Wood garlic

A tree, Scorodocarpus borneensis, native to Borneo and the Malay peninsula, has a garlic-like smell and is known as wood garlic . The fruit is used locally for seasoning. The major volatile flavor compounds from wood garlic are similar to those of garlic itself. Some of these materials are polysulfur compounds and have antimicrobial activity against some bacteria and fungi. These materials contain four sulfur atoms.75 They are either 2,4,6-trithiaheptane-5-thione-2,2-dioxide (CH3-SO2-CH2-S-CS-S-CH3) or derivatives of tetrathia-octane (CH3-S-CH2-S-S-CH2-S-CH 3, CH3-SO2-CH2-S-S-CH2-S-CH3, CH3-S-CH2-SO2-S-CH2-S-CH3). 

Sulfur Compounds in Wood Garlic Scorodocarpus borneensis Becc.) as Versatile Food Components... 

KUBOTA KOBAYASHI Sulfur Compounds in Wood Garlic... 

Figure 1. Fruit pulp and fruit with the nutshell of wood garlic.

The fruits of wood garlic (S, bomeensis) were collected in Sabah, Malaysia. Unless otherwise mentioned, after removing the outer shell of each fresh fruit, the pulp was used for the experiments. The volatiles were also collected from frozen leaves. 

The fruit covered with the outer shell does not emit a strong odor, but when the nutshell has been removed, or the pulp is cut, a strong odor results. This suggests that the odor of wood garlic might be formed enzymatically in the same way as in the Allium species. The flavor constituents were compared to those of Allium,... 

Table I. Composition of the Headspace Concentrate Obtained by the PTI Method from Wood Garlic Fruit...

Table II. Main Components of the Volatile Concentrate Obtained by Steam Distillation from the Fruit and Leaves of Wood Garlic...

Odor Significance of Compounds I and II in Wood Garlic. At high concentrations, I and II presented a considerably different aroma from that of the original wood garlic. On the other hand, the odor of each compound in the eluate from a capillary GC was reminiscent of the original wood garlic. We next determined their odor threshold values and re-evaluated them at dilute concentrations. 

Isolation of the Antimicrobial Compounds. Grated fruit pulp was soaked overnight in ethanol and then treated by sonicating for 30 min to extract the active components. The ethyl acetate-soluble fraction of the concentrate of the ethanol extract, which exhibited strong activity, was submitted to silica gel chromatography. Two active compounds were isolated with the yields shown in Table IV. One was CH3SCH2SSCH2SCH3, which was also identified as one of the potent odor components of wood garlic as already described. The other compound was obtained as crystals and then recrystallized with ethyl ether to afford colorless needles. This... 

Figure 2. Mass spectra of the poly sulfides isolated from wood garlic.

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