et al., 2006). The nutrition and bioactive composition
of vegetables make them very important in the
household, especially during times of food shortage.Vegetables have been found to improve nutrition,
boost food security, foster rural development, sup-
port sustainable land care and offer health protect-
ing properties (Agea et al., 2010). This illustrates the
relationship between nutrition and medicine that is
recognized in African cultures. Epidemiological
studies indicate a relationship between consump-
tion of vegetables and prevention of chronic dis-
eases such as cancer, hypertension and heart
diseases (Katt, 2005; Pieriniet al., 2008). Phyto-
chemicals found in vegetables such as flavanoids
exert a protective effect against these chronic dis-
eases (Frankeet al., 2004)Although many of the indigenous vegetables are
available and consumed in Africa, little is known
about their phytochemical composition that con-
tributes to their therapeutic effects. Recent trends
show that public health experts are interested to
know the composition of vegetables to provide proof
of their health benefits. This study evaluated the
phytochemical composition of selected indigenous
vegetables in Uganda.2. Materials and methods
2.1 Sample collection
About 5 kg of fresh, sorted and disease-free veg-
etable leaf samples that included: Amaranthus hy-
bridus,Amaranthus cruentus,Cleome gynandra,
Solanun aethiopicumandVigna unguiculata, were
purchased from a market vendor in Kampala,
Uganda in June 2009. These vegetable species are
among the most grown and consumed vegetables
in Uganda (Bukenya-Ziraba et al., 1999 ; Ssekabe-
mbe et al., 2003). The vegetable species were sci-
entifically identified by a taxonomist. Voucher
specimens were prepared and deposited at the
herbarium of the Natural Chemotherapeutics Re-search Institute, Ministry of Health, Kampala,
Uganda for future reference.2. 2 Sample preparation
The vegetable samples were cleaned with distilled
water and dried to a constant weight in vacuum oven
(40–50°C). The dry leaves were pulverized into pow-
der and kept in a cool dry place until extraction was
completed.2 .3 Extraction and analysis
The leaf powder of each vegetable sample was di-
vided into two portions. One portion was used for
qualitative phytochemical screening and another
portion for quantitative determination of total fla-
vanoids and total alkaloids. The sample portion for
phytochemical qualitative screening (200 g) was
analysed using standard methods reported by Culei
(1982) and Idu et al.(2006). In brief, diethyl ether and
96 percent ethanol solvents were used in soxhlet ap-
paratus extraction of the samples in a successive
manner. The residue of soxhlet extraction was then
boiled in distilled water to extract with water. The
extracts of diethyl ether and ethanol were then
concentrated under reduced pressure with rotary
evaporator, while the water extract was filtered. All
the extracts of diethyl ether, ethanol and water were
then subjected to qualitative phytochemical screening.The other vegetable sample portion was used for
determination of total flavanoids and total alkaloids
using standard method reported by Edeogaet al.
(2005). For determination of total flavanoids, 10 g of
vegetable leaf powder was put into a round bottom
flask and repeatedly extracted with 80% aqueous
methanol (100 ml) at room temperature for 4 hours
with regular shaking. The solution was then filtered
using whatman filter paper no. 1 and the filtrate
concentrated under reduced pressure with rotary
evapourator at 50°C. The concentrate was then
evaporated to dryness in a vacuum oven at 50°C and
total flavanoids were determined gravimetrically.208