proportion of children’s daily activity-related energy expenditure,this study assessed whether daily and bouted VPA were selectively related to cognitive control in preadolescents relative to other PA intensities.Methods:A total of 75 children between the ages of 8 and 10 years(49%girls)wore an ActiGraph wGT 3 X+on the hip for 7 days.The acceleration signal from the vertical axis was summarized over 1 s,5 s,and 15 s epochs.Daily and boutecd modercate PA,moderate-to-vigorous PA,and VPA were measured.PA bouts were expressed as the frequency and time spent in 2 different continuous PA bouts,one lasting≥10 s and the other lasting≥30 s at a given intensity.Inhibitory control was assessed using behavioral responses to a modified flanker task(mean reaction time(RTmean)and accuracy).Attentional resource allocation and co gnitive processing speed were measured using the amplitude and latency of the P3 component of event-related brain potentials,respectively.Associations between PA,behavioral indices of inhibitory control,P3 amplitude,and latency were assessed using hierarchical regression models.Results:Daily VPA was not related to RTmean or accuracy on either congruent or incongruent trials.In contrast,more time spent in VPA bouts lasting≥30 s predicted shorter P3 latency across epochs and flanker congruencies(allβ≤-0.24,all p≤0.04).The associations between shorter P3 latency and the time spent in moderate-to-vigorous PA bouts lasting≥30 s were less consistent and largely limited to congruent trials(congruent:β(-0.3 1,-0.34)).No significant associations were observed upon correction for false discovery rate.Conclusion:The pattern of uncorrected associations aligns with the dose-response literature and suggests that brief VPA bouts may yield the greatest benefits to cognitive processing speed in preadolescents.Future studies using measures of brain structure and function are needed to understand the mechanisms linking bouted VPA to neurocognitive function during childhood.

Lipase inhibitory activity of Lagenaria siceraria fruit as a strategy to treat obesity

Objective:To explore pancreatic lipase inhibitory activity under different extraction conditions in order to track the most potent extract.Methods:The methanolic extract and its fractions in solvents of increasing polarity,ether,chloroform,ethyl acetate,n-butanol and water,were made through cold maceration.Extracts in ethanol,ethyl acetate,acetone and chloroform were similarly prepared.Aqueous extract was prepared through hot decoction method.A reported method was used to determine lipase inhibitory activity of extracts and fractions over wide ranges of concentrations.Results:The extracts and fractions exhibited concentration dependent activity.The IC50(μg/mL)values of methanolic,ethanolic,chloroform,ethyl acetate,acetone,ethyl acetate(after washing with water)and aqueous decoction were 293.40,266.47,157.59,182.12,352.34,257.00,and 190.00,respectively.The activity of chloroform,ethyl acetate and aqueous extracts were close to that of the drug orlistat(IC50 146μg/mL).Out of the fractions of the methanolic extract,the chloroform fraction was most active(IC50 189.6μg/mL).The order of inhibitory activity of the fractions was as follows:chloroform>ether>n-butanolic>aqueous>ethyl acetate.The GC/MS analysis of the most active chloroform faction showed the presence of hexadecanoic acid,methyl hexadecanoate,isopropyl palmitate,methyl 9,12-octadecadienate,and methyl 9,12,15-octadecatrienoate.Conclusions:The study suggests that Lagenaria siceraria has potential to inhibit pancreatic lipase activity,suppressing lipid digestion and thereby diminishing entry of lipids into the body.Regular intake of aqueous decoction of the fruit may therefore be recommended for control of obesity.Fatty acids and their esters may play role as inhibitors of lipase.

Phenol content,antioxidant and tyrosinase inhibitory activity of mangrove plants in Micronesia

Objective:To find out and compare the in vitro antioxidant and tyrosinase inhibitory activities of two species of mangrove plants.Methods:Mangrove samples were harvested at the shoreline on the island of Weno,Chuuk State in Micronesia.The phenol content,antioxidant activity(based on DPPH-free radical scavenging)and tyrosinase inhibitory activity in different tissues(leaves,barks and roots)of Rhizophora stylosa(R.stylosa)and Sonneratia alba(S.alba),collected from the island of Weno.Results:Total phenol content ranged from 4.87 to 11.96 mg per g of freeze dried samples.The highest antioxidant activity was observed in R.styiosa bark(85.5%).The highest tyrosinase inhibitory activity was found in S.alba bark.Also,total phenol content and antioxidant activity were higher in methanol extracts than in aqueous extracts.Conclusions:Taken together,the results of this study proved that mangroves can be excellent sources of antioxidant compounds.

