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Quantitative and
qualitative analysis of sterols/sterolins and hypoxoside
contents of three Hypoxis (African potato) spp.
Gerhardt J. Boukes, Maryna van de Venter*
and Vaughan Oosthuizen
Department of Biochemistry and Microbiology, Faculty of
Science, PO Box 77000, Nelson Mandela Metropolitan
University, Port Elizabeth 6031, South Africa.
*Corresponding author. E-mail:
maryna.vandeventer@nmmu.ac.za. Tel: +27415042813. Fax:
+27415042814.
Accepted 25 April, 2008 |
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The glycoside, hypoxoside, identified and isolated
from the corms of the African potato (Hypoxis
hemerocallidea) has shown promising anticancer
activities. The African potato is used as an African
traditional medicine for its nutritional and medicinal
properties. Most research has been carried out on H.
hemerocallidea (formerly known as H. rooperi),
with very little or nothing on other Hypoxis spp.
Thin layer chromatography (TLC) was used to confirm the
presence of sterols/sterolins, whereas a GC method was
developed to identify and quantify sterols (especially
β-sitosterol) in chloroform extracts of H.
hemerocallidea, H. stellipilis and H. sobolifera
var. sobolifera. High performance liquid
chromatography (HPLC) was used to identify and quantify
hypoxoside content in these Hypoxis spp. TLC results
showed that H. sobolifera var. sobolifera
contained the most sterols and sterolins compared to the
other two Hypoxis spp. Gas chromatography (GC)
results show that β-sitosterol and campesterol were the two
main phytosterols present in the Hypoxis extracts.
H. sobolifera var. sobolifera and H.
hemerocallidea contained the most β-sitosterol and
hypoxoside, respectively. H. sobolifera and H.
hemerocallidea contained 74.69 μg of β-sitosterol and
12.27 μg of hypoxoside per 5 mg of chloroform extracts,
respectively. These results show a significant difference in
the sterol/sterolin and hypoxoside contents between species
of the genus Hypoxis, which may influence their
degree of biological activities.
Key words:
Hypoxis,
TLC, GC, HPLC, sterol(in)s, hypoxoside. |
