Naslov
Antioxidant potential of Mediterranean herbs and herb-based honeys

Autori
Belščak, Ana ; Komes, Draženka ; Piljac Žegarac, Jasenka

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Book of abstracts / 15th Young Investigators´ Seminar on Analytical Chemistry / Prosen, Helena - Ljubljana : Fakulteta za kemijo in kemijsko tehnologijo Univerze v Ljubljani, 2008, 46-49

ISBN
978-961-6286-96-1

Skup
15th Young Investigators´ Seminar on Analytical Chemistry

Mjesto i datum
Ljubljana, Slovenija, 02.07.2008. - 05.07.2008

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
antioxidants; honey; medicinal herbs; polyphenols

Sažetak
In the past few years, an increasingly growing interest in functional foods has triggered a large number of studies on phenolic antioxidants in plant-based products. Polyphenolic phytochemicals in native Mediterranean herbs, such as laurel (Laurus nobilis), basil (Basilicum ocimum), wild thyme (Thymus vulgaris L.), sage (Salvia officinalis L.) and lavender (Lavandula angustifolia Mill.), act as powerful antioxidants, and their application in functional food development has a significant potential. Honey exhibits many therapeutical properties that have been exploited in traditional medicine, and is easily accessible to most consumers. Until recently, the focus of the scientific community has been directed more to the other honey components such as amino acids, proteins, trace elements, sugars and pollen [1-3], rather than antioxidants. Many positive health effects of honey may be explained by the synergystic action of phenolic compounds. The purpose of our study was to determine the polyphenolic content and antioxidant capacity of commonly used herbal spices, herb-based honeys and special honey preparations (with added fruit or vegetable components). The Folin-Ciocalteu assay was used to determine the total phenol (TP) content, ferric reducing antioxidant power (FRAP) assay for reducing capacity and 1, 1-diphenyl-2-picryl-hydrazyl (DPPH) and 2, 2′ -azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) assays for radical scavenging capacity. High performance liquid chromatography (HPLC) was applied for identification of individual polyphenolic compounds in herbal spices. Significant linear correlation was obtained between the results of different methods, indicating that phenolics are mostly responsible for the reducing and antiradical capacity of tested herbs and honeys. The most abundant polyphenolic compound in herbal spices was rosmarinic acid (RA), extracted from wild thyme (20.45 mg/g dw). Among the tested herbal spices, the highest content of phenolic compounds was determined in wild thyme (48.5 mg GAE/g dw), which also exhibited the highest reducing power (4290  mol/L Fe(II)) and antiradical capacity (2.20 and 2.78 mmol/L Trolox in DPPH and ABTS assays, respectively), while lavender extract was characterized by the lowest content of phenolic compounds (8.7 mg GAE/g dw), as well as the lowest reducing power (960  mol/L Fe(II)) and antiradical capacity (0.40 and 0.64 mmol/L Trolox in DPPH and ABTS assays, respectively). In comparing the results for each particular method across all tested honeys, honey with cherry juice exhibited the highest FRAP value (459.21  mol/L Fe(II)) as well as DPPH and ABTS radical scavenging capacities (43.04 and 65.24 mg ascorbic acid equivalents AAE/100 g, respectively), while amorpha honey exhibited very low FRAP value (23.02  mol/L Fe(II)) and DPPH radical scavenging capacity (6.68 mg AAE/100 g), as well as the lowest ABTS radical scavenging capacity (6.83 mg AAE/100 g). The results obtained in this study verify the significant in vitro antioxidant properties of herbal spices, due to their high content of polyphenolic compounds, in particular rosmarinic acid. These findings also point to increased antioxidant capacity of special honey preparations containing various fruit and herbal components. The displayed results indicate that herbal spices, beside acting as astringents and flavoring agents, may also enhance the already confirmed beneficial effects of honey.

Izvorni jezik
Engleski

Znanstvena područja
Biotehnologija, Prehrambena tehnologija

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