- Title
- Impact of formulated soil types on growth performance, phytochemical constituents and pharmacological properties of solanum nigurm L. : a wild vegetable in the Eastern Cape Province, South Africa
- Creator
- Ogundola, Adijat Funke
- Subject
- Solanum Materia medica, Vegetable Medicinal plants -- South Africa -- Eastern Cape
- Date
- 2017
- Type
- Thesis
- Type
- Doctoral
- Type
- PhD
- Identifier
- http://hdl.handle.net/10353/8758
- Identifier
- vital:33519
- Description
- Solanum nigrum L. is a wild vegetable that is highly recognised for its high nutiritional and therapeutical purposes. However, proper identification of the plant is essential not only to plant scientists but to a wide range of users. Therefore, the plant’s roots, stems and leaves cultivated on different soil types were viewed under the Scanning Electron Microscope while the leaves were further viewed under the Light Microscope. significant increase was observed in densities of stomata, guard and subsidiary cells of leaves of S. nigrum grown on silty clay loam soil. The SEM analysis revealed abundant glandular and non-glandular trichromes on both surfaces of the leaves. The glandular trichome is known to be responsible for the storage of bioactive compounds for which this plant is well known. Cultivation was embarked upon, for the availability of the plant at all times. However, propagation was by seed alone, therefore, quality seed is necessary for cultivation. Study was carried out on seeds extracted from plants growing in the wild in Alice for the seed viability, germination and seedling emergence when subjected to different soil texture types and sowing depths. The seeds were 98.3 percent viable. Highest germination (94.66 percent) was recorded in sand paper scarification, 15, 20 and 25ºC. Continuous darkness and temperatures lower than 5ºC and higher than 35ºCwere detrimental to the seeds. Silty clay loam soil and a depth of 2 cm had the highest seedling emergence 90 percent and recommended as the ideal condition for seedlings emergence. The growth, yield and physiological response of S. nigrum to sandy clay loam, silty clay loam, clay loam, loam soils and control soil (sandy loam) were investigated in the glasshouse in two separate trials. The ANOVA analysed data results indicated that plant samples on silty clay loam significantly increased in height, stem girth, plant root, leaf area, number of leaves, number of branches, number of flowers, number of fruit bunch per plant dry weight, as well as weight of fruit bunch. However, plant samples grown on clay loam and loam soils recorded increased chlorophyll and produced dark green leaves. It is conceivable that silty clay loam soils have a strong ability to support the physiological growth and the yield of S. nigrum. These soils are therefore recommended for the cultivation of this plant. S. nigrum cultivated on these soils was evaluated for proximate compositions, anti-nutrients, vitamins A, C and E and mineral compositions using standard analytical methods. Using the translocation factor, the minerals’ toxicity accumulation levels in the plant were also determined. Accumulation of proximate parameters in the first and second trials are: ash (11.25-12.25 percent and 11.14- 11.54 percent), crude fibre (19.24-19.95 percent and 18.71-19.35 percent), protein (36.72-38.98 percent and 34.47-37.00 percent), phytate (0.84-1.17 and 0.88-1.15 mg/ml), saponnin (94.10-97.00 and 94.17-97.00 percent) and alkaloids (43.03-45.76 and 42.08- 44.10 percent) respectively. Vitamin A ranged between 117 and 137 mg/kg and betweens 108 and 128 mg/kg, vitamin C between 100 and 118 mg/kg and between 96 and 108 mg/kg and vitamin E between 250 and 269 mg/kg and between 227 and 261 mg/kg in the first and second trials respectively. The quantities of macro and micro-nutrients recorded in S. nigrum showed that this plant is a reservoir of nutrients. Plants cultivated on clay loam, silty clay loam and loam soils accumulated elevated nutritients compositions. Investigation was made on the ability of S. nigrum cultivated on different soil texture types to synthesise phytochemicals such as phenol, flavonoid, alkaloid proanthocyanidins, tannins, saponins and antioxidant. Highest concentrations of phenolics (73.87 mg/g), flavonoids (58.41 mg/g), proanthocyanidins (875.74 mg/g), tannins (49.32 mg/g), saponins (875.74 mg/g) and alkaloid (47.50 mg/g) contents were recorded in plant sample cultivated on silty clay loam soil. Also, highest radical scavenging power using DPPH (0.0102 mg/g), ABTS (0.1062 mg/g) and FRAP (0.8395 mg/g) were recorded in plant samples grown on silty clay loam and the next high values were recorded in plant samples grown on clay loam soil. It is showed in this study that silty clay loam soil and clay loam soils are the best soil types for cultivation of S. nigrum for increased antioxidant properties/ oxygen radical scavenging activities. Investigation was made on chemical compositions and antioxidant properties of essential oil extracts of S. nigrum shoot and root cultivated on different soil textures. The Gas Chromatography-Mass Spectrometry (GC-MS) profiling revealed variations in the quality index (QI) and number of chemical constituents of the oil of S. nigrum cultivated on different soil texture types. Geraniol and citronellol were two principal components of high quality common to oil from shoots and roots fromplants cultivated on all soil types. Results of DPPH and ABTS assays of the shoot oil showed that S. nigrum cultivated on clay loam soil had the highest antioxidant power. The presence of citronellol and geraniol among the major compounds is an indicaton of the plant’s role in defensive mechanisms. The work indicated that soil texture has effect on the quality, quantity and chemical compounds synthesised in the shoots and roots of S. nigrum. Antibacterial activities and the efficacy of S. nigrum cultivated on different soil types were carried out on reference strains of 4 gram-positive and 4 gram-negative bacteria. Toxicity evaluation of the plant’s acetone extract and water extract were also assessed on lethality of brine shrimp eggs. Plant water and acetone extracts exhibited strong antibacterial activity against Pseudomona aeruginosa, acetone extracts against Bacillus cereus, Listeria and Escherichia coli. Significantly (p< 0.05) low concentration (0.25 mg/mL) of acetone extracts from plant shoot cultivated on silty clay loam and clay loam soils inhibited B. cereus and P. aeruginosa. Antimicrobial activities of extracts of plant cultivated on clay loam appeared to be more superior to extracs from plants grown on other soil types. Toxicity of the plant extracts (water and acetone) was concentration and time dependent. The LD50 values for all plant extracts were greater than 1000 mg/mL which showed they are non-toxic.
- Format
- 2016 leaves
- Format
- Publisher
- University of Fort Hare
- Publisher
- Faculty of Science and Agriculture
- Language
- English
- Rights
- University of Fort Hare
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