*2.2. Bioassays*

All of the isolated compounds were tested for their antibacterial, antifungal, cytotoxic, and 1,10-diphenyl-2-picryl-hydazyl (DPPH) scavenging activities. Their protein tyrosine phosphatase 1 B (PTP1B) inhibitory activities were also measured—PTP1B is an important hypoglycemic target in diabetes. We found that compounds **2** and **3** displayed antibacterial activities against *Pseudomonas aeruginosa* ATCC 27853 with minimum inhibitory concentration (MIC) values of 64 μg/mL and 32 μg/mL, respectively. Intriguingly, compound **3** also exhibited antifungal activity against *Candida albicans* ATCC10231 with a MIC value of 32 μg/mL. Compounds **3**, **5**, and **7** showed PTP1B inhibitory activities with inhibitory concentration (IC)50 values of 12.25, 25.70 and 24.32 μM, respectively. In addition, compound **9** exhibited a weak DPPH scavenging activity, with an IC50 value of 147 μM. All of the isolated compounds showed no cytotoxicity.

#### **3. Materials and Methods**

## *3.1. Instrumentation*

Optical rotations were measured with a JASCO P-1020 digital polarimeter (Jasco Corp., Tokyo, Japan). UV spectra were recorded with a HITACHI UH 5300 UV spectrophotometer (Hitachi, Tokyo, Japan). ECD data were acquired on a J-815-150S Circular Dichroism spectrometer (JASCO Electric Co., Ltd., Tokyo, Japan). IR spectra were recorded with a Nicolet-Nexus-470 spectrometer (Thermo Electron Co., Madison, WI, USA) using KBr pellets. NMR spectra were acquired by a JEOL JEM-ECP NMR spectrometer (500 MHz for 1H and 125 MHz for 13C, JEOL, Tokyo, Japan), using tetramethylsilane (TMS) as an internal standard. High-resolution electrospray ionization mass spectrometry (HRESIMS) was measured with a Thermo MAT95XP high resolution mass spectrometer (Thermo Fisher Scientific, Bremen, Germany), and electron ionization mass spectrometry (EIMS) spectra with a Thermo DSQ EImass spectrometer (Thermo Fisher Scientific, Bremen, Germany). Single-crystal X-ray crystallographic analysis was performed on an Agilent Xcalibur Eos Gemini diffractometer (Agilent Technologies, Yarnton, England). Samples were analyzed and prepared using a Hitachi L-2000 HPLC system coupled with a Hitachi L-2455 photodiode array detector, and using a semi-preparative C18 column (Kromasil 250 mm × 10 mm, 5 μm). Silica gel (Qing Dao Hai Yang Chemical Group Co., Qing Dao China; 300−400 mesh) and Sephadex LH-20 (Amersham Biosciences, Inc., USA) were used for column chromatography (CC). Precoated silica gel plates (Yan Tai Zi Fu Chemical Group Co., Qing Dao China; G60, F-254) were used for thin-layer chromatography. PTP1B (human recombinant) was purchased from Abcam (ab51277).
