Introduction

Mulberry (Morus species) is a perennial deciduous woody tree belonging to Moraceae family. It is a fast-growing plant with unique adaptability to diverse climates, soil types (e.g., silt, sandy, and rocky), and altitudes from sea level up-to 4000 meters1,2. The plant has gained recognition as versatile, contributing to environmental conservation, medicinal uses, and industrial applications (e.g., healthcare, pharmaceuticals, nutritional, food, apiculture, silk industry)3,4,5.

Morus species originated from Himalayan foot hills of India and China, and widespread in many arid and semi-arid regions2. There are more than 15 species of mulberry, out of which M. nigra (black mulberry) and M. alba (white mulberry) are the ones with significant importance due to several applications (e.g., nutritional, and biological activity).

For instance, the leaves, fruits, roots, and the stem of M. nigra and M. alba are rich source of nutritional components that include minerals, carbohydrate, proteins, fat, fibers, vitamins, tannin, and phytochemical composition6,7,8,9. These natural bioactive components present great potential biological activities against various microbes. A Study showed that M. nigra genotypes grown in Turkey were found to be rich in nutrients; in which levels of sodium (Na), calcium (Ca), potassium (K), phosphorus (P), and magnesium (Mg) in leaves varied from 649 mg/100 g to 3402 mg/100 g. Leaves showed high levels of Na, Ca, and K. This has led to the recommendation that this species be widely utilized for human nutrition and as animal feed7. Another research conducted on M. alba recommended its leaves as a rich source of protein for sheep feeding. The analysis revealed that M. alba leaves contain 16.3% of ash, 20.1% of crude protein, and 12% of crude fiber6.

Furthermore, both Morus species have been reported to possess significant antimicrobial, antifungal, antioxidant, antiobesity, anticholesterol, antidiabetic, antimicrobial effects10,11,12,13,14. Despite the higher antimicrobial, antifungal and the other pharmaceutical benefits behind M. alba and M. nigra, some microbes have been adapted to many antibiotics15,16. Most of the earlier studies associated with anti-microbial activities and plant parts of Morus species showed an inhibition zone less than 20 mm17,18, which is not significantly enough to impact on the microbial activities. Microorganisms and especially bacteria and fungi have significant genetic ability to adjust their behavior according to the changes occurring in their environment19,20. Therefore, these groups of microbes are able to rapidly acquire resistance to drugs, which are used as therapeutic agents.

In this respect, the problem of microbial resistance is growing and the outlook for the use of antimicrobial drugs in the coming years is still uncertain2122,23,2425. Among the different groups of microbes that significantly alter human health, some groups of bacteria and fungi are the major pathogens that greatly impact on human body integrity since they are responsible for various infectious diseases26,27,28,29,30,31,32. For example, Staphylococcus aureus is considered a major pathogen that causes a wide range of clinical infections in human body, and its infectiousness covers about 30% of the human population33. Recent studies demonstrated that S. aureus strain was resistant to some referential antibiotic, such as, erythromycin, clindamycin, ciprofloxacin, rifampicin, gentamicin, and trime-thoprim-sulfamethoxazole respectively34. With regard to Escherichia coli, this microbe is considered the most dangerous pathogen that lives in human intestine, and can cause significant impact on human urinary tract, brain, lung, blood system, and has caused the emergence of antibiotic resistance35. As for, Bacillus cereus, it’s a gram-positive bacterium responsible for food alteration and human health due the production of enterotoxins36. With focus on Clostridium botulinum, it’s responsible for the botulism with neurotoxin considered the most known substance that can cause ill-ness and death in human population37. Emphasizing Aspergillus flavus, this pathogen can cause significant negative effects on human health through the production of mycotoxin38. Candida albicans is a major fungal pathogen of human body. Globally, the pathology associated with this microbe is responsible for about 200,000 deaths annually in human population39.

Consequently, researchers around the world need to carry out many studies in this thematic which associated climatic conditions of the specific geographical zone in order to qualitatively and quantitatively assess the microbe adaptations to drugs from the natural bioactive products26,27,28.

Globally, plants growing in the extreme environments face more stress than the other plants26,27,28. Therefore, exploring their chemical composition can allow to identify novel metabolites which could be used against many microbes and that could literally break down their tolerance levels. As per this, chemical compounds resulting from those plants could play crucial role in improving medicines40,41,42,43.

Located in one of the world’s arid regions, the United Arab Emirates (UAE) is home to Morus nigra and Morus alba, which naturally thrive in various wild habitats, including Fujairah. M. nigra is considered the only native Morus species in the country, while M. alba is classified as an exotic species44,45. In traditional folk practices, both species were utilized to treat ailments such as cough, fever, headache, toothache, and inflamed eyes. The edible fruits were consumed raw and used in jam preparation. Woody branches served as material for crafting cooking utensils, while the leaves were essential for feeding silkworms in silk production. Additionally, Morus nigra and Morus alba played a role in honey production, serving as nectar plants41,42 .

