Many rodents, game, cows, horses, snails and insects agree on one thing: keep your mouths off the black elderberry!

Sambucus nigra is probably one of the most unpopular plants in our forests; one rarely finds dead leaves or twigs. Even powdery mildew avoids this plant, although it enthusiastically attacks its close relative, the black elderberry or red elderberry (Sambucus racemosa).

There are very legitimate reasons for this aversion!

Many species use organic compounds to protect themselves from predators, but the black elderberry practically engages in biochemical overkill in this regard. A cocktail of three different substance classes (lectins, lignans, and cyanide glycolic acid) will thoroughly spoil the appetite of even the most persistent gourmet.

However, the toxicity of a plant can vary greatly even within the same systematic group of animals, so some species, such as goats, will be able to attack the black elderberry with impunity.

1. Lectins:

Lectins are relatively high-molecular-weight proteins. The most well-known are probably the highly toxic ricin from the castor oil plant (Ricinus communis) and phasin from raw beans (destroyed during cooking). Consumption leads to severe vomiting and diarrhea. Lectins also have antifungal (hence presumably the resistance to powdery mildew!), antibacterial, and insecticidal effects.

2. Lignans:

They belong to the group of phenols and are characterized primarily by their antibacterial effect.

3. Hydrocyanic acid glycosides:

Sambunigrin is stored in the cell vacuoles of the epidermis; in this form, it is still harmless. (As harmless as an unfired hand grenade! ). The enzymes that release hydrogen cyanide, on the other hand, are found in the cytoplasm and the green chloroplasts. When the leaves are bitten, both components are released and mixed. The countdown has begun!

On the one hand, hydrogen cyanide tastes bitter (the typical bitter almond taste of potassium cyanide, a salt of hydrogen cyanide), and on the other hand, it is anything but healthy; it blocks the formation of ATP in the respiratory chain.

Nevertheless, there are creatures that have managed to outsmart this deadly mechanism.

The elderberry aphid (Aphis sambuci) has apparently evolved a metabolic pathway that prevents the release of hydrogen cyanide. This kills two birds with one stone. Firstly, it lives in a competition-free environment, and secondly, it passes on the highly toxic sambunigrin accumulated in its body to all predators, thereby further increasing its chances of survival as a species. A louse that has been eaten can therefore at least enjoy a certain posthumous effect.

Many ladybug species that have spent time at the elderberry aphid buffet float off into ladybug heaven, with the exception of the two-spotted ladybug (Adalia bipunctata). This ladybug and its larva have also found a way to defuse the hydrogen cyanide glycoside, and both are making their way into the aphid colonies with impunity.

If a bird eats such a ladybug, it will probably spit it out in disgust because of its bitter taste and avoid this and similarly colored species in the future.

The elderberry protects itself from herbivores and herbivores with the hydrocyanic acid glycoside (sambunigrin), the elderberry aphid, for its part, eliminates competitors and becomes inedible to most predators, and the ladybird takes last place on the culinary hit list of birds.

And all this with the same active ingredient that was originally produced by the black elderberry.

Isn't nature simply fabulous!

PS: While sambunigrin accumulates in the aphids' bodies, it doesn't accumulate in the sugary sap they secrete! Therefore, any wood ant can enjoy its aphid shake in peace and without consequences.

PPS: Sambunigrin is heat-unstable. Elderberry juice or roasted lice can therefore be consumed without concern.

This also applies to flower syrup and elderberry cakes. Raw berries, however, can trigger severe vomiting, depending on the amount consumed.

By the way, all three of our elderberry species are poisonous to varying degrees because they have similar pharmacological ingredients:

* Red, grape, and mountain elderberry (Sambucus racemosa)

* Black elderberry (Sambucus nigra)

* Elderberry, dwarf elderberry (Sambucus ebolus)

Red and black elderberry are woody shrubs, while dwarf elderberry is a perennial but hardy.

Guest article by Werner David - 2.5.2023

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Photo credit: By Willow - Own work, CC BY 2.5, https://commons.wikimedia.org/w/index.php?curid=2643905