A new estimation of the total flavonoids in silkworm cocoon sericin layer through aglycone
determination by hydrolysis-assisted extraction and HPLC-DAD analysis
Engelsk titel: A new estimation of the total flavonoids in silkworm cocoon sericin layer through aglycone
determination by hydrolysis-assisted extraction and HPLC-DAD analysis
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Författare:
Zhao, Jin-Ge
;
Zhang, Yu-Qing
Email: sericult@suda.edu.cn
Språk: Eng
Antal referenser: 26
Dokumenttyp:
Artikel
UI-nummer: 16073006
Sammanfattning
Background: Silk sericin and a few non-protein components isolated from the cocoon layer
including two silk proteins in silkworm Bombyx mori has many bioactivities. The dietary sericin
possess antinatural oxidation, anticancer, antihyperlipidemic, and antidiabetic activities. The non-
protein components surrounding the sericin layer involve in wax, pigments mainly meaning
flavonoids, sugars, and other impurities. However, very few investigations have reported the
estimation of the total flavonoids derived from the cocoon layer. The flavonoids are commonly
present in their glycosylated forms and mostly exist as quercetin glycosides in the sericin layers of
silkworm cocoons.
Objective: The aim of this study was to find a more accurate method to estimate the level of the total
flavonoids in silkworm cocoons.
Design: An efficient procedure of hydrolysis-assisted extraction (HAE) was first established to
estimate the level of the total flavonoids through the determination of their aglycones, quercetin, and
kaempferol. Then, a comparison was made between traditional colorimetric method and our method.
In addition, the antioxidant activities of hydrolysis-assisted extract sample were determined.
Results: The average contents of quercetin and kaempferol were 1.98 and 0.42 mg/g in Daizo cocoon.
Their recoveries were 99.56 and 99.17%. The total sum of quercetin and kaempferol was detected to
be 2.40±0.07 mg/g by HAE-HPLC, while the total flavonoids (2.59±0.48 mg/g) estimated by the
traditional colorimetric method were only equivalent to 1.28±0.04 mg/g of quercetin. The HAE sample
also exhibits that IC50 values of scavenging ability of diphenyl picryl hydrazinyl (DPPH) radical and
hydroxyl radical (HO·) are 243.63 µg/mL and 4.89 mg/mL, respectively.
Conclusions: These results show that the HAE-HPLC method is specificity of cocoon and far superior
to the colorimetric method. Therefore, this study has profound significance for the comprehensive
utilization of silkworm cocoon and also may be applied to the estimation of total flavonoids in other
functional foods.