Volatile components of uncooked Khao Dawk Mali 105 brown rice were extracted using indirect steam distillation under reduced pressure and controlled temperature in order to prevent cooking. Analysis of the fresh extract by capillary gas chromatography-mass spectrometry revealed that there were >140 volatile constituents. Among these, 70 volatiles were identified, including 2-acetyl-1-pyrroline (2AP), a key aroma compound of cooked rice. Further study concentrated on an improved method for the quantification of 2AP in uncooked brown rice. The method was simplified by utilizing a solvent extraction procedure. Quantitative analysis was performed using a capillary gas chromatographic system employing a flame ionization detector with the aid of a more selective column, CP-Wax 51, for amines. This improved chromatographic system had remarkable detection sensitivity for 2AP in the rice extracts so that 2AP in an extract of only 0.5 g of uncooked Khao Dawk Mali 105 brown rice could be detected.

The essential oil of the leaves Solanum spirale Roxb. was isolated by hydrodistillation and analyzed for the first time using GC and GC-MS. Thirty-nine constituents were identified, constituting 73.36% of the total chromatographical oil components. (E)-Phytol (48.10%), n-hexadecanoic acid (7.34%), -selinene (3.67%), α-selinene (2.74%), octadecanoic acid (2.12%) and hexahydrofarnesyl acetone (2.00%) were the major components of this oil. The antioxidant activity of the essential oil was evaluated by using the DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging assay. The oil exhibited week antioxidant activity with an IC 50 of 41.89 mg/mL. The essential oil showed significant antibacterial activity against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus with MIC values of 43.0 g/mL and 21.5 g/mL, respectively. It also showed significant cytotoxicity against KB (oral cancer), MCF-7 (breast cancer) and NCI-H187 (small cell lung cancer) with the IC 50 values of 26.42, 19.69, and 24.02 µg/mL, respectively.