| Mulberry, a important nourishing traditional Chinese medicine, has long been used as a remedy of diabetes, deficiency of liver-kidney Yin, insomnia, tinnitus, body fluid deficiency, rheumatism, constipation, early graying hair and beard, neurasthenic, and drunkenness. One of the active substances in mulberry is resveratrol (Res) which has significant activities of anti-cancer, anti-tumor, cardiovascular protection, anti-oxidation and anti-free radical, neuroprotection, anti-inflammatory, anti-bacteria and fungi, plant estrogen-like, bone metabolism affection, endothelin antagonists, and so on.In the last 20 years, Res is the focus of medicinal researches all over the world, and it has been found in dozens of species of plants up to now. Mulberry is abound in Res and its glucoside (PD) which can be hydrolyze to give Res. However, Res and PD have not been well studied as yet. To acertain the best collection period and the cultivated variety with the highest content of Res and PD, this thesis investigated the trend of the contents of Res and PD in mulberries in the riping process and compared the contents of Res and PD in mulberries of different varieties. The stability of Res and PD to UV254nm was also studied in the existence of anthocyanin or mulberry juice,In this paper, a quantitative method was established to simultaneously determine the contents of Res and PD in mulberry by RP-HPLC. The chromatographic conditions were as follows: phenomenex C18 column (150 mm x 4.6 mm,4μm), gradient MeOH-H2O as eluant at the rate of 0.8ml/min, and monitored at 305 nm. The results of the methodological evaluation tests showed that the method was special, accurate, and stabile and the peak areas of Res was linear to the amount of Res injected into the column within 0.01-1μg and so was that of PD within 0.04-2μg. With this analytic method, the contents of Res and PD were determined in mulberries of Hongguo 2 in ripening process, and in red and purple mulberries from five varieties, Hongguo 1, Hongguo 2, Xinong 1, Jialing 30 No.1, and Jialing 30 No.2. The results revealed that during maturation the content of PD was always higher than that of resveratrol, and both of them reached the maximum in mid-red period, dropped a little when fruits turned to purple. The red mulberry of Xinong 1 had the highest total content of resveratrol which was 94.5μg/g. It was concluded that the content of resveratrol was high in mulberry, and that mulberry should be harvested just when berries turn from red to purple.The stability of trans-Res and trans-PD to UV254 was studied with the pure reference substance and the reference samples mixed with mulberry juice or anthocyanin solution. Compared to the pure reference substances, the converting rates of trans-Res and trans-PD caused by UV254 were scaled-up to cis-Res and cis-PD in the existence of low content of anthocyanins, which suggested that the reactivities of trans-Res and trans-PD were more active than anthocyanins. Whereas, the converting rates of trans-Res and trans-PD caused by UV254 were significantly reduced with high content of anthocyanins, the reason might be that the anthocyanins absorbed major UV so that little UV could reached the molecules of trans-Res and trans-PD. When mixed up with mulberry juice diluted by 10 times, trans-Res and trans-PD in UV254 converted to their cis-isomers at lower rates, which might be due to the high content of anthocyanins in the mulberry juice.The cDNA of phenylalanine ammonia-lyase gene (MaPAL) in mulberry (accession number: HM064433) was successfully cloned. The full length gene cDNA contains a 2181 bp open reading frame (ORF) which can encode 726 amino acid residues. The molecular weight of the deduced protein should be 78.49 kDa, predicted isoelectric point (pI) 8.2, atomic composition is C3453H5530N956O1074S27. The protein was conjectured to distribute in the chloroplast or thylakoid. From amino acid sequence homology analysis, the core area of the protein was found to be conservative but the both ends were low homogenous. The evident differences between the proteins from plants of gymnosperms and angiosperms indicated that the protein has existed before the divergence of angiosperms and gymnosperms.
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