Mangrove Actinomycetes Research Articles

Saccharopolyspora mangrovi sp. nov., a novel mangrove soil actinobacterium with distinct metabolic potential revealed by comparative genomic analysis.

A novel mangrove soil-derived actinomycete, strain S2-29T, was found to be most closely related to Saccharopolyspora karakumensis 5K548T based on 16S rRNA sequence (99.24% similarity) and genomic phylogenetic analyses. However, significant divergence in digital DNA-DNA hybridization, average nucleotide identity, and unique biosynthetic gene cluster possession distinguished S2-29T as a distinct Saccharopolyspora species. Pan genome evaluation revealed exceptional genomic flexibility in genus Saccharopolyspora, with > 95% accessory genome content. Strain S2-29T harbored 718 unique genes, largely implicated in energetic metabolisms, indicating different metabolic capacities from its close relatives. Several uncharacterized biosynthetic gene clusters in strain S2-29T highlighted the strain's untapped capacity to produce novel functional compounds with potential biotechnological applications. Designation as novel species Saccharopolyspora mangrovi sp. nov. (type strain S2-29T = JCM 34,548T = CGMCC 4.7716T) was warranted, expanding the known Saccharopolyspora diversity and ecology. The discovery of this mangrove-adapted strain advances understanding of the genus while highlighting an untapped source of chemical diversity.

Bioprospecting of novel peroxidase from Streptomyces coelicolor strain SPR7 for carcinogenic azo dyes decolorization

Peroxidase (POX) is a heme-containing oxidoreductase, its voluminous immuno-diagnostic and bioremediatory intuitions have incited optimization and large scale-generation from novel microbial repertoires. Azo dyes are the most detrimental classes of synthetic dyes and they are the common ecotoxic industrial pollutants in wastewater. In addition, azo dyes are refractory to degradation owing to their chemical nature, comprising of azoic linkages, amino moieties with recalcitrant traits. Moreover, they are major carcinogenic and mutagenic on humans and animals, whereby emphasizing the need for decolorization. In the present study, a novel POX from Streptomyces coelicolor strain SPR7 was investigated for the deterioration of ecotoxic dyestuffs. The initial medium component screening for POX production was achieved using, One Factor at a Time and Placket-Burman methodologies with starch, casein and temperature as essential parameters. In auxiliary, Response Surface Methodology (RSM) was recruited and followed by model validation using Back propagation algorithm (BPA). RSM-BPA composite approach prophesied that combination of starch, casein, and temperature at optimal values 2.5%, 0.035% and 35 °C respectively, has resulted in 7 folds enhancement of POX outturn (2.52 U/mL) compared to the unoptimized media (0.36 U/mL). The concentrated enzyme decolorized 75.4% and 90% of the two azo dyes with lignin (10 mM), respectively. Hence, this investigation confirms the potentiality of mangrove actinomycete derived POX for elimination of noxious azo dyes to overcome their carcinogenic, mutagenic and teratogenic effects on humans and aquatic organisms.

Identificación y caracterización morfológica de actinomicetos marinos como agentes de biocontrol de Fusarium solani en tomate

Fusarium spp. damages the roots of crops, its control is with synthetic fungicides, however, marine actinomycetes can be an option to the use of agrochemicals. The objective of this work was the identification and morphological characterization of marine actinomycetes as antagonists to Fusarium solani (Mart.) Sacc. Fusarium spp. was isolated from diseased tomato plants and mangrove sediment actinomycetes, both identified through taxonomic keys and molecular techniques. Eight isolates of Fusarium spp. were obtained, H8 being the most virulent and it was identified as F. solani. Thirty actinomycetes were isolated, of which only four inhibited the phytopathogen, being A19 the one that inhibited the fungus by 70% and was identified as Streptomyces sp. Marine actinomycetes may be an option for disease management in plants of agricultural interest.

Exploring the inhibitory potential of novel bioactive compounds from mangrove actinomycetes against nsp10 the major activator of SARS-CoV-2 replication.

