Acaricidal active fractions from acetone extract of <Emphasis Type="Italic">Aloe vera</Emphasis> L. against <Emphasis Type="Italic">Tetranychus cinnabarinus</Emphasis> and <Emphasis Type="Italic">Panonychus citri</Emphasis>

This study aimed to isolate acaricidal active fractions from acetone extract of Aloe vera L. and investigate the toxicity of these fractions against Tetranychus cinnabarinus (T. cinnabarinus) and Panonychus citri (P. citri). Acetone extract of A. vera L. was isolated by immersing in acetone for 72 h, and diverse fractions were fractionated by column chromatography. The acaricidal activity of each fractions was evaluated by corrected mortality of T. cinnabarinus through slide-dip bioassay. The 8th and 13th fractions of acetone extract with good acaricidal activity were indentified by LC/MS, and the toxicity of these two fractions to T. cinnabarinus and P. citri was identified by regression analysis. Acetone extract of A. vera L. exhibited obvious acaricidal activity, from which a total of 18 fractions were isolated. The 8th and 13th fractions with strong acaricidal activity against T. cinnabarinus were identified to be 3-O-alpha-d-mannopyranosyl-d-mannopyranose (OAMM) and aloe emodin. When compared with spirodiclofen, both OAMM and aloe emodin exhibited higher toxicity to T. cinnabarinus, while only OAMM exhibited a higher toxicity to P. citri (P < 0.05). OAMM and aloe emodin isolated from acetone extract of A. vera L. exhibited obvious acaricidal activities against T. cinnabarinus and P. citri.     

A saponin isolated from <Emphasis Type="Italic">Agapanthus africanus</Emphasis> differentially induces apoplastic peroxidase activity in wheat and displays fungicidal properties

A spirostane with an attached trisaccharide, (25R)-5α-spirostane-2α,3β,5α-triol 3-O-(O-α-l-rhamnopyranosyl-(1 → 2)-O-(β-d-galactopyranosyl-(1 → 3))-β-d-glucopyranoside), was isolated and identified from the aerial parts of Agapanthus africanus by activity-guided fractionation. Fungicidal properties of the crude extract, semi-purified fractions as well as the purified active saponin from A. africanus were screened in vitro against Fusarium oxysporum. At a concentration of 1 mg mL^?1, the crude extract and semi-purified ethyl acetate and dichloromethane fractions showed significant antifungal activity. The purified saponin inhibited the in vitro mycelial growth of F. oxysporum completely (100 %) at a concentration of 125 µg mL^?1. Furthermore, to verify previously observed induced resistance by crude extracts of A. africanus towards leaf rust, intercellular PR-protein activity was determined in wheat seedlings following foliar application of the purified saponin at 100 µg mL^?1. In vitro peroxidase enzyme activity increased significantly (60 %) in wheat seedlings 48 h after treatment with the purified saponin, demonstrating its role as an elicitor to activate a defence reaction in wheat.     

Evaluation of flavonoids from <Emphasis Type="Italic">Zostera asiatica</Emphasis> as antioxidants and nitric oxide inhibitors

Zostera asiatica is one of the five members of the genus Zostera that can be found in Korea. Studies have reported the phytochemical properties and bioactivities of Zostera species. Current study focused on the antioxidant effects of Z. asiatica as a part of ongoing research for bioactive substances from marine resources. Results indicated that a crude extract of Z. asiatica not only scavenged on peroxynitrite in vitro and on intracellular reactive oxygen species (ROS) but also inhibited production of nitric oxide (NO). The crude extract was subjected to solvent fractionation for bioactivity-based separation using aforementioned three bioassay systems. From the active n-butanol fraction, two flavonoids were isolated and characterized as luteolin (1) and luteolin-3’-sulfate (2). Both flavonoids showed significant antioxidant effects. In conclusion, Z. asiatica was demonstrated to possess antioxidant effect partly attributed to isolated flavonoids, the first such effect reported from Z. asiatica, to the best of our knowledge.     

