Thesis (M.Sc. (Horticulture)) -- University of Limpopo, 2020 / Most rural communities harvest different plant parts of Jatropha zeyheri for nutritional
and medicinal purposes. However, the decision of choosing to harvest the plant part
with desired chemical components is essential for quality purposes. Nevertheless,
there is a lack of information regarding the distribution of chemical composition in
different plant parts of J. zeyheri tea. Therefore, the objectives of the study were to:
(1) investigate the effect of different plant parts (stems, roots and leaves) of J. zeyheri
on mineral composition and, (2) determine the effect of different plant parts (stems,
roots and leaves) of J. zeyheri on phytochemicals and antioxidant activity. A study was
conducted with three treatments, namely stems, roots and leaves arranged in a
randomised complete block design (RCBD), with 10 replications. Plant materials were
collected in the wild from mature plants between June-July 2018. Leaves and stems
were manually separated, while roots were cut into smaller pieces, dried at 60°C for
48 hours in an air-forced oven and later finely ground using an electric grinder. Mineral
elements were determined using Inductive Coupled Plasma Emission (ICPE-9000
Shimadzu, Japan). Phytochemical tests were performed to detect the presence of
flavonoids, tannins, alkaloids and saponins, whereas 2,2-Diphenyl-1-picrylhydrazyl
(DPPH) antioxidant qualitative test was performed using TLC plates. Antioxidant
activity and phytochemicals constituents were quantified using UV/Visible
spectrophotometer. Results of this study demonstrated that plant parts had a highly
significant effect on essential mineral elements, copper (Cu), iron (Fe), potassium (K),
magnesium (Mg), zinc (Zn), manganese (Mn), phosphorus (P) and nickel (Ni)
contributing 82, 75, 97, 88, 86, 96, 79 and 82% to total treatment variation (TTV),
respectively, whereas, calcium (Ca) had a significant effect contributing 69%, while no
significant effect on sulphur (S) was observed. Among the tested essential mineral elements, Ca, Zn, Cu and Ni were consistently the highest in the leaf, followed by stem
whereas, the root had the lowest contents. Manganese and Mg were consistently the
highest in the stem, followed by leaf whereas, the root had the lowest content. Iron
was highest in the leaf followed by root and was lowest in the stem. Also, the stem
had the highest content of K whereas, the leaf and the root had moderately lower
content, and P was high in the leaf, whereas, stem and root had lower content.
Similarly, plant parts had a highly significant effect on non-essential mineral elements,
aluminium (Al), sodium (Na), cobalt (Co) and chromium (Cr) contributing 85, 72, 84
and 81% in TTV, respectively, whereas, not significant on silicon (Si). Among the
tested non-essential mineral elements, the leaf had the highest content of Al, Na, Cr,
and Co followed by the stem, whereas, the root had the lowest. The screening of
phytochemicals showed that flavonoids, tannins, alkaloids and saponins were present
within different plant parts of J. zeyheri. The results from DPPH qualitative assay of J.
zeyheri plant parts showed more yellow spots in leaf and root whereas, there was
lesser amount in stem indicating that the plant exhibited antioxidant activity. Plant parts
had highly significant effect on total flavonoids contributing 72% in TTV, however, had
a significant effect on tannins and antioxidant activity contributing 56 and 79% in TTV,
respectively. In contrast, plant parts were not significant on total phenols. The leaf had
the lowest of total flavonoids content, whereas root and stem reported the higher
contents and root had a lower content of tannins and antioxidant activity, whereas
stem and leaf reported higher contents. In conclusion, the majority of chemical
properties were recorded in leaves followed by stems and lastly in the roots. The result
of this study suggested that J. zeyheri tea beverage can be brewed from leaves
predominantly followed by stems or alternatively they can be combined. / National Research Foundation (NRF) and
Limpopo Agro-Food
Technology Station (LATS)
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ul/oai:ulspace.ul.ac.za:10386/3443 |
| Date | January 2020 |
| Creators | Mamabolo, Lerato Katedi |
| Contributors | Shadung, K. G., Maila, M. Y. |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | xvi, 83 leaves |
| Relation |
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