Studies reported the need to explore M. nigra and M. alba genotypes, highlighting that different climatic conditions significantly affect the physiocochemical and phytochemical composition6,7,8,9. Despite this fact, reviewing the literature, there is no scientific research done on the phytochemicals and antimicrobial activities of these two species widely grown under the UAE climatic conditions.

Consequently, the main objectives of this study are twofold: First, to investigate the mineral content, nutrients and phytochemical profiles of various parts (leaves, branches, and roots) of both M. nigra (native) and M. alba (exotic) specimens thriving in the natural habitats of Fujairah, UAE. Tested minerals include macronutrients (Ca, K, Mg, P), secondary macronutrients (Na), and micronutrients incuding manganese (Mn), zinc (Zn), nickel (Ni), copper (Cu), as well as the metalloid selenium (Se). Tested heavy metals include cadmium (Cd) and lead (Pb). Second, to assess the antimicrobial activity of the same plant parts across both species. The evaluated antibacterial properties include Staphylococcus aureus, Bacillus cereus, Escherichia coli, and Clostridium botulinum, while the tested antifungal actiivities encompass Aspergillus flavus, and Candida albicans. A diagram showing the overall conducted experiments in this study is represented in Fig. 1.

Fig. 1
figure 1

The overall conducted experiments in this study.

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The study hypothesized that there are significant differences between M. nigra and M. alba in terms of mineral content, nutrient levels, phytochemical profiles, and antimicrobial properties. This will enable the identification of which species may serve as a more suitable candidate for specific applications. Furthermore, this investigation represents a pioneering effort to study Morus species grown under the environmental conditions of the United Arab Emirates. The outcomes of this research are anticipated to significantly contribute to the advancement of sustainable development goals (SDGs), particularly in the context of rapid increases in the global population and the urgent imperative to identify new, sustainable natural resources for nutritional and medicinal applications.

Materials and methods

Plant sample collection and identification

Plant collection had been done from public areas where the collection of plant material for research purposes does not necessitate formal authorization. Full mature plant parts including leaves, branches, and roots of M. nigra (native) and M. alba (exotic) were collected during May 2023 from the plants growing in the natural habitats around Fujairah, United Arab Emirates (UAE) (25.1288° N, 56.3265° E), as indicated by ArcGIS Online (Version 8.1, “2025.1”), a Cloud-based platform, in Fig. 2. The climatic conditions of Fujairah, retrieved from the National Center of Meterology, are represented in Table 1. The collected herbarium samples were deposited and identified by Sharjah Seed Bank and Herbarium (SSBH), voucher specimen number for M. nigra (SSBH-4083) and for M. alba (SSBH-4082).

Fig. 2
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Location of plant sample collection as indicated by ArcGIS Online (Version 8.1 “2025, 1”).

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Table 1 Climatic conditions of Fujairah. Annual data retrieved from the National Center of Meteorology (Fujairah International Airport).
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Plant material preparation

Plant samples were taken to the laboratory, washed delicately with running tap water, and then rinsed with distilled water. Thereafter, the cleaned plant parts were taken to the Middle East Laboratory for further analyses. Three samples from each of the tested plant parts (leaves, branches, roots) for both species were analyzed and considered in the study. The branches used in the experiment were lignified samples and the root samples were collected at the depth of 20 cm from the topsoil. All the chemicals were purchased from Chemstock Company.

Mineral content

Na and K extractions were performed by digesting 1 g of each plant sample with nitric acid (Code 39,335, S D Fine – Chem Limited, Mumbai, India) and hydrochloric acid (Code 56,331, S D Fine – Chem Limited, Mumbai, India), and then the calibrated sample was read through flame photometry according to the Association of Official Agricultural Chemists (AOAC 969.23)46.

The amounts of Ca, Mn, Cu, Mg, P, Zn, Ni, and Se were determined by digesting 0.5 g of each sample with nitric acid and hydrochloric acid through a microwave digestor for 30 min. Afterward, the mineral composition of the digested sample was determined using an atomic absorption spectrophotometer following the methods of the official agricultural chemists (AOAC 2013.06)47.

Heavy metals content

The heavy metal content for Cd and Pb was determined by digesting 0.5 g of each sample with nitric acid and hydrochloric acid using a microwave digester. Following sample digestion, the solution was subjected to inductively coupled plasma atomic emission spectroscopy (ICP‒AES) (AOAC 2015.01)48.

