Thermo scientific ltq orbitrap xl spectrometer

Due to the small-scale fermentation, only two compounds were obtained from each extract. The pretreated crude extract of P18 (described in Section 3.4) was first subjected to octadecylsilyl silica gel (ODS) CC (RP18, 40–63 μm; Merck, Billerica, MA, USA), followed by step-gradient elution using MeOH-H₂O (30–50%) and purification via Sephadex LH-20 CC (GE Healthcare, Pittsburgh, PA, USA) using CH₂Cl₂-MeOH (v/v = 1:1) to yield 1 (4.4 mg) and 2 (2.1 mg). The EtOAc extract of P8 (described in Section 3.4, 20 bottles) was first subjected to ODS CC and eluted with 30–50% MeOH-H₂O, followed by separation by Sephadex LH-20 CC (CH₂Cl₂-MeOH; v/v = 1:1) and HPLC purification with 25% MeCN-H₂O to yield 3 (4.1 mg) and 4 (3.6 mg).
Optical rotations were measured on a Jasco P-1020 digital polarimeter (Jasco, Inc., Easton, MD, USA), and UV spectra were recorded on a Techcomp UV2310ΙΙ spectrophotometer (Techcomp, Ltd., Shanghai, China). ECD spectra were obtained on a Jasco J-815-150S circular dichroism spectrometer (Jasco, Inc., Tokyo, Japan). NMR spectra were recorded on an Agilent DD2 500 MHz NMR spectrometer (500 MHz for ¹H and 125 MHz for ¹³C; Agilent Technologies, Santa Clara, CA, USA) using tetramethylsilane as an internal standard. HRESIMS spectra were obtained from a Thermo Scientific LTQ Orbitrap XL spectrometer (Thermo Fisher Scientific, Waltham, MA, USA).

High-performance liquid chromatography (HPLC) was performed using a Waters ultra-performance liquid chromatography-class system equipped with a C₁₈ column (1.6 μm, 2.1 × 50 mm) and a photodiode array detector. The chromatographic conditions were as follows: mobile phase: 10% methanol (MeOH), 0–5 min; 10%–100% MeOH, 5–35 min; 100% MeOH, 35–45 min; 100%–10% MeOH, 45–50 min; 10% MeOH, 50–60 min; flow rate: 1 ml/min; ultraviolet detection: 235 nm. High-resolution electrospray ionization mass spectrometry (HRESIMS) data were obtained with a Thermo Scientific LTQ Orbitrap XL spectrometer (Thermo Scientific, Waltham, MA, USA). The ¹H, ¹³C, and two-dimensional nuclear magnetic resonance (NMR) spectra were measured using an Agilent DD2 spectrometer (500 and 125 MHz, respectively) (Agilent, Santa Clara, CA, USA). Open column chromatography was performed using silica gel (200−300 mesh, Qingdao Haiyang Chemical Factory, Qingdao, China), Lobar LiChroprep RP-18 (Merck, Darmstadt, Germany), and Sephadex LH-20 (Merck). All solvents used for HPLC, HRESIMS, and NMR analyses were of analytical grade (purchased from Merck, Darmstadt, Germany). The fungal strain, A. arundinis, was previously isolated from fresh leaves of Nicotiana tabacum L., with the GenBank number MK182939 and CGMCC number 14792 (Zhang et al., 2018 (link)).

UV spectrum was tested through an Implen Gmbh NanoPhotometer N50 Touch (Implen, Germany). NMR spectra were recorded on a Bruker AVANCE NEO (Bruker, Switzerland). Thermo Scientific LTQ Orbitrap XL spectrometer (Thermo Fisher Scientific, Bremen, Germany) was used to measure HRESIMS. UHPLC-MS/MS spectra were tested on a high-resolution Q-TOF mass spectrometry Bruker impactHD (Bruker, Germany), combined with Ultimate3000 UHPLC (Thermo Fisher Scientific, Waltham, MA, USA). The X-ray single crystals were measured by Bruker SMART APEX-II CCD diffractometer (Bruker, Germany). Hitachi Primaide Organizer Semi-HPLC (Hitachi High Technologies, Tokyo, Japan) was performed for HPLC purification. Chromatographic separations were performed using Silica gel (100–200 mesh and 200–300 mesh) and Sephadex LH-20 as stationary phase packing. Thin-layer chromatography was recorded on precoated silica gel GF254 plates.