天然彩色棉纤维色素成分的研究

Composition Analysis of Pigment in Colored Cotton Fiber

植物非光合色素主要由类黄酮和类胡萝卜素组成,但彩色棉纤维中色素种类及其结构尚不清楚。经测定,棕色棉(X0 0 8)、绿色棉(S0 2 9)和白色棉(徐州14 2 )成熟纤维中总黄酮含量分别为4 .4 2 4mg g、3.84 6mg g和0 .375mg g ,没有检测到类胡萝卜素。通过盐酸镁粉反应、四氢硼钠还原反应、碱反应、醋酸铅反应、氯化铁反应和紫外光谱吸收的分析表明,甲醇室温提取的棕色棉纤维色素可能是黄酮类化合物,B环上带有邻二酚羟基;甲醇室温提取的绿色棉纤维色素除黄酮类化合物外,还含有3 位羟基被糖甙化的黄酮醇类化合物,A、B环上都带有邻二酚羟基。绿色棉纤维色素中还可能含有分子结构类似于芦丁的黄酮醇化合物。

Flavonoid and carotenoid are the main two kinds of plant pigments, but which kind of pigment is in colored cotton fiber has not been studied. In this paper, flavonoid and carotenoid content in colored cotton fibers was tested and content of flavonoid in brown (X008), green (S029) and white (Xuzhou 142) mature cotton fiber was 4.424 mg·g -1,3.846 mg·g -1 and 0.375 mg·g -1, respectively, but carotenoid was not detectable (Table 1). The pigment in colored cotton fibers was extracted by methanol at room temperature. The results of color reactions (HCl-Mg reaction, NaBH 4 reaction, NaOH reaction, FeCl 3 reaction and Pb(Ac) 2 reaction) of the pigment extractive showed that the pigment extracted by methanol was flavone or flavonol with two adjacent hydroxide groups (Table 2, Fig.1) . The results of UV spectral analysis further proved that the pigment extracted by methanol from brown fiber belonged to flavone with two adjacent hydroxide groups in B ring, and that from the green fiber contained not only flavone but also flavonols with two adjacent hydroxide groups both in A ring and B ring and indican replaced a hydroxide group at 3-site of A ring (Fig.2-4, Fig.6-7). Also, the green fiber pigment might include a compound of flavonol which has the similar molecular structure as rutin (Fig.5).