International Center for Chemical and Biological Sciences, H E J Research Institute of Chemistry, University of Karachi, Karachi, Pakistan.
Pharm Biol. 2011 May;49(5):516-25. doi: 10.3109/13880209.2010.523006. Epub 2011 Feb 1.
Tagetes patula L. is one of the French marigold group of the Asteraceae family. It is recognized in folklore for its medicinal and pesticidal properties.
In search of more effective, but non-toxic compounds with antioxidative potential led to the bioassay guided isolation studies on the extracts of T. patula.
The bioassay on Tagetes patula flowers were carried out guided by in vitro antioxidant activity using DPPH assay. A minor but proven plant constituent methyl protocatechuate (1) was isolated by column chromatography, while patuletin (2) and patulitrin (3) obtained in bulk by employing solvent partition of methanol extract. Derivatization of patuletin into benzoyl, cinnamoyl and methyl was conducted to establish the structure activity relationship (SAR). Analgesic activity of compound 2 was evaluated using acetic acid-induced writhing test and hot-plate test in mice. The toxicity of methanol extract and compound 2 were also determined.
Polar extracts, fractions and phases demonstrated better antioxidant activity. The synthetic methyl protocatechuate (1) showed IC(50) value of 2.8 ± 0.2 μg/mL, whereas patuletin (2) (IC(50) = 4.3 ± 0.25 µg/mL) was comparable to quercetin and rutin but significantly better than patulitrin (3) (IC(50) = 10.17 ± 1.16 µg/mL). Toxicity test for the methanol extract and compound 2 did not elicit any behavioral changes or cause mortality in mice. Compound 2 also demonstrated mild analgesic property.
These findings demonstrate that the plant polar extracts and fractions possess significant antioxidant property with non-toxic effect. Compound 1 is a genuine plant constituent of T. patula.
万寿菊（Tagetes patula L.）属于菊科万寿菊属，是一种药食同源植物。在民间，万寿菊具有药用和驱虫等特性。
为寻找更有效且无毒的具有抗氧化活性的化合物，我们对万寿菊花的提取物进行了生物活性导向分离研究。
我们以 DPPH 法体外抗氧化活性为指标，对万寿菊花进行生物活性跟踪，通过柱色谱法分离得到含量较低但具有生物活性的化合物 3-甲氧基-4-羟基苯甲酸（1），并采用甲醇提取溶剂萃取法得到大量的佩枯苷（2）和佩枯亭（3）。对佩枯苷进行苯甲酰化、肉桂酰化和甲酯化衍生化，建立构效关系（SAR）。采用醋酸扭体法和热板法评估化合物 2 的镇痛活性。同时还测定了甲醇提取物和化合物 2 的毒性。
极性提取物、馏分和相显示出更好的抗氧化活性。合成的 3-甲氧基-4-羟基苯甲酸（1）的 IC50 值为 2.8 ± 0.2 μg/mL，而佩枯苷（2）（IC50 值为 4.3 ± 0.25 µg/mL）与槲皮素和芦丁相当，但明显优于佩枯亭（3）（IC50 值为 10.17 ± 1.16 µg/mL）。甲醇提取物和化合物 2 的毒性试验未引起小鼠出现任何行为改变或死亡。化合物 2 还表现出轻度的镇痛作用。
这些发现表明，植物极性提取物和馏分具有显著的抗氧化活性，且无毒性作用。化合物 1 是万寿菊的一种真正的植物成分。
