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Streptomyces tyrfis sp. nov., an actinobacterium isolated from Thai peat swamp forest soil and its promising secondary metabolites
(2026-12-01)
Kottip, Penkawee
;
Klanbut, Khanungkan
;
Fukasem, Poowadon
;
Pittayakhajonwut, Pattama
;
Intaraudom, Chakapong
An actinomycete strain, PTD5-9T, was isolated from peat swamp forest soil in Narathiwat Province, Thailand. Chemotaxonomic features and phylogenetic analysis based on the 16S rRNA gene sequence placed this strain within the genus Streptomyces. It exhibited the highest sequence similarity to Streptomyces gelaticus NRRL B-2928ᵀ (99.38%) and Streptomyces sanglieri NBRC 100784ᵀ (99.31%). However, the average nucleotide identity based on MUMmer (ANIm) values (88.48–88.56%), the average amino acid identity (84.37–84.97%), and digital DNA–DNA hybridization (dDDH) estimates (31.2–36.5%) were significantly below the accepted thresholds for species demarcation, supporting its classification as a new species within the genus. Accordingly, the name Streptomyces tyrfis sp. nov. is proposed. The crude extract derived from the culture broth of strain PTD5-9ᵀ exhibited potent antibacterial activity against Gram-positive bacteria (MIC ≤ 250 µg/mL). Subsequent chemical analysis led to the identification of ten bioactive secondary metabolites: isocycloheximide (1), (2R,4S,6E)-anhydrocycloheximide (2), actiphenol (3), (−)-phenatic acid A (4), 8-O-methyltetrangomycin (5), 8-O-methylrabelomycin (6), 4-hydroxy-8-O-methylrabelomycin (7), tetrangulol methyl ether (also known as X-14881 E) (8), (−)-elmonin (9), and 2-phenylacetamide (10). Among these, compounds 3, 6, 7, and 8, which were isolated in sufficient quantities, exhibited notable inhibitory activity against Mycobacterium tuberculosis, with MIC values ranging from 3.13 to 25.0 µg/mL. Furthermore, compounds 6, 7, and 8 demonstrated pronounced cytotoxicity against human small cell lung cancer (NCI-H187) cells (IC₅₀: 1.10–7.80 µM), and against human breast cancer (MCF-7) cells (IC₅₀: 1.21–24.6 µM).
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Antimalarial and antimicrobial substances from the endophytic fungus Chaetomium globosum BCC71876
(2026-01-01)
Bunbamrung, Nantiya
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Intaraudom, Chakapong
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Dramae, Aibrohim
;
Boonyuen, Nattawut
;
Choowong, Wilunda
Three previously undescribed compounds including 2′,3′-dihydroxy-4,5′,4″-trimethoxy-p-terphenyl (1), 5-methoxyhydroperoxycochliodinol (2), and 5-(3′,3′-dimethylallyl)indole-3-oxoacetic acid (17), along with fifteen known compounds (3–16 and 18), were isolated from the endophytic fungus, Chaetomium globosum BCC71876. The chemical structures were determined by NMR spectral information as well as the comparison with those closely related compounds reported in the literature. The compounds isolated were evaluated for biological properties including antimalarial, anti-TB, anti-plant pathogenic fungal, antibacterial, and cytotoxicity. The isolated compounds exhibited a wide range of biological activities against the tested cell lines and showed very low cytotoxicity against both cancerous (MCF-7 and NCI-H187) and non-cancerous (Vero) cells, except for compounds 5, 10, 11, 17, and 18 (IC<inf>50</inf> 0.47 − 114.8 µM). Cochliodinol (5) had the strongest antimalarial activity (IC<inf>50</inf> 4.39 µM), whereas chaetomugilin J (11) showed the strongest anti-TB activity (MIC 3.13 µg/mL).
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cis-Decalinoyltetramic Acid Derivatives from the Palm Fungus Leptosporella arengae TBRC-BCC32590
(2025-11-28)
Intaraudom, Chakapong
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Bunbamrung, Nantiya
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Dramae, Aibrohim
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Nithithanasilp, Sutichai
;
Boonyuen, Nattawut
Twelve hitherto undescribed cis-decalinoyltetramic acid derivatives (arengasetins A – L), a unique spiro[2.4]heptendione (spiroarengarone) and two benzoquinones (arengaquinones A and B), together with the highly oxygenated polycyclic molecule, epicolactone, were isolated from the palm fungus Leptosporella arengae TBRC-BCC 32590. Chemical structures were determined by extensive analyses of 2D NMR spectroscopic data and chemical means. The absolute configuration of arengasetin A (1) was confirmed by X-ray crystallographic information, while the absolute configurations of other related compounds were corroborated by comparison of NMR spectroscopic data and chemical reactions. The isolated compounds exhibited activity against Plasmodium falciparum (K1, multidrug-resistant strain, IC<inf>50</inf> 6.42 – > 38.76 μM), Bacillus cereus (MIC 0.78 – > 50.0 μg/mL), Staphylococcus aureus (MIC 1.56 – > 50.0 μg/mL), and Mycobacterium tuberculosis (MIC 6.25 – > 50.0 μg/mL). Cytotoxicity against both cancerous (MCF-7 and NCI-H187) and noncancerous (Vero) was also reported.
