Citrus limon Wastes from Part of the Eastern Cape Province in South Africa: Medicinal, Sustainable Agricultural, and Bio-Resource Potential
Abstract
:1. Introduction
2. Results
2.1. Physicochemical Properties of C. limon Oils
2.2. GC/MS Analysis of EOs of C. limon Leaves and Peel
2.3. Antioxidant Activity of C. limon Essential Oils
2.3.1. Ferric-Reducing Power
2.3.2. DPPH Radical-Scavenging Potential
2.4. Insecticidal Properties of C. limon Oils against Sitophilus zeamais
2.4.1. Repellent Activity
2.4.2. Fumigant Toxicity
2.4.3. Contact Toxicity
2.5. Agricultural and Socio-Economic Benefits of C. limon Peel
3. Discussion
4. Materials and Methods
4.1. Plant Material
4.2. Extraction of EOs from C. limon Leaves and Peel
4.3. GC and GC/MS Analysis of EOs
4.4. Antioxidant Analysis of C. limon EOs
4.4.1. Ferric-Reducing Antioxidant Power (FRAP) Assay
4.4.2. DPPH Radical Scavenging Assay
4.5. Insecticidal Study on C. limon Leaf and Peel EOs
4.5.1. Test Insects
4.5.2. Repellent Assay
4.5.3. Fumigant Assay
4.5.4. Contact Toxicity Test
4.6. Statistical Analysis
4.7. Simulation of Sustainable Agricultural and Socio-Economic Benefits of Lemon Peel
5. Conclusions
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
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Citrus limon EO | EO Smell | EO Color | Starting Material (g) | Mass of Oil (g) | % (w/w) |
---|---|---|---|---|---|
Fresh leaf | Sharp pungent citric smell | Colorless | 600.00 | 2.59 | 0.39 |
Dried leaf | Herbaceous smell | Yellowish | 600.00 | 4.14 | 0.69 |
Fresh peel | Sweet lemonade smell | Colorless | 600.00 | 4.98 | 0.83 |
Dried peel | Sharp lemon smell | Light yellowish | 600.00 | 9.72 | 1.62 |
Compound | KI Value | Percentage Composition (%) | |||
---|---|---|---|---|---|
C. limon (Peel) | C. limon (Leaf) | ||||
Fresh | Dry | Fresh | Dry | ||
Thujene | 932 | 0.3 | - | - | - |
α-Pinene | 934 | 1.5 | 0.2 | 1.1 | - |
Sabinene | 957 | 0.3 | 0.3 | - | - |
δ-3-Carene | 974 | - | - | 1.0 | - |
β-Pinene | 980 | 10.6 | 2.2 | 13.3 | - |
Myrcene | 991 | 1.4 | - | 1.4 | - |
6-Methyl-5-hepten-2-one | 989 | - | 0.3 | 2.7 | 1.8 |
Octanal | 1019 | 0.1 | 0.5 | - | - |
1,8-Cineole | 1022 | - | 0.2 | - | - |
Limonene | 1034 | 52.5 | 36.0 | 31.0 | 12.0 |
Limonene glycol | 1035 | - | - | - | 5.2 |
1,8 Cineole | 1036 | - | - | 1.2 | 2.1 |
Trans-β-ocimene | 1047 | 0.1 | 0.3 | 2.3 | - |
Linalool oxide | 1056 | - | - | - | 3.8 |
γ-Terpinene | 1066 | 8.8 | - | 0.5 | 8.6 |
Cyclo-octane | 1071 | - | 0.1 | - | - |
