The word "hoangnan" has a complex spelling, with several consonants and vowels that may be unfamiliar to English speakers. In IPA phonetic transcription, it is written as /hwɑŋnɑn/. The "hw" represents a voiceless labialized velar approximant, while the "ɑ" sound is an open central unrounded vowel. The "ŋ" is a velar nasal, and the second "n" is an alveolar nasal. Altogether, the word has a distinct sound that is difficult to describe using just English letters.
The bark of Strychnos malaccenis or S. galthieriana; it contains both the alkaloids of nux vomica; has been employed in the treatment of leprosy and scrofula in doses of gr. 2-5 (0.13-0.3).
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.