Do I have to remove the Cornus seed?

The Korean Pharmacopoeia defines the medicinal herb Cornus as "fruit with the seed removed." The seed is fibrous and differs from the flesh in composition, and a mouse experiment recorded toxicity of the seed extract, so removing the seed and using the flesh, as in the traditional method, is the standard approach.

How much Cornus can I eat per day?

There is no official standard for the daily intake of Cornus fruit or Cornus tea. Health functional foods have set intakes per ingredient, and in the human trial of the Cornus extract complex, 1,600 mg a day was used.

When is Cornus in season?

The harvest runs from late October to early November, when the fruit ripens to a dark red.

How to Eat Cornus Fruit: Should You Remove the Seed? From Preparation to Cornus Tea

Cornus fruit tastes sour and astringent, so it is not a fruit people enjoy eating raw. Instead, it is dried or made into tea or fermented extract. Here, in order, is what is worth knowing before you eat it.

Season and harvest

Cornus blooms yellow flowers in March and April before its leaves come out, and the fruit is a long oval 1.5 to 2 cm in length that ripens red in autumn. According to the Korea National Arboretum, harvest takes place in late October to early November, when the fruit has ripened to a dark red. Gurye in South Jeolla Province is a longtime growing region, where old records such as the Geography Section of the Annals of King Sejong mention Cornus being cultivated for tribute.

Why remove the seed?

The Korean Pharmacopoeia defines the medicinal herb "Cornus" as ripe fruit with the seed removed. Cornus as a medicinal herb has meant only the flesh from the start. The seed and flesh also differ in composition. In a study analysing Korean-grown Cornus, the seed was hard, with crude fibre at 38.6%, while the flesh was rich in moisture, free sugars, and malic acid.

On the safety of the seed, a 1993 study that gave seed extract to mice recorded toxicity at high doses, but that is not data on humans eating the seed. By contrast, a hot-water extract of the dried flesh caused no abnormalities in mice even at a single dose of 5,000 mg per kg of body weight. As in the traditional method, removing the seed and using the flesh is the standard approach.

How to prepare it

The Korea National Arboretum explains that harvested fruit is dried for 3 to 4 days in the sun or on a heated floor until semi-dried, then the seed is pushed out by pressing one end by hand, and the flesh is collected and dried again. In Gurye, the story is told that people once peeled off just the flesh with their front teeth, and today machines separate the seeds from the flesh.

Dried Cornus and Cornus tea

Well-dried Cornus is a flat, long oval, a dark reddish purple with a gloss, and tastes sour and slightly sweet. The Korea Forest Service explains that fresh fruit is mostly made into fermented extract or liquor, and dried Cornus is steeped and drunk as tea. There is no official standard for the amount or steeping time of Cornus tea, so if you buy a commercial product, follow the directions on the label.

How much can you eat per day?

There is no official standard for the daily intake of Cornus fruit or Cornus tea. The Korean Pharmacopoeia has no dosage entry, and on the MFDS food ingredient list, Cornus fruit is listed as usable as a food ingredient with no conditions of use. Health functional foods (a Korean regulatory category), on the other hand, have a daily intake for each ingredient that was confirmed through trials. For example, the human trial of the complex ingredient of Cornus fruit and Ribes fasciculatum leaf (Cornus extract complex) was conducted at 1,600 mg a day.

Points to watch

If you have a medical condition and are taking medication, talk to your health care provider before eating Cornus regularly.
The quality of Cornus is checked with marker compounds such as loganin. It is best to choose products that disclose their origin and test results.

Health column