Epoxylinalool | 1079 | - | 0.7 | - | - |
α-Terpinolene | 1084 | 0.5 | - | 0.3 | - |
Trans-linalool oxide | 1088 | - | 0.7 | 0.2 | 4.2 |
p-Cymene | 1092 | - | 0.2 | - | - |
Linalool | 1099 | 1.2 | 1.3 | 2.3 | |
Nonanal | 1104 | 0.2 | 0.2 | - | - |
Fenchol | 1117 | - | 0.1 | - | - |
Trans-p-2,8-menthadien-1-ol | 1122 | - | 1.1 | - | - |
Cis-limonene oxide | 1135 | - | 1.7 | 0.1 | - |
Trans-pinocarveol | 1152 | - | 0.8 | - | - |
Citronellal | 1155 | - | 0.2 | 0.3 | - |
Camphor | 1159 | - | 0.2 | - | - |
p-Menth-1-en-9-al | 1162 | - | 0.2 | - | - |
Pinocarvone | 1163 | - | 0.8 | - | - |
Borneol | 1165 | - | 0.3 | - | - |
1-Tert-butyl-3,3-dimethylcyclopropene | 1181 | - | 1.3 | - | - |
Terpinen-4-ol | 1182 | 1.1 | 1.1 | 1.0 | 1.5 |
α-Terpineol | 1192 | 2.7 | - | 1.5 | - |
Epoxy-linalol | 1198 | - | - | - | 1.1 |
Alloocimene | 1207 | - | 5.6 | - | - |
2-Butenal, 3-methyl | 1209 | - | 0.5 | - | - |
Citronellol | 1211 | - | 0.7 | - | 1.8 |
Nerol | 1228 | 1.7 | - | 0.7 | 2.3 |
Carveol | 1233 | 0.3 | - | - | 1.0 |
Trans-(+)-carveol | 1235 | - | 3.5 | - | - |
Exo-2-hydroxycineole | 1238 | - | 0.5 | - | - |
Z-Citral | 1240 | 4.3 | 0.7 | 10.3 | - |
Cis-carveol | 1242 | 1.0 | - | - | - |
Geraniol | 1245 | 1.3 | 4.1 | 1.3 | 1.3 |
S-Carvone | 1249 | 0.3 | - | 0.2 | 1.3 |
Piperitone | 1251 | - | 0.2 | - | - |
Cis-salvene | 1254 | - | 0.1 | - | - |
Geranial | 1258 | 5.7 | - | 13.2 | 4.1 |
Perillaldehyde | 1270 | - | 0.3 | - | - |
Methyl geraniate | 1323 | - | - | 0.2 | - |
Citronellyl acetate | 1338 | - | - | 0.3 | - |
Farnesol | 1345 | - | 0.3 | - | - |
α-Humulene | 1443 | - | - | 0.1 | - |
Neryl acetate | 1470 | 1.3 | 2.7 | 4.6 | 2.6 |
Spiro(5.6)dodecane | 1496 | - | - | - | 1.8 |
D-Nerolidol | 1539 | - | 0.2 | - | - |
1,10-Decanediol | 1548 | - | - | 0.2 | - |
Geranyl acetate | 1560 | 0.5 | - | 4.4 | - |
(+) Spathulenol | 1579 | - | - | - | 3.9 |
β-Caryophyllene | 1594 | 0.3 | - | 0.5 | - |
(-)-Humulene epoxide II | 1603 | - | - | - | 1.3 |
Zingiberene | 1611 | 0.6 | 0.2 | - | - |
Trans-sobrerol | 1623 | - | 0.1 | - | - |
4-Methyl-5-vinyl thiazole | 1673 | - | 0.2 | - | - |
1-(Dimethylamino)-3-borolene | 1681 | - | 0.2 | - | - |
Geranylacetate,2,3-epoxy | 1699 | - | 0.2 | - | - |
5-Methyl-tetradecane | 1710 | - | 1.2 | - | - |
Valencene | 1726 | - | 0.3 | - | - |
Dimethyl-2,6-octadienoic acid | 1730 | - | - | - | 2.8 |
β-Bisabolene | 1788 | 1.0 | 0.4 | - | - |
Caryophyllene oxide | 1962 | - | 0.5 | 0.2 | 17.7 |
Isonicotinic acid | 2088 | - | 0.1 | - | - |