Isolation Purification and Characterization of Antimicrobial Peptides from <Emphasis Type="Italic">Cuminum cyminum</Emphasis> L. Seeds

In this work, antimicrobial peptides from Cuminum cyminum L. seeds were isolated and purified for the first time by 50% ethanol extraction, C18 reverse phase column chromatography and ion exchange chromatography for separation different peptides fraction. Then isolated fractions were characterized by Gel electrophoresis (SDS-PAGE), high-pressure liquid chromatography and the peptides components and molecular weights were determined by liquid chromatography and mass spectrometry. The extracts were tested against some strains of bacteria (E. coli and Staphylococcus aureus) and one strain of fungi (Candida albicans) using well diffusion and broth dilution assays. The extracts from C. cyminum L. seeds demonstrated a high degree of activity (some antibacterial effect) against the bacteria strains and аntifungal activity against the Candida albicans. However, the study indicates that the crude peptide extracts from C. cyminum L. seeds have promising antimicrobial and antioxidant activities that can be harnessed as leads for potential bioactive compounds.     

Acaricidal and repellent effects of <Emphasis Type="Italic">Cnidium officinale</Emphasis>-derived material against <Emphasis Type="Italic">Dermanyssus gallinae</Emphasis> (Acari: Dermanyssidae)

The acaricidal activity of a methanolic extract and fractions from the rhizome of Cnidium officinale against Dermanyssus gallinae adults was investigated. The C. officinale methanolic extract exhibited 100% acaricidal activity after 48 h of treatment at a dose of 4000 ppm. The acaricidal constituents of the plant were sequentially partitioned with several solvents and then purified using silica gel column chromatography and high-performance liquid chromatography. Gas chromatography–mass spectrometry and nuclear magnetic resonance spectroscopy revealed (Z)-ligustilide as a constituent of C. officinale. Acaricidal activity was examined in three experimental tests (spray, fumigation and contact), with the spraying method being the most effective. The methanolic extract of C. officinale showed both contact and fumigant activities, though only fumigant activity was observed with (Z)-ligustilide. The fumigant effects of the methanolic extract and (Z)-ligustilide caused 86.5 and 62.6% mortality, respectively, of D. gallinae adults at 48 h. Among (Z)-ligustilide, acaricides (bifenthrin, cypermethrin and spinosad) and butylidenephthalide, bifenthrin displayed the highest acaricidal activity, and the activity of butylidenephthalide was 2.3-fold higher than that of (Z)-ligustilide. These results suggest that C. officinale-derived material can be used for the development of a control agent for D. gallinae.     

Solvent-partitioned fractions from <Emphasis Type="Italic">Ishige okamurae</Emphasis> extract inhibit MMP-2 and MMP-9 activities in human fibrosarcoma cells in vitro

Matrix metalloproteinases (MMPs) are endopeptidases that take significant roles in extracellular matrix degradation and therefore linked with several complications such as metastasis of cancer progression, oxidative stress, and hepatic fibrosis. Ishige okamurae, a brown alga, has been reported to possess various bioactivities including but not limited to antiviral, antimicrobial, and anti-inflammatory. In this study, the potential of I. okamurae against cancer cell invasion was evaluated through MMP inhibitory effect in HT1080 fibrosarcoma cells in vitro. I. okamurae crude extract was fractionated with organic solvents, namely water (H₂O), n-butanol (n-BuOH), 85% aqueous methanol (85% aq. MeOH), and n-hexane (n-Hex). The non-toxicity of fractions was confirmed by MTT assay. All fractions inhibited the enzymatic activities of MMP-2 and MMP-9 according to gelatin zymography assay. Cell migration was also inhibited by 85% aq. MeOH fraction, significantly. In addition, both gene and protein expressions of MMP-2 and MMP-9, and tissue inhibitor of MMPs (TIMPs) were evaluated by RT-PCR and Western blotting, respectively. Fractions suppressed the mRNA and protein levels of MMP-2 and MMP-9 while elevating the TIMP-1 and TIMP-2, H₂O fraction being the least effective while 85% aq. MeOH fraction the most. Collectively, 85% aq. MeOH fraction from brown algae could be a potential inhibitor of MMPs, suggestively considering presence of poly-unsaturated fatty acids in high amounts.     

Bioactive compounds from marine <Emphasis Type="Italic">Streptomyces</Emphasis> sp. VITPSA as therapeutics

Background

Marine actinomycetes are efficient producers of new secondary metabolites that show different biological activities, including antibacterial, antifungal, anticancer, insecticidal, and enzyme inhibition activities.

Methods

The morphological, physiological, and biochemical properties of the strain Streptomyces sp. VITPSA were confirmed by conventional methods. Antibacterial, anti-oxidant, anti-inflammatory, anti-diabetic, and cytotoxic activities of Streptomyces sp. VITPSA extract were determined. The media were optimized for the production of secondary metabolites. Characterization and identification of secondary metabolites were conducted by high-performance liquid chromatography, gas chromatography-mass spectroscopy, and Fourier transform infrared spectroscopy analysis.