The current study reveals the inhibitory potential of novel bioactive compounds of mangrove actinomycetes against nsp10 of SARS-CoV-2. A total of fifty (50) novel bioactive (antibacterial, antitumor, antiviral, antioxidant, and anti-inflammatory) compounds of mangrove actinomycetes from different chemical classes such as alkaloids, dilactones, sesquiterpenes, macrolides, and benzene derivatives are used for interaction analysis against nsp10 of SARS-CoV-2. The six antiviral agents sespenine, xiamycin c, xiamycin d, xiamycin e, xiamycin methyl ester, and xiamycin A (obeyed RO5 rule) are selected based on higher binding energy, low inhibition constant values, and better-docked positions. The effective hydrogen and hydrophobic (alkyl, pi–sigma, pi–pi T shaped and pi-alkyl) interaction analysis reveals the four antivirals sespenine, xiamycin C, xiamycin methyl ester, and xiamycin A are supposed to be the most auspicious inhibitors against nsp10 of SARS-CoV-2. Quantum chemistry methods such as frontier molecular orbitals and molecular electrostatic potential are used to explain the thermal stability and chemical reactivity of ligands. The toxicity profile shows that selected ligands are safe by absorption, distribution, metabolism, excretion, and toxicity profiling and also effective for inhibition of nsp10 protein of SARS-CoV-2. The molecular dynamic simulation investigation of apo and halo forms of nsp10 done by RMSD of Calpha atoms of nsp10, all amino acid residues RMSF, count total number of hydrogen bonds and radius of gyration (Rg). MD simulations reveal the complexes are stable and increase the structural compactness of nsp10 in the binding pocket. The lead antiviral compounds sespenine, xiamycin C, xiamycin methyl ester, and xiamycin A are recommended as the most promising inhibitors against nsp10 of SARS-CoV-2 pathogenicity.Graphical abstract Supplementary InformationThe online version contains supplementary material available at 10.1007/s11696-021-01997-x.

Two new α-Methoxy-γ-Pyrones From the Mangrove Sediment-Derived Streptomyces psammoticus SCSIO NS126

Two new α-methoxy- γ-pyrone analogs, 2-methoxy-3-methyl-5,6-diethyl- γ-pyrone (2) and 2-methoxy-3,5-dimethyl-6-propyl- γ-pyrone (3), together with 2-methoxy-3,5-dimethyl-6-ethyl- γ-pyrone (1), firstly isolated from natural sources, were obtained from the EtOAc-solube extract of the mangrove sediment-derived actinomycete strain Streptomyces psammoticus SCSIO NS126, under the optimized fermentation conditions. Their structures were elucidated by detailed spectroscopic analysis and by comparison of their spectroscopic data with those reported in the literature. Those α-methoxy-γ-pyrones were evaluated for their acetylcholinesterase inhibitory activity; however, none of them exhibited obvious activity. Moreover, their biosynthetic relationship with piericidins was also discussed.

Exploring prospective forested wetland — Actinomycetes for biodeterioration of genotoxic textile azo dyes

disposal of synthetic textile dye effluents into waterbodies is a major cause of water pollution and undesirable toxicity on aquatic organisms affecting their metabolic and hormonal cycles. Moreover, it affects human health significantly by carcinogenic and mutagenic effects. Therefore, this study targets the biotreatment of azo dyes as a green eco-friendly tool using the tropical mangrove actinomycete, Streptomyces coelicolor strainSPR7, that manifests versatile decolourization of azo dyes. The highest decolourization rate (97.5%) was achieved using Methylene Blue (MB) within 72 h under the optimal conditions. Molecular docking analysis was accomplished by Autodock software, to discern docking score, binding pocket residues and interaction of azoreductase, DyP-type peroxidase and laccase with MB. The in vitro findings were highly correlating with in silico appraisals. UV-vis spectrometry, HPLC and FTIR were validating the MB biodecolourization and degradation. Interestingly, the strain detoxified MB viz . further validated by the Vignaradiata toxicity assay. Supplementarily, azo reductase was assessed to be the key biocatalyst for decolourization, while other two enzymes were involved in further mineralization of decolourized metabolites. Henceforth, a coupled in silico cum biological dye deterioration is a booming strategy for an economical, eco-friendly and time saving bioremediation to reuse textile wastewater.

