Studies On Insecticidal Components From The Root Bark Of Celastrus Angulatus And Their Quantitative Structure-Activity Relationship

Celastrus angulatus Max. is a traditional insecticidal plant in China, and its insecticidal ingredients were a series of sesquiterpene polyol esters bearingβ-dihydroagaro furan skeleton. In this paper, the components and bioactivities of the non-polar fraction of the petroleum ether extract and the benzene extract from the root bark of C. angulatus, the quantitative structure-activity relationship (QSAR) and the pathway of fragments forming and cleavage principle of the insecticidalβ-dihydroagarofuran sesquiterpere polyol esters have been carried out. The main results are as follows:1. The constitutes of non-polar fraction of the petroleum ether extract from the root bark of C. angulatus were analyzed by GC-MS. Total of 13 compounds were identified by comparison with NIST2001 mass spectral library. They were identified as phthalic acid di-isobutyl ester, palmitic acid, oleic acid, linoleic acid, 1,1,4a,7,7 -pentamethyl-4,4a,5,6, 7,8,10,10a-octahydrophenanthren-2(1H,3H,4bH)-one, retinal, ferruginol, ferruginyl methyl ether, squalene, farnesol, (2Z,6E)-3,7,11-trimethyldodeca-2,6,10-trien-1-ol,(2E,6E)-3,7,11 -trimethydodeca-2,6, 10-trien-1-ol and gamma-tocopherol, respectively.2. The non-polar fraction of the petroleum ether extract from the root bark of C. angulatus exhibited stronger antifeeding activity against the 4th instar larvae of Mythimna separata and moderate inhibition on some bacteria, such as Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, Escherichis coli and Pseudomonas aeruginos, whereas no inhibition was observed on the pathogenic fungi. The antioxidant activity were evaluated by measuring the scavenging activity on superoxide anion and hydrogen peroxide, the results showed the non-polar fraction had more significant hydrogen peroxide scavenging activity.3. Twenty eight compounds were isolated from the benzene extract of the root bark by means of macroporous resin adsorption, silica gel column chromatography and pre-HPLC orderly. The structures of these compounds were elucidated mainly based on the data of NMR and MS. Total of twenty seven compounds were identified asβ-dihydroagarofuran sesquite- rpene polyol esters, and twelve of them were novel compounds: 1β-acetoxy-2β-(α-methyl)- butanoyloxy-8α,2-di-isobutyryl-9β-benzoyl-4α,6α-dihydroxy-β-dihydroagarofuran(NW12), 1β,2β,12-triacetoxy-8β-furoyloxy-9β-benzoyl-4α,6α-dihydroxy-β-dihydroagarof-uran(NW18),1β,2β,6α-triacetox-y-9α-benzoyl-12-iso-butyryl-4α-hydroxy-β-dihydroagarofu-ran(NW19), 1β,2β,8β,12-tetraacet-oxy-9β-furoyloxy-4α-hydroxy-β-dihydroagarofuran(NW21), 1β,2β-di- acetyl-8α-(α-methyl)-butanoyloxy-9β-benzoyl-12-iso-butyryl-4α,6α-dihydroxy-β-dihydroagarofuran(NW22),1β,2β,8β-triacetoxy-9β-benzoyl-12-iso-butyryl-4α,6α-dihydroxy-β-dihydroagarofuran(NW24),1β,2β,6α,8β,12-pentaacetyl-9β-benzoyl-β-dihydroagarofuran(NW25), 1β, 2β,6α,12–tetraacetoxy-8β-(α-methyl)-butanoyloxy-9α-benzoyl-β-dihydroagarofuran (NW27), 1β,2β,6α-triacetoxy-9α-furoyloxy-12-iso-butyryl-4α-hydroxy-β-dihydroagarofuran(NW28), 1β,2β,6α,8β-tetraacetoxy-12-iso-butyryl-9α-benzoyl-β-dihydroagarofuran(NW31), 1β,2β,6α, 12-tetraacetoxy-9-β-furoyloxy-4α-hydroxy-β-dihydroagarofuran(NW33) and 1β, 2β, 6α-tri- acetoxy-8β,12-di-(α-methyl)-butanoyloxy-9α-benzoyl-4α-hydroxy-β-dihydroagarofuran(NW37).4. The insecticidal activities ofβ-dihydroagarofuran sesquiterpene polyol esters against the 3rd instar larvae of Aedes albopictus and the 4th instar larvae of Mythimna separata were tested. The results showed that the larvae of A. aegypti were insensitive to tested compounds except pyridine alkaloids. The results also showed that the symptom of poisoned the 4th instar larvae of Mythimna separata and the insecticidal activity of tested compounds varied with their substituted groups evidently.5. The antitumor activity ofβ-dihydroagarofuran sesquiterpene polyol esters was screened by SRB method. The results indicated that the tested compounds have stronger inhibitory activities against human breast cancer cell line Bcap-37 than human colon cancer cell lines HT-29 and Lung cancer cell line NCI-H460. Compounds NW12 and NW55 have stronger inhibitory activities against all of them. In summary, this type of compounds only exhibited minor antitumor activity.6. The cytotoxicity ofβ-dihydroagarofuran sesquiterpene polyol esters against Trichoplusia ni embryonic cell was measured by the method of MTT. The results showed all of them had weaker inhibition against Trichoplusia ni embryonic cell.7. 3D-QSAR ofβ-dihydroagarofuran sesquiterpene polyol esters was studied by database alignment and the CoMSIA model was set up. The results showed that CoMSIA model had more accurate prediction for the activity of this type of compounds.8. The pathway of fragments forming and cleavage principle ofβ-dihydroagarofuran sesquiterpene polyol esters were investigated by ESI-MS/MS and the results could be used to identify this type of compounds in the process of screening novel compounds from Celastraceae. In addition, the ESI-MS/MS spectral library ofβ-dihydroagarofuran sesquiterpene polyol esters of C. angulatus was set up. The chemical constitutes of the cultured plant and wild plant of C. angulatus were investigated by means of LC-MS/MS, and their structures were identified or deduced based on the ESI-MS/MS spectral library.