Results

The strain showed significant antibacterial, anti-oxidant, and cytotoxic activities, moderate anti-inflammatory activity, and no satisfactory anti-diabetic activity. The ethyl acetate extract of Streptomyces sp. VITPSA showed maximum antibacterial activity against two gram-positive and gram-negative bacteria at 0.5 mg/mL. The antioxidant potential of the crude extract exhibited strong reducing power activity at 0.5 mg/mL with 95.1% inhibition. The cytotoxic effect was found to be an IC₅₀ of 50 μg/mL on MCF-7 cell lines. Experimental design of optimization by one-factor analysis revealed the most favorable sucrose, yeast extract, pH (7.25), and temperature (28°C) conditions for the effective production of secondary metabolites.

Conclusion

This study revealed that Streptomyces sp. VITPSA is an excellent source of secondary metabolites with various bioactivities.

     

Expression of an endochitinase gene from <Emphasis Type="Italic">Trichoderma virens</Emphasis> confers enhanced tolerance to <Emphasis Type="Italic">Alternaria</Emphasis> blight in transgenic <Emphasis Type="Italic">Brassica juncea</Emphasis> (L.) czern and coss lines

An endochitinase gene ‘ech42’ from the biocontrol fungus ‘Trichoderma virens’ was introduced to Brassica juncea (L). Czern and Coss via Agrobaterium tumefaciens mediated genetic transformation method. Integration and expression of the ‘ech42’ gene in transgenic lines were confirmed by PCR, RT-PCR and Southern hybridization. Transgenic lines (T₁) showed expected 3:1 Mendelian segregation ratio when segregation analysis for inheritance of transgene ‘hpt’ was carried out. Fluorimetric analysis of transgenic lines (T₀ and T₁) showed 7 fold higher endochitinase activity than the non-transformed plant. Fluorimetric zymogram showed presence of endochitinase (42 kDa) in crude protein extract of transgenic lines. In detached leaf bioassay with fungi Alternaria brassicae and Alternaria brassicicola, transgenic lines (T₀ and T₁) showed delayed onset of lesions as well as 30–73 % reduction in infected leaf area compared to non-transformed plant.     

Culture Optimization Strategy for 1-Deoxynojirimycin-producing <Emphasis Type="Italic">Bacillus methylotrophicus</Emphasis> K26 Isolated from Korean Fermented Soybean Paste, <Emphasis Type="Italic">Doenjang</Emphasis>

1-Deoxynojirimycin (1-DNJ) is an α-glucosidase inhibitor that is used for the treatment of type 2 diabetes. In this study, we isolated Bacillus methylotrophicus K26 with α-glucosidase inhibition (AGI) activity from Korean fermented soybean paste (Doenjang) and confirmed that the genome harbored the DNJ biosynthesis genes including gabT1, yktc1, and gutB1 by PCR screening, while 1-DNJ production was confirmed by ultra-performance liquid chromatography–quadrupole time-of-flight–mass spectrometry. To increase 1-DNJ production by B. methylotrophicus K26, culture conditions were optimized with one-factor-ata- time (OFAT) and response surface methodology (RSM) approaches. Screen of 11 carbon and 9 nitrogen sources by the OFAT method identified sucrose and yeast extract as optimal culture components. Sucrose concentration (X₁), yeast extract concentration (X₂), and culture temperature (X₃) were selected as independent variables for central composite design. The coefficient of determination (R²) for the model was 0.927, and the probability value of the regression model was highly significant. RSM predicted the optimal conditions for 1-DNJ production by B. methylotrophicus K26 as sucrose and yeast extract concentrations of 4.61% and 7.03%, respectively, at a temperature of 34°C. Under these conditions, AGI activity was experimentally measured as 89.3%, which was close to the predicted value of 91.9%.     

Hyporientalin A,an anti-<Emphasis Type="Italic">Candida</Emphasis> peptaibol from a marine <Emphasis Type="Italic">Trichoderma orientale</Emphasis>

A Trichoderma orientale strain LSBA1 was isolated from the Mediterranean marine sponge Cymbaxinella damicornis. The crude extract of T. orientale mycelium showed inhibitory activity against growth of Gram-positive and Gram-negative bacteria as well as clinical isolates of Candida albicans. Purification of the anti-Candida component was performed using a combination of open silica gel-60 column and reverse phase high performance liquid chromatography. The active compound called hyporientalin A has been identified as a peptaibol analogue of longibrachin-A-II using mass spectrometry. It exhibited fungicidal activity against clinical isolates of C. albicans with minimal inhibitory concentrations (MICs) ranging from 2.49 to 19.66 µM, comparable to that of the antifungal agent amphotericin B. Our data support the use of hyporientalin A as a promising new and efficient antifungal drug in the treatment of candidiasis while controlling toxicity.     