Antioxidant and α-glucosidase inhibitor activities of natural compounds isolated from Quercus gilva Blume leaves

Objective: To isolate and investigate antioxidant and α-glucosidase inhibitor compounds in the leaves of Quercus gilva Blume(Q. gilva).Methods: Dry leaves of Q. gilva were extracted with methanol and the methanolic extract was further separated by silica gel column chromatography using several solvents with increasing polarity. The antioxidant activities of the isolated compounds were evaluated using various in vitro assays: 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity, hydrogen peroxide radical scavenging activity, β-carotene bleaching assay, and reducing power assay. The α-glucosidase inhibitory assay was conducted against α-glucosidase from Saccharomyces cerevisiae.Results: Three compounds were isolated and their structures were identii ed as catechin(1), epicatechin(2), and tiliroside(3) using an instrumental analysis. Compound 2 had higher antioxidant activity with inhibitory concentrations(IC50) of(22.55 ± 2.23) μmol/L than that of quercetin, which was used as the standard, with an IC50 of(28.08 ± 2.39) μmol/L, followed by compound 1 with IC50 of(40.86 ± 3.45) μmol/L. On the other hand, compound 3 had the lowest antioxidant activity with an IC50 of(160.24 ± 8.15) μmol/L. However, compound 3 had the highest α-glucosidase inhibitory activity with an IC50 of(28.36 ± 0.11) μmol/L, followed by compounds 1 and 2 with(168.60 ± 5.15) and(920.60 ± 10.10) μmol/L, respectively.Conclusions: The results obtained for the antioxidant activities and α-glucosidase inhibitory activities in a methanolic extract from the leaves of Q. gilva coni rmed the potential of this plant as a source of natural antioxidants and antidiabetic medicine.

In vitro Inhibitory Activity of Shisandra chinensis and Polygonatum sibiricum against Vibrio harveyi and Its Biofilms

[Objective] This study aimed to analyze the in vitro inhibitory activity of Shisandra chinensis and Polygonatum sibiricum against Vibrio harveyi and its biofilms. [Result] By agar diffusion test, in vitro inhibitory activity of 5. chinensis and P. sibiricum against V. harveyi was investigated. The minimal inhibitory concentration （ MIC） and minimal bactericidal concentration （MBC） of 5. chinensis and P. sibiricum against V. harveyi were determined by doubling dilution meth-od. The inhibitory activity of 5. chinensis and P. sibiricum on the formation of V. harveyi biofilms was evaluated by modified MTT assay. [ Result ] Both 5. chinen-sis and P. sibiricum had inhibitory activity against V. harveyi. The inhibition zone diameter of 5. chinensis against V. harveyi was 17. 95 mm; MIC and MBC of 5. chinensis were both 3.125 mg/ml. The inhibition zone diameter of P. sibiricum against V. harveyi was 12. 22 mm; MIC and MBC of P. sibiricum were 3.125 and 6.250 mg/ml, respectively. When the concentration was higher than 6. 25 mg/ml, 5. chinensis decoction had extremely significant inhibitory activity against V. harveyi （P 〈 0. 01） ; when the concentration was higher than 3. 125 mg/ml, P. sibiricum had extremely significant inhibitory activity against V. harveyi （P 〈0. 01）. [ Conclusion] 5. chinensis and P. sibiricum could significantly inhibit V. harveyi and its biofilms.

Identification and dipeptidyl peptidase Ⅳ(DPP-Ⅳ) inhibitory activity verification of peptides from mouse lymphocytes

The objective of this study was to isolate and identify the intracellular bioactive peptides from mouse lymphocytes before and after lipopolysaccharide(LPS)stimulation,to explore novel peptides and to research the bioactive function.Mouse spleen lymphocytes were isolated and cultured with LPS stimulation(experimental group)or not(control group)to collect intracellular peptides.Totally 385 peptides were analyzed by nanoliter liquid phase-Q Exactive quadrupole ultra-high resolution orbitrap mass spectrometer(Nano LC-Q Exactive Plus)and identifi ed by PEAKS X software.After compared with peptides reported,131 novel peptides were discovered,which then were predicted bioactivity by Peptide Ranker and 6 peptides with high bioactivity were predicted function by BIOPEP-UMW database.Prediction data showed that they may have dipeptidyl peptidase IV(DPP-IV)inhibitory activity.Finally,two peptides showed better potent inhibition were verifi ed with competitive and noncompetitive modes.

