New Secondary Metabolites from Marine-Derived Fungus Talaromyces minnesotensis BTBU20220184

Abstract

Six new compounds, talamitones A and B (1 and 2), demethyltalamitone B (3), talamiisocoumaringlycosides A and B (4 and 5), and talaminaphtholglycoside (6), together with six known compounds (7–12), were isolated from the marine-derived fungus Talaromyces minnesotensis BTBU20220184. The new structures were characterized by using HRESIMS and NMR. This is the first report of isocoumaringlycoside derivatives from a fungus of the Talaromyces genus. Compounds 5, 6, and 9 showed synergistic antibacterial activity against Staphylococcus aureus.

1. Introduction

The marine ecosystem is a rich pool for filamentous fungi. With the quick development in sampling using marine and molecular taxonomy technology, the fungal diversity of the marine environment has been greatly improved [1]. Over 1800 species of marine-derived fungi, belonging to 769 genera, have been studied, such as Aspergillus, Penicillium, Trichoderma, Eurotium, Talaromyces, and so on [2,3]. The section of Talaromyces was first introduced by Stolk and Samson in 1972 [4], and over 200 species have been reported in this genus [5,6]. Species of Talaromyces are commonly distributed in various environments, such as soil [6,7], marine [8], food products [9], leaf litter [10], and atmospheric environments [11]. A chemical investigation of Talaromyces species revealed the potential for new bioactive chemical entries [12]. A panel of new structural classes have been reported from this fungus, including ergosteroids [13,14], meroterpenoids [15], and pyridone derivatives [16,17]. Nicoletti reviewed the chemical diversity of Talaromyces species from marine environments. Over 500 natural products have been identified from fungi of the Talaromyces genus, and 45% of the compounds were new structures. These compounds displayed a wide spectrum of biological activities and chemical diversity, attracting researchers to screening new pharmaceutical entries [18].

In our ongoing chemical investigation of marine-derived microorganisms, new antibacterial compounds have been identified from marine-derived Talaromyces strains [19,20]. Further research on a marine-derived fungus from Qinzhou Bay, Guangxi Province, China, resulted in the identification of twelve compounds, including six new compounds, talamitones A and B (1 and 2), demethyltalamitone B (3), talamiisocoumaringlycosides A and B (4 and 5), and talaminaphtholglycoside (6), along with six reported compounds, mucorisocoumarin B (7), diaportinol (8), peniisocoumarin E (9), dichlorodiaportin (10), orsellinic acid (11), and 4-(hydroxymethyl)-5-hydroxy-2H-pyran-2-one (12) (Figure 1), from T. minnesotensis BTBT20220184. Compounds 5, 6, and 9 showed synergistic antibacterial activity against Staphylococcus aureus. This paper focuses on the isolation, detailed structure elucidation, and antimicrobial activity evaluation of these compounds.

2. Results

2.1. Structure Determination

Compound 1 was isolated as a light-yellow oil. The molecular formula of 1 was determined to be C₂₀H₁₆O₈ based on the HRESIMS spectrum (m/z [M + H]⁺ 385.0923, calcd for C₂₀H₁₇O₈, 385.0918), indicating thirteen degrees of unsaturation (Figure S1). The ¹H NMR data of 1 (

Table 1. ¹H (500 MHz) and ¹³C NMR (125 MHz) data of 1–3 (CD₃OD).

Pos	1		2		3
	δC, Type	δH, (J in Hz)	δC, Type	δH, (J in Hz)	δC, Type	δH, (J in Hz)
1	198.5, C		201.0, C		201.2, C
2	136.7, C		38.8, CH2	3.06, t (7.0)	38.8, CH2	3.06, t (7.0)
3	154.0, C		202.8, C		202.9, C
3a	134.8, C		136.8, C		136.5, C
4	152.6, C		155.2, C		155.2, C
5	126.8, CH	7.50, d (1.5)	121.7, C	7.68, d (1.0)	121.8, CH	7.68, d (1.5)
6	134.4, C		132.8, C		133.7, C
7	115.4, CH	7.51, d (1.5)	122.0, C	8.07, d (1.0)	122.0, CH	8.08, d (1.5)
7a	133.1, C		137.3, C		137.3, C
8	20.7, CH2	2.44, m	20.4, CH2	1.90, quint (7.0)	20.5, CH2	1.90, quint (7.0)
9	32.9, CH2	2.46, m	33.7, CH2	2.35, t (7.0)	33.9, CH2	2.35, t (7.0)
10	175.3, C		175.5, C		177.2, C
11	168.9, C		168.6, C		169.3, C
1′	110.7, C		112.2, C		112.2, C
2′	156.7, C		163.3, C		163.3, C
3′	107.6, CH	6.39, d (8.0)	108.1, CH	6.28, d (8.5)	108.1, CH	6.28, d (8.0)
4′	130.9, CH	7.04, t (8.0)	137.4, CH	7.21, t (8.5)	137.4, CH	7.21, t (8.0)
5′	107.6, CH	6.39, d (8.0)	108.1, CH	6.28, d (8.5)	108.1, CH	6.28, d (8.0)
6′	156.7, C		163.3, C		163.3, C
10-OCH3	52.1, CH3	3.60, s	52.1, CH3	3.64, s

