## 2 Materials and Methods
### Extraction and Isolation of Compounds 1-12 from EEP GIA-4  
The air-dried and powdered propolisis samples GUA-4 were extracted with ethanol for up to one week and the resultant extract was concentrated in vacuo. A portion of ethanol-soluble extract (10.3 g) was subjected to a silica gel vacuum column chromatography (VLC) and eluted with a gradient mixture of dichloromethane-acetone (1:0 \(\rightarrow\) 0:1) to give eight pooled fractions (F2-F8). Fractions F2, F4, and F7 showed the best antioxidant activity. Fraction F2 was chromatographed over a Sephadex LH-20 column and eluted with methanol to yield **1** (40 mg). Fraction F4, eluted with dichloromethane-acetone (9:1), was chromatographed over a Sephadex LH-20 column, using methanol as eluent, to give six fractions. Fraction F4-3 (100 mg) was separated by TLC with dichloromethane-acetone (99:1), followed by TLC with dichloromethane-acetone (98:2), to give **2** (20 mg) and **3** (65 mg). Fraction F5 waschromatographed on a Sephadex LH-20 column using methanol as solvent to give six subfractions (F5-1: 10 mg; F5-2: 12.3 mg; F5-3: 17.5 mg; F5-4: 15.7 mg; F5-5: 25.3 mg; F5-6: 18.1 mg). Subfraction F5-1 yielded crystals of 4. F5-5 (25.3 mg) yielded crystals of 5 (9.0 mg). Mother liquor was subjected to a preparative thin-layer chromatography (PTLC) with acetone-toluene (5:95) to give 6. Subfraction F5-6 (18.1 mg) yielded crystals of 7 (11.0 mg). Fraction F7 was chromatographed on silica gel using a hexane-EtOAc gradient system to give five fractions (F7-1: 13.9 mg; F7-2: 517.7 mg; F7-3: 28.4 mg; F7-4: 16.7 mg; F7-5: 32.8 mg; F7-6: 56.8 mg; F7-7: 45.1 mg). Subfraction F7-1 was identified as 8. Subfraction F7-2 was chromatographed by RP-MPLC, using H\({}_{2}\)O-CH\({}_{3}\)CN (1:0 \(\rightarrow\) 0:1) to afford five subfractions (F7-2.1: 125.3 mg; F7-2.2: 275.1 mg; F7-2.3: 67.8 mg; F7-2.4: 37.0 mg; F7-2.5: 12.3 mg). Subfraction F7-2.3 was identified as 9. Subfractions F7-2.4, F7-2.5, and F7-2.6 were dissolved in CH\({}_{2}\)Cl\({}_{2}\)-MeOH and left overnight to give crystals of 10, 11, and 12, respectively.  
Head Space Solid Phase Microextraction (HS-SPME), GC-MS Analysis, and Identification of Volatile Components  
The HS-SPME was performed using a Stabelflex(r) fiber 50/30 \(\upmu\)m DVB/CAR/PDMS (1 cm) as described in our previous work [17].  
The analysis of volatile compounds was carried out on a GC Agilent 6890 N (Agilent Technology, Santa Clara, CA, USA) series gas chromatograph coupled to a LECO time of flight mass spectrometer (LECO Corporation, St. Joseph, MI, USA). The volatile compounds were separated on a 5% diphenyl-95% dimethyl polysiloxane (30 m \(\times\) 0.18 mm i.d.; 0.18 \(\upmu\)m film thickness) capillary column (Bellefonte, PA, USA). The carrier gas was helium with a flow rate of 1 mL/min and split ratio of 1:50. The column initial temperature was 40 \({}^{\circ}\)C. It was then raised to 300 \({}^{\circ}\)C with a rate of 20 \({}^{\circ}\)C/min and was held for 5 min. The ionization electron energy was 70 eV and the mass range scanned was 40-400 \(m\)/z. The injector and MS transfer were set at 300 and 250 \({}^{\circ}\)C, respectively. The volatile constituents of propolis were identified by co-injection of the sample with standard samples when available; based on their Kovats Index, calculated in relation to the retention times of a series of alkanes (C-8-C-20), in comparison with those of the chemical compounds gathered by [PERSON] [18] and by comparing their MS fragmentation patterns with those of pure compounds in the spectral database of the National Institute of Standards and Technology (NIST) [19].