Makhwaen fruit (ผลมะแขว่น)

Makhwaen (มะแขว่น, Zanthoxylum myriacanthum) is a spice fruit used in Northern Thai cuisine. A 2009 taxonomic survey (Table 1) records its fruit as used as a 『商業的な調味料（condiment, commercial）』 (in translation: "commercial condiment"). This is described as a different use from Z. armatum, whose leaves and bark are recorded as being boiled to ease tooth pain.

According to a footnote in the same survey, local people sell makhwaen fruit both fresh and dried in markets, described as being under the Thai Industrial Standards Institute’s 『コミュニティ製品標準2006』 (in translation: "Community Product Standard 2006"). The standard itself was not independently checked for this account; the information is treated as a citation within the taxonomic paper.

A government extension resource explains that Northern-style larb gets its distinctive bold flavor and aroma from the chili-paste seasoning called prik larb, to which makhwaen is added as the 『主役（ตัวชูโรง）』 (in translation: "star ingredient"). This is a general description of larb, not a recipe study with measured quantities or an identification of a particular cultivar.

The same resource describes makhwaen as having a pungent, strong aroma, mild heat (รสเผ็ดร้อนเล็กน้อย), and a 『痺れを伴う辛さ（เผ็ดชา）』 (in translation: "numbing spiciness"). It says that cooking with it produces heat and numbness on the tongue, a sensation Northern Thai speakers call 『デーオリン（เด้าลิ้น、舌の跳ね返り）』 (in translation: "dao lin, tongue rebound"). These are descriptions of heat and numbness, not bitterness. The source contains no chemical analysis, including of sanshools, and this account does not link the numbness to a particular compound.