3,5-Dimethyladamantan-1-ol | 2102 | - | 0.3 | - | - |
(+,-)-(Z)-Dihydrofarnesal | 2166 | - | 0.1 | - | - |
Trans-chrysanthenol | 2174 | - | 0.2 | - | - |
Total % of compounds | 81.9 | 86.3 | 96.4 | 82.4 |
Concentration (μg mL−1) | Mean Percentage Ferric-Reducing Power (%) | |||||
---|---|---|---|---|---|---|
Fresh Leaf | Dry Leaf | Dry Peel | Fresh Peel | ASC | BHT | |
160 | 65.91 ± 1.21 b | 65.43 ± 1.19 b | 64.30 ± 1.07 b | 63.65 ± 0.29 b | 63.81 ± 0.33 b | 58.48 ± 0.97 a |
80 | 64.94 ± 0.43 c | 61.71 ± 1.26 b | 63.81 ± 0.54 bc | 63.33 ± 0.20 b | 63.33 ± 0.24 b | 56.06 ± 1.03 a |
40 | 62.19 ± 0.25 c | 53.63 ± 2.18 a | 58.64 ± 1.69 b | 57.51 ± 1.55 b | 57.51 ± 0.94 b | 52.99 ± 1.36 a |
20 | 49.11 ± 1.14 c | 45.23 ± 2.05 b | 43.78 ± 3.15 b | 29.24 ± 2.79 a | 48.79 ± 1.18 c | 47.17 ± 1.22 bc |
Mean Percentage Inhibition of the DPPH Radical (%) | IC50 ± SEM (µg mL−1) | ||||
---|---|---|---|---|---|
C. limon Oil | 20 µg mL−1 | 40 µg mL−1 | 80 µg mL−1 | 160 µg mL−1 | |
Fresh leaf | 43.44 ± 1.74 b | 54.89 ± 0.43 a | 62.93 ± 0.28 b | 73.75 ± 0.15 a | 34.54 ± 3.01 e |
Dry leaf | 50.78 ± 0.69 c | 56.95 ± 0.87 b | 66.88 ± 0.56 d | 84.01 ± 0.45 b | 12.59 ± 1.48 c |
Fresh peel | 45.32 ± 2.56 b | 55.92 ± 0.80 ab | 64.27 ± 0.21 c | 75.82 ± 0.61 a | 27.15 ± 2.72 d |
Dry peel | 52.41 ± 0.26 d | 58.70 ± 0.62 c | 67.00 ± 0.02 e | 87.68 ± 0.01 c | 8.79 ± 1.30 b |
ASC | 54.25 ± 3.55 cd | 61.09 ± 1.17 d | 70.08 ± 0.17 f | 92.81 ± 0.95 d | 3.01 ± 0.23 a |
BHT | 36.59 ± 2.85 a | 55.82 ± 5.51 abcd | 60.67 ± 0.32 a | 73.53 ± 4.79 a | 27.58 ± 3.16 d |
C. limon Oil | Repellent Activity (%) | Statistical Analysis | ||||
---|---|---|---|---|---|---|
10 µL | 20 µL | 30 µL | 40 µL | F3,56 | p-Value | |
Dry peel | 52.00 ± 5.09 | 69.33 ± 5.47 | 57.33 ± 5.81 | 82.67 ± 4.73 | 6.6455 | <0.001 |
Dry leaf | 73.33 ± 6.95 | 72.00 ± 5.45 | 82.67 ± 4.73 | 78.33 ± 2.82 | 1.4180 | >0.05 |
C. limon Essential Oil | Exposure Time (h) | No. of Insects Tested | LC50 (95% CI) (µL mL−1 air) | Slope ± SEM | χ2 (df) | p-Value |
---|---|---|---|---|---|---|
Dry peel | 48 | 150 | 0.34 b | 1.35 ± 0.55 | 17.92 (10) | >0.05 |
72 | 150 | 0.28 (0.13–49.30) | 1.20 ± 0.50 | 13.62 (10) | >0.05 | |
96 | 150 | 0.08 (0.06–0.16) | 2.15 ± 0.49 | 4.21 (10) | >0.05 | |
Dry leaf | 48 | 150 | 0.17 (0.12–0.48) | 3.08 ± 0.96 | 5.45 (10) | >0.05 |
72 | 150 | 0.09 (0.07–0.11) | 3.11 ± 0.61 | 7.87 (10) | >0.05 | |
96 | 150 | 0.06 (0.05–0.07) | 2.54 ± 0.49 | 5.58 (10) | >0.05 |
