Comparative study of phytochemical composition and insecticidal properties of Lemon species from Eastern Cape and KwaZulu-Natal
- Authors: Nodola, Phumelele
- Date: 2019
- Subjects: Phytochemical -- Insecticidal properties Lemon - - Species – Eastern Cape - - South Africa Citrus limon
- Language: English
- Type: Thesis , Masters , M Sc
- Identifier: http://hdl.handle.net/11260/1348 , vital:32261
- Description: Citrus limon commonly known as lemon is the third most cultivated citrus genus in South Africa mainly cultivated for its juice. This study aims at analysing the chemical composition of Citrus limon waste (leaf and peel) and evaluation of their insecticidal properties. Leaves and peels of Eureka lemons were collected from three South African citrus farms (Addo, Riverside and Mystic), while Lisbon lemons were only collected from two citrus farms (Addo and Riverside) in 2017 and 2018. A total of 36 essential oils were extracted using the Clevenger like apparatus. Analyses of these oils were done using GCMS. An infusion extract of C. limon was prepared according to the standard method and subjected for phytochemical screening to detect and quantify secondary metabolites present. D-Limonene was the major compound identified in all the 36 oils from Eureka and Lisbon peels and leaves (27.9-74.8%). Other dominant compounds identified in Eureka leaf and peel oils were -pinene (5.8-13.2%), -terpinene (4.8-6.7%), geranial (4.0-15.4%), z-citral (6.7-11.7%), sabinene (4.5-6.3%), nerol (4.0-5.4%) and neryl acetate (6.3-9.5%). Some compounds were however present only in some oil such caryophyllene (6.5%) in Mystic dry leaf oil, geraniol (8.0%) in Addo dry leaf oil, as significant compounds. Lisbon leaf and peel essential oils -pinene (4.4- 11.8%), p-cymene (4.2-6.3%), -terpinene (4.4-6.9%), geranial (8.6-17.3%), z-citral (7.1-13.6%), neryl acetate (4.7-9.1%) (5.4-5.9%) were the other prominent peaks identified in the oils. These C. limon essential oils were further tested for insecticidal activities against maize weevils by conducting repellent assay, fumigant assay and contact toxicity; also plant viii powder was used against maize weevils. In general, for all the bioassay, mortality of the insect increased as the contact days with the oil increased. Contact toxicity assays of C. limon peel essential oils were most effective against S. zeamais in which all weevils were dead by day 3 (100% mortality) at 300 μL, while at other concentrations (50, 100, 200 μL) over 50% mortality was observed. The fumigant potential was high with the peel oil with over 50% mortality at 32 and 40 μL in day 4. The oil had moderate repellent effect on the maize weevil. Riverside Eureka dried powder peel was the most effect in all. These results unveil the medicinal potential of South African citrus waste in post-harvest crop protection and good sources of some chemical compounds which are of medicinal value. Furthermore, this study also reveals the economic potential of these wastes in job creation.
- Full Text:
- Date Issued: 2019
- Authors: Nodola, Phumelele
- Date: 2019
- Subjects: Phytochemical -- Insecticidal properties Lemon - - Species – Eastern Cape - - South Africa Citrus limon
- Language: English
- Type: Thesis , Masters , M Sc
- Identifier: http://hdl.handle.net/11260/1348 , vital:32261
- Description: Citrus limon commonly known as lemon is the third most cultivated citrus genus in South Africa mainly cultivated for its juice. This study aims at analysing the chemical composition of Citrus limon waste (leaf and peel) and evaluation of their insecticidal properties. Leaves and peels of Eureka lemons were collected from three South African citrus farms (Addo, Riverside and Mystic), while Lisbon lemons were only collected from two citrus farms (Addo and Riverside) in 2017 and 2018. A total of 36 essential oils were extracted using the Clevenger like apparatus. Analyses of these oils were done using GCMS. An infusion extract of C. limon was prepared according to the standard method and subjected for phytochemical screening to detect and quantify secondary metabolites present. D-Limonene was the major compound identified in all the 36 oils from Eureka and Lisbon peels and leaves (27.9-74.8%). Other dominant compounds identified in Eureka leaf and peel oils were -pinene (5.8-13.2%), -terpinene (4.8-6.7%), geranial (4.0-15.4%), z-citral (6.7-11.7%), sabinene (4.5-6.3%), nerol (4.0-5.4%) and neryl acetate (6.3-9.5%). Some compounds were however present only in some oil such caryophyllene (6.5%) in Mystic dry leaf oil, geraniol (8.0%) in Addo dry leaf oil, as significant compounds. Lisbon leaf and peel essential oils -pinene (4.4- 11.8%), p-cymene (4.2-6.3%), -terpinene (4.4-6.9%), geranial (8.6-17.3%), z-citral (7.1-13.6%), neryl acetate (4.7-9.1%) (5.4-5.9%) were the other prominent peaks identified in the oils. These C. limon essential oils were further tested for insecticidal activities against maize weevils by conducting repellent assay, fumigant assay and contact toxicity; also plant viii powder was used against maize weevils. In general, for all the bioassay, mortality of the insect increased as the contact days with the oil increased. Contact toxicity assays of C. limon peel essential oils were most effective against S. zeamais in which all weevils were dead by day 3 (100% mortality) at 300 μL, while at other concentrations (50, 100, 200 μL) over 50% mortality was observed. The fumigant potential was high with the peel oil with over 50% mortality at 32 and 40 μL in day 4. The oil had moderate repellent effect on the maize weevil. Riverside Eureka dried powder peel was the most effect in all. These results unveil the medicinal potential of South African citrus waste in post-harvest crop protection and good sources of some chemical compounds which are of medicinal value. Furthermore, this study also reveals the economic potential of these wastes in job creation.
