HPTLC-Guided Preparative Flash Chromatography Tested Against Olive Flower Extracts

In a recent study led by scientists from Sechenov First Moscow State Medical University in Moscow, Russia and Monash University Malaysia in Subang Jaya, Malaysia, scientists analyzed how effectively high-performance thin-layer chromatography (HPTLC)-guided preparative flash chromatography to separate and isolate bioactive compounds from olive flower extracts. Their findings were published in the Journal of Chromatography A (1).

Flowering olive branch in Tuscany | Image Credit: © Andris Tkachenko - stock.adobe.com

A Mediterranean diet is a way of eating that emphasizes plant-based foods and healthy fats. Focusing on vegetables, fruits, and whole grains, this type of diet can lower the risk of cardiovascular diseases and other types of chronic conditions (2). The beneficial effects of this diet could be attributed to its antioxidant and anti-inflammatory properties. Some important parts of the Mediterranean diet include olive oil and table olives, which serve as the primary source of fat in the diet. Consuming olive oil is strongly correlated with reducing risk of certain diseases, notably those caused by oxidative stress and inflammation. This has led to olive oil being thought of as a functional food, though olive oil is not the only product that can come from olive tree cultivation.

Recently, new studies have noted the potential health effects of olive tree flowers. Using HPTLC, bioactive compounds were detected and identified in olive flowers extracts with anti-inflammatory and antibacterial activity via HPTLC bioautography. HPTLC hyphenated with enzymatic and bacterial in situ bioassays, also known as bioautography, was used to detect bioactive zones in the chromatograms. By comparing the locations of bioactive bands to coeluted standards, bioactive compounds were tentatively identified.

In this study, the scientists used preparative flash chromatography for the HPTLC-guided isolation of a sufficient quantity of bioactive compounds from olive flower extracts at the required purity in the most cost-effective way. Flash chromatography is a separation technique used to purify chemical mixtures (3). The structure and purity of isolated bioactive compounds were assessed using Fourier-transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopy. When using flash chromatography for the olive flower extract, the scientists successfully isolated pure oleanolic and maslinic acids. Oleanolic acid is a pentacyclic triterpenoid that is widely found in plants, such as fruits and vegetables, that has been noted to have potential therapeutic effects on different diseases and their symptoms (4). Maslinic is also a pentacycle triterpene, but unlike oleanolic acid, it differs in how hydroxyl groups are arranged and is commonly found in leaves and virgin olive oil (5). Further, the flash chromatography of the extract enabled isolation and phytochemical analysis of the extract’s most lipophilic fraction, which was found to contain n-eicosane and n-(Z)-eicos-5-ene. These substances were not previously isolated with preparative TLC, the scientists wrote.

References

(1) Agatonovic-Kustrin, S.; Wong, S.; Dolzhenko, A. V.; Gegechkori, V.; Morton, D. W. HPTLC-Guided Flash Chromatographic Isolation and Spectroscopic Identification of Bioactive Compounds from Olive Flowers. J. Chromatogr. A 2024, 1735, 465310. DOI: 10.1016/j.chroma.2024.465310

(2) Mediterranean Diet. Cleveland Clinic 2024. https://my.clevelandclinic.org/health/articles/16037-mediterranean-diet (accessed 2024-9-30)

(3) Bickler, B. What is Flash Chromatography and Why Should I Do It? Biotage 2024. https://www.biotage.com/blog/what-is-flash-chromatography-and-why-should-i-do-it (accessed 2024-10-1)

(4) Ayeloso, T. B.; Matumba, M. G.; Mukwevho, E. Oleanolic Acid and Its Derivatives: Biological Activities and Therapeutic Potential in Chronic Diseases. Molecules 2017, 22 (11), 1915. DOI: 10.3390/molecules22111915

(5) Maslinic Acid. ScienceDirect 2020. https://www.sciencedirect.com/topics/nursing-and-health-professions/maslinic-acid (accessed 2024-10-1)