ISOLATION OF ACTINOMYCETES FROM THE SEDIMENTS OF PICHAVARAM MANGROVE FOREST, SOUTH INDIA AND ANALYSING THEIR ANTIBACTERIAL EFFICACY

Objective: The aim of the present investigation is to isolate actinomycetes from the sediments of Pichavaram mangrove forest, South India, and to screen for their antibacterial efficiency.
 Methods: Actinomycetes were isolated by culturing the samples in Starch Casein Agar medium; they were screened primarily for their antibacterial efficiency against Gram-positive and Gram-negative bacterial organisms. Solvent extraction was done with 50% (percentage) ethyl acetate, crude extracts of actinomycetes were prepared at different concentrations using dimethyl sulfoxide and treated against the bacterial organisms. Antibacterial assay was done in Mueller–Hinton agar medium.
 Results: Thirteen actinomycetes were isolated; among them, four actinomycete isolates (Pichavaram mangrove actinomycete 2 [PMA2], PMA6, PMA9, and PMA13) exhibited antibacterial activity.
 Conclusion: Isolate PMA2 exhibited very strong antibacterial activity and isolate PMA13 is weakly active against the tested bacterial organisms.

Diversity, Antimicrobial Capabilities, and Biosynthetic Potential of Mangrove Actinomycetes from Coastal Waters in Pahang, Malaysia

ABSTRACT Zainal Abidin, Z.A.; Chowdhury, A.J.K.; Abdul Malek, N., and Zainuddin, Z., 2018. Diversity, antimicrobial capabilities, and biosynthetic potential of mangrove actinomycetes from coastal waters in Pahang, Malaysia. In: Ashraf, M.A. and Chowdhury, A.J.K. (eds.), Coastal Ecosystem Responses to Human and Climatic Changes throughout Asia. Actinomycetes are biotechnologically important for their unparalleled capability to produce various bioactive secondary metabolites. The diversity and antimicrobial capabilities were investigated for actinomycetes, which were previously isolated from mangrove sediment of the Pahang mangrove forest. The biosynthetic potential using type I polyketide synthase (PKS-I) and nonribosomal peptide synthetase (NRPS) genes and the morphological characteristics of actinomycetes were also determined. Representative isolates were selected from five sampling locations in the Kuantan mangrove forest. Antimicrobial activities of crude ethyl acetate extract of these actinomycetes ag...

Evaluation of antibacterial potential of mangrove sediment-derived actinomycetes

Actinomycetes are well-known as the source of bioactive metabolites. In this work, 16 out of 118 (13.6%) isolates of mangrove sediment-derived actinomycetes showed potential antibacterial activity against at least one bacterial strain. Five extracts from isolates AMA11, AMA12 and AMA21 exhibited a broad spectrum antibacterial activity against Staphylococcus aureus ATCC25923, Staphylococcus epidermidis ATCC35984, methicillin-resistant S. aureus (MRSA) SK1, Acinetobacter baumannii NPRC004 and Escherichia coli ATCC25922. Ethyl acetate extract from the cells of AMA11 (AMA11CE) showed high activity against S. aureus and MRSA with the lowest minimum inhibitory concentration (MIC) of 0.5 μg ml−1. At concentration of four times its MIC, AMA11CE destroyed MRSA cells as analysed by the scanning electron microscopy. In addition, AMA11CE, ethyl acetate extract from the culture broth of AMA12 (AMA12BE), AMA12CE and AMA21CE reduced violacein production in Chromobacterium violaceum. Furthermore, at concentrations lower than 10 μg ml−1, all five extracts inhibited biofilm formation by S. epidermidis ATCC35984. The chemical analysis of the most active fraction from AMA11CE by GC-MS revealed the presence of 3-nitro-1,2-benzenedicarboxylic acid, hexadecanoic acid, quinoxaline-2-carboxamide and pentadecanoic acid. The 16S rDNA sequencing analysis revealed that these three potential isolates belonged to the genus Streptomyces. The results revealed that the actinomycetes from mangrove environment would be a good source of bioactive metabolites against pathogenic bacteria.