- Full Text:
- Date Issued: 2019
Extraction, isolation and characterization of oleanolic acid and its analogues from Syzygium aromaticum (cloves) and evaluation of their biological activities
- Authors: khwaza, Vuyolwethu
- Date: 2019
- Subjects: Antibacterial agents
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/19076 , vital:39882
- Description: Pathogenic microorganisms have serious impact on people's lives. Every year, millions of people around the world die of bacterial infections. Resistance to common antibacterial drugs has proven to be a challenging problem in control of bacterial infections. In an attempt to develop an effective and affordable treatment for bacterial infections, oleanolic acid isolated from syzygium aromaticum conjugates incorporating other pharmaceutical scaffolds such as chloroquine derivatives, curcumin, and ergocalciferol etc have been developed. Based on the previous successes of testing combination of antimicrobial drugs and pharmaceutical drugs which appeared to be the promising strategy to overcome treatment failure; a series of hybrid compounds containing oleanolic acid and other pharmaceutical scaffolds were synthesized. 4- Aminoquinoline derivatives were first hybridized with selected organic compounds to form a class of hybrid compounds containing either amide bond or ester bond as a linker between the precursor molecules. Analogues/hybrid compounds can overcome the disadvantages of combination therapy such as drug-drug interaction. The structural effects of this type of conjugation of oleanolic acid and other pharmaceutical scaffolds were characterised by FTIR, Mass Spec and NMR spectroscopy. These compounds were studied along with the monosubstituted oleanolic acid analogues and the organic components in order to compare the effects of the substitution on their biological response.‖ All the synthesized analogues were tested against 11 bacterial strains on both Gram-positive and Gram-negative bacteria. The synthesized compounds showed selectivity and higher activity against Enterococcus faecalis (EF), Klebsiella oxytoca (KO), Escherischia coli (EC), Staphylococcus aureous (SA), Proteus vulgaris (PV) and Bacillus subtilis (BS) with MIC values; ranging between of 1.25 mg/mL to 0.072 mg/mL
- Full Text:
- Date Issued: 2019
- Authors: khwaza, Vuyolwethu
- Date: 2019
- Subjects: Antibacterial agents
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/19076 , vital:39882
- Description: Pathogenic microorganisms have serious impact on people's lives. Every year, millions of people around the world die of bacterial infections. Resistance to common antibacterial drugs has proven to be a challenging problem in control of bacterial infections. In an attempt to develop an effective and affordable treatment for bacterial infections, oleanolic acid isolated from syzygium aromaticum conjugates incorporating other pharmaceutical scaffolds such as chloroquine derivatives, curcumin, and ergocalciferol etc have been developed. Based on the previous successes of testing combination of antimicrobial drugs and pharmaceutical drugs which appeared to be the promising strategy to overcome treatment failure; a series of hybrid compounds containing oleanolic acid and other pharmaceutical scaffolds were synthesized. 4- Aminoquinoline derivatives were first hybridized with selected organic compounds to form a class of hybrid compounds containing either amide bond or ester bond as a linker between the precursor molecules. Analogues/hybrid compounds can overcome the disadvantages of combination therapy such as drug-drug interaction. The structural effects of this type of conjugation of oleanolic acid and other pharmaceutical scaffolds were characterised by FTIR, Mass Spec and NMR spectroscopy. These compounds were studied along with the monosubstituted oleanolic acid analogues and the organic components in order to compare the effects of the substitution on their biological response.‖ All the synthesized analogues were tested against 11 bacterial strains on both Gram-positive and Gram-negative bacteria. The synthesized compounds showed selectivity and higher activity against Enterococcus faecalis (EF), Klebsiella oxytoca (KO), Escherischia coli (EC), Staphylococcus aureous (SA), Proteus vulgaris (PV) and Bacillus subtilis (BS) with MIC values; ranging between of 1.25 mg/mL to 0.072 mg/mL
- Full Text:
- Date Issued: 2019
