Antimycobacterial polyynes of Devil's Club (Oplopanax horridus), a North American native medicinal plant.

Two new (3 and 5), as well as three known (1, 2, and 4), polyynes were isolated from Devil's Club (Oplopanax horridus; Araliaceae), a medicinal plant of North America. The structures were established by 1H and 13C NMR. The absolute configurations of 2 and 5 were determined by application of Mosher's method. All the polyynes exhibited significant anti-Candida, antibacterial, and antimycobacterial activity, with an ability to kill Mycobacterium tuberculosis and isoniazid-resistant Mycobacterium avium at 10 micrograms/disk in a disk diffusion assay.

Further toxic properties of the fungal metabolite dothistromin.

The toxicity of the fungal phytotoxin dothistromin (l) to microorganisms, its lysis of human red blood corpuscles and beetroot tissue, and its unexpectedly selective inhibition of radicle elongation for Trigonella foenum-graecum were strongly light-dependent. Dothistromin was also toxic to Artemia salina but without requiring light activation. It was not active as a wilt or necrosis toxin, possible because of its ready adsorption onto external plant tissue.

Some biological properties of traversianal, a strongly molluscicidal diterpenoid aldehyde from Cercospora traversiana.

The diterpenoid aldehyde traversianal, a metabolite of the fenugreek pathogen Cercospora traversiana, has been shown to be highly toxic to brine shrimp and snails, and to lyse human red blood cells at concentrations as low as 5 x 10(-7) M. The compound also induced betacyanin leakage from beetroot slices but was essentially inactive in other standard tests for phytotoxicity despite its structural similarities to known phytotoxins. It was inactive in the chick bioassay.

Thiarubrine A, a bioactive constituent of Aspilia (Asteraceae) consumed by wild chimpanzees.

Two African species of Aspilia (Asteraceae), which are used medicinally by man and which are eaten by wild chimpanzees in an unusual manner, were found to contain the potent antibiotic thiarubrine A as a major leaf phytochemical. Its presence in leaf material strengthens the view that the feeding behavior of wild chimpanzees is related to special physiological or pharmacological effects on the animals.

Berberine: A naturally occurring phototoxic alkaloid.

The isoquinoline alkaloid berberine, present in nine different plant families was found to be phototoxic to mosquito larvae. In the presence of near UV the LC50 for acute 24-hr toxicity was 8.8 ppm compared to 250 ppm for dark controls. Mosquito larvae that were treated with 10 ppm berberine plus near UV for 24 hr and then transferred to berberine-free water showed decreased larval survival and resulted in a smaller cumulative number of pupae and adults as compared to controls, during a subsequent 4-week development period. Berberine was found to be a singlet O2 generator in experiments with the chemical trap 2,5-dimethyl furan. A slight increase in chromosome aberrations in Chinese hamster cells was also observed with berberine plus near UV treatment. The significance of the phototoxicity of berberine is discussed in relation to plant-insect relations.

UV-mediated genotoxicity of furanoquinoline and of certain tryptophan-derived alkaloids.

Certain furanoquinolines of the Rutaceae and a number of the widely distributed beta-carboline or harmane alkaloids are photosensitizers in near ultraviolet light (320-400 nm). These compounds have been shown to be phototoxic to yeasts and bacteria. In addition, two canthinones of the Rutaceae and the N-methylpyrolidine substituted harmane alkaloid, brevicolline (from Carex), display phototoxicity towards bacteria and fungi in near ultraviolet light. All of these alkaloids are phototoxic to Chinese hamster ovary cells, inhibiting mitosis and causing gross chromosomal changes. The target for their phototoxicity appears to be the cell nucleus.

Photobiological studies with dictamnine, a furoquinoline alkaloid.

Dictamnine, a naturally occurring furoquinoline, produces bacterial frameshift mutations in the dark. It does not form DNA interstrand crosslinks in bacterial cells in the presence of near-ultraviolet light (300-380 nm). It is more active than angelicin but slightly less active than 8-MOP as a phototoxic agent with E. coli. It is however a more active mutagen than 8-MOP at equivalent concentration. Dictamnine is slightly more potent than the same concentration of angelicin in producing photosensitized lethality in Chinese hamster cells. It does, however, produce almost twice as many sister-chromatid exchanges per lethal event than angelicin. The concept of 'unit dose' relating the observable photoinduced damage by the photosensitizer and the total irradiation appears to apply reasonably well to the actions of dictamnine in killing bacterial and mammalian cells, in the formation of sister-chromatid exchanges, but not to the induction of bacterial mutations.