ANTIDERMATOPHYTIC ACTIVITY OF STREPTOMYCES CACAOI SUBSP. CACAOI. M20

Objective: This study is an approach to find the alternative drug for the dermatophytosis because some of the existing antibiotics cause toxicity and also found expensive. Methods: There were 25 actinomycetes isolated from the soil sample of the mangrove, Avicennia marina from Ariyankuppam backwater area, Puducherry. Among the 25 isolates, the most active isolate, M20 was selected initially based on its antifungal activity, and it was checked for antidermatophytic activity against three dermatophytes, Microsporum gypseum, Trichophyton mentagrophytes, and Epidermophyton floccosum by agar plug method, well diffusion method followed by food poisoning technique. Release of volatile compounds from the isolate M20 has also been tested. Ultraviolet (UV)-vis spectral analysis of partially purified yellow compound fraction was done. Results: The isolate M20 actively controlled the growth of dermatophytes by agar plug method in the primary screening, well diffusion method in the secondary screening. The isolate was identified as Streptomyces cacaoi sub sp. cacaoi by 16sRNA sequencing analysis. The 10% (10 ml) culture filtrate of the isolate M20 was found to control the radial growth of these three dermatophytic fungi by food poisoning technique. Volatile compounds of the isolate M20 affected the mycelial growth of M. gypseum tremendously. Complete arrest of growth of M. gypseum was noticed with the combination of both volatile and non-volatile antibiotic compound of the isolate M20. The partially purified compound fraction (yellow) (0.5 mg/6 mm disc) inhibited the growth of M. gypseum (12 mm), and it was compared with the standard antibiotic clotrimazole (0.5 mg/6 mm disc), whose inhibition on M. gypseum was only 6 mm. UV-vis spectral analysis revealed the compound belonged to nucleoside antibiotics. Conclusion: It is evident that the mangrove actinomycetes are potential for preparing biomedicines for human welfare.

Rare Polyene-polyol Macrolides from Mangrove-derived Streptomyces sp. ZQ4BG

Bioactive natural products from mangrove-derived actinomycetes are important sources for discovery of drug lead compounds. In this study, an extract prepared from culture of an actinomycete Streptomyces sp. ZQ4BG isolated from mangrove soils was found to have activity in inhibiting proliferation of glioma cells. Large culture of this mangrove actinomycete in Gause’s liquid medium resulted in isolation of seven novel polyene-polyol macrolides, named as flavofungins III–IX (3–9), together with known flavofungins I (1) and II (2) and spectinabilin (10). Structures of these isolated compounds were elucidated by extensive NMR analyses and HRESIMS data. The stereochemical assignments were achieved by a combination of NOE information, universal NMR database, and chemical reactions including preparation of acetonide derivatives and Mosher esters. Flavofungins IV–VIII (4–8) are rare 32-membered polyene-polyol macrolides with a tetrahydrofuran ring, while flavofungin IX (9) represents the first example of this type of macrolide with a unique oxepane ring. Flavofungins I (1) and II (2) and spectinabilin (10) showed anti-glioma and antifungal activities.

Bisamides and rhamnosides from mangrove actinomycete Streptomyces sp. SZ-A15

Four new bisamides 1–4, and two new rhamnosides (5, 6), along with four known compounds 7–10, were isolated from a scale culture of the mangrove-derived actinomycete Streptomyces sp. SZ-A15. All structures were determined through analysis of the UV, IR, HRESIMS, 1D and 2D NMR spectra as well as by comparison with literature data. BRD4 inhibition of all isolated compounds was evaluated. As for the ability to inhibit protein BRD4, compound 9 exhibited moderate activity with the value of 78.4 ± 2.2% at 10 μM.

Identification and Antimicrobial Properties of Malaysian Mangrove Actinomycetes

The mangrove area is one of the more unique and less studied habitats for the discovery of biologically active secondary metabolites from potential actinomycetes. For this reason, isolation, characterization and screening of antimicrobial properties of actinomycetes from mangrove soils collected at the selected mangrove areas in Malaysia were conducted. A total of 73 actinomycetes were isolated. Of these, 9.6% (direct broth culture) and 8.2% (ethyl acetate extract) of these isolates demonstrated antimicrobial activities active against Staphylococcus aureus , Bacillus subtilis , Candida albicans as well as Saccharomyces cerevisiae by disc diffusion assay. Hexane extracts, however, exhibited no activity. A modified microdilution plate assay showed that 16.4% (ethyl acetate extract) of these strains were able to generate antimicrobial compounds active against Staphylococcus aureus , Bacillus subtilis, and Candida albicans . In addition, morphological observations and 16S rRNA sequence analysis indicate the presence of representative species from at least 3 genera Streptomyces , Pseudonocardia and Saccharomonospora . Thus, Malaysian mangrove soils could be an interesting source to explore for antimicrobial secondary metabolites and considered to have a diversity of marine actinomycetes.

