Results
The flowers had a higher moisture content (9.40%), whereas the stems had a higher ash content (18.58%) than the leaves and flowers. The flowers also had higher lipid, carbohydrate, and crude protein contents (4.33, 66.16, and 15.29%, respectively). The leaves of the N. oleander produced a maximum yield followed by flowers and stems, respectively. The highest percentage extractive yield was demonstrated by water extracts, which were followed by methanol, acetone, ethyl acetate petroleum ether extracts. The findings of the study showed that alkaloids, flavonoids, tannins, glycosides, steroids, coumarins, quinones, phenols, cardiac glycosides, and terpenoids were found by phytochemical analysis of N. oleander in different parts, while saponins and anthraquinones were completely absent in all parts. On the other hand, anthocyanins are present only in flowers and completely absent in stems and leaves. The greatest levels of phenol content, flavonoids and tannins were found in acetone extract of the flowers (157.12 ± 17.62 mg GAE/g, 187.43 ± 15.91 mg QE/g, and 89.93 ± 18.77 mg TAE/g, respectively), while the petroleum ether extract of stems had the lowest amount (5.45 ± 2.65 mg GAE/g, 6.43 ± 0.29 mg QE/g and 3.45 ± 2.05 mg TAE/g, respectively). Antimicrobial tests revealed the extract's ability to inhibit several Gram-positive bacteria (Staphylococcus aureus ATCC 6538 and Bacillus subtilis ATCC 6633), Gram-negative bacteria (Pseudomonas aeruginosa ATCC 9027, Salmonella Typhimurium ATCC 14028 and Escherichia coli ATCC 11229), and eukaryotic strains such as unicellular fungi (Candida albicans ATCC 10231).