Nutrients and phytochemical content

  • Dry matter 5 g of dry matter from each sample was oven-dried at 105 °C for 3 h until a constant weight was reached (AOAC, 922.06)46.

  • Crude protein 1 g sample digested by using sodium sulfate (Code 28,214, S D Fine—Chem Limited, Mumbai, India) and copper sulphate (Code 37,849, S D Fine—Chem Limited, Mumbai, India) with sulphuric acid (Code 40,325, S D Fine—Chem Limited, Mumbai, India) and nitrogen is estimated by using distillation and applying factor 6.25 protein is calculated (AOAC 2001.11)49 (Device: Buchi Multikjel, USA).

  • Crude fiber Fiber content was determined by digesting 2 g of each sample with 1.25% sodium hydroxide (Code 40,166, S D Fine—Chem Limited, Mumbai, India) and 1.25% sulfuric acid (28,204, S D Fine—Chem Limited, Mumbai, India) for 30 min. Afterward, the obtained residues were cooled and then collected in a crucible through filtration followed by hot water. Subsequently, the collected residues were oven-dried at 130 °C for 2 h, followed by ignition at 600 °C for 30 min. The weight of the remaining residues in the crude fiber was assessed after ignition (AOAC 962.09)50.

  • Ash content Ash determination was performed by taking 2 g of each sample in a silica crucible at 600 °C in a muffle furnace for 2 h (AOAC 942.05)51 (Device: Nabertherm 30–3000, Germany).

  • Crude fat Fat was extracted through a Soxhlet apparatus by refluxing 2 g of each plant sample with petroleum ether for 16 h. Subsequently, the crude fat was obtained after evaporating the petroleum ether (Code 39,824, S D Fine—Chem Limited, Mumbai, India) and taking the weight (AOAC 920.39)52 (Device: Raypa, soxtest sx-6, Germany).

  • Total digestible nutrients (TDN) TDN was estimated from fat, protein, crude fiber, and nonvolatile ether extracts.

  • Tannin content Tannin extraction was performed by titrating the extract with standard potassium permanganate solution (Code 39,644, S D Fine—Chem Limited, Mumbai, India) through indigo carmine solution (Code 88,552, S D Fine—Chem Limited, Mumbai, India) and potassium permanganate solution (Code 39,644, S D Fine—Chem Limited, Mumbai, India) to obtain a light yellowish color (AOAC 955.35)46 (Device: Hach, DR, 6000,USA).

  • Total phenol The phenol content was determined by using Folin-Ciocalteu (Code 29,058, S D Fine—Chem Limited, Mumbai, India) 1 N reagent followed by taking absorbance at UV Spectrophotometer (ISO 14,502–2)53 (Device: Hach, DR, 6000, USA).

  • Flavonoid contents To assess the flavonoid contents, each plant part was minced into small pieces and macerated with methanol (1:20, w/v) for 72 h at room temperature (28 ± 2 °C) with occasional stirring. The extract was then filtered, and the obtained residue was remacerated with the same solvent until the extraction was exhausted. The filtrates obtained from the maceration were subsequently combined and then evaporated with a rotary evaporator. Twenty-five milligrams of the extract was weighed and dissolved in 10 mL of ethanol to obtain a concentration of 2500 ppm. A 1 mL aliquot was pipetted from the solution, after which 3 mL of methanol (Code 76,380, S D Fine—Chem Limited, Mumbai, India), 0.2 mL of 10% aluminium chloride (Code 37,073, S D Fine—Chem Limited, Mumbai, India), 0.2 mL of 1 M potassium acetate (Code 39,581, S D Fine—Chem Limited, Mumbai, India), and 10 mL of aquadestilata were added. Afterward, the samples were incubated for 30 min at room temperature, after which the absorbance was measured via Ultraviolet–Visible Spectrophotometry (UV‒Vis spectrophotometry) at a wave-length of 431 nm. The readings were performed from three replications for each analysis. The levels of flavonoids were obtained through the following equation:

    $$\begin{aligned} Total \, Flavonoid \, = & \, Sample \, Volume \, \times \, Initial \, Concentration \, \\ & \quad \times \, Dilution \, Factor \, of \, Sample \, weight \\ \end{aligned}$$

Preparation of Standard Solution: 10 mg of standard quercetin standard (Code 23,160, S D Fine—Chem Limited, Mumbai, India) was weighed and dissolved in 10 mL of methanol purissma analytica (p.a) (Code 76,380, S D Fine—Chem Limited, Mumbai, India) for 1000 ppm concentration. The stock solution of 1000 ppm qusercetin (Code 23,160, S D Fine—Chem Limited, Mumbai, India), pipetted 1 mL and dissolved in 10 mL of methanol p.a to obtain 100 ppm, Then made several concentrations of 4 ppm, 5, 6 ppm, 7 ppm, and 8 ppm. From each concentration of the quercetin standard solution, add 3 mL of methanol, 0.2 mL of 10% AlCl3, 0.2 mL of 1 M potassium acetate were added, and add aquadestilata up to 10 mL, incubated for 30 min at room temperature. The absorbance was measured on UV–Vis spectrophotometry with a wavelength of 431 nm.

