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Daphnenoids A−C (1−3), three unusual sesquiterpenes with distinctive ring skeletons, together with a biogenetically related daphnenoid D (4) were obtained from the herb of Daphne penicillata by molecular networking strategies. Daphnenoid A (1) possesses a unique caged tetracyclo [5.3.2.0 1 , 6 .0 4 , 11 ] dodecane scaffold by unexpected cyclizations of C-1/C-11 and C-2/C-14. Daphnenoids B and C (2 and 3) were the first discovered natural sesquiterpenes with unique 5/5 spirocyclic systems in nature. Their structures were determined by NMR spectroscopic analysis, computer-assisted structure elucidation methods, quantum chemical calculations, and X-ray diffraction. A hypothetical biogenetic pathway begins with typical guaiane sesquiterpene (a), including a key intermediate (4) was proposed. Daphnenoids B and C (2 and 3) exhibited potential inhibitory activities on the production of NO against LPS-induced BV2 microglial cells.

Prunus tomentosa seeds were researched for antioxidant and anti-inflammatory constituents. By activity-guided fractionation of P. tomentosa seed extract, six new dihydrobenzofuran neolignans, prunustosanans AI-IV (1-4) and prunustosanansides AI and AII (5 and 6), together with 10 known compounds (7-16) were isolated from bioactive fraction. The structures were determined by spectroscopic analyses, especially NMR, HRESIMS, and CD spectra. The antioxidant activity was greatest for 5, 10, and 12 against DPPH radical and for 8, 9, and 13 against ABTS radical. Moreover, compounds 7 and 11 exhibited much stronger inhibitory activity on nitric oxide (NO) production in murine microglia BV-2 compared with positive control minocycline (IC50 = 19.7 ± 1.5 μM). The results show that P. tomentosa seeds can be regarded as a potential source of antioxidants and inflammation inhibitors.

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