Freddy Krueger ha scritto:
> Tutti i funghi hanno delle tossine, chi + chi meno,
Tossine pericolose ci sono in molti, ma non tutti i funghi. In quelli
velenosi come è ovvio, e anche in diversi funghi che vengono consumati
ma necessitano di precauzioni.
Però ci sono anche alcuni funghi che non contengono più tossine di
quante ne puoi trovare nelle verdure e perciò un adulto può consumarne
in comparabili quantità senza alcun danno, e uno di questi funghi
è appunto Boletus edulis, il porcino comune. Io, quando ne compro un
barattolo medio-piccolo sott'olio, lo consumo tutto in un solo pasto e
non ho mai avuto problemi per questo. Anzi, gli antiossidanti (tra cui
certi polisaccaridi) contenuti nei porcini sembrano più efficaci delle
vitamine C ed E (vedi referenze in fondo).
Devi considerare che escludere dalla dieta alimenti contenenti minime
quantità di tossine, come un bicchiere piccolo di vino (etanolo), le
melanzane e altre solanacee (solanina, nicotina), o i funghi porcini,
non migliora lo stato di salute, ma paradossalmente lo peggiora...
questo strano effetto si chiama ormesi.
Riguardo alle sostanze contenute nei porcini:
https://en.wikipedia.org/wiki/Boletus_edulis#Bioactive_compounds
Boletus edulis fruit bodies contain about 500 mg of ergosterol per
100 g of dried mushroom.[130] Ergosterol is a sterol compound common
in fungi. Additionally, the fruit bodies have about 30 mg of ergosterol
peroxide per 100 g of dried mushroom. Ergosterol peroxide is a steroid
derivative with a wide spectrum of biological activity, including
antimicrobial and anti-inflammatory activity, and cytotoxicity
to various tumor cell lines grown in laboratory culture.[131]
The mushroom also contains a sugar-binding protein, or lectin,
that has affinity for the sugars xylose and melibiose. The lectin
is mitogenic - that is, it can stimulate cells to begin the process of
cell division, resulting in mitosis. Further, the lectin has antiviral
properties: it inhibits the human immunodeficiency virus enzyme reverse
transcriptase.[132] Other studies suggest that B. edulis also has
antiviral activity against Vaccinia virus[133] and tobacco mosaic virus
grown in culture.[134] Antiviral compounds from mushrooms are a subject
of interest in biomedical research for their potential to advance
the knowledge of viral replication, and as new drugs in the treatment
of viral disease.[135]
The fruit bodies have a high antioxidative capacity, due probably to
a combination of various organic acids (such as oxalic, citric, malic,
succinic and fumaric acids), tocopherols, phenolic compounds[136]
and alkaloids; the highest antioxidant activity is in the mushroom
caps.[137] Furthermore, fruit bodies were determined to have 528 mg of
the antioxidant compound ergothioneine per kilogram of fresh mushroom;
this value was the highest among many food items tested in one
study.[138] Porcini were thought to have anti-cancer properties
according to Hungarian research conducted in the 1950s,[139] but
later investigations in the United States did not support this.[100]
Se ti preoccupano le lectine, considera che sono contenute anche
in lenticchie (LCH), arachidi (PNA), germe di grano (WGA):
https://en.wikipedia.org/wiki/Lectin
Table of the major lectins [6]
Infine, riguardo al potenziale antiossidante dei porcini:
http://www.ncbi.nlm.nih.gov/pubmed/22766800 (2012)
Purification, characterization and antioxidant activities in vitro
and in vivo of the polysaccharides from Boletus edulis bull.
A water-soluble polysaccharide (BEBP) was extracted from Boletus
edulis Bull using hot water extraction followed by ethanol
precipitation. The polysaccharide BEBP was further purified
by chromatography on a DEAE-cellulose column, giving three major
polysaccharide fractions termed BEBP-1, BEBP-2 and BEBP-3. In the next
experiment, the average molecular weight (Mw), IR and monosaccharide
compositional analysis of the three polysaccharide fractions were
determined. The evaluation of antioxidant activities both in vitro and
in vivo suggested that BEBP-3 had good potential antioxidant activity,
and should be explored as a novel potential antioxidant.
http://www.ncbi.nlm.nih.gov/pubmed/24250542 (2012)
Mushrooms as possible antioxidant and antimicrobial agents.
The aim of the study is to examine in-vitro antioxidant and
antimicrobial activity of the acetonic and methanolic extracts of
the mushrooms Boletus aestivalis, Boletus edulis and Leccinum carpini.
Antioxidant activity was evaluated by using free radical scavenging
activity and reducing power. In addition, total content of phenol and
flavonoid in extracts were determined as pyrocatechol equivalent, and
as rutin equivalent, respectively. As a result of the study acetonic
extracts from Boletus edulis was more powerful antioxidant activity
with IC50 value of 4.72 μg/mL which was similar or greater than the
standard antioxidants, ascorbic acid (IC50 = 4.22 μg/mL), BHA (IC50 =
6.42 μg/mL) and α-tocopherol (IC50 = 62.43 μg/mL). Moreover, the tested
extracts had effective reducing power. A significant relationship
between total phenolic and flavonoid contents and their antioxidative
activities was significantly observed. The antimicrobial activity of
each extract was estimated by determination of the minimum inhibitory
concentration by using microdilution plate method against five species
of bacteria and five species of fungi. Generally, the tested mushroom
extracts had relatively strong antimicrobial activity against the
tested microorganisms. The minimum inhibitory concentration for both
extracts related to the tested bacteria and fungi were 1.25 - 10
mg/ mL. The present study shows that tested mushroom species
demonstrated a strong antioxidant and antimicrobial activity.
It suggests that mushroom may be used as good sources of natural
antioxidants and for pharmaceutical purposes in treating of various
diseases.
http://www.ncbi.nlm.nih.gov/pubmed/24299786 (2014)
Pulsed counter-current ultrasound-assisted extraction and
characterization of polysaccharides from Boletus edulis.
Four methods for extracting polysaccharides from Boletus edulis,
namely, hot-water extraction, ultrasonic clearer extraction, static
probe ultrasonic extraction, and pulsed counter-current probe
ultrasonic extraction (CCPUE), were studied. Results showed that CCPUE
has the highest extraction efficiency among the methods studied. Under
optimal CCPUE conditions, a B. edulis polysaccharide (BEP) yield
of 8.21% was obtained. Three purified fractions, BEP-I, BEP-II, and
BEP-III, were obtained through sequential purification by DEAE-52 and
Sephadex G-75 chromatography. The average molecular weights of BEP-I,
BEP-II, and BEP-III were 10,278, 23,761, and 42,736 Da, respectively.
The polysaccharides were mainly composed of xylose, mannose,
galactose, and glucose; of these, mannose contents were the highest.
The antioxidant activities of the BEPs were further investigated
by measurement of their ability to scavenge DPPH and hydroxyl radicals
as well as their reducing power. The results indicated that the BEPs
have good antioxidant activity.
Bye,
*GB*