, Figure S2) showed five aromatic protons at δ_H 7.50 (d, J = 1.5 Hz, H-5), 7.51 (d, J = 1.5 Hz, H-7), 6.39 (d, J = 8.0 Hz, H-3′, 5′), and 7.04 (t, J = 8.0 Hz, H-4′); two methylenes at δ_H 2.44 (m, H₂-8) and 2.46 (m, H₂-9); and one methoxy at δ_H 3.60 (s, 10-OCH₃). The ¹³C and HSQC spectra of 1 (Figures S3 and S4) displayed twenty carbon signals (Table 1), including one carbonyl at δ_C 198.5 (C-1); two carboxyl carbons at δ_C (175.3, C-10) and (168.9, C-11); eight sp² quaternary carbons at δ_C 136.7 (C-2), 154.0 (C-3), 134.8 (C-3a), 152.6 (C-4), 134.4 (C-6), 133.1 (C-7a), 110.7 (C-1′), and 156.7 (C-2′, 6′); five sp² methine carbons at δ_C 126.8 (C-5), 115.4 (C-7), 107.6 (C-3′, 5′), and 130.9 (C-4′); two methylene carbons at δ_C 20.7 (C-8) and 32.9 (C-9); and one methoxy carbon at δ_C (52.1, 10-OCH₃). The ¹H-¹H COSY correlations (Figure 2 and Figure S5) revealed the fragments of C-8/C-9 and C-3′/C-4′/C-5′. In the HMBC spectrum (Figure S6), the correlations from H-5 to C-3, C-3a, C-4, C-6, and C-7; from H-7 to C-1, C-3a, and C-5; and from H-5 and H-7 to C-11, along with the chemical shift of C-4 (δ_C 152.6), suggested that the hydroxyl and carboxyl substituted the inden-1-one moiety (Figure 2). The HMBC correlations from H-4′ to C-2′ and C-6′ and from H-3′ and H-5′ to C-1′ indicated the 1,2,3-trisubstituted benzene fragment. The HMBC correlations from H₂-8, H₂-9, and H₃-OMe to C-10 confirmed the presence of a C-8/C-9/C-10/OMe moiety. The HMBC correlations from H₂-8 to C-1, C-2, and C-3; from H₂-9 to C-2; and from H-3′ and H-5′ to C-1′ and C-3 revealed the connection from C-2 to C-8 and from C-3 to C-1′, respectively. Therefore, the structure of 1 was assigned as shown in Figure 1 and named talamitone A.

Compound 2 was isolated as a light-yellow powder. The molecular formula of 2 was determined to be C₂₀H₁₈O₉ based on the HRESIMS spectrum (m/z [M + H]⁺ 403.1011, calcd for C₂₀H₁₉O₉, 403.1024), indicating twelve degrees of unsaturation (Figure S7). The analysis of the ¹H, ¹³C, HSQC, and ¹H-¹H COSY spectra (Table 1, Figures S8–S11) revealed the presence of two substituted benzene rings (δ_C 136.8, C-3a; δ_C 155.2, C-4; δ_C 121.7/δ_H 7.68, C-5/H-5; δ_C 132.8, C-6; δ_C 122.0/δ_H 8.07, C-7/H-7; δ_C 137.3, C-7a; δ_C 112.2, C-1′; δ_C 163.3, C-2′,6′; δ_C 108.1/δ_H 6.28, C-3′,5′/H-3′,5′; δ_C 137.4/δ_H 7.21, C-4′/H-4′); three sp³ methylenes (δ_C 38.8/δ_H 3.06, C-2/H-2; δ_C 20.4/1.90, C-8/H-8; δ_C 33.7/δ_H 2.35, C-9/H-9); one methoxy (δ_C 52.1/δ_H 3.64, 10-OCH₃); two carbonyls at δ_C 201.0 (C-1) and 202.8 (C-3); as well as two carboxyls at δ_C 175.5 (C-10) and δ_C 168.6 (C-11). All of the above NMR data indicated that the structure of 2 is similar to that of 1. A detailed comparison of the NMR data of compounds 1 and 2 showed that the double bond C-2/C-3 was modified. The double bonds of C-2/C-3 in 1 were replaced by one sp³ methylene (δ_H 3.06, 2H, t, J = 7.0 Hz; δ_C 38.8, C-2) and one carbonyl (δ_C 202.8, C-3). In the HMBC spectrum (Figure 2 and Figure S12), the long-range correlation from H-5 to C-3 confirmed the carbonyl (C-3)’s bearing on C-3a. The HMBC correlations from H-3′ and H-5′ to C-3 and from H₂-2 to C-1 and C-7a indicated that the α,β-unsaturated moiety of C-1/C-2/C-3 in 1 changed to the moiety of C-1 (carbonyl)/C-2 (methylene) and the other carbonyl of C-3 in 2. Therefore, the structure of 2 was assigned as shown in Figure 1 and named talamitone B.