BIOCONTROL OF FUSARIUM OXYSPORUM IN UNSTERILIZED SOIL BY NOVEL STREPTOMYCES CACAOI SUBSP CACAOI [M20

Objective: To find bio fungicide from mangrove actinomycetes for controlling seed and soil borne pathogen-Fusarium oxysporum. Methods: A total of 25 actinomycetes were isolated by pour plate method. These were screened for fungicidal activity by agar plug method. The isolate M20 was characterised further for identification. The phytotoxicity study was done; biocontrol of Fusarium oxysporum with 10% culture filtrate was done using food poisoning technique. Volatile toxicity of isolate M20 was studied by inverted plate technique. The methanolic crude extract was subjected for UV–Vis spectral analysis for identifying the group of compound present.Results: The isolated M20 found to be better in antifungal activity. 10% culture filtrate actively inhibited the growth of Fusarium oxysporum (77.7%), 10% culture filtrate was taken as a standard concentration for biocontrol of Fusarium oxysporum using green gram as the test plants. The 15th-day green gram plants under treatment with the antagonist (A), antagonist+pathogen (A+P), antagonist+pathogen+rhizobium (A+P+R) yielded high biomass and better growth. The disease development by the pathogen in green gram was controlled by the antagonist. The compounds (pyrimidine nucleosides-neutral and acidic polyoxins (230 nm), (270-290 nm) and heptaene antifungal antibiotics (406-417 nm)) are preliminarily confirmed from the methanolic crude extract of the isolate M20-Streptomyces cacaoi subsp cacaoi.Conclusion: Since the isolate M20 controlled the growth and disease causing potentiality of Fusarium oxysporum, it can be effectively used to control seed and soil borne diseases that are caused by Fusarium oxysporum.

Biotechnological potential of Kuantan mangrove actinomycete, Micromonospora K3-13

Introduction: Mangrove is a complex and unique ecosystem which experiences periodical tidal flooding inundated with low, moderate and high salinity water. Its muddy soil is rich in organic matter derived from the efficient nutrient cycling system and decomposition of mangrove leaves. An adaptation of mangrove microorganisms towards these environmental factors could promote the production of interesting bioactive compounds and enzymes. Methods: This study determines to unravel the identity and biotechnological potential of a Kuantan mangrove actinomycete, strain K3-13, through morphology observation, molecular identification, antimicrobial test and xylan degradation test. Results: The orange-colored mycelium-forming isolates produced spores after a long incubation period, and showed characteristics that resembled Micromonaspora colonies. Phylogenetic analysis of the 16S rRNA gene sequence of strain K3-13 indicated that the highest similarity was to Micromonospora carbonacea DSM43168 (99%). It was observed that K3-13 produced blue diffusible pigment upon cultivation on agar media. Cross streak assay conducted to detect antimicrobial activity indicated that K1-13 has strong antibacterial activity against Bacillus subtilis and Staphylococcus aureus. K3-13 also showed positive xylanase activity by exhibiting decolourization zone in the agar-based assay using azo-xylan as substrate. Conclusions: On the basis of its ability to produce blue pigment, antimicrobial activity against at least two test organisms and positive xylan degrading activity, Micromonaspora K3-13 is concluded as strain worth exploring for its potential biotechnological application as a natural dye, antibacterial drugs and Xylan biodegraders.

Halichoblelide D, a New Elaiophylin Derivative with Potent Cytotoxic Activity from Mangrove-Derived Streptomyces sp. 219807.

During our search for interesting bioactive secondary metabolites from mangrove actinomycetes, the strain Streptomyces sp. 219807 which produced a high elaiophylin yield of 4486 mg/L was obtained. A new elaiophylin derivative, halichoblelide D (1), along with seven known analogues 2–8 was isolated and identified from the culture broth. Their chemical structures were determined by detailed analysis of 1D and 2D NMR and HRMS data. The absolute configuration of halichoblelide D (1) was confirmed by comparing the CD spectrum with those of the reported analogues. Compounds 1–7 exhibited potent cytotoxic activities against HeLa and MCF-7 cells with IC50 values ranging from 0.19 to 2.12 μM.