Antimicrobial activities (Inhibition zone)

Antibacterial and antifungal tests were performed by the Disk Diffusion Method (ISO 16,782:2016). Staphylococcus aureus, Bacillus cereus, Clostridium botulinum, and Escherichia coli were the bacterial strains, while Aspergillus flavus and Candida albicans were the fungal strains.

Antibacterial activities The antimicrobial activities of extracts of M. nigra and M. alba plant parts were determined on Mueller Hinton agar using the agar disc method54. Bacterial inoculation was performed by suspending colonies from a 24-h culture in 9 ml of sterile distilled water saline. Subsequently, a spectrophotometer (DO = 0.08–0.1/ = 625 nm) was used to modify the cell density of each inoculum to achieve a final concentration of approximately 108 colony forming unit (CFU) (0.5 McFarland standard). In this approach, a 108 CFU inoculum is dispersed over the surface of 3–4 mm thick Mueller–Hinton agar. Wattman paper discs (N°3, 6 mm) containing 10 µl of crude extract of each plant organ were dissolved in 100% Dimethyl Sulfoxide (DMSO) and placed on plates after drying (for no more than 15 min). After 24 h of incubation at 37 °C, the diameter of the inhibitory zone (in mm) was determined to determine the antimicrobial activity of each tested microbe.

Antifungal activities The antifungal activities of the tested fungi were similar to those of the bacteria. The density was maintained between 0.12 and 0.15 at 530 nm by analyzing the microbes in liquid form using the Spectrometer (Hach, DR, 6000,USA) at 530 nm through dilution. However, the culture medium was adjusted to Mueller Hinton + 2% glucose + 0.5 g/ml methylene blue/pH 7.4. A spectrophotometer was used to regulate the cell density of the inoculum (DO = 0.12–0.15/ = 530 nm), and then the readings were obtained. As reference antimicrobials, ciprofloxacin, gentamycin, and amphotericin B were utilized as positive controls, and pure solvent was used. Antimicrobial activity is assessed beginning with a diameter of 6 mm or greater according to the Agar disk-diffusion method.

Statistical analysis

The collected data were analyzed in triplicate, and two-way analysis of variance (ANOVA) was conducted to assess the effect of species and plant parts on the nutritive value of the tested plants. Two-way ANOVA was also performed to assess the effect of species and plant part extracts on the microbial activities of the studied microbes. Tukey’s test (honest significant difference, HSD) was used to identify significant differences between the means. Scatterplots and linear regressions were generated to assess the associations between the flavonoid extracts and antimicrobial activities, and ANOVA was subsequently performed to determine the significance of the relationships. All the data were statistically analyzed with SYSTAT (version 13).

Results

Mineral content variability in plant parts of both species

The two species, plant parts, and their interactions had significant (p < 0.001) effects on the mineral composition of M. nigra and M. alba (Fig. 3 and Table 2). The concentrations of the different elements varied strongly between the two plant species and within the plant parts. The levels of Ca, K and Mn recorded in the leaves of the two plant species were greater than those recorded in the branches and roots. The leaves of M. nigra had significantly greater amounts of Ca (1514.01 mg/100 g), K (1182.44 mg/100 g) and Mn (2.07 mg/100 g) than those of the branches and roots, and these values were greater than that of M. alba. Cu (1.08 mg/100 g) levels were significantly greater in the leaves of M. alba than in the branches and roots, and these concentrations were greater than those observed in the plant parts of M. nigra. The roots of M. nigra contained more Mg (454.18 mg/100 g), Na (183.54 mg/100 g), P (398.67 mg/100 g), and Ni (1.36 mg/100 g) than did the leaves and branches, and these levels were greater than those of M. alba. With regard to Zn concentrations, the branches of the two plant species showed significant differences compared to the leaves and roots, and greater amounts of Zn were detected in the branches of M. alba (1.58 mg/100 g). Se contents of the plant leaves, branches, and roots of the two species were also analyzed, but the analyzed samples had no Se content.

Fig. 3
figure 3

Effects of species and plant parts on the mineral composition of M. nigra and M. alba.