Compound 3 was isolated as a light-yellow powder. The molecular formula of 3 was determined to be C₁₉H₁₆O₉ based on the HRESIMS spectrum (m/z [M + H]⁺ 389.0871, calcd for C₁₉H₁₇O₉, 389.0867), indicating twelve degrees of unsaturation (Figure S13). Compound 3 showed similar NMR data to those of 2. By comparing the molecular formula and NMR data (Table 1, Figures S14 and S15), 3 was deduced to be the product of the demethylation of 2. The structure of 3 was confirmed by detailed analysis of the HSQC, ¹H-¹H COSY, and HMBC spectra (Figures S16–S18). The long-range correlation from H-5 to C-3 confirmed the carbonyl (C-3)’s bearing on C-3a. The presence of HMBC correlations from H₂-8 and H₂-9 to C-10 indicated the carboxyl of C-10. Therefore, the structure of 3 was assigned as shown in Figure 1 and named demethyltalamitone B.

Compound 4 was isolated as a light-yellow powder. The molecular formula of 4 was determined to be C₁₉H₂₄O₁₁ based on the HRESIMS spectrum (m/z [M + Na]⁺ 451.1204, calcd for C₁₉H₂₄O₁₁Na, 451.1211), indicating eight degrees of unsaturation (Figure S19). The ¹H and ¹³C NMR data of 4 (

Table 2. ¹H (500 MHz) and ¹³C NMR (125 MHz) data of 4–6 (CD₃OD).

Pos	4		5		6
	δC, Type	δH, (J in Hz)	δC, Type	δH, (J in Hz)	δC, Type	δH, (J in Hz)
1	167.9, C		167.5, C		110.0, CH	6.89, s
2	-		-		158.4, C
3	157.9, C		154.0, C		119.5, C
4	101.2, CH	6.94, s	103.6, CH	7.04, s	131.3, CH	9.17, s
4a	133.5, C		133.0, C		118.6, C
5	132.9, C		133.2, C		154.0, C
6	161.1, C		161.1, C		120.7, C
7	99.7, CH	6.63, s	100.1, CH	6.66, s	160.5, C
8	161.8, C		161.9, C		104.4, CH	6.76, s
8a	99.3, C		99.3, C		140.4, C
9a	30.7, CH2	2.63, m	39.4, CH2	3.15, dd (15.0, 4.0)	207.0, C
9b				2.88, dd (15.0, 9.5)
10	30.8, CH2	1.90, tt (7.0)	60.4, CH	4.32, m	27.2, CH3	2.76, s
11	61.7, CH2	3.63, m	66.8, CH2	3.78, m	10.9, CH3	2.34, s
1′	105.9, CH	4.70, d (7.5)	106.0, CH	4.70, d (7.5)	107.1, CH	4.78, d (7.5)
2′	75.6, CH	3.50, m	75.6, CH	3.51, dd (9.0, 7.5)	75.8, CH	3.69, m
3′	77.8, CH	3.42, m	77.8, CH	3.44, m	78.2, CH	3.47, m
4′	71.2, CH	3.42, m	71.2, CH	3.44, m	71.4, CH	3.47, m
5′	78.2, CH	3.17, m	78.1, CH	3.17, m	77.9, CH	3.13, m
6′a	62.5, CH2	3.76, dd (11.5, 2.5)	62.4, CH2	3.76, dd (11.5, 2.5)	62.6, CH2	3.76, dd (11.5, 2.5)
6′b		3.66, dd (11.5, 5.0)		3.67, dd (11.5, 4.5)		3.67, m
6-OCH3	56.8, CH3	3.94, s	56.9, CH3	3.94, s