Efficient inhibition of some multi-drug resistant pathogenic bacteria by bioactive metabolites from <Emphasis Type="Italic">Bacillus amyloliquefaciens</Emphasis> S<Subscript>5</Subscript>I<Subscript>4</Subscript> isolated from archaeological soil in Egypt

Sixty-eight bacterial cultures were isolated from 5 archaeological soils in Egypt. It is necessary to characterize bacteria from ancient temples to develop protection programs for such archaeological places. Purified bacterial cultures were then tested for their capability to inhibit some multi-drug resistant (MDR) pathogenic bacteria including Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus, Escherichia coli and Klebsiella pneumoniae. Among the most active 10 antibacterial isolates, only one isolate designated as S₅I₄ was selected, characterized and identified as belonging to Bacillus amyloliquefaciens. The strain identification was confirmed by amplification of its 16S rRNA gene. The partial nucleotide sequence of the amplified 16S rRNA gene of the tested strain was submitted in GenBank with accession number AB813716. The physical and nutritional parameters were optimized to improve the production of antimicrobial agents by the B. amyloliquefaciens S₅I₄. The maximum antagonistic effect of this strain against the tested MDR pathogenic bacteria was achieved in presence of 1% galactose and 0.5% yeast extract at 37°C and pH 7.0 after 48 h incubation. The antibacterial compounds of B. amyloliquefaciens S₅I₄ were extracted, purified and characterized using spectroscopic analysis (IR, UV, proton NMR and MS). The compound having inhibitory activity was identified as butanedioic acid, octadecyl,1(1carboxy1methylethyl) 4octyl ester.     

Purification and activity characterization of polysaccharides in the medicinal lichen <Emphasis Type="Italic">Umbilicaria tornata</Emphasis> from Taibai Mountain,China

Water-soluble polysaccharides from Umbilicaria tornata (UTP) were purified and preliminarily characterized. The antioxidant and antitumor activities of crude UTP and two purified fractions (UTP-1 and UTP-2) were evaluated using in vitro experiments. The results showed that the molecular weights of UTP-1 and UTP-2 were 84.86 and 28.66 kDa, respectively. Both UTP-1 and UTP-2 were composed of glucose and xylose, with their molar ratios being 1.3:0.9 and 0.9:4.6, respectively. In addition, crude UTP, UTP-1 and UTP-2 showed dose-dependent DPPH and hydroxyl radical scavenging and reducing activities. However, crude UTP exhibited stronger antioxidant activity than UTP-1 and UTP-2, particularly in terms of DPPH radicals. Crude UTP and the two purified fractions inhibited the growth of HeLa, HepG2, A375, MCF-7, SGC7901 and Caco2 cancer cells in vitro. Compared with UTP-1 and UTP-2, crude UTP presented significantly higher antitumor activity in vitro against HeLa and HepG2 cells (p?<?0.05). These findings provide a scientific basis for the deeper exploration and resource development of U. tornata.     

Isolation and characterization of trichalasin-producing endophytic fungus from <Emphasis Type="BoldItalic">Taxus baccata</Emphasis>

An endophytic fungus (strain T1) isolated from Taxus baccata was studied for the production of metabolites with anticancer and antioxidant activities. This fungus was identified as Diaporthe sp. based on rDNA-internal transcribed spacer (ITS) sequence analysis. The crude extract showed cytotoxic activity against MCF-7 and HeLa cancer cell lines, with IC₅₀ (concentration inhibiting 50% of growth rate) values of 1058?±?44 and 1257?±?80 μg ml^?1, respectively. The scavenging activity of fungal extract increased significantly with increasing concentration [IC₅₀ (concentration required to scavenge 50% of free radicals) 482?±?9 μg ml^?1]. Ultra-high-performance liquid chromatography-quadrupole-time of flight analysis revealed the presence of three trichalasins (trichalasin E, F and H) in the crude extract of T1 which are known to have antitumour and antioxidant activities. These results suggest that Diaporthe sp. has the potential to be used for therapeutic purposes because of its antiproliferative and antioxidant potential and also for the production of cytochalasins.     

