Sch-53823

Three new spirobisnaphthalenes (1-3), a new, natural spirobisnaphthalene product (4), and two new 12-membered ring lactones (11-12), with six known compounds (5-10), were isolated from the seeds of Strychnos angustiflora. Their structures were elucidated by extensive spectroscopic analysis. The absolute configurations of 1-4 were assigned by computational methods. Compounds 1, 5 and 9 inhibited lipopolysaccharide-induced NO production in BV2 cells with IC50 values of 4.85, 2.05, and 1.16μM, respectively (positive control curcumin, IC50=1.42μM). This is the first report on the anti-inflammatory activities of spirobisnaphthalenes.

Nine new meroterpenes (1-9) and one new dioxolanone derivative (10), along with seven known compounds (11-17), were isolated from solid cultures of the endophytic fungus Guignardia sp., obtained from Euphorbia sieboldiana. Their structures were elucidated by analysis of UV, IR, 1D and 2D NMR, and HRESIMS data, and their absolute configurations were determined by a combination of single-crystal X-ray studies, modified Mosher methods, and Rh2(OCOCF3)4- and Mo2(OCOCH3)4-induced electronic circular dichroism experiments. All compounds were evaluated for their inhibitory effects alone and with fluconazole on the growth and biofilms of Candida albicans. At 6.3 μg/mL combined with 0.031 μg/mL of fluconazole, compounds 8 and 16 were found to have prominent inhibition on the growth of C. albicans with fractional inhibitory concentration index values of 0.23 and 0.19, respectively. Combined with fluconazole, both of them (40 μg/mL for 8 and 20 μg/mL for 16) could also inhibit C. albicans biofilms and reverse the tolerance of C. albicans biofilms to fluconazole.