, Figures S20 and S21) showed signals for one isocoumarin substructure at δ_C 167.9 (C-1, carboxyl), 157.9 (C-3, oxygenated), δ_C 101.2 (C-4)/δ_H 6.94 (s, H-4), 133.5 (C-4a), 132.9 (C-5), 161.1 (C-6, oxygenated), δ_C 99.7 (C-7)/δ_H 6.63 (s, H-7), 161.8 (C-8, oxygenated), and 99.3 (C-8a); one hydroxypropyl at δ_C 30.7 (C-9)/δ_H 2.63 (m, H₂-9), δ_C 30.8 (C-10)/δ_H 1.90 (tt, J = 7.0 Hz, H₂-10), and δ_C 61.7, C-11/δ_H 3.63 (m, H₂-11); one glucose at δ_C 105.9 (C-1′)/δ_H 4.70 (d, J = 7.5 Hz, H-1′), δ_C 75.6 (C-2′)/ δ_H 3.50 (m, H-2′), δ_C 77.8 (C-3′)/δ_H 3.42 (m, H-3′), δ_C 71.2 (C-4′)/δ_H 3.42 (m, H-4′), δ_C 78.2, C-5′/δ_H 3.17 (m, H-5′), δ_C 62.5, C-6′)/ δ_H 3.76 (dd, J = 11.5, 2.5 Hz, H-6′a), and 3.67 1H (dd, J = 11.5, 4.5 Hz, H-6′b); and one methoxy at δ_C 56.8/δ_H 3.94 (s, 6-OCH₃). The protonated carbons and correlations were confirmed by the HSQC and ¹H-¹H COSY spectra (Figures S22 and S23). In the HMBC spectrum (Figure 2 and Figure S24), the correlations from H₃-6-OMe to C-6 revealed the methoxy’s bearing on C-6. The HMBC correlations from H-4 to C-3 and C-9 and from H₂-9 and H₂-10 to C-3 indicated the hydroxypropyl at C-3. The connection between C-5 and C-1′ through an oxygen atom was confirmed by the HMBC correlations from H-1′ to C-5. Therefore, the planar structure of 4 was assigned and named talamiisocoumaringlycoside A.

Compound 5 was isolated as a light-yellow powder. The molecular formula of 5 was determined to be C₁₉H₂₃ClO₁₁ based on the HRESIMS spectrum (m/z [M + Na]⁺ 485.0830, calcd for C₁₉H₂₃ClO₁₁Na, 485.0821), indicating eight degrees of unsaturation (Figure S25). The ¹H and ¹³C NMR data of 5 (Table 2, Figures S26 and S27) showed similar signals to those of 4, except for the methylene of CH₂-10, which was replaced by one sp³ methine. Through analysis of the molecular formula, chemical shift of ¹³C NMR, and 2D NMR data (Figures S28–S30), the chloro-substituted methine at δ_C 60.4 (C-4)/δ_H 4.32 (m, H-4) was deduced. By comparison of the optical rotations of 5 (${\left[\mathrm{\alpha }\right]}_{\mathrm{D}}^{25}$ + 26.0) and peniisocoumarin E (${\left[\mathrm{\alpha }\right]}_{\mathrm{D}}^{25}$ + 69.2), the configuration of C-10 was assigned to be the same as the known compound peniisocoumarin E (9) [21]. Therefore, the planar structure of 5 was assigned as shown in Figure 1 and named talamiisocoumaringlycoside B.

