*3.2. General Experimental Procedure*

Optical rotations were measured in MeOH, using a Sac-i SACCHARIMETER instrument (ATAGO, Minato-ku, Tokyo, Japan. LC-HR-ESI-MS data was acquired using a maXis impact mass spectrometer (Bruker Daltonics, Billerica, MA, USA) coupled to a 1290 Agilent LC (Agilent, Santa Clara, CA, USA). The analysis of the fractions was performed using an Agilent HPLC 1200 Series (Agilent, Foster City, CA, USA) with a RP C18 Gemini column (250 × 4.6 mm; 5 μm) (Phenomenex, Torrence, CA, USA) using an adequate gradient with acetonitrile: water acidified. Chromatographic separations were performed on RP-C18

and silica cartridges and RP-C18 columns using a CombiFlash Rf flash chromatography (Combiflash Rf, Teledyne ISCO, Lincoln, NE, USA) equipped with a quaternary pump. Waters DeltaPrep preparative HPLC (Waters Delta Prep 4000; Waters, Milford, MA, USA) was used for final purification of certain compounds using a Phenomenex Gemini column (250 × 21.2 mm, 5 μm).

1D (1H; 13C and DEPT 135) and 2D NMR spectra [heteronuclear multiple-quantum correlation spectroscopy (gHMQC), double quantum filter correlation spectroscopy (DQ-COSY), Total correlation spectroscopy (TOCSY), heteronuclear multiple-bond correlation spectroscopy (gHMBC) and nuclear Overhauser effect spectroscopy (NOESY)] were recorded on a JEOL USA, Inc. spectrometer (Peabody, MA, USA) at 25 ◦C, operating at 400 MHz ( 1H) and 100 MHz (13C) using standard JEOL pulse programs. All samples were run in methanol-*d*4, except for **2** and **3,** which, because of insufficient solubility in methanol-*d*4, were run in pyridine-*d*5. The chemical shifts are given in *δ* (ppm) and were referenced to residual solvent signals.

#### *3.3. Plant Material*

Fresh fruits of *Momordica charantia* (81 kg) were purchased from BCS Food Market, College Station, TX, USA. Bitter melons were cut into 0.5 inches size, seeds were removed manually, and the remaining pericarp was dried under shade, powdered using a home blender to get 60–80 mesh size, and stored at 25 ◦C until further use.
