The olive tree Oleaceae family is a traditional character of wealth, beauty and peace [1]. The height of this heavily branching evergreen tree ranges from 2 to 15 meters (7 to 50 feet). The leaves are whole, ranging in length from three to seven cm (1.2-2.8 in) and width from eight to twenty-five millimeters (0.3-1 in), with an opposing, decussate pattern. One of the greatest prevalent and traditional herbal teas used by people in Mediterranean to heal numerous illnesses is olive leaf tea [2]. Abundant studies showed it have the anti-atherosclerotic, antioxidant, antihypertensive, hypoglycemic andantibacterial properties of olive leaves [3]. Numerous factors, including the leaves' origin, the number of branches on the tree, how they are stored, the climate, the moisture content and the extent of soil and oil contamination, affect the chemical composition of olive leaves [4,5].

Oleuropein and oleacein are the most prevalent secondary metabolites in olive leaves, followed by verbascoside, hydroxytyrosol and the flavone-7-glucosides of luteolin and apigenin [6].

The study's objective was to investigate O. europaea leaves grown in Iraq pharmacognostically. In addition to employing thin layer chromatography to identify the active ingredient in the alcoholic extract of O. europaea leaves (Figure 1,2).

Figure 1: Leaves of Olive Tree

Figure 2: Chemical Structure of the Most Abundant Phenolic Compounds in Olive Leaf Extract

Plant Material

The Olea europaea plant's leaves were collected from the Al Zahwraa park in Baghdad, Iraq. The leaves of the plants were harvested in October 2022 and allowed to dry at room temperature in the shade for 14 days. After that, they were ground into a powder and weighed.

Extraction

The 50 g of powdered O. Europaea leaves were defatted using 350 mL of hexane. Using a soxhlet extractor, the defatted plant material was further extracted with 85% ethanol (600 mL). Using a rotary evaporator, the ethanolic extract was concentrated through evaporation at a lower pressure. Thin layer chromatography was used to analyses the hexane and defatted extract [7].

Preliminary Phytochemical Study of Olea Europaea Leaves

To determine the primary classes of naturally occurring secondary metabolites, Olea europaea leaf extracts were tested using accepted qualitative research techniques [8,9].

Microscopical Examination

Leaf Microscopy: Fresh leaf fragments were mounted in chloral hydrate to reveal the outer epidermal layer, which was then examined under a microscope. The kind of stomata and the existence of trichomes were noted [10].

Detection of Apigenen and Kaempferol by Thin Layer Chromatography (TLC)

Applying a tiny, concentrated quantity of defatted extract to an analytical TLC plate (20 x 20 cm, 0.25 mm is the thickness of aluminium silica gel) and drying the spots prior to development in a closed glass jar saturated for 30 minutes with an appropriate solvent system [11,12].

The many phytochemical kinds that are present in the plant extract can only be predicted with the help of the preliminary testing as showed in Table 1.

Microscopical Examination

When the leaf was examined under a microscope, it was shown that the trachoma cells were multicellular in nature, but the scale cells, which had hairs around them, were indistinguishable from other epidermal cells, as seen in Figure 3.

Figure 3: Microscopical Examination of O. Europaea. Leaves

Figure 4: TLC Plates for Detection of Apigenen and Kaempferol in Comparison with Standard Apigenen and Standard Kaempferol Under UV Light at 254nm

Table 1: Qualitative Estimation of the Phytoconstituants Found in The Leaves of Olive Plant

Table 2: Detection of Apigenen and Kaempferol Using 2 Mobile Phases

In addition to environmental elements including humidity, temperature, light, atmospheric gases and nutrient availability, heredity also plays a role in determining the types of stomata.

Detection by Thin Layer Chromatography (TLC)

Using two solvent systems, as shown in Table 2 and Figure 4, analytical TLC of the alcoholic extract verified the presence of apigenen and kaempferol in the plant extract when compared with standard apigenen and standard kaempferol.

This investigation demonstrated the presence of several Iraqi secondary metabolites, including flavonoids, terpenes, carbohydrates and saponin, in an extract from farmed O. europaea leaves. Moreover, Apigenen and Kaempferol are Using TLC, two flavonoids were found in the alcoholic extract. Ultimately, a microscopic analysis of the leaf revealed the existence of scale cells encircled by hairs. Additionally, the type of trachomas were multicellular.

Acknowledgment

All authors would like to thank Mustansiriyah University (www.uomustansiriyah.edu.iq) Baghdad-Iraq for its support in the present work.

1. Gershenzon, J. and C. Ullah. “Plants protect themselves from herbivores by optimizing the distribution of chemical defenses.” Proceedings of the National Academy of Sciences, vol. 119, Jan. 2022.

2. Soni, M.G. et al. “Safety assessment of aqueous olive pulp extract as an antioxidant or antimicrobial agent in foods.” Food and Chemical Toxicology, vol. 44, 2006, pp. 903–915.

3. United Nations Food and Agriculture Organization. FAO Yearbook: Production. vol. 48, Rome, 1995, pp. 118–119.

4. Tawfeeq, T.A. et al. “Isolation of umbelliferone from leaves of conocarpus erectus L. cultivated in Iraq.” Al-Mustansiriyah Journal of Pharmaceutical Sciences, vol. 20, no. 4, 2020, pp. 82–92.

5. Japon-Lujan et al. “Dynamic ultrasound-assisted extraction of oleuropein and related polyphenols from olive leaves.” Journal of Chromatography A, vol. 1108, 2006, pp. 76–82.

6. Rasha, W.M.K.A.A. and W. Abdul Kareem. “GC-MS analysis of Iraqi Silybum Marianum flowers, leaves and seeds extracts.” Al-Mustansiriyah Journal of Pharmaceutical Sciences, vol. 20, no. 4, 2020, pp. 93–112.

7. Somova, L.I. et al. “Antihypertensive, antiatherosclerotic and antioxidant activity of triterpenoids isolated from olea europaea subsp. Africana leaves.” Journal of Ethnopharmacology, vol. 84, 2003, pp. 299–305.

8. Molina-Alcaide, E. and D.R. Yáñez-Ruiz. “Potential use of olive by-products in ruminant feeding: A Review.” Animal Feed Science and Technology, vol. 147, 2008, pp. 247–264.

9. Sato, H. et al. “Anti-Hyperglycemic activity of a TGR5 agonist isolated from Olea europaea.” Biochemical and Biophysical Research Communications, vol. 362, 2007, pp. 793–798.

10. Martin-Garcia, A.I. and E. Molina-Alcaide. “Effect of different drying procedures on the nutritive value of olive (Olea europaea var. europaea) leaves for ruminants.” Animal Feed Science and Technology, vol. 142, 2008, pp. 317–329.

11. Visioli, F. et al. “The effect of minor constituents of olive oil on cardiovascular disease: new findings.” Nutrition Reviews, vol. 56, no. 5, 1998, pp. 142–147.

12. Komaki, E. et al. “Identification of anti-α-amylase components from olive leaf extracts.” Food Science and Technology Research, vol. 9, 2003, pp. 35–39.