Abstract:
This work presents the first report on the phytochemical investigation of Harpephyllum
caffrum Bernh. gum exudate. A known cardanol, 3-heptadec-120-Z-enyl phenol (1) and three new
alk(en)ylhydroxycyclohexanes, namely, (1R,3R)-1,3-dihydroxy-3-[heptadec-120(Z)-enyl]cyclohexane
(2) (1S,2S,3S,4S,5R)-1,2,3,4,5-pentahydroxy-5-[octadec-130(Z)-enyl]cyclohexane (3) and (1R,2S,4R)-
1,2,4-trihydroxy-4-[heptadec-120(Z)-enyl]cyclohexane (4) were isolated from the gum. The structures
of the compounds were determined by extensive 1D and 2D NMR spectroscopy and HR-ESI-MS
data. The ethanolic extract of the gum was found to be the most potent tyrosinase inhibitor with IC50
of 11.32 g/mL while compounds 2 and 3, with IC50 values of 24.90 and 26.99 g/mL, respectively,
were found to be potential anti-tyrosinase candidates from the gum. Gum exudate may be a potential
source for non-destructive harvesting of selective pharmacologically active compounds from plants.
The results also provide evidence that H. caffrum gum may find application in cosmetics as a potential
anti-tyrosinase agent.
Description:
SUPPLEMENTARY MATERIALS : FIGURE S1 to S36 containing 1D and 2D NMR spectra, FT-IR, ECD spectra and high-resolution mass spectra of compounds 1–4.