Compound 6 was isolated as a light-yellow powder. The molecular formula of 6 was determined to be C₁₉H₂₂O₉ based on the HRESIMS spectrum (m/z [M + H]⁺ 395.1338, calcd for C₁₉H₂₃O₉, 395.1337), indicating nine degrees of unsaturation (Figure S31). The ¹H and ¹³C NMR data of 5 (Table 2, Figures S32 and S33) showed signals for one glucose moiety as in 4 or 5 at δ_C 107.1 (C-1′)/δ_H 4.78 (d, J = 7.5 Hz, H-1′), 75.8 (C-2′)/δ_H 3.69 (m, H-2′), 78.2 (C-3’)/δ_H 3.47 (m, H-13′), 71.4 (C-4′)/δ_H 3.47 (m, H-4’), 77.9 (C-5′)/δ_H 3.13 (m, H-5’), δ_C (62.6, C-6’)/δ_H 3.76 (dd, J = 2.5, 11.5 Hz, H-6’a), and 3.67 (m, H-6’b); three aromatic methines at δ_C 110.0 (C-1)/δ_H 6.89 (s, H-1), 131.3 (C-4)/δ_H 9.17 (s, H-4), and 104.4 (C-8)/δ_H 6.76 (s, H-8); two methyls at δ_C 27.2 (C-10)/δ_H 2.76 (s, H₃-10) and 10.9 (C-11)/δ_H 2.34 (s, H₃-11); one carbonyl at δ_C 207.0 (C-9); and seven sp² quaternary carbons at δ_C 158.4 (C-2, oxygenated), 119.5 (C-3), 118.6 (C-4a), 154.0 (C-5, oxygenated), 120.7 (C-6), 160.5 (C-7, oxygenated), and 140.4 (C-8a). The protonated carbons were confirmed by the HSQC and ¹H-¹H COSY spectra (Figures S34 and S35). The substituted naphthalene substructure was confirmed by the HMBC correlations (Figure 2 and Figure S36) from H-1 to C-3, C-4a, and C-8; from H-4 to C-2, C-5, C-8a, and C-9; from H-8 to C-1, C-4a, and C-6; from H₃-10 to C-3 and C-9; as well as from H₃-11 to C-5, C-6, and C-7. The connection between C-5 and C-1′ through an oxygen atom was characterized by the HMBC correlation from H-1′ to C-5. Therefore, the planar structure of 6 was assigned and named talaminaphtholglycoside.

With almost identical NMR data, the sugar moieties of 4–6 were deduced to be the same configurations. The anomeric protons H-1′ of 4–6 showed large coupling constants (J = 7.5 Hz), indicating the presence of a β-glycosidic bond [22]. In the ROESY spectrum (Figure 2 and Figure S37), H-1′ showed crossing peaks with H-3′ and H-5′, which revealed the axial–axial relationship. Through a detailed comparison of the ¹³C NMR data for the sugar moiety of 1-hydroxy-3-methoxy-8-methyl-2-O-β-D-glucopyranosylnaphthaline [23] with those of 4–6, the sugar moieties were determined as β-D glucopyranose.

The known compounds were isolated from T. minnesotensis BTBT20220184 and determined as mucorisocoumarin B (7) [24], diaportinol (8) [25], peniisocoumarin E (9) [21], dichlorodiaportin (10) [25], orsellinic acid (11) [26], and 4-(hydroxymethyl)-5-hydroxy-2H-pyran-2-one (12) [27] by comparing their spectroscopic data with those reported in the literature.

2.2. Biological Activity

The biological evaluations were conducted to assess the antibacterial activities against Candida albicans ATCC 10231, Staphylococcus aureus ATCC 25923, and Escherichia coli ATCC 25923. None of the compounds showed markable antimicrobial activities, except for 8 inhabiting the growth of S. aureus at 200 μg/mL. When combing them with 0.125 μg/mL of methicillin, 5, 6, and 9 showed synergistic antibacterial activity against S. aureus at concentrations of 25, 50, and 12.5 μg/mL, respectively.

3. Materials and Methods

3.1. General Experimental Procedures

Optical rotations ${\left[\mathrm{\alpha }\right]}_{\mathrm{D}}^{25}$ were recorded on an Anton Paar MCP 200 Modular Circular Polarimeter (Austria) in a 100 × 2 mm cell. NMR spectra were measured on a Bruker Avance 500 spectrometer with residual solvent peaks as references (CD₃OD: δ_H 3.31, δ_C 49.0). High-resolution HRESIMS measurements were obtained on a Xevo G2 XS QToF system (Manchester, UK) in positive-ion mode. HPLC was performed using an Agilent 1200 Series separation module equipped with an Agilent 1200 Series diode array and Agilent 1260 Series fraction collector and an Agilent ZORBAX RX-C8 column (250 × 9.4 mm, 5 µm).

3.2. Microbial Material, Fermentation, Extraction, and Purification

The strain T. minnesotensis BTBU20220184 was isolated from a sediment sample collected from Qinzhou Bay, Guangxi Province, China. It was cultured on a malt extract agar plate at 26 °C for 4 days. The genomic DNA of T. minnesotensis BTBU20220184 were extracted using a Fungi Genomic DNA Extraction Kit (Solarbio Life Sciences, Beijing, China). The β-tubulin gene sequence region was amplified using the conventional primer pair of Bt2a (5′-GGTAACCAAATCGGTGCTGCTTTC-3′) and Bt2b (5′-ACCCTCAGTGTAGTGACCCTTGGC-3′). PCR products were sent to Beijing Qingke Biotechnology Co., Ltd. (Beijing, China) for DNA sequencing. BTBU20220184 was identified as T. minnesotensis by comparing the β-tubulin gene sequence with the GenBank database using the BLAST program. A neighbor-joining (NJ) tree (Figure S38) was constructed using a software package, Mega version 5 [28]. The fungus was assigned the accession number BTBU20220184 in the culture collection at Beijing Technology and Business University, Beijing.

