Chemical Modification And Their Insecticidal&Antifungal Activities Of Two Natural Products

This thesis covers the synthesis and bioassay of two kinds of natural products isolatedfrom Parnassia wightiana and I.britannica, respectively. According to reports, these productspossess a broad spectrum of biological activities such as cytotoxic, insect antifeedant,insecticidal, anti-HIV, antifungal, antibacterial activity and antitumor activity and so on.A dihydro-β-agarofuran sesquiterpene （CE-353-1） was found from Parnassia wightianafor the first time obtained. Moreover, five new dihydro-β-agarofuran derivatives （FY-2^FY-6）were semi-synthesized at the2-or8-position of CE-353-1by Dess-Martin oxidation,acylation, reduction, Yamaguchi esterification, and amination, respectively. Meanwhile,1-O-Acetylbritannilactone （ABL） was isolated from I.britannica, and eleven derivatives（FY-7^FY-17） were obtained by modifying the6-OH of ABL with esterification. Thestructures were elucidated by spectral data (MS、1H NMR and¹³C NMR).In addition, antifeedant activity of these compounds was tested against the3rd-instarlarvae （Mythimna separata Walker）. Preliminary results indicated that compounds （CE-353-1and FY-2^FY-6） exhibited moderate antifeedant activity at100μg/mL, and the most potentone was compound （FY-4）72.5%, which showed more antifeeding effect than the parentcompound CE-353-1. However, compounds ABL and FY-7^FY-13had no potentialantifeedant activity at100μg/mL. Besides, compounds （ABL and FY-7^FY-17） were alsoevaluated for in vitro antifungal activities against phytopathogenic fungi and bacteria.Preliminary results indicated that all compounds showed various degrees of inhibition against4phytopathogenic fungi （Gibberella sanbinetti, Fusarium solani, F.oxysporum f. sp.Vasinfectum and Colletorrichum gloeosporiodes）. Among them, FY-7^FY-13and FY-17exhibited potent antifungal activities against Colletorrichum gloeosporiodes with MIC valuesbetween0.78to12.5μg/ml, which were comparable to two positive controls carbendazim andhymexazol. Meantime, ABL and FY-7^FY-17also showed different degrees of inhibitionagainst4bacteria （Bacillus subtilis, Escherichia coli, Staphyloccocus aureus andPseudomonas syringaepv altinidia）. Among them, FY-14and FY-15were found with stronganti-bacteria activity against Pseudomonas syringaepv altinidia with MIC values of0.78μg/ml.