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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.

Activity-guided fractionation of the 95% ethanol extract from the stem bark of Iryanthera megistophylla led to the isolation of two new compounds, named megislignan [2,3-dimethyl-4-(4-methoxyphenyl)-6-hydroxynaphthalene] (1) and megislactone [(2R,3R,4R)-3-hydroxy-4-methyl-2-(hexacos-17-enyl)butanolide] (2), along with seven known compounds, grandinolide (3), iryantherin K (4), iryantherin L (5), cinchonain I b (6), cinchonain I a (7), procyanidin B-2 (8), and cinchonain IIa (9). The structures of the new compounds were elucidated by spectral data interpretation. Isolates were evaluated for their antibacterial, antifungal, antiviral, and antiacetylcholinesterase activities.

A study of the antimicrobial compounds from Moneses uniflora resulted in the isolation of a novel compound, 8-chloro-2,7-dimethyl-1,4-naphthoquinone (8-chlorochimaphilin) (1), together with chimaphilin (2) and 3-hydroxychimaphilin (3) as the antimicrobial components. 2,7-Dimethyl-1,3-dihydroxynaphthyl 4-O-alpha-L-rhamnopyranoside (4) and 2,7-dimethoxy-1,4,8-trihydroxynaphthalene (6) were also isolated and identified.

La benzofuranne 6-methoxyeuparine et 2 chromenes l'encecaline et la 7 demethylencecaline provenant d'E. lacinata, E. palmeri et E. ventorum (Baja California, Mexique) se sont revelees phototoxiques vis-a-vis de plusieurs bacteries et levures en UV de grande longueur d'onde. L'encecaline a aussi montre une activite insecticide vis-a-vis des larves d'Oncopeltus fasciatus

The tropical weed Bidens pilosa L. (Asteraceae) contains a number of polyacetylenes which are phototoxic to bacteria, fungi, and human fibroblast cells in the presence of sunlight, artificial sources of long-wave ultraviolet light, or cool-white fluorescent light. The principle photoactive compound in the leaf, phenylheptatriyne, is present in the cuticle as well as in the underlying cells. Experiments with calf thymus DNA indicate that, unlike photoactive furanocoumarins, phenylheptatriyne does not form interstrand cross linkages with DNA in ultraviolet light.

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.