The strain T. minnesotensis BTBU20220184 was inoculated on a potato dextrose agar plate and cultured for 5 days. Then, a slit of agar with fungus was cut from the plate and inoculated into 250 mL conical flasks as seeds and cultured at 28 °C (180 rpm) for 3 days. Then, 5 mL of seed culture was added in to twenty 1 L conical flasks, each containing a solid medium consisting of rice (160 g) and artificial seawater (3.5%; 140 mL), and the flasks were incubated under static conditions at 26 °C for 29 days. The cultures were extracted three times with a mixture of EtOAc:MeOH (80:20), and the combined extracts were evaporated in vacuo to yield a residue. The residue was suspended in 800 mL distilled water and partitioned with isometric EtOAc. Then, the EtOAc layer was dried in vacuo to give a dark residue (57.30 g). The EtOAc fraction was fractionated by a vacuum liquid silica gel chromatography (90 × 400 mm column, Silica gel 60 H for thin-layer chromatography) using a stepwise gradient of 50–100% hexane/CH₂Cl₂ and then 0–50% MeOH/CH₂Cl₂ to afford 17 fractions (A–Q). Fraction I was subjected to a Sephadex LH-20 column using an isocratic elution of CH₂Cl₂:MeOH (2:1) to yield twelve subfractions (I1–I12), and subfraction I8 was further fractionated by HPLC (Agilent ZORBAX RX-C8, 9.4 × 250 mm, 5 μm column, 3.0 mL/min, elution with 30% to 45% acetonitrile/H₂O) to yield 1 (2.5 mg) and 2 (4.2 mg). Subfraction I12 was further fractionated by HPLC (Agilent ZORBAX RX-C8, 9.4 × 250 mm, 5 μm column, 3.0 mL/min, elution with 25% to 45% acetonitrile/H₂O) to yield 3 (1.7 mg) and 11 (2.3 mg). Fraction J was fractionated on a Sephadex LH-20 column using an isocratic elution of CH₂Cl₂:MeOH (2:1) to yield fifteen subfractions (J1–J15). Subfraction J6 was further fractionated by HPLC (Agilent ZORBAX RX-C8, 9.4 × 250 mm, 5 μm column, 3.0 mL/min, elution with 10% to 85% acetonitrile/H₂O) to yield 8 (7.0 mg), 7 (11.0 mg), 10 (10.2 mg), and 9 (6.8 mg). Subfraction J11 was further fractionated by HPLC (Agilent ZORBAX RX-C8, 9.4 × 250 mm, 5 μm column, 3.0 mL/min, elution with 15% to 62% acetonitrile/H₂O) to yield 12 (7.0 mg). Fraction K was fractionated on a Sephadex LH-20 column using an isocratic elution of CH₂Cl₂:MeOH (2:1) to give nine subfractions (K1–K9). Subfraction K4 was further fractionated by HPLC (Agilent ZORBAX RX-C8, 9.4 × 250 mm, 5 μm column, 3.0 mL/min, elution with 19% to 81% acetonitrile/H₂O) to yield 4 (2.1 mg) and 5 (2.6 mg). Subfraction K9 was further fractionated by HPLC (Agilent ZORBAX RX-C8, 9.4 × 250 mm, 5 μm column, 3.0 mL/min, elution with 15% to 36% acetonitrile/H₂O) to yield 6 (2.5 mg).

Talamitone A (1): Light-yellow oil; ${\left[\mathrm{\alpha }\right]}_{\mathrm{D}}^{25}$ + 63.5 (c 0.00625, MeOH); ¹H and ¹³C NMR data, Table 1; HRESIMS m/z 385.0923 [M + H]⁺ (calcd for C₂₀H₁₇O₈, 385.0918).

Talamitone B (2): Light-yellow powder; ${\left[\mathrm{\alpha }\right]}_{\mathrm{D}}^{25}$ + 16.0 (c 0.025, MeOH); ¹H and ¹³C NMR data, Table 1; HRESIMS m/z 403.1011 [M + H]⁺ (calcd for C₂₀H₁₉O₉, 403.1024).

