Response of bioactive compounds in coriander (Coriandrum sativum L.) to foliar application of Moringa and barley seed extracts and biofertilization

Introduction

Coriandrum sativum L., commonly known as coriander, is an annual herbaceous plant belonging to the Apiaceae (Umbelliferae) family. It is characterized by a strong aromatic scent and can grow up to 50 cm in height. The plant has finely divided upper leaves and small white flowers. Coriander is widely recognized as a popular spice. Its native origin is believed to be Italy, and it is cultivated extensively across Mediterranean countries, as well as in India, South America, and Europe. It is grown both as a leafy vegetable-where its fresh leaves are used to enhance the flavor of dishes-and for its seeds, which are commonly used as a spice. The seeds contain essential oils ranging between 0.6-1%, the most significant of which include linalool (75%), borneol, geraniol, carvone, anethole, pinene, and limonene. Coriander essential oil is used medicinally as a carminative, analgesic, and for treating colic and irritable bowel syndrome (IBS). It also serves as a digestive stimulant, appetite enhancer, diuretic, and cholagogue. According to Simon et al. (1984) [30] , coriander exhibits antispasmodic effects and regulates gastrointestinal activity, helping eliminate excess salts, reduce the risk of thrombosis, and protect against inflammation due to its antioxidant content. It also lowers cholesterol levels and serves as a natural analgesic. The essential oil of coriander seeds is also employed in the cosmetic industry, perfumes, and certain soap varieties. Al-Dajwi (1996) [5] noted that coriander is a high-value leafy herb and one of the most widely cultivated herbs globally, with India, China, and Turkey being the largest producers and exporters. Different parts of the plant-fresh and dried leaves and seeds-are used in spice production. Green coriander leaves are rich in vitamin C (250 mg/100g) and carotene (2005 µg/100 g) (Chakravarty, 1976) [11] . The mature seeds contain water, fats, starch, sugar, proteins, fibers, and minerals such as calcium, phosphorus, and iron, along with essential oils (Diederichsen, 1996) [12] . Coriander also exhibits antibacterial and antifungal properties (Fleming, 1998) [15] and has a hypoglycemic effect (League of Arab States, 1988). In recent years, biofertilizers have been adopted as an alternative to chemical fertilizers. Interest in biofertilizer technologies and microbial inoculation of crops has grown as a sustainable approach to supply nutrients, partially mitigate nutrient deficiencies, and reduce reliance on chemical inputs, thereby minimizing environmental pollution. Biofertilization mechanisms include enhancing nutrient availability, producing growthpromoting substances, increasing nutrient uptake, and protecting the host plant from pathogens. Biofertilizers are cost-effective and safe, capable of reducing chemical fertilizer use by at least 25%, in addition to mitigating pollution problems (Al-Haddad, 1998) [6] . According to El-Shahat (2007) [13] , biofertilizers should not completely replace chemical fertilizers but rather complement them by improving their efficiency and effectiveness. Another approach to reducing chemical fertilizer dependency is the use of plant-based extracts, particularly those derived from germinated seeds. These extracts have gained popularity due to their richness in compounds absent in mature plants, as well as their simple molecular forms that are readily absorbed. Germinated seeds are rich in gibberellins and low in abscisic acid, making their extracts abundant in natural growth-promoting hormones (Taiz), as well as easily absorbable nutrients, vitamins, amino acids, and sugars (Mandoki & Marton, 2010) [24] . These extracts can be applied directly to plants as foliar sprays. Furthermore, extracts from Moringa leaves (Moringa oleifera) are widely used due to their high content of proteins, calcium, potassium, magnesium, iron, carotenoids, cytokinins, and vitamins such as vitamin C and tocopherol. Moringa leaves contain plant-based compounds and hormones beneficial for plant growth, especially zeatin (a type of cytokinin), along with organic pigments like carotenoids, flavonoids, anthocyanins, niazimicin, glucosinolates, minerals, and sterols. These components contribute significantly to the plant's antioxidant capacity (Fuglie et al., 1999) [16] .

