Olive

Botanical Profile

Note on raw-material differentiation: Olive leaf, olive fruit and olive oil have different phytochemical and regulatory contexts.

Olea europaea is the olive tree, an evergreen, long-lived species of the Oleaceae with outstanding cultural-historical importance in the Mediterranean region. From a raw-material perspective, fruit, oil, leaf and by-products of olive processing must be distinguished; each has its own sensory, chemical and traditional context.

Olea europaea L. is an evergreen shrub to tree with leathery, opposite, narrowly lanceolate leaves, silvery-grey undersides, small whitish flowers and single-seeded drupes. The species is closely associated with Mediterranean cultural landscapes and has been cultivated since antiquity. Old olive trees may develop gnarled trunks, pronounced regenerative capacity and strong drought adaptation. The fruit is a drupe with a fleshy mesocarp and hard endocarp; its ripening stage ranges from green to dark violet or black. Olive oil is obtained from the fruit flesh, while leaves are described as a separate botanical raw material. Botanically, distinction between fruit and leaf raw materials is relevant because the two groups differ substantially in composition, processing and use.

Phytochemistry

Olive fruits and olive oil contain mainly monounsaturated fatty acids, especially oleic acid, along with other fatty acids, tocopherols, phytosterols, squalene, pigments and accompanying phenolic substances. In virgin olive oil, hydroxytyrosol, tyrosol, oleuropein degradation products, secoiridoids and lignans are important minor constituents. Olive leaves have a different profile and are particularly characterised by secoiridoids such as oleuropein, as well as flavonoids, phenolic acids, triterpenes and other polyphenolic components. Levels of individual substances depend strongly on cultivar, climate, harvest time, leaf age, processing and extraction conditions. Sensorially, bitterness and astringency are associated primarily with phenolic fractions, while oil quality is additionally determined by fatty-acid pattern, oxidation status and processing.

Traditional Uses

The olive tree is among the oldest cultivated plants of the Mediterranean. Fruits and oil have for millennia formed part of nutrition, trade, religious symbolism, body care and artisanal processing. Olive oil was historically used as edible oil, lamp oil, ointment base and cosmetic carrier. Olive leaves appear in the European herbal tradition as a distinct leaf raw material. In Mediterranean regions, press residues, wood and leaves also formed part of agricultural cycles. The cultural-historical importance of the olive therefore rests not on a single plant part but on the connection among tree, fruit, oil, leaf, landscape and processing technology.

Current Research

Modern research on Olea europaea is broad. For olive oil, fatty-acid profile, phenolic minor constituents, oxidative stability, sensory properties, cultivar differences and nutritional-science questions are central. For olive leaves, oleuropein, hydroxytyrosol, flavonoids and triterpene-like components are investigated particularly. Experimental studies address antioxidant, antimicrobial, enzymatic and metabolic model questions. European herbal assessment considers olive leaves in the context of traditional herbal medicinal products; this classification is based on long-standing use and a limited clinical evidence base. Research results on isolated constituents or highly concentrated extracts must be carefully distinguished from the properties of traditional leaf preparations, foods or cosmetic raw materials.

Sources

• Plants of the World Online: Olea europaea L.; Royal Botanic Gardens, Kew.
• EMA/HMPC/359238/2016. European Union herbal monograph on Olea europaea L., folium.
• EMA/HMPC/359236/2016 and EMA/HMPC/432213/2024. Assessment report and addendum on Olea europaea L., folium.