Demethyltalamitone B (3): Light-yellow powder; ${\left[\mathrm{\alpha }\right]}_{\mathrm{D}}^{25}$ + 12.0 (c 0.025, MeOH); ¹H and ¹³C NMR data, Table 1; HRESIMS m/z 389.0871 [M + H]⁺ (calcd for C₁₉H₁₇O₉, 389.0867).

Talamiisocoumaringlycoside A (4): Light yellow powder; ${\left[\mathrm{\alpha }\right]}_{\mathrm{D}}^{25}$ + 8.0 (c 0.1, MeOH); ¹H and ¹³C NMR data, Table 2; HRESIMS m/z 451.1204 [M + Na]⁺ (calcd for C₁₉H₂₄O₁₁Na, 451.1211).

Talamiisocoumaringlycoside B (5): Light yellow powder; ${\left[\mathrm{\alpha }\right]}_{\mathrm{D}}^{25}$ + 26.0 (c 0.1, MeOH); ¹H and ¹³C NMR data, Table 2; HRESIMS m/z 485.0830 [M + Na]⁺ (calcd for C₁₉H₂₃ClO₁₁Na, 485.0821).

Talaminaphtholglycoside (6): Light yellow powder; ${\left[\mathrm{\alpha }\right]}_{\mathrm{D}}^{25}$ + 12.0 (c 0.025, MeOH); ¹H and ¹³C NMR data, Table 2; HRESIMS m/z 395.1338 [M + H]⁺ (calcd for C₁₉H₂₃O₉, 395.1337).

Mucorisocoumarin B (7): ¹H NMR (500 MHz, DMSO-d₆) δ_H: 11.02 (1H, s), 6.60 (1H, d, J = 7.0 Hz), 6.53 (1H, s), 6.51 (1H, d, J = 7.0 Hz), 3.96 (1H, m), 3.85 (3H, s), 3.80 (1H, m), 2.64 (1H, dd, J = 14.5, 4.0 Hz), 2.46 (1H, dd, J = 14.5, 8.5 Hz), 1.58 (1H, m), 1.43 (1H, m), 1.07 (3H, d, J = 6.0 Hz); ¹³C NMR (125 MHz, DMSO-d₆) δ_C: 165.7 (C-1), 155.7 (C-3), 105.7 (C-4), 139.7 (C-4a), 101.1 (C-5), 166.5 (C-6), 100.3 (C-7), 162.5 (C-8), 99.4 (C-8a), 41.3 (C-9), 66.2 (C-10), 46.0 (C-11), 64.1 (C-12), 23.7 (C-13), 55.9 (6-OCH₃); ESIMS m/z 293.1 [M − H]⁻.

Diaportinol (8): ¹H NMR (500 MHz, DMSO-d₆) δ_H: 10.97 (1H, s), 6.59 (1H, d, J = 2.5 Hz), 6.54 (1H, s), 6.51 (1H, d, J = 2.5 Hz), 4.89 (1H, d, J = 5.0 Hz), 4.73 (1H, t, J = 5.5 Hz), 3.85 (3H, s), 3.81 (1H, m), 3.40 (1H, m), 3.30 (1H, m), 2.74 (1H, dd, J = 14.5, 3.5 Hz), 2.39 (1H, dd, J = 14.5, 9.0 Hz); ¹³C NMR (125 MHz, DMSO-d₆) δ_C: 165.6 (C-1), 155.9 (C-3), 105.5 (C-4), 139.7 (C-4a), 101.1 (C-5), 166.5 (C-6), 100.3 (C-7), 162.5 (C-8), 99.4 (C-8a), 37.8 (C-9), 69.0 (C-10), 65.4 (C-11), 55.9 (6-OCH₃); ESIMS m/z 267.1 [M + H]⁺.

Peniisocoumarin E (9): ¹H NMR (500 MHz, DMSO-d₆) δ_H: 10.93 (1H, s), 6.65 (1H, s), 6.63 (1H, d, J = 2.5 Hz), 6.55 (1H, d, J = 2.5 Hz), 4.30 (1H, m), 3.85 (3H, s), 3.66 (2H, m), 3.17 (1H, dd, J = 15.0, 10.0 Hz), 2.78 (1H, dd, J = 15.0, 4.0 Hz); ¹³C NMR (125 MHz, DMSO-d₆) δ_C: 165.1 (C-1), 153.7 (C-3), 106.2 (C-4), 139.2 (C-4a), 101.5 (C-5), 166.6 (C-6), 100.8 (C-7), 162.6 (C-8), 99.4 (C-8a), 37.8 (C-9), 60.2 (C-10), 65.0 (C-11), 56.0 (6-OCH₃); ESIMS m/z 285.1 [M + H]⁺.