Research Objectives 1. To evaluate the response of bioactive compounds in coriander (Coriandrum sativum L.) to foliar application of Moringa leaf extract and germinated barley seed extract. 2. To assess the influence of biofertilization treatmentsincluding mycorrhiza, Trichoderma, and Bacillus species-on the accumulation of bioactive compounds in coriander.

3. To investigate the interaction effect between foliar organic extracts and biofertilizers on the levels of bioactive compounds in coriander plants.

Materials and Methods

The Preparation of Moringa Leaf Extract: Fresh Moringa leaves (10 g) were mixed with 100 ml of water (10 ml per 10 g fresh weight). The mixture was manually ground using a mortar and pestle to extract the juice, which was then filtered through a fine cloth. The filtrate was re-filtered to obtain a clear solution (Fuglie, 1999) [16] . The extract was diluted with distilled water at a ratio of 1:32 (v/v) and applied as a foliar spray to coriander plants within five hours of preparation. This extract contains amino acids, fatty acids, vitamins, nutrients, carbohydrates, and proteins. One thousand grams of barley seeds (Abha 265 cultivar) were washed and soaked in water for 24 hours, then drained and spread in a single layer on trays lined with cheesecloth in a dark place. The seeds were kept moist as needed to maintain hydration. After 72 hours, when the radicles emerged, the grains were germinated. The germinated seeds were thoroughly ground using an electric blender, filtered, and the volume was adjusted to 10 liters. The extract was used immediately for foliar spraying. It contains nitrogen, phosphorus, calcium, magnesium, iron, zinc, and gibberellins.

Experimental Measurements: On December 16, 2024, five plants were randomly selected from each experimental unit to measure plant height (cm), number of branches per plant, and number of leaves per plant. Leaf samples were analyzed for total amino acid content (mg/100 g) according to Sadasivam and Manickam, and antioxidant content (mg/100 g) following the method described by Oyaizu (1986) [28] .

The results presented in Table (1) indicate that there were significant differences among the microbial inoculation treatments in terms of plant height in coriander. The treatment M4 (Bacillus) recorded the highest plant height, reaching 111.33 cm, while the control treatment (M1) recorded the lowest height, at 104.56 cm. Similarly, significant differences were observed among foliar spray treatments, where treatment E3 (germinated barley extract) resulted in the highest average height of 108.50 cm, compared to the lowest value of 105.25 cm recorded in the control spray treatment (E1).Regarding the interaction between the two factors, the combination M4E3 exhibited a significant superiority, achieving the maximum plant height of 114.00 cm, followed by M4E1, which recorded 110.67 cm. On the other hand, the lowest plant height was observed in the control interaction treatment (M1E1), which recorded 99.33 cm.

Total Number of Leaves (leaves•plant⁻¹)

The results presented in Table (2) show that there were significant differences among the microbial inoculation treatments in terms of the total number of leaves per coriander plant. The treatment M4 (Bacillus) recorded the highest number, reaching 112.0 leaves•plant⁻¹, while the control treatment (M1) recorded the lowest number, at 100.1 leaves•plant⁻¹.In contrast, no significant differences were observed among the foliar spray treatments regarding the total number of leaves. As for the interaction between the two factors, the combination M4E1 showed a significant superiority, achieving the highest number of leaves, with 125.6 leaves•plant⁻¹, whereas the lowest value was recorded in the control interaction treatment (M1E1), with 86.9 leaves•plant⁻¹.

