Naphthoquinone esters from the root of Rhinacanthus nasutus.
Reinvestigation of the root of Rhinacanthus nasutus afforded, in addition to rhinacanthin-A to -D reported previously, two new dimethyldihydropyranonaphthoquinone esters (5, 6) and eight new 2-hydroxy-1,4-naphthoquinone esters (7-14) were isolated. The stereochemistry of rhinacanthin-A was determined as the R configuration. Compounds rhinacanthin-G to -N, belong to a class of 2-hydroxy-3-(3-hydroxy-2,2-dimethylpropyl)-1,4-naphthoquinone esters, and so far have been isolated only in this plant. Their biosynthesis is also discussed.
Wu
T S
TS
Department of Chemistry, National Cheng Kung University, Tainan, Taiwan, R.O.C.
Hsu
H C
HC
Wu
P L
PL
Leu
Y L
YL
Chan
Y Y
YY
Chern
C Y
CY
Yeh
M Y
MY
Tien
H J
HJ
D000959:Antihypertensive Agents / Q000737:chemistry / Q000302:isolation & purification; D000998:Antiviral Agents / Q000737:chemistry / Q000302:isolation & purification*; D004952:Esters / Q000737:chemistry / Q000302:isolation & purification*; D009682:Magnetic Resonance Spectroscopy; D009285:Naphthoquinones / Q000737:chemistry / Q000302:isolation & purification*; D010946:Plants, Medicinal / Q000737:chemistry*
D000959:Antihypertensive Agents; D000998:Antiviral Agents; D004952:Esters; D009285:Naphthoquinones