Three new diterpenoids isolated from Euphorbia nematocypha Hand.-Mazz and their anti-fungal activity.

Three new diterpenoids, named nematocynine A-C (1-3), together with twelve known compounds (4-15) were isolated from the aerial part of Euphorbia nematocypha Hand.-Mazz (Hereinafter referred to E. nematocypha). Their structures were elucidated by detailed spectroscopic analysis and comparison with literature data. In addition, all the compounds were tested for their anti-candida albicans activities used alone or in combination with fluconazole against sensitive strain and resistant strain in vitro. Wherein only compound 11 shows weak activity against candida albicans resistant strain (MIC50 = 128.15 µg/mL) when used alone. Compounds 1, 4, 7, 8, 9, 10, 12, 13 and 15 in combination with fluconazole showed potent anti-fungal activities (MIC50 = 15 ± 5 µg/mL, FICI = 0.05 ± 0.04) against the Candida albicans resistant strain SC5314-FR. The synergistic effects were weaker against the Candida albicans resistant strain SC5314-FR when the compounds 2, 3, 5 and 14 were combined with fluconazole (FICI = 0.16 ± 0.06).

Nudifloids A-N, structurally diverse 3,4-seco-labdane diterpenoids from Callicarpa nudiflora with inflammatory inhibitory activity.

Fourteen undescribed seco-type diterpenoids, named nudifloids A-N, together with ten known analogs, were isolated from the leaves of Callicarpa nudiflora. Nudifloids A-N had a characteristic 3,4-seco-labdane-type diterpenoid skeleton, whereas nudifloids A-C and K-N were 3,4-seco-norditerpenoids. Nudifloid A was the first example of a 3,4-seco-12,13,14,15,16-quartnor-labdane diterpenoid, with a seven-membered lactone ring formed through esterification between C-3 and C-11. Nudifloids B and C were a pair of highly modified 3,4-seco-labdane nor-diterpenoid epimers, of which C-2 and C-18 were cyclized together to form a cyclohexene fragment. The structures of these undescribed diterpenoids were established by spectroscopic analysis and reference data. The anti-inflammatory activity of diterpenoids in rich yield was evaluated by analyzing the inhibition of lipopolysaccharide plus nigericin-induced pyroptosis in J774A.1 cells. Nudifloids D and E exhibited prominent anti-NLRP3 inflammasome activity, with IC50 values of 1.80 and 1.59 µM, respectively. Cell permeability assays revealed that nudifloid D inhibited pyroptosis, which could ameliorate inflammation by blocking the activation of the NLRP3 inflammasome.

A pair of new oxindole alkaloids isolated from Uncaria macrophylla.

A pair of new oxindole alkaloids, named macrophyllines C (1) and D (2), together with two known oxindole alkaloids isorhynchophylline (3) and corynoxine (4) were isolated from Uncaria macrophylla. Their structures were elucidated based on detailed spectroscopic analysis and by comparison with literature data. In addition, all the isolates were tested for their anti-HIV activities and cytotoxicities in C8166 cells and compounds 2-4 showed weak anti-HIV activities with EC50 values of 11.31 ± 3.29 µM, 18.77 ± 6.14 µM and 30.02 ± 3.73 µM, respectively.

Ten new prenylated flavonoids from Macaranga denticulata and their antitumor activities.

Ten new prenylated flavonoids, named denticulains A-J (1-10), together with seven known prenylated flavonoids (11-17) were isolated from Macaranga denticulata. Their structures were elucidated on the basis of detailed spectroscopic analysis and by comparison with literature data. In addition, compounds 1 and 14 inhibited the proliferation of SW620 and HCT-116 cell lines with an IC50 value of 46.08 µM and 56.83 µM, respectively.