The results presented in Table (4) indicate the presence of significant differences among the microbial inoculation treatments in terms of total yield per hectare. The treatment M3 (Trichoderma) recorded the highest yield, reaching 3652 kg•ha⁻¹, followed by treatment M2 (Mycorrhiza), which recorded 3529 kg•ha⁻¹. In contrast, the control treatment (M1) recorded the lowest yield, with 2857 kg•ha⁻¹.The results also show significant differences among the foliar spray treatments. The treatment E3 (sprouted barley extract) achieved the highest yield, with 3532 kg•ha⁻¹, while the control foliar spray (E1) recorded the lowest yield, at 3147 kg•ha⁻¹.However, the interaction between the two factors (microbial inoculation × foliar spray) did not show significant differences in total yield. [22,20] . The treatment with Bacillus spp.-beneficial root-colonizing bacteria-has shown to significantly stimulate plant growth and yield when applied to seeds or roots. These bacteria can solubilize insoluble phosphate minerals, making them available for root absorption, and also produce growth hormones and antibiotics. In coriander, the combination of Bacillus and fungi led to notable increases in vegetative growth traits, such as plant height, number of branches, and dry biomass. The addition of biofertilizers notably improved nutrient concentration in the leaves, particularly potassium. This can be attributed to the microorganisms' ability to secrete organic acids and growth regulators that positively influence plant development. These findings are consistent with those of Ali et al. (2023) [7] . The positive effects of biofertilizers on plant development are also due to their role in improving soil fertility by releasing organic acids that lower soil pH, thereby converting nutrients into forms accessible to plant roots. This leads to better stem elongation and overall plant height. Biofertilizers also stimulate branching and enhance enzymatic activity that drives photosynthesis, resulting in greater production of nutritional compounds. This promotes vegetative traits by stimulating bud growth, especially due to the presence of humic and fulvic acids, ultimately improving foliage and vegetative yield. Plants respond favorably to bacterial inoculation, particularly in seed germination, root development, and leaf area (Abdel Salam et al., 2022; Suleiman, 2018; Mounika, 2017; Abdulaziz) [2, 31, 27, ] . These findings are also supported by Metwaly and Abd-El-Sayed (2018) [26] [23] , Abd-ElKafie et al. (2016) [3] , Al-Tufaili (2023) [8] , and Mahdawi et al.

(2023) [25] . Sprouted barley seed extract, rich in essential minerals such as calcium, phosphorus, potassium, and nitrogen, along with carbohydrates and proteins, is also a potent source of natural plant hormones that promote growth. The application of barley extract significantly improved vegetative parameters in coriander, including plant height, number of branches, and dry matter percentage. The benefits of seed sprouting extend beyond basic germination, enhancing bioavailability and the absorbability nutrients, vitamins, amino acids, and sugars by living tissues (Marton & Mandoki, 2010) [24] . Sprouted seeds also contain high levels of gibberellins and low levels of abscisic acid, making them a rich source of natural growth stimulants (Bhatia & Lal, 2019) [10] .

The results in Table (5) indicate the presence of significant differences among the microbial inoculation treatments regarding total amino acid content in coriander leaves. The M4 treatment (Bacillus) recorded the highest concentration, reaching 8.9722 mg•100g⁻¹, while the control treatment (M1) recorded the lowest value at 8.9116 mg•100g⁻¹.Similarly, significant differences were observed among the foliar spray treatments. The E3 treatment (sprouted barley extract) showed the highest amino acid content, with 8.9507 mg•100g⁻¹, whereas the control spray (E1) recorded the lowest value at 8.9203 mg•100g⁻¹.Regarding the interaction between the two factors, the combination M4E3 showed a significant superiority, recording the highest value of 9.0310 mg•100g⁻¹, followed by M4E2 with 8.9653 mg•100g⁻¹. In contrast, the control treatment combination recorded the lowest value, 8.8823 mg•100g⁻¹.