The influence of Lactobacillus plantarum fermentation in selenium-enriched Brassica napus L.:changes in the nutritional constituents,bioactivities and bioaccessibility

Selenium(Se)-enriched Brassica napus L.is a valuable organic Se supplement.In this study,the fermentation broth enriched with organic Se(FFS)was prepared using Lactobacillus plantarum to ferment the substrate of Se-enriched Brassica napus L.Significant increases were observed after fermentation in total sugars,reducing sugars,soluble proteins,total phenolic content(TPC),and total flavonoid content(TFC).The organic Se was retained at a concentration of 54.75 mg/g in the freeze-dried sample.Principal component analysis and cluster analysis showed good separation between the FFS and unfermented(FS)groups.Fragrant 2-ethyloxetane had the highest content among all volatiles,while sinapine had the highest content among all phenolic compounds.The fermentation process showed remarkable improvement in the abundance and concentration of volatile compounds and phenolic contents,making FFS exhibit strong antioxidant activity and inhibitory capacity againstα-glucosidase activity.The bioaccessibility of phenolic compounds was significantly greater in FFS compared to FS.ADMET analysis revealed that the majority of phenolic compounds contained in FFS did not exhibit mutagenicity toxicity,hepatotoxicity,skin sensitization,or blood-brain barrier penetration,indicating a favorable level of biosafety.Overall,our study provides a new insight into the further utilization of Se-enriched Brassica napus L.in foods.

DISTRIBUTION OF β-GLUCOSIDASE ACTIVITIES IN THE SOUTH CHINA SEA

Distribution of extracellular β-glucosidase activity (β-GlcA), bacteria abundance andTOC were investigated during tbe SCSMEX98 cruise in May and June 1998 in the South China Sea. Re-sults showed that β-GlcA varied significantly in both vertical and horizontal distribution. Hydrolysis rateranged from under detectable limit to 29% /h. In most cases, β-GlcA was highest in surface water; some-times there was a second-highest value at the bottom of the euphotic zone. Temperature controlled experi-ments showed that low temperature could significantly decrease β-GlcA; but that the low β-GlcA in

Crystal Structure and Inhibitory Activity against Xanthine Oxidase of Bis(μ_2-chloro)-chloro-(μ-N,N'-(2-pyridylmethylene) Furanmethanoamine Copper(II) Complex

A chloro-bridged dinuclear copper（H） complex with ligand 2-pyridylme-thylene- furfurylamine has been synthesized and characterized by single-crystal X-ray diffraction, and its inhibitory activity on xanthine oxidase （XO） was also evaluated. It crystallizes in the triclinic system, space group P 1 with a = 8.0441（16）, b = 8.5663（17）, c = 10.060（2）A, α = 77.52（3）, β = 72.04（3）, γ = 70.12（3）°, V = 615.3（2）A^3, Z = 1, Dc = 1.731 g/cm^3, F（000） = 322, the final R = 0.0401 and wR = 0.0934 for 1971 observed reflections with I 〉 2σ（I）. X-ray analysis reveals that the Cu（II） cation is five-coordinated by two N atoms of Schiff base and three Cl anions. The C-H…Cl intermolecular and intramolecular hydrogen bonds connect the molecules to form a three-dimensional network. This copper（II） complex shows more potent inhibitory activity against XO with IC50 = 3.48μM than the standard inhibitor allopurinol.

Development and assessment of tyrosinase inhibitory activity of liposomes of Asparagus racemosus extracts

The purpose of this study was to develop liposomal formulations of Asparagus racemosus root extract(AR1-6)as well as evaluate the physicochemical properties and in vitro tyrosinase inhibitory activity.Liposomes composed of AR1-6 to lipid weight ratio of 1:10 and lecithin(LEC)or Phospholipon
90G(PC90G)as structural phospholipid at 7:3 molar ratio to CHOL were prepared by various methods,i.e.chloroform-film(CF),reverse-phase evaporation(REV),polyol dilution(PD),and freeze-drying of monophase solution(MFD)methods.The results revealed that vesicles prepared by CF and MFD were multilamellar whereas those prepared by REV and PD were oligolamellar in nature with particle sizes ranging from 0.26 to 13.83 mm.The zeta potentials were in the range of
1.5 to
39.3 mV.AR1-6 liposomes with LEC possessed significantly higher entrapment than those with PC90G.The highest entrapment efficiency and in vitro tyrosinase inhibitory activity of 69.08%and 25%,respectively,were obtained from liposomes having LEC and prepared by PD method.The tyrosinase inhibitory activity were in the rank order of LEC>PC90G,and PD>CF>REV>MFD.It could be concluded that the mechanism of vesicle forming in each method of preparation was the key factor influencing physicochemical properties,particularly vesicle type,size,surface charge,and entrapment,which were well correlated with the biological activity.