Phytochemical Analysis and Biological potential of leaves and peels of three Eastern Cape Citrus Species
- Authors: Matuka, Thandiswa
- Date: 2019
- Subjects: Phytochemical -- Analysis Biology -- Leaves and peels Citrus species -- Eastern Cape -- South Africa
- Language: English
- Type: Thesis , Masters , M Sc
- Identifier: http://hdl.handle.net/11260/1362 , vital:32263
- Description: Citrus sinensis, Citrus reticulata and Citrus clementine are citrus species that belong to a large family Rutaceae. Citrus leaves and peels are often regarded as waste products. In view of the environment pollution impact, the search for end use of citrus waste products for economic value and medicinal purposes was sort after. The aim of this study was to investigate chemical composition of citrus waste products (leaves and peels) essential oils and determine biological active volatile compounds from Citrus sinensis, Citrus reticulata and Citrus clementine Leaves and peels of Citrus sinensis, Citrus reticulata and Citrus clementine collected twice from citrus farm were extracted for essential oils using hydrodistillation method and analysed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) for plant samples collected in 2016 and, gas chromatography (GC) and gas chromatography-triple quadrupole-mass spectrometry (GC-MSMS) for plant samples collected in 2017. The oil yield for Citrus sinensis was 0.19 - 0.85 %v/w for fresh and dried leaf and peels for samples collected in 2016 and 0.26 – 0.87% v/w for those collected in 2017. Analysis of the essential oils analyses identified sabinene (20.4% GCMS, 22.6% GCMSMS), terpinen-4-ol (13.2% GCMS, 6.8% GCMSMS) and linalool (7.6% GCMS, 19.3% GCMSMS) as major compounds in fresh leaves essential oils while β-elemene (16.3% GCMS, 21.4% GCMSMS) and sabinene (10.7% GCMS, 20.8% GCMSMS) were major compounds characterized in dried leaves essential oils. Fresh and dried peels essential oils had limonene as the major constituent (49.6% GCMS, 87.1% GCMSMS) and (73.6% GCMS, 88.3% GCMSMS) respectively. Citrus reticulata essential oils percentage yield range between 0.44-0.80% v/w for fresh and dried leaf and peel oils. Analyses of the GCMS and GCMSMS chromatogram of the volatile oils analyses revealed linalool (33.4% GCMS, 19.6% GCMSMS), (+)-spathulenol (15.2% GCMS, 10.1% GCMSMS) and terpinene-4-ol (4.5% GCMS, 11.9% GCMSMS) as major compounds in fresh leaf essential oils while, sabinene (20.8% GCMS, 32.5% GCMSMS) and linalool (17.2% GCMS, 20.4% GCMSMS) were the major compounds found in dried leaf essential oils. Limonene (55.2%, 75.4% GCMS; 39.5%, 80.8% GCMSMS) was the major prominent compound identified in the C. reticulata peel essential oils in fresh and dried peels respectively, followed by linalool (12.8%, 2.9% GCMS; 48.4%, 7.4% GCMSMS). Percentage yields for the essential oils from C. clementine fresh and dried leaves and peels ranges from 0.40-0.62% v/w for. Fresh and dried leaves volatile oils had sabinene (22.7-27.1%) for GCMS and GCMSMS respectively), linalool (18.5- 20.9% GCMS and GCMSMS) and terpinene-4-ol (6.5- 11.8% GCMS and GCMSMS) as main compounds while fresh and dried peels oils were dominated by limonene (38.9- 86.5% GCMS and GCMSMS). Phytochemical screening experiment of the three citrus species leaves and peels aqueous extract reveal the prominent presence of flavonoids and phenolic compounds in high concentrations. C. reticulata and C. clementine peels and leaves volatile oils exhibited higher antioxidant activity as DPPH free radical scavengers and Ferric reducing power (FRAP) ability, when compared to C. sinensis essential oils which exhibited minimum antioxidant activity. Antioxidant activity of leaves and peels essential oils maybe due to the presence of oxygenated monoterpenes and high limonene content. C. sinensis peels oils showed non-toxic to extremely very low toxicity effect at highest dose 2000 mg/kg. C. reticulata and C. clementine peels oils showed toxicity effect in mice at high dose levels. It is suggested that citrus volatile oils could be safe to use at lower dose levels. Citrus species peels and leaves volatile compounds limonene linalool and sabinene exhibited antiinflammatory activity by significantly reducing rats paw oedema size induced by fresh egg albumin. The study suggests the use of Citrus waste products (leaves and peels) as natural antioxidants with antiinflammatory properties for medicinal value and volatile oils compounds for aroma in beverages and cosmetic industries.