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Table 2 Results of two-way ANOVA (F-values) testing the effects of species (M. nigra and M. alba) and plant organs on magnesium (Mg), phosphorous (P), calcium (Ca), potassium (K), sodium (Na), manganese (Mn), and zinc (Zn) amounts (mg/100 g).
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Heavy metal analysis

Plant parts of M. nigra and M. alba were subjected to the toxicity analyses associated with Pb and Cd. The analysed plants samples had no toxicity related to Pb and Cd.

Nutrient and phytochemical contents in plant parts of both species

Statistically, plant parts and the two species had significant (p < 0.001) effects on the nutritional components of the tested plants (Fig. 4 and Table 3). Dry matter contents were greater in the plant branches of M. alba (74.45%) than the root and the leaves, and these amounts were significantly higher compared to those of M. nigra. Plant leaves of M. alba showed more important contents in proteins (8.14 g/100 g) than the branches and the roots, and these values were greater than those of the M. nigra. Plant branches of M. alba revealed more important crude fiber (25.97%) than the root and the root and the leaves, and that observed in M. nigra. Significantly higher concentrations of ash (8.77%) were obtained in the plants leaves of M. nigra compared than the roots and the branches, and these levels were more important than those of M. alba. No significant difference was obtained between the two plants species and their different parts on the ash contents. TDN percentages were greater in the branches of M. alba (69.18%) than the roots and the leaves, and these amounts were significantly higher compared with that of M. nigra. No significant difference was obtained in tannin levels of the two plants species, but great effect (p < 0.001) was observed between different plant parts of the two species, and their interactions. The leaves of M. nigra showed significant amounts of tannin (4.16%) compared with the branches and the roots, and these levels were more important than those of M. alba. Plant roots of M. alba revealed greater levels of flavonoids (3089.32 mg/kg) than the leaves and branches, and these values were more important that of the M. nigra. Recorded crude fat levels were seen to be less than 0.1% for the two plants species. Plant parts of the two species were also investigated for phenol contents, and no levels of detectability was revealed.

Fig. 4
figure 4

Proximate and phytochemical analyses of the leaves, branches, and roots of M. nigra and M. alba.

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Table 3 Results of two-way ANOVA (F-values) assessing the effects of species (M. nigra and M. alba) and plant parts on the proximate and phytochemical analyses of M. nigra and M. alba.
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Antimicrobial activities in plant parts of both species

Plants species and plant organs had significant (p < 0.001) effects on the microbial activities (Fig. 5 and Table 4). The interactions between plant species and parts had significant (p < 0.01) effects on the microbial activities compared with the other microbes. In sum, plant roots of the two species had greater antimicrobial effects than the branches and the leaves. The effects of antimicrobial activities were roots > branches > leaves. Roots extracts of M. alba showed significant (p < 0.001) higher antimicrobial activities than that of M. nigra. The values of inhibition zones were 32.66 mm, 32.66 mm, 31.66 mm, 24.66 mm, 21.66 mm and 20.66 mm respectively for the root extracts of M. alba on S. aureus, E. coli, B. cereus, C. albicans, A. flavus, and C. botulinum. Those for M. nigra were 30.33 mm, 29.33 mm, 29.33 mm, 21.66 mm, 20.66 mm, and 19.66 mm respectively on the antimicrobial of E. coli, S. aureus, B. cereus, C. albicans, C. botulinum, and A. flavus. It was found that antibacterial activities were higher than antifungal activities with a maximum of 32.66 mm in S. aureus against 24.66 mm in C. albicans.

Fig. 5
figure 5

Zone of inhibitions from the plant parts of M. nigra and M. alba against Staphylococcus aureus, Bacillus cereus, Escherichia coli, Clostridium botulinum, Aspergillus flavus, Candida albicans.

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Table 4 Results ANOVA (F-values) assessing the effects of species (M. nigra and M. alba) and plant parts extracts against Staphylococcus aureus, Bacillus cereus, Escherichia coli, Clostridium botulinum, Aspergillus flavus, Candida albicans.
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Correlation between flavonoids extracts and the antimicrobial activities

Morus nigra

Flavonoids extracts showed positive and moderate correlation with the antimicrobial activities of S. aureus, E. coli, B. cereus, C. albicans, and C. botulinum. The relationship observed between flavonoids extracts and antimicrobial activities were significant (p < 0.05, p < 0.01) for S. aureus, E. coli, B. cereus, and C. botulinum, and non-significant for C. albicans (Fig. 6, and Table 5).

Fig. 6
figure 6

M. nigra was studied for its flavonoids extracts and their correlation with antimicrobial activities against Staphylococcus aureus, Bacillus cereus, Escherichia coli, Clostridium botulinum, Aspergillus flavus, and Candidas albicans.