The Phenolic Contents and Antimicrobial Activities of Some Marine Algae from the Mediterranean Sea (Algeria)

In this study, three marine algae collected from western coast of algerian mediteranean sea (Ulva lactuca, Dictyota dichotoma, and Corallina elongata) were tested using the agar-well diffusion method for their production of antibacterial and antifungal agents on various organisms that cause diseases of humans and plants (Eschirichia coli ATCC 25922, Staphylococcus aureus ATCC 25923, Salmonella sp, Candida albicans, and Penicillium sp.). The total phenol content and antimicrobial activity were determined using different crude seaweeds extracts (methanol, diethylether, and chloroform). The results show that the chloroform extracts of (Ulva lactuca and Corallina elongata) had the highest activity against E. coli and Salmonella sp. The methanol extract obtained from (Ulva lactuca, Dictyota dichotoma, and Corallina elongata) showed antifungal activity for Candida albicans. The results of the study revealed that the seaweeds from Algeria appear to have immense potential as a source of antibacterial and antifungal compounds; they can be used in treating diseases caused by these organisms.     

Construction of flavocytochrome <Emphasis Type="Italic">b</Emphasis><Subscript>2</Subscript>-overproducing strains of the thermotolerant methylotrophic yeast <Emphasis Type="Italic">Hansenula polymorpha</Emphasis> (<Emphasis Type="Italic">Pichia angusta</Emphasis>)

L-Lactate cytochrome c oxidoreductase (flavocytochrome b ₂, FC b ₂) from the thermotolerant methylotrophic yeast Hansenula polymorpha (Pichia angusta) is, unlike the enzyme form baker’s yeast, a thermostable enzyme potentially important for bioanalytical technologies for highly selective assays of L-lactate in biological fluids and foods. This paper describes the construction of flavocytochrome b ₂ producers with over-expression of the H. polymorpha CYB2 gene, encoding FC b ₂. The HpCYB2 gene under the control of the strong H. polymorpha alcohol oxidase promoter in a plasmid for multicopy integration was transformed into the recipient strain H. polymorpha C-105 (grc1 catX), impaired in glucose repression and devoid of catalase activity. A method was developed for preliminary screening of the transformants with increased FC b ₂ activity in permeabilized yeast cells. The optimal cultivation conditions providing for the maximal yield of the target enzyme were found. The constructed strain is a promising FC b ₂ producer characterized by a sixfold increased (to 3 μmol min^?1 mg^?1 protein in cell-free extract) activity of the enzyme.     

Purification and Characterization of Exo-Inulinase from <Emphasis Type="Italic">Paenibacillus</Emphasis> sp. d9 Strain

This study intended to purify and characterise exo-inulinase of diesel-degrading Paenibacillus sp. D9. The whole genome sequencing of Paenibacillus sp. D9 revealed to possess the sacC gene that is encoded as exo-inulinase/levanase. This isolate was capable of producing a maximum of 50.9 IU/mL of exo-inulinase activity within 3 days at 30?°C, 200 rpm and pH of 7.0 on minimal salt medium agar supplemented with 1% (w/v) inulin. An exo-inulinase of 58.5 kDa was purified using ammonium sulphate precipitation, HiTrap QFF column and MMC column chromatographies with a specific activity of 4333 IU/mg, 7.1% recovery and a 4.3-fold increase in purity. The purified D9 exo-inulinase had temperature and pH optimum at 40?°C and pH 4.0, respectively, with the Michaelis constant of 5.5 mM and a maximal velocity of 476.2 IU/mg, respectively. Catalytic constant, k _cat was calculated to be 42.6 s^?1 with a catalytic efficiency (k _cat /K _m ) of 7.6 s^?1 mM^?1. The presence of Ca²⁺ enhanced the activity of D9 exo-inulinase while Hg²⁺ completely inhibited the activity, other compounds such as Fe³⁺ and Cu²⁺ had an inhibitory effect. The results of amino acid alignment and the complete degradation of inulin into fructose by the purified enzyme confirmed that inulinase from Paenibacillus sp. D9 is an exo-form. The phylogenetic tree based on the protein sequences indicates that bacterial exo-inulinases possess a common ancestry.     

Metabolomic analysis of the mechanism of action of yerba mate aqueous extract on <Emphasis Type="Italic">Salmonella enterica</Emphasis> serovar Typhimurium

Introduction

Salmonella enterica serovar Typhimurium is a Gram-negative enteropathogen that infects millions of people worldwide each year; the emergence of drug-resistant strains has heightened the need for novel treatments. Aqueous extracts of yerba mate (Ilex paraguariensis) effectively inhibit drug-resistant S. Typhimurium in vitro. Some chemical constituents that contribute to the extract’s antibacterial activity have been identified, but the mechanism of action of the extract is still unknown.

