Influence of drying conditions on the quality of Origanum syriacum L

Comparison between Quality Traits of Solar-Dried and Freeze-Dried Origanum syriacum L. (Za'atar)

There is growing interest in Origanum syriacum due to attractive culinary applications and functional properties. Solar drying is the most common conventional method for drying Origanum syriacum L. (Za’atar) in Mediterranean region. This study aimed to evaluate the quality traits of solar dried za’atar in comparison to freeze dried za’atar. Proximate composition (moisture, protein, fat, fiber, carbohydrates, and ash), color index (L*a*b*), macro and microstructure, sensory, and microbiological characteristics were evaluated. Solar dried za’atar exhibited significantly lower fat content (1.10 vs. 1.64%, p < 0.05) than freeze dried za’atar. Solar drying led to severe changes in color values compared to freeze drying. Solar drying exhibited loss in the structural integrity and leave hairs more than freeze drying. Moreover, freeze-dried za’atar exhibited significantly lower total aerobic count (4.92 vs. 5.23, p < 0.05) and yeasts and mold count (4.59 vs. 5.36, p < 0.05) than solar-dried za’atar. Panelists were able significantly to differentiate between solar- and freeze dried za’atar. Freeze-dried za’atar had significantly lower hedonic score of color, odor, taste, and overall acceptance than solar dried za’atar. In conclusion, using freeze drying achieved good improvements in some quality traits for za’atar while solar dried za’atar showed better sensory perception.

Origanum syriacum L. (Za'atar), from Raw to Go: A Review

The interest in za'atar has increased in recent years due to its economic, cultural, and functional importance. The traditional za'atar mix made from dried Origanum syriacum is now a demanded product nationally and internationally. Air-drying at low temperatures can preserve za'atar quality traits better than other techniques such as oven-drying. The Palestinian za'atar market has the potential to develop and increase its value. However, it is facing many challenges. Another valuable product of za'atar is essential oil. Za'atar essential oil quantity and quality are affected by many factors including geographical location, cultivation, harvesting season, soil, extraction method, temperature, and others. These factors interact with za'atar and with each other; therefore, some factors are more effective than others and further research is needed to determine the optimum condition for producing and obtaining za'atar essential oil. Antimicrobial and antioxidant activities are the main functionalities of za'atar essential oil that are behind its medicinal importance. One hundred and twenty-one compounds have been identified in za'atar essential oil. The most common compounds are thymol, γ-terpinene, carvacrol, and α-pinene. The variation in the composition among za'atar essential oil samples results from the different conditions of the studies during za'atar growth as well as essential oil extraction.

Bioassay-guided isolation, identification of compounds from Origanum rotundifolium and investigation of their antiproliferative and antioxidant activities

CONTEXT

Origanum (Lamiaceae) has been used in food and pharmaceutical industries.

OBJECTIVE

Isolation and identification of bioactive compounds from Origanum rotundifolium Boiss. and investigation of their antiproliferative and antioxidant activities.

MATERIALS AND METHODS

The aerial part of O. rotundifolium was dried and powdered (1.0 kg ±2.0 g) then extracted with hexane, ethyl acetate, methanol and water. Solvent (3 × 1 L) was used for each extraction for a week at room temperature. The aqueous extract was partitioned with ethyl acetate (3 × 1 L) to yield the water/EtOAc extract subjected to chromatography to isolate the active compounds. The structures of isolated compounds were elucidated by 1 D, 2 D NMR and LC-TOF/MS.

RESULTS

Apigenin (1), ferulic acid (2), vitexin (3), caprolactam (4), rosmarinic acid (5), and globoidnan A (6) were isolated and identified. Globoidnan A (6), vitexin (3), and rosmarinic acid (5) revealed the excellent DPPH^• scavenging effect with IC₅₀ values of 22.4, 31.4, 47.2 μM, respectively. Vitexin (3) (IC₅₀ 3.6), globoidnan A (6) (IC₅₀ 4.6), apigenin (1) (IC₅₀ 8.9) and ferulic acid (2) exhibited more ABTS^•+ activity than standard Trolox (IC₅₀ 13.8 μg/mL). Vitexin (3) revealed the most antiproliferative activity against HeLa, HT29, C6 and Vero cells lines with IC₅₀ values of 35.6, 32.5, 41.6, 46.7 (μM), respectively.

DISCUSSION AND CONCLUSION

Globoidnan A (6) has the most antioxidant effects on all assays. This has to do with the chemical structure of the compound bearing the acidic protons. Vitexin (3) could be a promising anticancer agent.

Isolation and identification of chemical constituents from Origanum majorana and investigation of antiproliferative and antioxidant activities

BACKGROUND

Origanum majorana L., belonging to the Lamiaceae family, has great potential and has been used as a folk medicine against asthma, indigestion, headache and rheumatism; in addition, the essential oils of this plant have been used widely in the food industry. Plant materials have been harvested from the Medicinal and Aromatic Plant Field of Gaziosmanpasa University. Air-dried plant materials were boiled in water, filtered, and the solvent part subsequently extracted with hexane and ethyl acetate. The chromatographic method was applied to the ethyl acetate extract to isolate bioactive secondary metabolites, the structures of which were elucidated by spectroscopic techniques: basically one-dimensional and two-dimensional nuclear magnetic resonance and quadrupole time-of-flight liquid chromatography. Antiproliferative and antioxidant activities of isolated secondary metabolites were determined.

RESULTS

5,6,3'-Trihydroxy-7,8,4'-trimethoxyflavone, hesperetin, hydroquinone, arbutin and rosmarinic acid were isolated from the water-soluble ethyl acetate extract of aerial parts of O. majorana. Antioxidant activities of isolated compounds and water-soluble ethyl acetate extract were investigated using assays of DPPH(•), ABTS(•+), reducing power and total phenolic content. Antiproliferative activities of the isolated compounds and plant extracts were investigated against C6 and HeLa cell lines using BrdU cell proliferation enzyme-linked immunosorbent assay and xCELLigence assay, respectively. Both hesperetin and hydroquinone were determined to have stronger antiproliferative activities against C6 and HeLa cells than the other isolated compounds and 5-fluorouracil.

CONCLUSION

The results showed that the extract and isolated compounds exhibited significant antioxidant activities. Hence this plant has the potential to be a natural antioxidant in the food industry and an anticancer drug.