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Streptomyces telluris sp. nov., a promising terrestrial actinobacterium with antioxidative potentials
(2023-06-01)
Thayanuwadtanawong, Onnicha
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Duangupama, Thitikorn
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Bunbamrung, Nantiya
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Pittayakhajonwut, Pattama
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Intaraudom, Chakapong
An actinomycete strain, AA8T, which produced a long straight chain of spores (verticillati type), was isolated from the rhizosphere soil of Mangifera indica in Bangkok, Thailand. A polyphasic taxonomic study was carried out to establish the taxonomic position of the strain. Strain AA8T formed a tight taxonomic position in the 16S rRNA gene tree with Streptomyces roseifaciens MBT76T. In contrast, the genome-based taxonomic analysis showed that strain AA8T shared low average nucleotide identity-BLAST (94.1%), the digital DNA–DNA hybridization (58.2%), and the average amino acid identity (93.6%) values with S. roseifaciens MBT76T. Moreover, a combination of physiological and biochemical properties indicated that strain AA8T was distinguished from all Streptomyces species with effectively published names. Strain AA8T, therefore, represents a novel species of Streptomyces, and the name Streptomyces telluris is proposed for the strain. The type strain is AA8T (= TBRC 8483T = NBRC 113461T). The chemical investigation led to the isolation of nine known compounds (compounds 1–9). Among these compounds, compound 7 (3,4-dihydroxybenzaldehyde) possesses strong antioxidant activity equal to ascorbic acid, a powerful antioxidative agent.
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Antimalarial and antimicrobial substances isolated from the endophytic actinomycete, Streptomyces aculeolatus MS1-6
(2023-03-01)
Kuncharoen, Nattakorn
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Bunbamrung, Nantiya
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Intaraudom, Chakapong
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Choowong, Wilunda
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Thawai, Chitti
Seven undescribed compounds, including four naphthoquinone terpenoids (aculeolatins A – D), one rare 2-nitropyrrole terpenoid (nitropyrrolin F), and two hydroxamate siderophores (aculeolamides A and B) and one further undescribed compound (2,5,7-trihydroxy-3,6-dimethylnaphthalene-1,4-dione), together with eleven known compounds (arromycin, phenaziterpene A, nitropyrrolin A, heronapyrroles A and B, salaceyin A, 5,7-dihydroxy-2-isopropylchromone, 1-hydroxyphenazine, 1-methoxyphenazine, 1-acetyl-β-carboline, and N-(2-phenylethyl) acetamide), were isolated from the cultures of the endophytic Streptomyces aculeolatus MS1-6. The structures of the isolated compounds were determined using NMR spectroscopy and corroborated using chemical modification. These compounds exhibited a broad spectrum of biological activities, including antimalarial (IC<inf>50</inf> 6.03–9.84 μg/mL), antitubercular (MIC 3.13–6.25 μg/mL), anti-plant pathogenic fungal (MIC 25.0–50.0 μg/mL), and antibacterial (MIC 3.03–50 μg/mL) activities; however, they displayed unremarkable cytotoxicity against cancerous (MCF-7 and NCI–H187) and non-cancerous (Vero) cell lines.
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Diphenyl ethers and depsidones from the endophytic fungus Aspergillus unguis BCC54176
(2022-01-22)
Sadorn, Karoon
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Saepua, Siriporn
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Bunbamrung, Nantiya
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Boonyuen, Nattawut
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Komwijit, Somjit
Four new diphenyl ethers, aspergillusethers G−J (1–4), and one new depsidone, emeguisin D (7), together with eighteen known compounds have been isolated and characterized from the endophytic fungus Aspergillus unguis BCC54176. The chemical structures were established based on spectroscopic evidence in conjunction with a chemical transformation. Furthermore, the chemical structure of compound 7 was verified by single-crystal X-ray diffraction data. The isolated compounds were evaluated for biological activity. Compound 7, emeguisin C (10), and nidulin (14) showed antibacterial activity against Bacillus cereus with an equal MIC value of 1.56 μg/mL, while emeguisin A (8), nornidulin (13), 2-chlorounguinol (16), and aspergillusidone C (21) displayed anti-phytopathogenic activity against Colletotrichum acutatum with the equal MIC value of 3.13 μg/mL. Compound 7 was also active against Staphylococcus aureus with an MIC value of 1.56 μg/mL. However, none of the tested compounds had cytotoxicity against cancerous (MCF-7 and NCI–H187) and non-cancerous (Vero) cells.