C. limon Essential Oil | Exposure Period (h) | Number of Weevils Tested | LC50 (95% CI) (µL g−1) | Slope ± SE | χ2 (df) | p-Value |
---|---|---|---|---|---|---|
Dry peel | 24 | 300 | 2.02 (1.76–2.27) | 4.07 ± 0.46 | 8.29 (10) | >0.05 |
48 | 300 | 1.66 (1.41–1.89) | 3.82 ± 0.49 | 10.80 (10) | >0.05 | |
72 | 300 | 1.39 (0.95–1.74) | 3.34 ± 0.47 | 15.33 (10) | >0.05 | |
Dry leaf | 24 | 300 | 4.09 (3.01–5.61) | 3.94 ± 0.44 | 42.02 (10) | <0.001 |
48 | 300 | 3.19 (2.44–4.11) | 2.91 ± 0.34 | 21.84 (10) | <0.05 | |
72 | 300 | 2.39(1.76–3.02) | 2.92 ± 0.35 | 20.41(10) | <0.05 |
Simulated Agricultural and Socio-Economic Benefits of C. limon (Lemon) Peel Waste | Values |
---|---|
Total amount of lemons produced (2023) | 653,000 MT |
Total amount of lemons imported | 3000 MT |
Total amount of lemons exported (2023) | 573,000 MT |
Total amount of lemons consumed/wasted within South Africa (2023) | 83,000 MT |
Average weight (wet) of fruit peel per lemon | 39.70 g |
Average dehydrated (dry) of fruit peel per lemon | 9.19 g |
Total available dehydrated lemon peel within South Africa (2023) | 0.762 MT |
Total maize used for animal feed (2023) in South Africa | 6.650 MT |
Cost of lemon peel as an alternative energy-producing ingredient in animal feed (at the current maize market price of ZAR 3754/ton) | ZAR 2,869,548,000:00 |
Cost of maize used in animal feed (2024) in South Africa (January 2024 market price/ton) | ZAR 24,964,100,000:00 |
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Nodola, P.; Miya, G.M.; Mazwi, V.; Oriola, A.O.; Oyedeji, O.O.; Hosu, Y.S.; Kuria, S.K.; Oyedeji, A.O. Citrus limon Wastes from Part of the Eastern Cape Province in South Africa: Medicinal, Sustainable Agricultural, and Bio-Resource Potential. Molecules 2024, 29, 1675. https://doi.org/10.3390/molecules29071675
Nodola P, Miya GM, Mazwi V, Oriola AO, Oyedeji OO, Hosu YS, Kuria SK, Oyedeji AO. Citrus limon Wastes from Part of the Eastern Cape Province in South Africa: Medicinal, Sustainable Agricultural, and Bio-Resource Potential. Molecules. 2024; 29(7):1675. https://doi.org/10.3390/molecules29071675
Chicago/Turabian StyleNodola, Phumelele, Gugulethu M. Miya, Vuyokazi Mazwi, Ayodeji O. Oriola, Opeoluwa O. Oyedeji, Yiseyon S. Hosu, Simon K. Kuria, and Adebola O. Oyedeji. 2024. "Citrus limon Wastes from Part of the Eastern Cape Province in South Africa: Medicinal, Sustainable Agricultural, and Bio-Resource Potential" Molecules 29, no. 7: 1675. https://doi.org/10.3390/molecules29071675