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Table 5 ANOVA (F-Values) and coefficient of correlation between flavonoids extracts from M. nigra plant parts and antimicrobial activities against Staphylococcus aureus, Bacillus cereus, Escherichia coli, Clostridium botulinum, Aspergillus flavus, and Candidas albicans.
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Morus alba

Flavonoids extracts from the different plant parts revealed positive and moderate, and non-significant (p < 0.01) correlation with S.aureus (0.49), B. cereus (0.53), and E. coli (0.515) (Fig. 7, and Table 6). The associations between flavonoids extracts and C. botulinum were positive and strong (0.713), and significant (p < 0.05). Correlation between flavonoids extract and C. albicans was weaker and non-significant. Negative (− 0.053) and non-significant correlation was observed with the effects of A. flavus.

Fig. 7
figure 7

M. alba was studied for its flavonoids extracts and their correlation with antimicrobial activities against Staphylococcus aureus, Bacillus cereus, Escherichia coli, Clostridium botulinum, Aspergillus flavus, and Candida albicans.

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Table 6 ANOVA (F-Values) and coefficient of correlation between flavonoids extracts from M. alba plant parts and antimicrobial activities against Staphylococcus aureus, Bacillus cereus, Escherichia coli, Clostridium botulinum, Aspergillus flavus, and Candida albicans.
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Discussion

This research investigated the chemical composition of different parts (leaves, branches, and roots) of two Morus species (the native M. nigra and the exotic M. alba), naturally grown in the UAE’s wild flora.

In M. nigra, our proximate analyses showed rich mineral contents for the macronutrients (Ca, K, Mg, P) and higher secondary macronutrients (Na), as well as, high micronutrients (Mn, Ni). Leaves were rich in Ca, K, and Mn, with content levels of 1514.01, 1182.44, and 2.07 mg/100 g, respectively. While roots were rich in Mg, P, Na, and Ni, with content levels 454.18, 398.67, 183.54, and 1.36 mg/100 g, respectively.

The leaves of the native M. nigra exhibit notably high Ca content, with levels (1514.01 mg/100 g) significantly surpassing those documented in other studies55 and exceeding daily Ca requirements. This makes M. nigra leaves a potential valuable Ca source for food production, important for bone health and quality56. The elevated levels of Mg, P, Na, and Ni in the roots of M. nigra underscore their essential role in promoting root growth under stressful conditions58,59. In addition, play vital roles in human metabolism, including muscle and nerve health, sugar regulation60, and metabolic and hormonal activities61,62. In order to preserve the roots’ high detected Mg levels, it is recommended to ash the samples and then use it to determine the amounts of Mg through atomic absorption. Ni is crucial for metabolic reactions in plants and for hormonal activities and lipid metabolism in animals. Our study reveals a Na/K ratio (0.166) considered acceptable for food quality, potentially reducing the risk of cardiovascular disorders63. Although the K levels identified are below daily requirements, they are higher than those reported in prior research57. This macronutrient is crucial for maintaining the body’s water balance and mineral regulation.

In M. alba, our proximate analyses reported rich mineral contents for the micronutrients Cu and Zn. Leaves showed the highest Cu content (around 1.05 mg/100 g), while branches showed the highest Zn content (around 1.55 mg/100 g). Both minerals play significant roles in plant and human physiology, with Cu being essential for photosynthesis and immune function, and Zn for enzymatic reactions, ion transport, and cell growth64,65,66,67. The levels of Cu identified suggest that M. alba could be an excellent source of this mineral, meeting and possibly exceeding daily requirements. Our observation aligns with other findings reported by Hudzicki, J. (2009)43, and it underscores the intricate relationship between plant species’ adaptability to environmental conditions and their nutritional and mineral content.

Notably, the both species tested showed no content of Se, as well as the heavy metals Cd, and Pb, highlighting their potential safety for consumption68,69.

This detailed mineral analysis contributes to understanding the adaptive strategies of Morus species in the UAE’s challenging environmental conditions and their potential health benefits, aligning with the broader goal of exploring sustainable natural resources.

This study revealed that M. nigra showed higher levels of ash content (around 8%) and higher levels of tannins, in leaves (around 4.2%). While the exotic M. alba demonstrated significantly higher levels of dry matter, protein, crude fibers, TDN, and flavonoids compared to the native M. nigra. The nutritional superiority of M. alba may contribute to its aggressive invasiveness in non-native environments, a characteristic observed in various countries. This aligns with70 observations in Australia, where exotic plants were found to have higher nutritive value than natives, potentially due to their more efficient exploitation of soil nutrients, as suggested by71.

Proteins and fibers play crucial roles in both plant and animal physiology. In humans, proteins are essential for growth, development, and various regulatory functions, while dietary fibers can reduce cardiovascular disease risk by lowering cholesterol levels. Remarkably, our findings indicate that M. alba contains more protein than common vegetables like lettuce, highlighting its potential as a superior dietary source72.