Discussion of Results

The results indicated that the application of bio-fertilizers and foliar extracts led to a significant increase in the amino acid content of coriander plants compared to untreated controls. This increase may be attributed to the presence of beneficial microorganisms and their effective role in promoting plant growth, as well as the nutrients, vitamins, and phytohormones they provide, which contribute to enhancing amino acid levels in coriander tissues. Biofertilizers play a vital role in improving plant growth and increasing physiological efficiency. One of their most notable effects is the enhancement of free amino acids, which are essential for the synthesis of proteins, enzymes, and other bioactive compounds. Beneficial microorganisms such as Trichoderma spp., Bacillus spp., and arbuscular mycorrhizal fungi (AMF) have shown a strong capacity to stimulate the accumulation of amino acids by improving nitrogen uptake and activating metabolic processes. Studies have reported that Trichoderma enhances primary metabolism, including the biosynthetic pathways of amino acids such as glutamine and proline, through the secretion of plant growth regulators and active enzymes (Harman et al., 2004). Likewise, Bacillus contributes to the production of auxins and improves the uptake of both micro-and macronutrients, thereby increasing the levels of amino acids-especially those associated with stress tolerance, such as proline and aspartic acid (Idris et al., 2007) [19] . On the other hand, arbuscular mycorrhizal fungi (AMF) enhance the absorption of phosphorus and water, which indirectly supports the biochemical processes involved in amino acid synthesis. Experimental evidence on medicinal and aromatic plants-including coriander-shows that AMF inoculation increases the content of free amino acids and total protein in leaves and seeds compared to non-inoculated plants (Giri et al., 2005; Kapoor et al., 2004) [17,21] . Moreover, foliar application of plant extracts also resulted in a significant increase in amino acid levels. This increase is likely due to the bioactive compounds found in plant-based extracts, including hormones, vitamins, and nutrients, particularly those derived from biologically rich sources such as Moringa, barley, or yeast. These components stimulate metabolic processes within the plant, including the biosynthesis of proteins and amino acids. It is also likely that the organic compounds, vitamins, and minerals in these extracts enhanced enzymatic activities related to amino acid biosynthesis. Additionally, plant extracts help improve nitrogen absorption and boost cellular activity, leading to higher amino acid concentrations in plant leaves, consistent with the findings of El-Sherbeny et al. (2007) [14] .

The results in Table (6) reveal significant differences among the microbial inoculation treatments in terms of total antioxidant capacity in coriander leaves. The M4 treatment (Bacillus) exhibited the highest value, reaching 62.51 mg•100g⁻¹, followed by M3 (Trichoderma) with 61.61 mg•100g⁻¹, whereas the control treatment (M1) recorded the lowest value at 53.41 mg•100g⁻¹.Significant differences were also observed among the foliar spray treatments, where E2 (Moringa leaf extract) resulted in the highest antioxidant content at 61.61 mg•100g⁻¹, while the control spray (E1) recorded the lowest value of 58.19 mg•100g⁻¹.Regarding the interaction effect between the microbial inoculants and foliar sprays, the combination M4E1 achieved significant superiority, yielding the highest antioxidant capacity of 65.44 mg•100g⁻¹, followed by M3E1 with 63.15 mg•100g⁻¹, whereas the control combination recorded the lowest value, 46.51 mg•100g⁻¹.

Discussion of Results

The findings of the current study demonstrated that the application of bio-fertilizers and foliar extracts led to a significant increase in antioxidant content in coriander plants compared to untreated controls. This increase in the concentration of antioxidants, such as total phenolics and flavonoids, may be attributed to the vital role played by the microorganisms present in bio-fertilizers in enhancing the uptake of essential nutrients, particularly nitrogen and phosphorus, which are critical for metabolic processes. Moreover, the positive interaction between beneficial microbes and plant roots contributes to the stimulation of enzymes involved in the biosynthetic pathways of antioxidant compounds, such as phenylalanine ammonialyase (PAL). This supports the hypothesis that the role of bio-fertilization extends beyond improving vegetative growth to enhancing the phytochemical quality of the plant. The increase in antioxidant content and oxidative activity in the vegetative parts of the plant may also be a cumulative result of improved vegetative indicators due to biofertilization, which led to increased accumulation of dry matter. This enhancement is primarily driven by elevated rates of photosynthesis, which produce primary metabolites, and consequently increase the accumulation of intermediate compounds that participate in secondary metabolism for the synthesis of phenolic and flavonoid compounds. Furthermore, the observed correlation between increased vegetative growth indicators and enhanced photosynthetic activity may reflect a heightened demand of the biological system for antioxidant compounds. These compounds are essential for maintaining enzymatic reactions involved in biomass production and for protecting against free radicals and reactive oxygen species generated during energy transfer reactions. This relationship is particularly evident when bio-inoculation is accompanied by elevated levels of ascorbic acid, which plays a crucial role in the Ascorbate-Glutathione Cycle in combating intracellular H₂O₂ resulting from intensified metabolic activity. The simple linear correlation between vegetative growth parameters and the content of phenolics, flavonoids, carotenoids, and antioxidant activity is statistically expressed as a strong positive association (Al-Asadi, 2018) [4] . In addition, treatments with foliar extracts of Moringa and barley also led to a significant increase in total antioxidant content in coriander plants. This improvement may be attributed to the rich content of these extracts in nutrients, amino acids, vitamins, and plant hormones, which serve as a good reservoir of growth-promoting substances. Moreover, the integration of such natural inputs into plant nutrition management can have a pronounced effect on the quality and composition of bioactive compounds within the plant.

