Suillus Spp
Eshed Haklai

Several studies have examined the medicinal properties of Suillus species. In a 2024 study, researchers investigated the effects of eight different phenolic compounds isolated from the common slippery jack (Suillus granulatus) and tested their efficacy against liver cancer tumors. The results showed significant activity for five of these compounds.
There are different Suillus species, and foragers who are not experienced may not necessarily distinguish between them. One of these species is Suillus bellinii. This mushroom is less common in Israel and has also been studied. In a study published in April 2024, S. bellinii was evaluated for antioxidant, antimicrobial, and acetylcholinesterase-inhibiting activity.
During the experiment, 30 g of dried mushroom (dried for 6 hours at 50°C) were extracted using ethanol, and an additional extraction was performed using methanol. To evaluate the effectiveness of the extracts in inhibiting acetylcholinesterase, the two extracts were compared with galantamine, a drug known to inhibit this enzyme. According to the results, S. bellinii extracts were able to inhibit cholinesterases. The methanol extract was more active than the ethanol extract, although both were less effective than galantamine.
The conclusion regarding the antimicrobial activity of Suillus was that the extracts were effective as antimicrobial agents and may potentially be used as medicinal substances in the future.
In the third part of the experiment, the extracts were tested for antioxidant activity. Overall, the methanol extract contained higher levels of antioxidants. In the study itself, the results were compared with findings from other mushroom studies, which are discussed on page 19 of the article. The antioxidant capacity of S. bellinii was not particularly impressive, as it ranked somewhere in the middle—between mushrooms not known for strong antioxidant activity and mushrooms that are well known as potent antioxidants. A 2024 literature review comparing wild mushrooms and their antioxidant capacity in much greater detail is also available and worth consulting.
In another review published in August 2024, the anticancer properties of several mushrooms commonly foraged in Europe (most of which also grow in Israel) were examined. Section 2.1.4 focuses on the common slippery jack (S. granulatus). This section presents an interesting detail that may be related to the previous study: an aqueous extract of S. granulatus contained more beta-glucans than an ethanol extract. Beta-glucans may be responsible for the antioxidant, antimicrobial, and acetylcholinesterase-inhibiting activity observed in S. bellinii.
The review describes the ability of S. granulatus to support conditions related to liver cancer (as shown in the first study) and presents an active compound called suillin, which was proven to have anticancer activity, along with six additional newly identified compounds extracted from S. granulatus that also exhibit anticancer properties. Another Suillus species, Suillus luteus, demonstrated antimicrobial, antioxidant, and anticancer activity. The review highlights Suillumide, an active compound found in this species that showed activity against melanoma and breast cancer. This review is particularly interesting because it focuses not on well-known medicinal mushrooms but on commonly foraged mushrooms.
In an additional study published in July 2023, another Suillus species, Suillus grevillei, was shown to contain two newly identified compounds, Bolegrevilol B and Bolegrevilol C, which are potent antioxidants.

Summary:
In recent years, Suillus species have been studied and shown to possess anticancer activity (liver, breast, melanoma), antioxidant properties, and antimicrobial effects. The extraction method is important for obtaining the relevant bioactive compounds. There are also certain differences between species within the same genus in terms of their active compounds.

Recipes

Suillus Jam:

Clean the mushrooms and cut into small cubes.
For 1 kg of cleaned mushrooms, add 500 g of sugar (more can be added if preferred).
Add 1–2 grated or finely diced Granny Smith apples and the juice of half a lemon.
Cook over low heat. The mushrooms will release liquid; allow the liquid to evaporate until the desired consistency is reached.

Pickled Suillus:

Clean the mushrooms, preferably young and small ones.
Bring water to a gentle boil with salt (40 g per liter), black pepper (preferably whole), and bay leaves. After a brief boil, add the cleaned mushrooms and boil for an additional 5 minutes (make sure they do not become too soft).
Allow to cool, transfer the mushrooms to a sterilized jar, and pour the cooking liquid over them. Add a small amount of lemon juice and ensure the mushrooms are fully submerged.
Add a layer of bay leaves, seal the jar, and let sit for about 10 days before consumption.

Basic Sauce Recipe:

Clean the mushrooms thoroughly and cut into cubes.
Sauté an onion over medium heat (with olive oil or butter) until translucent.
Add the mushrooms and allow them to release their liquid.
Once the liquid has been released, begin reducing it and add either cooking cream/plant-based cream or white wine (according to preference).
Season with salt, freshly ground black pepper, and fresh thyme. Reduce to the desired thickness.

Small tip: every mushroom pairs perfectly with thyme 🌿