Furthermore, M. alba exhibits a significant flavonoid content, surpassing that of M. nigra. Flavonoids are known for their various functions in plants, including cell growth, pollination, and stress response, and have been observed in higher concentrations in exotic species like Acacia dealbata compared to native plants73,74. This suggests that regular consumption of flavonoid-rich M. alba could offer health benefits, underscoring its potential medicinal value. M. alba was found to contain higher levels of tannins extracted from their branches and roots comparing to M. nigra. Tannin compounds recognized for their anticancer, antimicrobial, and anti-inflammatory properties75,76. This difference highlights the unique phytochemical profiles and potential health benefits of each species.

The study noted that crude fat levels were below 0.1%, lower than daily requirements, indicating that fat content varies with plant parts, age, and environmental conditions77. Despite the low fat content observed, fats remain an essential nutrient, underscoring the importance of balanced dietary intake to meet nutritional needs. Besides, the analysis of total phenols indicated that no detectable levels were observed. Further investigation may be necessary to pinpoint the exact reasons for the undetectable levels of both crude fat and total phenol content. This could include optimizing extraction techniques, expanding the analysis to include a larger sample size, and considering different environmental or biological factors that may influence phenolic content.

The antimicrobial effects of extracts from different parts (leaves, branches, and roots) of M. nigra and M. alba were studied on a range of microbial species including S. aureus, E. coli, B. cereus, C. albicans, A. flavus, and C. botulinum. The results indicate significant variability in antimicrobial activity between the Morus species, with extracts from the roots of M. alba (exotic) showing notably higher efficacy against these microbes, particularly bacteria over fungi. This finding aligns with the understanding that fungi possess greater efficiency in nutrient assimilation and storage, rendering them more specialized than bacteria78.

In contrast to previous research, our study emphasizes the importance of examining the effects of specific plant parts in a congeneric approach. The antimicrobial activities we observed were significantly stronger than those reported in other studies involving the same plant species and other botanicals, including some reference antibiotics. For instance, research on Arnica montana and Chamaemelum nobile indicated in-hibition zones against E. coli and B. cereus that were considerably smaller than those we measured79. Similarly, studies on Moringa oleifera and Psidium guajava against S. aureus and C. albicans, respectively, showed lesser antimicrobial effects compared to our findings80.

Our results also exceed the antimicrobial activity reported against A. flavus in prior research, highlighting the exceptional antimicrobial potential of the exotic Morus species. This enhanced activity may be attributed to its distinct chemical composition, especially the correlation between flavonoid content in M. alba and antimicrobial effects against S. aureus, B. cereus, E. coli, and C. botulinum, echoing the findings of other studies78. Flavonoids, recognized for their broad-spectrum antimicrobial properties, impact different pathogens variably, as demonstrated by other scientists in their study on the varied effects of flavonoids on S. aureus strains81.

Additionally, tannins have been identified as possessing potent antimicrobial properties. Research characterizing the tannin profile of Cytinus hypocistis and Chromobacterium rubrum revealed strong activity against Staphylococcus species and Enterococcus faecium7482, further supporting our observations. This comprehensive analysis underscores the potential of the exotic M. alba, facilitated by its unique phytochemical profile, to serve as a powerful source of antimicrobial agents.

Our findings advocate for the continued research and development of Morus species as a significant natural resource. The distinctive nutritional, phytochemical, and antimicrobial profiles of M. M. nigra and alba highlight their potential as sustainable sources for food, health, and medicinal applications, paving the way for their integrated use in addressing global health and environmental sustainability objectives. This research not only advances our understanding of the adaptive strategies and potential health benefits of the Morus species in the UAE, but also contributes to the global efforts towards achieving Sustainable Development Goals (SDGs). By exploring sustainable natural resources for medicinal and nutritional applications, this study underscores the importance of conserving and utilizing biodiversity in a manner that supports the health and well-being of the global population amid rapid environmental changes and challenges.

Further research should aim to optimize extraction methods and expand sample sizes to better assess the phytochemical composition of both species. Ultimately, this research not only contributes to our understanding of the nutritional and medicinal potential of Morus species but also informs future conservation efforts and utilization strategies for these valuable plants.

Future studies are required to examine the influence of seasonal variations on the two species’ mineral content, phytochemical profiles, and antimicrobial activities. Furthermore, it is needed to investigate the same for fruits of M. nigra and M. alba. In addition, in vivo and clinical studies are essential for nutritional, healthcare and medicinal applications. In addition, exploring the mechanisms of action and the active compounds responsible for these effects, which could inform practical applications in medicine and agriculture.