Dichlorodiaportin (10): ¹H NMR (500 MHz, DMSO-d₆) δ_H: 10.97 (1H, s), 6.62 (1H, s), 6.61 (1H, d, J = 2.5 Hz), 6.54 (1H, d, J = 2.5 Hz), 6.31 (1H, d, J = 3.0 Hz), 6.13 (1H, d, J = 6.0 Hz), 4.18 (1H, m), 3.85 (3H, s), 2.88 (1H, dd, J = 14.5, 3.0 Hz), 2.64 (1H, dd, J = 14.5, 9.5 Hz); ¹³C NMR (125 MHz, DMSO-d₆) δ_C: 165.3 (C-1), 153.7 (C-3), 106.3 (C-4), 139.4 (C-4a), 101.4 (C-5), 166.5 (C-6), 100.5 (C-7), 162.5 (C-8), 99.5 (C-8a), 36.4 (C-9), 72.2 (C-10), 77.0 (C-11), 56.0 (6-OCH₃); ESIMS m/z 319.1 [M + H]⁺.

Orsellinic acid (11): ¹H NMR (500 MHz, CD₃OD) δ_H: 6.19 (1H, d, J = 2.5 Hz), 6.13 (1H, d, J = 2.5 Hz), 2.49 (3H, s); ¹³C NMR (125 MHz, CD₃OD) δ_C: 105.1 (C-1), 163.6 (C-2), 101.7 (C-3), 166.9 (C-4), 112.2 (C-5), 145.2 (C-6), 175.2 (C-7), 24.3 (8-CH₃); ESIMS m/z 169.1 [M + H]⁺.

4-(Hydroxymethyl)-5-hydroxy-2H-pyran-2-one (12): ¹H NMR (500 MHz, DMSO-d₆) δ_H: 8.03 (1H, s), 6.33 (1H, s), 4.28 (2H, s); ¹³C NMR (125 MHz, DMSO-d₆) δ_C: 174.0 (C-2), 109.8 (C-3), 145.7 (C-4), 168.1 (C-5), 139.3 (C-6), 59.5 (C-7).; ESIMS m/z 143.0 [M + H]⁺.

3.3. Biological Activity

Compounds 1–12 were evaluated against S. aureus, E. coli, and C. albicans for their antimicrobial activities in 96-well plates according to the Antimicrobial Susceptibility Testing Standards outlined by the Clinical and Laboratory Standards Institute document M07-A7 (CLSI) [29] and our previous report [30,31]. The MIC was defined as the minimum concentration of the compound that prevented visible growth of the microbes. The synergistic antimicrobial activities were determined by combing one-fourth of the minimum inhibitory concentration of the positive control (MIC of methicillin was 0.5 μg/mL) for S. aureus with two-fold diluted tested compounds. The synergistic antimicrobial activities were calculated based on a previous report [32]. Briefly, final concentrations were preprepared from 1.5625 to 100 μg/mL of isolated compounds. Methicillin was added by a column, while the tested compounds were diluted 2-fold by row in a 96-well microtiter plate. The fractional inhibitory concentration index (FICI) was calculated as the sum of the MIC of each drug when used in combination, divided by the MIC of the drug used alone. Synergistic antibacterial activity was defined by FICI ≤ 0.5.

4. Conclusions

In summary, 12 compounds, including 6 new compounds, talamitones A and B (1 and 2), demethyltalamitone B (3), talamiisocoumaringlycosides s A and B (4 and 5), and talaminaphtholglycoside (6), together with 6 previous reported compounds, mucorisocoumarin B (7), diaportinol (8), peniisocoumarin E (9), dichlorodiaportin (10), orsellinic acid (11), and 4-(hydroxymethyl)-5-hydroxy-2H-pyran-2-one (12), were isolated from the marine sediment-derived fungus T. minnesotensis BTBU20220184. The structures of the new compounds were characterized by HREIMS and NMR data analysis. All of the compounds were screened for activity against S. aureus, E. coli, and C. albicans. Compound 8 exhibited weak antibacterial activity against S. aureus at a concentration of 200 μg/mL. Compounds 5, 6, and 9 showed synergistic antibacterial activity against S. aureus at concentrations of 25, 50, and 12.5 μg/mL with 0.125 μg/mL of methicillin.