References

1. Abdel Aziz M, Mohamed H, Yaqoub R. Effect of the biofertilizer EMI and its application method on some morphological and productive traits of coriander (Coriandrum sativum). Tartous University Journal. 2019;3(3).
2. Abdel Salam MM, Mekhemar GAA, Roshdy NM. Effect of organic and bio-fertilization on cuttings of Ruby Seedless grapes cultivated in clay and sandy soils. SVU-Int J Agric Sci. 2022;4(4):8-28.
3. Abd-ElKafie OM, Kasem MM, Abd-ElBaki SM, Sidky MM. Improving the vegetative growth and chemical contents of coriander (Coriandrum sativum L.) plant by using Moringa leaf extract. J Plant Prod. 2016;7(12):1357-1363.
4. Al-Asadi MHS. Fundamentals of medicinal plants and their active compounds. Baghdad: Dar Al-Warith for Printing and Publishing, University of Al-Qasim AlKhadra; 2018. p. 271.
5. Al-Dajwi A. Technology of vegetable cultivation and production. Cairo: Madbouly Library; 1996. p. 399400.
6. Al-Haddad MSM. The role of biofertilizers in reducing agricultural costs, minimizing environmental pollution, and increasing crop productivity. National Training Course on Production and Use of Biofertilizers; 1998 May 16-21; Hashemite Kingdom of Jordan: Faculty of Agriculture, Ain Shams University.
7. Ali MA, Hassan EA, Ebrahim AE, Ismail SA, Soliman TMA. Response of coriander plants to some organic and bio-fertilizer treatments. New Valley J Agric Sci. 2023;3(10):80-94.
8. Al-Tufaili AFS. Effect of Moringa leaf extract, cytokinin, and humic acid on growth and yield of arugula and molecular analysis of the zeatin gene. AlQasim: College of Agriculture, University of Al-Qasim; 2023.
9. Arab League, Arab Organization for Agricultural Development. Medicinal, aromatic, and toxic plants in the Arab world. Khartoum: Dar Misr for Printing; 1988. p. 250-251.
10. Bhatla SC, Lal MA. Plant physiology, development, and metabolism. Cham: Springer Nature; 2019. p. 1237.
11. Chakravarty HI. Plant wealth of Iraq. A dictionary of economic plants. Vol. 1. Baghdad; 1976. p. 160-162.
12. Diederichsen A. Coriandrum sativum L. Promoting the conservation and use of underutilized and neglected crops. 3. Rome: IPGRI; 1996. p. 8-32.
13. El-Shahat MRT. Biofertilizers and organic agriculture: healthy food and clean environment. 1 st ed. Cairo: Dar Al-Fikr Al-Arabi; 2007. p. 95-200.
14. El-Sherbeny SE, Khalid KA, Hussein MS. Response of coriander plants (Coriandrum sativum L.) to organic fertilization. J Appl Sci Res. 2007;3(9):1136-1142.
15. Fleming T, editor. PDR for herbal medicines. 1st ed. Montvale: Medical Economic Company Inc.; 1998. p. 775-776.
16. Fuglie LJ. The miracle tree: Moringa oleifera: natural nutrition for the tropics. Dakar: Church World Service; 1999. p. 68. Revised in 2001 as The Miracle Tree: The Multiple Attributes of Moringa, p. 172.
17. Giri B, Kapoor R, Mukerji KG. Influence of arbuscular mycorrhizal fungi and salinity on growth, biomass and mineral nutrition of Acacia auriculiformis. Biol Fertil Soils. 2005;41(3):164-168.