Chemical characterization & bioactivity of diketopiperazine derivatives from the mangrove derived Pseudonocardia endophytica

Sediment samples from the mangrove ecosystem of Nizampatnam have been analyzed for actinomycetes as an elite source to screen for the formulation and production of antimicrobial and cytotoxic compounds. The actinomycetes strain VUK-10 has an interesting bioactivity profile and was isolated during our systematic study of mangrove actinomycetes. It was identified as Pseudonocardia endophytica with the aid of polyphasic taxonomy. The ethyl acetate extract of the actinobacterial culture filtrate has been purified by gel-filtration and silica gel column chromatographic purifications led to the isolation of two diketopiperazine compounds, (3S,8aS)-3-isobutylhexahydropyrrolo[1,2-a]pyrazine-1,4-dione (1) and (3R,8aS)-3-isobutylhexahydropyrrolo[1,2-a]pyrazine-1,4-dione (2). The compounds listed, alluring cytotoxic activity against MDA-MB-231, HeLa, MCF-7 and OAW-42 cancer cell lines and also exhibited antimicrobial activities against gram-positive, gram-negative bacteria and fungi. Compound 1 recorded significant antibacterial activity against Xanthomonas campestris and Escherichia coli (8μg/ml) and compound 2 presented highest activity against Bacillus subtilis (4μg/ml). Compounds 1 and 2 were active against pathogenic fungi to plants and human beings. The activity was compared with griseofulvin and amphotericin-B, which are standard fungicides. The activity of 16μg/ml by compound 1 was recorded against Epidermophyton floccosum; an anthropophilic dermatophyte responsible for tinea pedis, tinea cruris and tinea corporis. To the best of our knowledge this is the first narration on the isolation of supra said compounds from the genus Pseudonocardia.

PreQ0 base, an unusual metabolite with anti-cancer activity from Streptomyces qinglanensis 172205.

PreQ0 base (7-cyano-7-deazaguanine, compound 1) is the biosynthetic precursor of queuosine-tRNA and important synthetic intermediate for bioactive compounds. It was obtained for the first time as a new natural product from a mangrove actinomycete Streptomyces qinglanensis 172205, during the course of searching for anti-cancer compounds from marine microbes. PreQ0 base showed anti-HeLa (IC50 = 62.0 μg/ml) and anti-HepG2 (IC50 = 80.6 μg/ml) activities, higher cytotoxicity than the positive control, fluorouracil. Furthermore, it exhibited weak α -glucosidase inhibitory activity, but no obvious antimicrobial and Aβ1-42 fibrillation inhibitory activities. In silico analysis of the genome of the strain 172205 revealed a putative biosynthetic gene cluster directing the biosynthesis of PreQ0 base. The gene cluster only contained three Open Reading Frames (ORFs), queC, queD and queE. The absence of the key gene queF encoding 7-cyano-7-deazaguanine reductase catalyzing PreQ0 base to PreQ1 base suggested that the strain only has the capacity of accumulation of PreQ0 base as a metabolite, consistent with our observation in chemical identification.

Natural products from mangrove actinomycetes.

Mangroves are woody plants located in tropical and subtropical intertidal coastal regions. The mangrove ecosystem is becoming a hot spot for natural product discovery and bioactivity survey. Diverse mangrove actinomycetes as promising and productive sources are worth being explored and uncovered. At the time of writing, we report 73 novel compounds and 49 known compounds isolated from mangrove actinomycetes including alkaloids, benzene derivatives, cyclopentenone derivatives, dilactones, macrolides, 2-pyranones and sesquiterpenes. Attractive structures such as salinosporamides, xiamycins and novel indolocarbazoles are highlighted. Many exciting compounds have been proven as potential new antibiotics, antitumor and antiviral agents, anti-fibrotic agents and antioxidants. Furthermore, some of their biosynthetic pathways have also been revealed. This review is an attempt to consolidate and summarize the past and the latest studies on mangrove actinomycetes natural product discovery and to draw attention to their immense potential as novel and bioactive compounds for marine drugs discovery.

Benzamides and Quinazolines from a Mangrove Actinomycetes Streptomyces sp. (No. 061316) and Their Inhibiting Caspase-3 Catalytic Activity in Vitro

One new benzamide, 3-hydroxyl-2-N-iso-butyryl-anthranilamide (1), together with two known benzamides (2, 3) and three known quinazolines (4-6), was isolated from a mangrove actinomycetes Streptomyces sp. (No. 061316), which displayed inhibiting Caspase-3 activity in vitro. The structure of 1 was elucidated by electrospray ionization (ESI)-MS, NMR spectroscopies and X-ray crystal diffraction. After evaluation of all compounds for their inhibitory effect on Caspase-3 in vitro, 3-hydroxyl-anthranilamide (2) and 8-hydroxyl-2,4-dioxoquinazoline (6) showed activity against Caspase-3 with IC(50) values of 32 and 36 µM, respectively.