Objectives

This study sought to gain insight into the antibacterial mechanism of yerba mate extract against S. Typhimurium.

Methods

Assays for catalase activity and membrane permeability were used to select time points for an LC-MS metabolomics analysis of S. Typhimurium intracellular components.

Results

Yerba mate extract induced changes in central carbon metabolism in S. Typhimurium, reduced catalase activity by means other than direct inhibition, and did not change membrane integrity despite a significant increase in the production of a cell wall precursor. Additional significant differences were observed in the global metabolic regulators alpha-ketoglutarate and acetylphosphate, the energy-related molecule NAD⁺, and in an unexpected match to the antibacterial compound yohimbine.

Conclusion

This work provides the first evaluation of the mechanism of action of yerba mate extract on S. Typhimurium, revealing a major impact on central carbon metabolism, catalase activity, and possible metabolic links to interference in energy production and membrane integrity. The putative identification of the antibacterial compound yohimbine and the many unidentified compounds provides additional avenues for future investigations of yerba mate compounds capable of traversing or binding to S. Typhimurium’s membrane.

     

Terpenoid bioactive compound from <Emphasis Type="Italic">Streptomyces rochei</Emphasis> (M32): taxonomy,fermentation and biological activities

The present study emphasized the production of biologically active terpenoid compound from Streptomyces rochei M32, which was isolated from Western Ghats ecosystem, South India. The presence of resistant genes like mecA, vanA of Staphylococcus aureus and bla _SHV, bla _TEM of Pseudomonas aeruginosa was confirmed by molecular studies. The isolated compound from Streptomyces rochei M32 inhibited wide range of standard and clinical drug resistant pathogens and enteric pathogens. The rice bran supplemented basal medium influenced the active compound production on 8th day of fermentation and yielded 1875 mg of crude extract from 10 g of rice bran substrate. Purification and characterization of crude ethyl acetate extract was achieved by preparative thin layer chromatography. The active fraction was identified as terpenoid class compound by chemical screening. Based on the results of spectral studies (NMR, LC–MS, FTIR, etc.), the active compound was tentatively identified as 1, 19-bis (3-hydroxyazetidin-1-yl) nonadeca-5, 14-diene-1, 8, 12, 19-tetraone with molecular weight 462.41 g/mol. Minimum inhibitory concentration value ranges between 7.6 and 31.2 µg/mL against test organisms was observed. The cytotoxicity results on cervical cancer (HeLa) cell line showed IC₅₀ value of 2.034 µg/mL. The corresponding compound is not previously reported from any microbial resources.     

Trypsin Hydrolysed Protein Fractions as Radical Scavengers and Anti-bacterial Agents from <Emphasis Type="Italic">Ficus deltoidea</Emphasis>

Different molecular sizes of protein hydrolysates were prepared from the crude protein extract of Ficus deltoidea using the technique of membrane ultrafiltration after trypsin hydrolysis. Gel electrophoretic images shows the presence of 12, 8, 7 and 7 protein bands for the protein fractions prepared from the molecular weight cut-off of 3, 10, 30 and 100 kDa, respectively. The protein hydrolysates were found to have higher radical scavenging activity than those unhydrolysed fractions at the similar molecular size. They exhibited significant differences in the radical scavenging activities based on one-way analysis of variance, except for the protein hydrolysates of 30 and 100 kDa. The smallest protein hydrolysates, 3 kDa appeared to have the comparable activity (30%) with bovine serum albumin as a positive control in this study. Similarly, the 3 kDa protein hydrolysates achieved the highest inhibitory activity (87.5%) against Pseudomonas aeruginosa at the concentration of 128 µg/mL. The protein hydrolysates were found to be more effective against gram negative bacteria (P. aeruginosa and Escherichia coli) because of lower minimum inhibitory concentration (MIC) and effective inhibitory concentration at 50% (EC₅₀) than gram positive bacterium (Staphylococcus aureus). Trypsin catalysed hydrolysis seemed to improve the anti-bacterial activity of protein hydrolysates in a bacterial strain dependent manner. The MIC could achieve 1–55 µg/mL at different molecular sizes of protein fractions. Mass spectra matching revealed that 26% of 226 identified proteins belonged to the category of plant defensive proteins in stress management and metal handling.