Chorizanthe brevicornu
Newberry Mts., Lake Mead National Rec. Area, NV
Spjut 15282, May 2003

Chorizanthe brevicornu
Newberry Mts., Lake Mead National Rec. Area, NV
Spjut 15282, May 2003

Chorizanthe staticoides
Transverse Ranges, S of
Palmdale, CA, Spjut 15342,
 Jun 2003

Chorizanthe diffusa

 Santa Barbara Co., CA, Robert H. Miller 3535, 27 May 1965

Chorizanthe watsonii
CNPS Survey, north drainage of El Paso Mountains, Apr 2010.

Chung H.S., L. C. Chang, S. K. Lee, L. A. Shamon, R. B. van Breemen, R. G. Mehta, N. R. Farnsworth, J. M. Pezzuto and A. D. Kinghorn.  1999. Flavonoid constituents of Chorizanthe diffusa with potential cancer chemopreventive activity.  J. Agric. Food Chem. 47(1): 36-41. “An ethyl acetate-soluble extract of Chorizanthe diffusa was found to exhibit significant antioxidant activity, as judged by scavenging stable 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radicals and inhibition of 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced free radical formation with cultured HL-60 cells. Bioassay-directed fractionation of this extract using the DPPH antioxidant assay as a monitor led to the isolation of five structurally related flavonoids (1-5), including the novel compound 5,8,3',4',5'-pentahydroxy-3, 7-dimethoxyflavone (1). Isolates 1-5 demonstrated varying degrees of antioxidant or antimutagenic activity. Two of the compounds, 5,7,3', 4'-tetrahydroxy-3-methoxyflavone (2) and quercetin (4), were subsequently found to inhibit carcinogen-induced preneoplastic lesions in a mouse mammary organ culture model. Inhibitory activity of this type is known to correlate with cancer chemopreventive effects in full-term models of tumorigenesis.”

Lee S. K., Z. H. Mbwambo, H. Chung, L. Luyengi, E. J. Gamez, R. G. Mehta, A. D. Kinghorn and J. M. Pezzuto.  1998. Evaluation of the antioxidant potential of natural products.  Comb. Chem. High Throughput Screen 1(1): 35–46. “Since reactive oxygen radicals play an important role in carcinogenesis and other human disease states, antioxidants present in consumable fruits, vegetables, and beverages have received considerable attention as cancer chemopreventive agents. Thus, in order to identify antioxidants in plant extracts, test materials were assessed for potential to scavenge stable 1,2-diphenyl-2-picrylhydrazyl (DPPH) free radicals, reduce TPA-induced free radical formation in cultured HL-60 human leukemia cells, and inhibit responses observed with a xanthine/xanthine oxidase assay system. Approximately 700 plant extracts were evaluated, and 28 were found to be active in the DPPH free radical scavenging assay. Based on secondary analyses performed to assess inhibition of 7,12-dimethylbenz(a)anthracene-induced preneoplastic lesion formation with a mouse mammary organ culture model, Chorizanthe diffusa Benth. (Polygonaceae), Mezoneuron cucullatum Roxb. (Leguminosae), Cerbera manghas L. (Apocynaceae) and Daphniphyllum calycinum Benth. (Daphniphyllaceae) were selected and subjected to bioassay-guided fractionation. 5,7,3',5'-Tetrahydroxy-8,4'-dimethoxyflavonol, 5,8,4'-trihydroxy-7,3'-dimethoxyflavonol, 5,3',4'-trihydroxy-7-methoxyflavonol, and 6,3',4'-trihydroxy-7-methoxyflavonol were identified as active principles from C. diffusa. Piceatannol, trans-resveratrol, apigenin and scirpusin A were found as the active principles of M. cucullatum, olivil, (-)-carinol, and (+)-cycloolivil were active principles from C. manghas, and 5,6,7,4'-tetrahydroxyflavone 3-O-rutinoside and kaempferol 3-O-neohesperidoside were active principles from D. calycinum. Of these substances, the hydroxystilbenes piceatannol and transresveratrol have thus far been shown to inhibit carcinogen-induced preneoplastic lesion formation in the mouse mammary gland organ culture model.”