Cembranoids are a class of glandular trichome exudates with a variety of structural variations and biological activities, and are found in high quantities in tobacco (Nicotiana tabacum L.). However, few studies have conducted preparative separation and examined the activities of cembranoids other than (1S,2E,4S,6R,7E,11E)-2,7,11-cembratriene-4,6-diol (α-CBT-diol, 1) and (1S,2E,4R,6R,7E,11E)-2,7,11-cembratriene-4,6-diol (β-CBT-diol, 2); thus, the structure-activity relationship (SAR) of cembranoids remains unclear. Here, to deduce the SAR of cembranoids, raw cembranoid extract was systematically separated through an activity-oriented approach with preparative reversed-phase liquid chromatography. Each fraction was identified, and their antifungal, insecticidal, and cytotoxic bioactivities were evaluated. Composition analysis and activity detection of primary fractions (Fr.1–Fr.10) revealed that cembranoid activity might be influenced by the number of hydroxyl groups and degree of unsaturation (macrocycle and double bonds). Sub-fraction analysis showed that the antifungal activity of cembranoids was related to the number of hydroxyl groups and double bonds, and that their cytotoxic activity was affected by the type and position of substituents. Furthermore, all four factors could influence insecticidal activity. By conducting in-depth studies of single cembranoids, their SARs were summarized. The existence of Δ^11,12/Δ^7,8 and hydroxylation at C-6/C-4 contributed to the antifungal activity of cembranoids. Variation in the type and position of substituents also significantly affected antifungal activity, of which Δ^11,12 was the most influential factor. Additionally, the change in substituent configuration at C-4 and C-12 had no significant effect on antifungal activity. The insecticidal activity of cembranoids benefited from the existence of 4-hydroxyl, which greatly enhanced their binding affinity; however, functional groups substituted at other positions decreased insecticidal activity. Cytotoxic activity was positively correlated with α-configuration at C-4 and hydroxylation at C-6 but inversely correlated with 4-methoxy substitution. Among them, 6-hydroxyl formed the core; the α-/β-configuration at C-12 and 4-/12-substitution of cembranoids did not affect their insecticidal activity. Insecticidal activity might play a key role by restraining acetylcholinesterase activity through hydrophobic interactions between the cembranoid carbon skeleton and residues located at the acetylcholinesterase binding pocket. These findings may provide a foundation for the development of novel cembranoid-based pesticides and medicines.

Cembranoids 是一类具有多种结构变异和生物活性的腺毛状体分泌物，在烟草 ( Nicotiana tabacum L.) 中大量存在。然而，很少有研究对除 (1 S ,2 E ,4 S ,6 R ,7 E ,11 E )-2,7,11-cembratriene-4,6-diol ( α -CBT-二醇, 1 ) 和 (1 S ,2 E ,4 R ,6 R ,7 E ,11 E )-2,7,11-cembratriene-4,6-diol ( β-CBT-二醇，2); 因此，cembranoids 的构效关系 (SAR) 仍不清楚。在这里，为了推断西松的 SAR，我们通过活性导向方法和制备型反相液相色谱系统地分离了西松原提取物。确定了每个部分，并评估了它们的抗真菌、杀虫和细胞毒性生物活性。初级馏分（Fr.1-Fr.10）的组成分析和活性检测表明，西松的活性可能受羟基数量和不饱和度（大环和双键）的影响。亚组分分析表明，西松的抗真菌活性与羟基和双键的数量有关，其细胞毒活性受取代基的类型和位置的影响。此外，所有四个因素都会影响杀虫活性。通过对单个西松的深入研究，总结了它们的 SARs。Δ的存在^11,12 /Δ ^7,8和 C-6/C-4 处的羟基化作用有助于 cembranoids 的抗真菌活性。取代基的类型和位置的变化也显着影响抗真菌活性，其中Δ ^11,12是影响最大的因素。此外，C-4 和 C-12 处取代基构型的变化对抗真菌活性没有显着影响。Cembranoids的杀虫活性得益于4-羟基的存在，大大增强了它们的结合亲和力；然而，在其他位置取代的官能团会降低杀虫活性。细胞毒活性与α呈正相关-C-4 处的构型和 C-6 处的羟基化，但与 4-甲氧基取代呈负相关。其中，6-羟基形成核心；cembranoids 的 C-12 和 4-/12-取代的α- / β-构型不影响其杀虫活性。杀虫活性可能通过 Cembranoid 碳骨架和位于乙酰胆碱酯酶结合口袋的残基之间的疏水相互作用抑制乙酰胆碱酯酶活性而发挥关键作用。这些发现可能为开发新型西松类农药和药物奠定基础。