3.1. General Experimental Procedures

Optical rotation was measured on a Rudolph research analytical Autopol III S2 polarimeter (Rudolph Research Analytical, Hackettstown, NJ, USA). UV spectra were obtained on a Shimadzu UV-1650PC spectrophotometer (Shimadzu Corporation, Kyoto, Japan). IR spectra were recorded on a JASCO FT/IR-4100 spectrophotometer (JASCO Corporation, Tokyo, Japan). NMR spectra were collected on a Bruker AVANCE III 600 spectrometer (Bruker BioSpin GmbH, Rheinstetten, Germany) operating at 600 MHz (¹H) and 150 MHz (¹³C). LRMS data were acquired on an Agilent 6100 single quadrupole mass spectrometer (Agilent Technologies, Santa Clara, CA, USA) with electron ionization (EI). HRESIMS was obtained with a Waters SYNPT G2 Q-TOF mass spectrometer (Waters Corporation, Milford, CT, USA) at Korea Basic Science Institute (KBSI) in Cheongju, Republic of Korea. HPLC was performed using a PrimeLine binary pump (Analytical Scientific Instruments, Inc., El Sobrante, CA, USA) with Shodex RI-101 refractive index detector (Shoko Scientific Co. Ltd., Yokohama, Japan) and S3210 variable UV detector (Schambeck SFD GmbH, Bad Honnef, Germany). Columns used for HPLC were YMC-Pack Silica (250 mm × 10 mm i.d., 5 µm), YMC ODS-A (250 mm × 10 mm i.d., 5 μm) and YMC-Triart C₁₈ (250 mm × 10 mm i.d., 5 µm and 250 mm × 4.6 mm i.d., 5 µm). Silica gel 60 (Merck, 230–400 mesh) and RP-C₁₈ silica gel (YMC-Gel ODS-A, 12 nm S-75 μm) were used for open column chromatography. Mass culture was carried out in a 100 L fermenter (Fermentec Corporation, Cheongju, Republic of Korea). All solvents used were either HPLC grade or distilled prior to use.