>Magister Scientiae - MSc / Sutherlandia frutescens (L.) R. Br. (Fabaceae), indigenous to the Western Cape region of South Africa, is found in a Mediterranean-type climate known for its many environmental stressors that can influence the levels of metabolites found in plants. Sutherlandia frutescens contains many known potential active constituents among them, flavonoids such as sutherlandins 3 and 4 (Su3 and Su4) and terpenoids such as sutherlandiosides B and D (SuB and SuD). Whether the profiles and levels of Su3, Su4, SuB and SuD are significantly affected by the environmental factors found in this area is however, unknown. iBatech™ is an ethanolic plant extract that is manufactured by researchers in the Department of Medical Biosciences, UWC, for use as a pesticide. HPLC analysis performed on Lycopersicon species treated with the iBatech™ product have shown that it also caused an increase in the concentrations of total polyphenols in the plant (Klaasen et.al., unpublished data). Whether the treatment with iBatech™ might also cause an increase in the polyphenols such as sutherlandins 3 and 4 and sutherlandiosides B and D is also unknown. The objectives of this study were to determine the concentrations of sutherlandins 3 and 4 (Su3 and Su4) and sutherlandiosides B and D (SuB and SuD) in S. frutescens collected from different sites and after the treatment with the iBatech™ product. The specific objectives were: a) to locate and categorize sites where S. frutescens is grown, based on a selection of pertinent environmental growth factors, b) to determine and compare the concentrations of sutherlandins 3 and 4 and sutherlandiosides B and D in S. frutescens collected from the different environmental growth sites and after treatment with the iBatech™ product. To realize these objectives, S. frutescens samples were collected from eight different sites and broadly categorized into three environmental categories. A high-performance liquid chromatography (HPLC) method using diode array ultraviolet detection (HPLC-DAD) for the simultaneous analysis of flavonoids and terpenoids was developed and validated, and used for the profiling and determination of the average levels of sutherlandins 3 and 4 and sutherlandiosides B and D in the samples from the sites and that treated with the iBatech™ product. The Kruskal-Wallis test was used to determine statistically significant differences among the environmental categories. The post ANOVA, Dunn's Multiple Comparison test was performed to determine which groups were significantly different. The Mann-Whitney, two-tail, t-test was used to compare each environmental category to the standard and the column statistics of the raw data was analyzed to determine significant differences among samples from the same environmental category. In the samples collected from the sites, the values represent the average levels of metabolites for each environmental category whereas the significance values indicated were among samples from the same environmental category. The levels for sutherlandin 3 were Afriplex™ (Std.) 2495.08, the natural field (NF) 2810.33 (P=0.0005), the cultivated field (CF) 2519.81 and the greenhouse (GH) 2580.25. The levels for sutherlandin 4 were significantly different when comparing the (NF) 1495.67 (P=0.0001), (CF) 3114.42 (P=0.0140) and (GH) 2361.72 (P=0.0001), with the CF group showing the highest levels of Su4 and the NF showing the lowest. The levels for sutherlandioside B were (NF) 189.7 (P=0.0189), (CF) 594.56 (P=0.0140) and (GH) 326.72 (P=0.0001), however, the CF group showed the highest average levels for SuB. The levels for sutherlandioside D were (NF) 144.1 (P=0.0192), (CF) 544.37 (P=0.0308) and (GH) 387.49 (P=0.0001), with the NF category having the lowest average levels. In the iBatech™ treated samples, the values indicate the average levels of three samples in each treatment group. The levels for sutherlandin 3 were (control) 9758.43, the (50%) 2232.63 and the (100%) 2031.97 treatment groups. The levels for sutherlandin 4) were (control) 2241.63, the (50%) 2247.47 and the (100%) 2392.60, with the 100% treatment group having the highest levels. The levels for sutherlandioside B were (control) 289.66, the (50%) 284.93 and the (100%) 332.30. The levels for sutherlandioside D were (control) 282.77, the (50%) 280.60 and the (100%) 315.13 treatment groups, with the 100% treatment group having the highest levels. The levels of Su3, Su4, SuB and SuD were significantly different (P=0.0001) among all treatment groups. In conclusion, the data shows that only sutherlandin 4 (Su4) was significantly different when comparing the environmental groups. Due to the significant differences in the Su3, Su4, SuB and SuD levels among samples from the same group the levels of these metabolites cannot be correlated with the environmental groups.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uwc/oai:etd.uwc.ac.za:11394/5410 |
| Date | January 2011 |
| Creators | Whisgary, Darryn |
| Contributors | Syce, James A. |
| Publisher | University of the Western Cape |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Rights | University of the Western Cape |
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