<i>In-Vitro</i>Inhibitory Effect of Methanol Extracts of Chinese Herbal Drugs on Supercoiling Activity of Bacterial DNA Gyrase

A large number of Chinese herbal drugs (CHDs) exhibit antibacterial activities both in vivo and in vitro, but until now little is known regarding their inhibitory mechanisms. Bacterial DNA gyrase is a proven target for antibacterial agents. Aim of this study was to investigate the in-vitro inhibitory effect of methanol extracts of CHDs against supercoiling activity of bacterial DNA gyrase. Fifteen CHDs were selected and extracted with methanol, respectively. Inhibitory effect of the extracts on DNA gyrase was tested using gel-based DNA supercoiling assay. Among fifteen CHDs tested, methanol extracts of Lonicerae Japonicae Flos (S2), Taraxaci Herba (S7), Glycyrrhizae Radix et Rhizoma Praeparata cum Melle (S8) demonstrated an obvious inhibitory effect against supercoiling activity of DNA gyrase, and the others were either less active or could not be determined with the present method. Moreover, it was likely that S7 and S8 inhibit gyrase in a concentration-dependent manner. In conclusion, DNA supercoiling assay is a promising method to study the inhibitory activity of CHDs on bacterial DNA gyrase. Some CHDs do have gyrase-inhibitory activity as proposed. Further investigations are needed to elucidate the inhibition mechanism of these CHDs on supercoiling activity of gyrase.

Exploring QSARs for Inhibitory Activity of Cyclic Urea and Nonpeptide-Cyclic Cyanoguanidine Derivatives HIV-1 Protease Inhibitors by Artificial Neural Network

Quantitative structure–activity relationship study using artificial neural network (ANN) methodology were conducted to predict the inhibition constants of 127 symmetrical and unsymmetrical cyclic urea and cyclic cyanoguanidine derivatives containing different substituent groups such as: benzyl, isopropyl, 4-hydroxybenzyl, ketone, oxime, pyrazole, imidazole, triazole and having anti-HIV-1 protease activities. The results obtained by artificial neural network give advanced regression models with good prediction ability. The two optimal artificial neural network models obtained have coefficients of determination of 0.746 and 0.756. The lowest prediction’s root mean square error obtained is 0.607. Artificial neural networks provide improved models for heterogeneous data sets without splitting them into families. Both the external and cross-validation methods are used to validate the performances of the resulting models. Randomization test is employed to check the suitability of the models.

Enzymatic activities and kinetic properties of β-glucosidase from selected white rot fungi

Beta-glucosidase is among the suite of enzymes produced by white rot fungi (WRF) to biodegrade plant biomass. This study investigated the enzymatic activities and kinetic properties of β-glucosidase from seventeen WRF comprised of the following species from various geographical locations: Pleurotus ostreatus, Auricularia auricular, Polyporus squamosus, Trametes versicolor, Lentinula edodes, and Grifola frondosa. All the WRF studied showed β-glucosidase activities. Significant variations in protein and carbohydrate contents were also recorded. Beta-glucosidase activities after 30 min of incubation ranged from 6.4 μg (T. versicolor) to 225 μg (G. frondosa). The calculated kinetic constant (Km) ranged from 0.47 μM (A. auricular-1120) to 719 μM (L. edodes-7). The Vmax depending on the kinetic transformation model ranged from 0.21 μg·min-1 (T. versicolor) to 9.70 μg·min-1 (G. frondosa-28). Beta-glucosidase activities also exhibited pH optima between 3.5 and 5.0 while temperature optima were between 60°C and 70°C with some media exhibiting a secondary temperature peak at 90°C attributable to the presence of thermostable isoenzyme. WRF if appropriately screened and purified can be harnessed to potentially improve the bio-conversion of cellulose to glucose and also facilitate efficient plant biomass biodegradation and production of useful plant bio-products.