Department of Chemistry, Faculty of Sciences, University of Douala, P.O. Box 24157, Douala, Cameroon.
University of Yaoundé I, Faculty of Sciences, P.O. Box 812, Yaoundé, Cameroon.
Chem Biodivers. 2022 Jul;19(7):e202101033. doi: 10.1002/cbdv.202101033. Epub 2022 Jun 9.
The stem bark of Citrus × paradisi Macfad. (Rutaceae) gave (23S)-isolimonexic acid (1), limonin (2), citracridone II (3), citpressine II (4), citpressine I (5), grandisine (6), 2-hydroxynoracronycine (7), citracridone I (8), 5-methoxyseselin (9), umbelliferone (10), scopoletin (11), naringenin (12), apigenin (13), friedelin (14), agrostophyllinone (15) and stigmasterol-3-O-β-D-glucopyranoside (16). The structures of the compounds were determined using NMR and MS spectroscopic data, and by comparison with published data. The relative configuration of 1 was proposed as (23S)-isolimonexic acid using NOE studies. Hydrogenation reaction of compound 3 led to the new derivative 3',4'-dihydrocitracridone II (3a). Cytotoxicity activities against the human adenocarcinoma alveolar basal epithelial cell lines A549 and the Caucasian prostate adenocarcinoma cell lines PC3, using the MTT assays showed that the methanol crude extract was significant with IC values of 30.1 and 31.7 μg/mL, respectively, with the positive control, doxorubicin giving an IC of 0.9 μM. In addition, compounds 3, 7 and 8 gave moderate cytotoxic activities with IC values of 33.1, 31.2 and 32.5 μM for A549 cells and 35.7, 33.8 and 34.9 μM for PC3 cells, respectively. The hydrogenated 3a was less active than 3, suggesting that the presence of the double bond in pyrans is important for structure-activity relationship.
橘柚（Citrus × paradisi Macfad.）的茎皮中分离得到（23S）-isolimonexic 酸（1）、柠碱（2）、citracridone II（3）、citpressine II（4）、citpressine I（5）、grandisine（6）、2-羟基诺卡酮（7）、citracridone I（8）、5-甲氧基芹菜素（9）、伞形花内酯（10）、东莨菪内酯（11）、柚皮苷（12）、芹菜素（13）、羽扇豆醇（14）、agrostophyllinone（15）和豆甾醇-3-O-β-D-吡喃葡萄糖苷（16）。化合物的结构通过 NMR 和 MS 光谱数据确定，并与已发表的数据进行比较。通过 NOE 研究，提出了化合物 1 的相对构型为（23S）-isolimonexic 酸。化合物 3 的加氢反应得到了新的衍生物 3'，4'-二氢 citracridone II（3a）。MTT 测定法对人腺癌细胞系 A549 和高加索前列腺癌细胞系 PC3 的细胞毒性活性表明，甲醇粗提物具有显著的活性，IC 值分别为 30.1 和 31.7μg/mL，阳性对照柔红霉素的 IC 值为 0.9μM。此外，化合物 3、7 和 8 对 A549 细胞的 IC 值分别为 33.1、31.2 和 32.5μM，对 PC3 细胞的 IC 值分别为 35.7、33.8 和 34.9μM，具有中等的细胞毒性活性。氢化产物 3a 的活性低于 3，表明吡喃中的双键对于构效关系很重要。
