Autolysis of Lentinan, an Antitumor Polysaccharide, during Storage of Lentinus edodes, Shiitake Mushroom

Abstract

The lentinan contents in the Lentinus edodes fruit body during storage were examined by ELISA method using anti-lentinan antibodies. The lentinan content (12.8 mg.g(-)(1) dw) before storage decreased to 3.7 mg.g(-)(1) dw over 7 days at 20 degrees C. However, it only slightly decreased at 1 degrees C and only decreased to 9.3 mg. g(-)(1) dw at 5 degrees C. Glucanase activity, which seems to be associated with lentinan degradation, increased more during storage of L. edodes at 20 degrees C than it did at lower temperatures. In addition, only glucose was detected as a degraded product from lentinan by the glucanase. This suggested that this enzyme would fit the profile of an exo-type glucanase. Also, polyphenol oxidase activity, known as an index of freshness reduction in the mushroom, increased approximately 2.7-fold (to 61.5 units.mg(-)(1)) over 7 days during storage at 20 degrees C. However, its activity changed little during storage at lower temperatures. These results indicate that the reduction during storage of the quality of L. edodes as a functional food is accompanied by the decrease of lentinan, and by browning, and that exo-glucanase plays an important role in the decrease of lentinan content.

Investigation of Antimicrobial Activity of Grapefruit Seed Extract and Its Application to Air Filters with Comparison to Propolis and Shiitake

“…The mushroom extract was obtained from dried mushroom caps through ethanol extraction. The extraction process started with 100.12 g of dried mushroom caps in the market (Mungyeong, Korea) and the extract was 9.09 g. Lentinan is one of the most active 1,3/1,6-β-Dglucans and its amount in the dried Japanese L. edodes was reported as 10~15 mg/g (Minato et al, 1999).…”

Senescence of the Lentinula edodes Fruiting Body After Harvesting

“…However, lentinan content decreases during postharvest storage (Minato et al, 1999). The reported structure of lentinan is a β-1,3-linked-D -glucan with β-1,6 branches (Chihara et al, 1969), and it appears that postharvest degradation of lentinan during mushroom storage is mediated by β-1,3-glucanase (Minato et al, 1999). Four glucanases have been reported in L. edodes fruiting bodies, two exo-β-1,3-glucanases, EXG1 (Sakamoto et al, 2005a) and EXG2 (Sakamoto et al, 2005b), and two endo-β-1,3-glucanases, TLG1 (Sakamoto et al, 2006) and GLU1 ).…”

“…Lentinan, a β-1,3-glucan used for tumor immunotherapy (Chihara et al, 1969), is purified from fresh shiitake mushrooms. However, lentinan content decreases during postharvest storage (Minato et al, 1999). The reported structure of lentinan is a β-1,3-linked-D -glucan with β-1,6 branches (Chihara et al, 1969), and it appears that postharvest degradation of lentinan during mushroom storage is mediated by β-1,3-glucanase (Minato et al, 1999).…”

Lentinula edodes tlg1 Encodes a Thaumatin-Like Protein That Is Involved in Lentinan Degradation and Fruiting Body Senescence

“…The reported structure of lentinan comprises b-1,3-linked-D-glucan containing b-1,6 branches (Chihara et al, 1969). However, although it can be purified from fresh Shiitake mushrooms (L. edodes), its content decreases during storage as a result of increased glucanase activity (Minato et al, 1999(Minato et al, , 2004. Previously, we reported that two exo-b-1,3-glucanase-encoding genes (exg1 and exg2) are involved in morphogenesis of L. edodes (Sakamoto et al, 2005a(Sakamoto et al, , 2005b and that the enzyme encoded by exg2 is also involved in postharvest degradation of lentinan (Sakamoto et al, 2005b).…”