- Full Text:
- Date Issued: 2019
- Authors: Matuka, Thandiswa
- Date: 2019
- Subjects: Phytochemical -- Analysis Biology -- Leaves and peels Citrus species -- Eastern Cape -- South Africa
- Language: English
- Type: Thesis , Masters , M Sc
- Identifier: http://hdl.handle.net/11260/1362 , vital:32263
- Description: Citrus sinensis, Citrus reticulata and Citrus clementine are citrus species that belong to a large family Rutaceae. Citrus leaves and peels are often regarded as waste products. In view of the environment pollution impact, the search for end use of citrus waste products for economic value and medicinal purposes was sort after. The aim of this study was to investigate chemical composition of citrus waste products (leaves and peels) essential oils and determine biological active volatile compounds from Citrus sinensis, Citrus reticulata and Citrus clementine Leaves and peels of Citrus sinensis, Citrus reticulata and Citrus clementine collected twice from citrus farm were extracted for essential oils using hydrodistillation method and analysed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) for plant samples collected in 2016 and, gas chromatography (GC) and gas chromatography-triple quadrupole-mass spectrometry (GC-MSMS) for plant samples collected in 2017. The oil yield for Citrus sinensis was 0.19 - 0.85 %v/w for fresh and dried leaf and peels for samples collected in 2016 and 0.26 – 0.87% v/w for those collected in 2017. Analysis of the essential oils analyses identified sabinene (20.4% GCMS, 22.6% GCMSMS), terpinen-4-ol (13.2% GCMS, 6.8% GCMSMS) and linalool (7.6% GCMS, 19.3% GCMSMS) as major compounds in fresh leaves essential oils while β-elemene (16.3% GCMS, 21.4% GCMSMS) and sabinene (10.7% GCMS, 20.8% GCMSMS) were major compounds characterized in dried leaves essential oils. Fresh and dried peels essential oils had limonene as the major constituent (49.6% GCMS, 87.1% GCMSMS) and (73.6% GCMS, 88.3% GCMSMS) respectively. Citrus reticulata essential oils percentage yield range between 0.44-0.80% v/w for fresh and dried leaf and peel oils. Analyses of the GCMS and GCMSMS chromatogram of the volatile oils analyses revealed linalool (33.4% GCMS, 19.6% GCMSMS), (+)-spathulenol (15.2% GCMS, 10.1% GCMSMS) and terpinene-4-ol (4.5% GCMS, 11.9% GCMSMS) as major compounds in fresh leaf essential oils while, sabinene (20.8% GCMS, 32.5% GCMSMS) and linalool (17.2% GCMS, 20.4% GCMSMS) were the major compounds found in dried leaf essential oils. Limonene (55.2%, 75.4% GCMS; 39.5%, 80.8% GCMSMS) was the major prominent compound identified in the C. reticulata peel essential oils in fresh and dried peels respectively, followed by linalool (12.8%, 2.9% GCMS; 48.4%, 7.4% GCMSMS). Percentage yields for the essential oils from C. clementine fresh and dried leaves and peels ranges from 0.40-0.62% v/w for. Fresh and dried leaves volatile oils had sabinene (22.7-27.1%) for GCMS and GCMSMS respectively), linalool (18.5- 20.9% GCMS and GCMSMS) and terpinene-4-ol (6.5- 11.8% GCMS and GCMSMS) as main compounds while fresh and dried peels oils were dominated by limonene (38.9- 86.5% GCMS and GCMSMS). Phytochemical screening experiment of the three citrus species leaves and peels aqueous extract reveal the prominent presence of flavonoids and phenolic compounds in high concentrations. C. reticulata and C. clementine peels and leaves volatile oils exhibited higher antioxidant activity as DPPH free radical scavengers and Ferric reducing power (FRAP) ability, when compared to C. sinensis essential oils which exhibited minimum antioxidant activity. Antioxidant activity of leaves and peels essential oils maybe due to the presence of oxygenated monoterpenes and high limonene content. C. sinensis peels oils showed non-toxic to extremely very low toxicity effect at highest dose 2000 mg/kg. C. reticulata and C. clementine peels oils showed toxicity effect in mice at high dose levels. It is suggested that citrus volatile oils could be safe to use at lower dose levels. Citrus species peels and leaves volatile compounds limonene linalool and sabinene exhibited antiinflammatory activity by significantly reducing rats paw oedema size induced by fresh egg albumin. The study suggests the use of Citrus waste products (leaves and peels) as natural antioxidants with antiinflammatory properties for medicinal value and volatile oils compounds for aroma in beverages and cosmetic industries.
- Full Text:
- Date Issued: 2019
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