Rao S R, Ravishankar G A
Plant Cell Biotechnology Department, Central Food Technological Research Institute, Mysore, India.
J Biotechnol. 2000 Jan 21;76(2-3):137-46. doi: 10.1016/s0168-1656(99)00177-7.
Freely suspended cells and immobilized cell cultures of Capsicum frutescens Mill. were treated with phenylpropanoid intermediates--protocatechuic aldehyde and caffeic acid to study their biotransformation ability. It was found that externally fed protocatechuic aldehyde and caffeic acids were biotransformed to vanillin and capsaicin. It was noted that this culture biotransformed externally fed protocatechuic aldehyde to vanillin more than its conversion to capsaicin, whereas, caffeic acid-treated cultures accumulated more capsaicin than vanillin. The maximum accumulation of vanillin (5.63 mg l(-1)) and capsaicin (3.83 mg l(-1)) was recorded on the 6th and 15th day, respectively in immobilized C. frutescens cell cultures treated with protocatechuic aldehyde, which was 1.8 and 1.4 times higher than in protocatechuic aldehyde-treated freely suspended cell cultures. Caffeic acid-treated immobilized C. frutescens cell cultures accumulated maximum vanillin and capsaicin at 2.68 and 3.03 mg l(-1) culture, respectively, on the 9th and 12th day, which was 1.65 and 1.33 times over freely suspended cultures treated with caffeic acid. The addition of S-adenosyl-L-methionine, a methyl donor, to protocatechuic aldehyde-treated immobilized C. frutescens cell cultures, resulted in accumulation of vanillin (14.08 mg l(-1)) on the 4th day, which was 2.5-fold higher than that in cultures treated with protocatechuic aldehyde alone, suggesting the influence of S-adenosyl-L-methionine on O-methylation of protocatechuic aldehyde, resulting in more vanillin accumulation. The increase in vanillin accumulation was well correlated with an increase in specific activity of caffeic acid O-methyltransferase in protocatechuic aldehyde and S-adenosyl-L-methionine-treated immobilized C. frutescens cell cultures. This study also provides an example for an alternative route to formation of vanillin by C. frutescens cell cultures.
对小米辣（Capsicum frutescens Mill.）的游离悬浮细胞和固定化细胞培养物用苯丙烷类中间体——原儿茶醛和咖啡酸进行处理，以研究它们的生物转化能力。结果发现，外源添加的原儿茶醛和咖啡酸被生物转化为香草醛和辣椒素。值得注意的是，这种培养物将外源添加的原儿茶醛生物转化为香草醛的量多于转化为辣椒素的量，而用咖啡酸处理的培养物积累的辣椒素比香草醛更多。在用原儿茶醛处理的固定化小米辣细胞培养物中，香草醛（5.63 mg l⁻¹）和辣椒素（3.83 mg l⁻¹）的最大积累量分别在第6天和第15天记录到，这分别比用原儿茶醛处理的游离悬浮细胞培养物中的积累量高1.8倍和1.4倍。用咖啡酸处理的固定化小米辣细胞培养物在第9天和第12天分别积累了最大量的香草醛和辣椒素，分别为2.68 mg l⁻¹和3.03 mg l⁻¹培养物，这比用咖啡酸处理的游离悬浮培养物分别高1.65倍和1.33倍。向用原儿茶醛处理的固定化小米辣细胞培养物中添加甲基供体S-腺苷-L-甲硫氨酸，在第4天导致香草醛积累（14.08 mg l⁻¹），这比仅用原儿茶醛处理的培养物中的积累量高2.5倍，表明S-腺苷-L-甲硫氨酸对原儿茶醛的O-甲基化有影响，从而导致更多香草醛的积累。在用原儿茶醛和S-腺苷-L-甲硫氨酸处理的固定化小米辣细胞培养物中，香草醛积累量的增加与咖啡酸O-甲基转移酶的比活性增加密切相关。本研究还为小米辣细胞培养物形成香草醛的替代途径提供了一个例子。