Conclusion

This study revealed a significant difference between M. nigra (native) and M. alba (exotic) grown naturally in Fujairah, in terms of mineral content, phytochemical composition, and antimicrobial profile. In which the plant parts of each species demonstrated unique superior performance across different analyses.

The investigation revealed that M. nigra showed rich mineral contents for the macronutrients (Ca, K, Mg, P) and higher levels from the secondary macronutrients (Na), as well as, high micronutrients (Mn, Ni). M. nigra Leaves showed high levels of Ca, K, and Mn, with notably high Ca content (1514.01 mg/100 g) exceeding daily Ca requirements and significantly surpassing those documented in other studies. While roots were rich in Mg, P, Na, and Ni, with content levels of 454.18, 398.67, 183.54, and 1.36 mg/100 g, respectively. While M. alba showed also rich mineral content, especially in Cu and Zn, in which high levels of Cu extracted from the leaves (1.08 mg/100 g) with levels exceeding the daily requirements, and rich levels of Zn extracted from the branches (1.58 mg/100 g). Both M. nigra and M. alba did not show detectable levels of Se in the analysis. Furthermore, there were no signs of toxicity related to Pb and Cd, supporting their safe consumption.

The nutritional profiles revealed that M. nigra leaves exhibited higher ash content (8.77%) and tannin levels (4.16%), while M. alba demonstrated superior nutritional qualities, including increased dry matter (Extracted from branches: 74.45%), protein (Extracted from leaves: 8.14 g/100 g), crude fibers (Extracted from leaves: 25.97%), TDN (Extracted from branches: 69.18%), and flavonoids (Extracted from roots: 3089.32 mg/kg). The notable nutritional superiority of M. alba may explain its aggressive invasiveness in non-native environments, consistent with patterns observed in other regions. Proteins and fibers are critical for promoting healthy physiological functions in both humans and animals, with M. alba standing out as a promising dietary source compared to common vegetables. Furthermore, its high flavonoid content suggests potential health benefits, emphasizing its medicinal value. The enhanced levels of tannins in M. alba indicate additional therapeutic possibilities due to their known anticancer, antimicrobial, and anti-inflammatory properties.

While the analysis indicated low crude fat levels and undetectable phenolic content, these findings underscore the complexity of plant nutrient profiles influenced by various factors, including plant parts, age, and environmental conditions.

The antimicrobial analysis demonstrated that extracts from M. alba, especially from its roots, possess significantly higher antimicrobial activity against a range of bacteria and fungi. Notably, root extracts of M. alba showed significantly higher antimicrobial activities (p < 0.001) than those of M. nigra. The inhibition zones for M. alba were recorded at 32.66 mm against the bacteria S. aureus, and same inhibition zone against the bacteria E. coli, 31.66 mm against the bacteria B. cereus, 24.66 mm against the fungus C. albicans, 21.66 mm against the fungus A. flavus and 20.66 mm against the bacteria C. botulinum. In contrast, M. nigra demonstrated inhibition zones of 30.33 mm against the bacteria E. coli, 29.33 mm against the bacteria S. aureus, and same inhibition zone against the bacteria B. cereus, 21.66 mm against the fungus C. albicans, 20.66 mm against the bacteria C. botulinum, and 19.66 mm against the fungus A. flavus.

The results indicate that antibacterial activities were consistently higher than antifungal activities, with the maximum antibacterial effect observed at 32.66 mm for S. aureus, compared to 24.66 mm for C. albicans. This enhanced antimicrobial potential may be closely linked to its phytochemical composition, including flavonoids and tannins, which have been identified as key contributors to the observed antimicrobial efficacy.

These findings underscore the medicinal and therapeutic potential of both species, particularly M. alba, in developing natural antimicrobial alternatives, as well as new antibiotics and antifungal drugs. Both serve as sources of bioactive compounds and offer innovative natural solutions to combat antimicrobial resistance. In addition to their medicinal and pharmaceutical applications, their rich mineral and nutrient profiles highlight their significant potential for industrial use in food supplements and healthcare sectors. Furthermore, their antimicrobial properties make them valuable in food preservation and cosmetic industries by inhibiting microbial growth. Notably, both species also show promise for environmental applications in agriculture, such as soil enrichment and biopesticide development, and their potential application as nutritious animal feed.

Overall, M. nigra and M. alba provide notable nutritional and antimicrobial benefits, making both species valuable resources for various promising industrial applications. Further studies should explore the impact of seasonal variations on their phytochemical profile and microbial activity. This crucial step aims to identify and optimize the agricultural parameters to maximize yield and efficacy. Additionally, clinical studies are necessary to develop integrated approaches for safe and effective therapeutic applications.