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Abyssomicin derivatives from the rhizosphere soil actinomycete Microbispora rhizosphaerae sp. nov. TBRC6028
(2021-05-01)
Bunbamrung, Nantiya
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Kittisrisopit, Suchada
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Intaraudom, Chakapong
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Dramae, Aibrohim
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Thawai, Chitti
Three undescribed abyssomicin derivatives, including microbimisin, abyssomicins Z1, and Z2, were isolated from the soil actinomycete Microbispora rhizosphaerae sp. nov. TBRC6028. Chemical structures were determined by NMR spectroscopic data (1H, 13C, COSY, HSQC, HMBC, and NOESY spectra) and the absolute configurations were verified by single-crystal X-ray diffraction analyses together with the ECD spectral data. Microbimisin and abyssomicin Z1 exhibited weak antibacterial activity against Bacillus cereus with MIC values of 25.0 and 50.0 μg/mL without cytotoxicity against MCF-7 and Vero cells at the concentration of 50 μg/mL.
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Neuroprotective potential of new chromones isolated from the soil actinomycete Microbispora sp. TBRC6027
(2021-01-01)
Kittisrisopit, Suchada
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Bunbamrung, Nantiya
;
Thawai, Chitti
;
Tadtong, Sarin
;
Niemhom, Nantawan
Nine new chromone analogs (1–9) were isolated from the soil actinomycete Microbispora sp. TBRC6027. The chemical structures were determined based upon NMR spectroscopic methods. These compounds were evaluated in vitro by using P19-derived neurons for neuroprotective activity against oxidative stress induced by serum deprivation and showed % viability of neurons at the concentration of 1 ng/mL varied from 43.51% to 52.99% without significant neurotoxicity for P19-derived neurons at the same concentration. Moreover, all tested compounds were inactive for antibacterial activity against both Gram-positive and Gram-negative bacteria and for cytotoxicity against MCF-7 (human breast cancer) and Vero cells at maximum tested concentration 50 μg/mL. However, compounds 4, 6, and 7 displayed weak cytotoxicity against NCI-H187 (human small-cell lung cancer) cells with IC<inf>50</inf> in a range of 87.99–91.57 μM.
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A novel diterpene agent isolated from Microbispora hainanensis strain CSR-4 and its in vitro and in silico inhibition effects on acetylcholine esterase enzyme
(2020-12-01)
Thawai, Chitti
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Bunbamrung, Nantiya
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Pittayakhajonwut, Pattama
;
Chongruchiroj, Sumet
;
Pratuangdejkul, Jaturong
An actinomycete strain CSR-4 was isolated from the rhizosphere soil of Zingiber montanum. Taxonomic characterization revealed strain CSR-4 was a member of the genus Microbispora. Whole-genome sequence analysis exhibited the highest average nucleotide identity (ANI) value (95.34%) and digital DNA–DNA hybridization (DDH) value (74.7%) between strain CSR-4 and the closest relative M. hainanensis DSM 45428T, which was in line with the assignment to same species. In addition, a new diterpene compound, 2α-hydroxy-8(14), 15-pimaradien-17, 18-dioic acid, and nine known compounds were isolated from the ethyl acetate crude extract of fermentation broth. Interestingly, a new diterpene displayed the suppressive effect on the recombinant human acetylcholinesterase (rhAChE) enzymes (IC<inf>50</inf> 96.87 ± 2.31 μg/ml). In silico studies based on molecular docking and molecular dynamics (MD) simulations were performed to predict a binding mode of the new compound into the binding pocket of the rhAChE enzyme and revealed that some amino acids in the peripheral anions site (PAS), anionic subsite, oxyanion site and catalytic active site (CAS) of the rhAChE have interacted with the compound. Therefore, our new compound could be proposed as a potential active human AChE inhibitor. Moreover, the new compound can protect significantly the neuron cells (% neuron viability = 88.56 ± 5.19%) from oxidative stress induced by serum deprivation method at 1 ng/ml without both neurotoxicities on murine P19-derived neuron cells and cytotoxicity against Vero cells.
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Antibacterial, antitubercular, antimalarial and cytotoxic substances from the endophytic Streptomyces sp. TBRC7642
(2020-04-01)
Bunbamrung, Nantiya
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Intaraudom, Chakapong
;
Dramae, Aibrohim
;
Thawai, Chitti
;
Tadtong, Sarin
Eight previously undescribed naturally-occurring compounds, including abyssomycins Y - Z, methyl aeruginoate, desferri-ferrithocin-4-hydroxyphenethylester, streptomethiocins A - B, furaquinocin I, and streptolactone, along with eleven known compounds were isolated from the endophytic Streptomyces sp. TBRC7642. The chemical structures were determined based on spectroscopic means including 1D, 2D NMR spectroscopy and mass spectrometry. The absolute configurations were assigned by relying on CD spectra and their optical rotations. In addition, the isolated compounds were evaluated for biological activity, such as antimalarial, antitubercular, antibacterial (both Gram-positive and Gram-negative bacteria), as well as for cytotoxicity against MCF-7, NCI–H187, and Vero cells.

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