**6. Abscisic acid**

**5. Phenolic compounds**

68 Honey Analysis

honey tends to have enhanced properties [4, 15].

herbivores, and UV radiation [5, 17].

Phenolic compounds are plant-derived secondary metabolites, biosynthesized mainly for protection against stress and oxidative damage and transferred via the nectar to the honey. The intensity of the color of a honey may be associated with the antioxidant strength of the honey. The phenolic, flavonoid, and carotenoid content is increased in darker honeys and reduced in lighter more transparent honey. As a result, biological properties, such as antioxidant activities and antibacterial capabilities, of the honey are related to its color, and darker

The most common phenolic compounds are phenolic acids and flavonoids [16]. Phenolic acids constitute an important class of phenolic compounds with bioactive functions typically found in vegetable products and foods. Also are secondary metabolites required for normal operation of naturally occurring plants. They can be divided into two subgroups according to their structure: the hydroxybenzoic and hydroxycinnamic acids. Acids derived from hydroxybenzoic acids include þ-hydroxybenzoic, vanillic, syringic, salicylic (2-hydroxybenzoate), gallic, and ellagic. These compounds might be existing in soluble form in cells, along with sugars or organic acids, or formed with cells linked to lignins. Hydroxycinnamic acids occur normally in their conjugated form as esters of hydroxy acids such as tartaric acid and shikimic as well as in their pure form, including þ-coumaric, caffeic, ferulic, and sinapic acids. Flavonoids (flavones, flavonols, flavanones, flavanols, anthocyanidin, isoflavones and chalcones) are the largest group of plant phenolic compounds. This group represents over 50% of all naturally occurring phenolic compounds. They are generally distributed in the seeds, bark, leaves, and flowers of plants and trees. In plants, these compounds give protection, against pathogens,

The qualitative and quantitative difference in the phenolic profile of honey according to the different botanical sources represents the scientific basis of the two main lines of research about the study of honey phenolic fraction. The first approach is focused on the evaluation of the bioactive properties of honeys while the second approach attempts to attribute the botanical and/or the geographical origin of honey based on the existence and the abundance of at least one or more specific phenolic compounds, thus proposed as chemical marker(s) of origin. The results of these research studies are relevant in both directions; honey of varying botanical origins show a wide range of health-promoting properties like antibacterial, antiinflammatory, antioxidant, and radical-scavenging activity [4, 16, 18]. A wide range of phenolic constituents are present in honey such as quercetin, caffeic acid, caffeic acid phenethyl ester (CAPE), acacetin, kaempferol, galangin, chrysin, pinocembrin, pinobanksin, and apigenin,

Pinocembrin, pinobanksin, and chrysin are the characteristic flavonoids of propolis and these flavonoids have been found in European [19, 21] and Chilean honey samples [22]. Small amounts of propolis might be incorporated into honey; therefore, propolis flavonoids might contribute to the phenolic composition of honey. In temperate areas, the main sources of propolis are poplar (*Populus*) bud exudates. The identification of propolis-derived compounds like pinocembrin and chrysin could have an important contribution to the phenolic composition

which have promising effects in the treatment of some diseases [19, 20].

and antioxidant activity in corcolen (*Azara petiolaris*) Chilean honey [22].

Abscisic acid, a plant hormone related to the protection of plants in environmental stress conditions, has been detected in corcolen and quillay honeys. The existence of abscisic acid in nectar is well established and is affected by environmental conditions, which might regulate the biosynthesis of certain secondary metabolites, such as phenolic compounds and abscisic acid. The biosynthesis of these compounds may be stimulated by plants, lowering damages through their capacity to capture free radicals under stress conditions, and reduce the penetration of UV-B ultraviolet radiation. The representation of these compounds in honey produced from *Q. saponaria* may be associated with the high interannual variability of climate conditions of the central zone of Chile [13, 30].
