Narihiko Fukamiya

Inhibitory effects of quassinoids on Epstein-Barr virus activation

Short-term in vitro assays for tumor promoters and anti-tumor promoters (Epstein-Barr virus activation test) were carried out for 45 quassinoids. As a result, some quassinoids showed potent activity, more than 50% inhibition at a molar ratio of 1:1 (TPA/quassinoids). These results led to the following structure-activity relationships: (1) a methyleneoxy bridge and side chain enhance the activity and (2) a sugar moiety reduces the activity.

Anti-HIV activity of quassinoids

Abstract Eighteen quassinoid glycosides and nine known quassinoids were tested for inhibitory activity against HIV replication in H9 lymphocytic cells. Of the compounds tested, shinjulactone C ( 20 ) demonstrated the highest anti-HIV activity (EC 50 = 10.6 μM) in the absence of cytotoxicity with a therapeutic index of >25.

Quassinoids as inhibitors of Epstein-Barr virus early antigen activation

Short-term in vitro assays for tumor promoters and antitumor promoters (Epstein-Barr virus activation test) were carried out for 14 quassinoids isolated from Ailanthus altissima. Some quassinoids, including ailantinol B, ailantinol C, ailanthone, and shinjulactone A, showed moderate activity at a molar ratio of 1:100 (TPA/quassinoids), and the results led to the elucidation of structure-activity relationships.

Antifeedant and Insecticidal Activity of Quassinoids against Diamondback Moth (Plutella xylostella)

The antifeedant and insecticidal activities of sixteen quassinoids against 3rd instar larvae of the diamondback moth (Plutella xylostella) were compared with those of known insect antifeedant chlordimeform (1), and the structure-activity relationship was discussed. The insecticidal activity of quassin (2) was higher than that of 1, although its antifeedant activity was nearly the same as that of the reference compound.

Multidrug Resistant Cancer Cells Susceptibility to Cytotoxic Taxane Diterpenes from Taxus yunnanensis and Taxus chinensis

Twelve taxane diterpenes (1-12), which were isolated previously from the EtOH extract of the aerial parts of Taxus yunnanensis or Taxus chinensis, were evaluated for cytotoxicity against the multidrug resistant cancer cells KB-VIN and KB-7d. Compounds and showed significant cytotoxicity in these cell lines. Compounds and also demonstrated significant activity against KB-7d. The biflavonoid isolated from T. yunnanensis was only marginally cytotoxic against the A549 (lung) cell line, but a simple methoxylated analogue (14) was inactive.

Synthesis of cytotoxic fluorinated quassinoids

The C-15 senecioyl side chain of brusatol was interchanged with fluorinated acyl groups, and the C-3 hydroxy group of bruceolide was esterified with fluorinated acyl chlorides. These fluorinated quassinoids 11, 12, 13, and 17 showed significant cytotoxic activity against eight human cancer cell lines including small and non-small cell lung, colon, CNS, ovarian and renal cancers, leukemia, and melanoma with 17 being about 100 times more potent than 11, 12, and 13. The activity of 17 was similar to that of bruceantin (1) in this in vitro cell line panel.

The nematocidal activity and the structure-activity relationships of stilbenes.

The pinewood nematode, Bursaphelenchus xylophilus (Steiner et Buhrer) Nickle, is the causative agent of the pine wilt disease which has been devastating forests of Pinus densiflora Sieb.et Zucc. and P. thunbergii Parl. in Japan. To prevent the pine wilt disease, the development of nematocidal compound is required. Twenty-one synthesized stilbenes (1)–(20), (23), salicylic acid (21), and phenylsalicilate (22) were examined for their nematocidal activity against an isolate of B. xylophilus (T-4). Among the tested compounds, two fluorinated stilbenes (15) and (13), were found to be most potent compounds against T-4, demonstrating 99% and 98% lethality at 10 ppm concentration. The LD50 values of compounds 15 and 13 were 3 ppm, respectively.

A new quassinoid, ailantinol H from Ailanthus altissima

A new quassinoid, ailantinol H, was isolated from the aerial parts of Ailanthus altissima. The structure was elucidated based on spectral evidence.

Cytotoxity of non-alkaloidal taxane diterpenes from Taxus chinensis against a paclitaxel-resistant cell line

Seven taxane diterpenes were isolated from the EtOH extract of the aerial parts of Taxus chinensis, and evaluated for cytotoxicity against nine human cell lines, including a beta-tublin mutant resistant to paclitaxel. Compound 2, a non-alkaloid-type taxane diterpene, showed significant cytotoxicity in most cell lines, and notably, equipotent against both parental and beta-tublin mutant tumor cell lines.

Structure of bisclausarin, a new bicoumarins from Citrus plant

A new type bicoumarin, named bisclausarin, was isolated from the roots of Citru hassaku (Rutaceae) and the structure was elucidated as 1 on the basis of spectroscopic data