18. Harman GE, Howell CR, Viterbo A, Chet I, Lorito M. Trichoderma species-opportunistic, avirulent plant symbionts. Nat Rev Microbiol. 2004;2(1):43-56.
19. Idris EE, Iglesias DJ, Talon M, Borriss R. Tryptophandependent production of indole-3-acetic acid (IAA) affects level of plant growth promotion by Bacillus amyloliquefaciens FZB42. Mol Plant Microbe Interact. 2007;20(6):619-626.
20. Japanis FG, Vetaryan S, Raja NKK, Mokhtar MAA, Fishal EMM. The impact of Trichoderma spp. on agriculture and their identification. Malays Appl Biol. 2022;51(6):1-15.
21. Kapoor R, Giri B, Mukerji KG. Improved growth and essential oil yield and quality in Foeniculum vulgare Mill. on mycorrhizal inoculation supplemented with Pfertilizer. Bioresour Technol. 2004;93(3):307-11.
22. Kumar D, Priyanka P, Yadav P, Yadav A, Yadav K. Arbuscular mycorrhizal fungi-mediated mycoremediation of saline soil: current knowledge and future prospects. In: Recent Advancement in White Biotechnol Through Fungi. New York: Springer; 2019. p. 319-48.
23. Maishanu HM, Mainasara MM, Yahaya S, Yunusa A. The use of Moringa leaves extract as a plant growth hormone on cowpea (Vigna anguiculata). Traektoria Nauki Path Sci. 2017;3(12):3001-6.
24. Marton M, Mandoki Z. The role of sprouts in human nutrition: a review. Acta Univ Sapientiae Alimentaria. 2010;(3):81-117.
25. Mehdawe A, Mahadeen A, Al-Ramamneh EAD. Foliar application of Moringa leaf extracts affects growth, yield, and mineral composition of pepper (Capsicum annuum L.) under greenhouse conditions. J Ecol Eng. 2023;24(6):329-337.
26. Metwaly HA, Abd-El-Sayed MA. Suppression of damping-off disease by some microorganisms on sweet basil (Ocimum basilicum L.) plants under field conditions. Sci J Flowers Ornamental Plants. 2018;5(1):15-29.
27. Mounika Y, Sivaram GT, Reddy PSS, Ramaiah M. Effect of biofertilizers and micronutrients on growth, leaf yield, and quality of coriander (Coriandrum sativum L.) cv. Sadhana. J Hortic Sci. 2017;12(2):113117.
28. Oyaizu M. Studies on products of browning reaction. Antioxidative activities of products of browning reaction prepared from glucosamine. Jpn J Nutr. 1986;44(6):307-315.
29. Pandey N, Adhikhari M, Bhantana B. Trichoderma and its prospects in agriculture of Nepal: an overview. Int J Appl Sci Biotechnol. 2019;7(3):309-316.
30. Simon JE, Chadwick AF, Craker LF, editors. Herbs: An Index Bibliography, 1971-1980. Hamden, CT: Archon Books; 1984.
31. Suleiman NE. Effect of biofertilizer EMI treatment on growth and yield of lettuce (Lactuca sativa L). Tishreen Univ J Res Stud Biol Sci Ser. 2018;40(1).
32. Zidan RSN, Othman J. Effect of foliar application with different concentrations of the biofertilizer EMI on growth and yield of potato (Solanum tuberosum). Tishreen Univ J Res Sci Stud Biol Sci Ser. 2017;39(1):39-50.