James H. Tatum

Six new flavonoids from Citrus

Abstract Valencia orange ( C. sinensis ) and Robinson tangerine [( C. paradisi × C. reticulata ) × ( C. reticulata )] were examined for flavonoids. Thirteen flavonoids were isolated, six of which are new constituents of citrus peel. These are: 3,5,6,7,3′,4′-hexamethoxyflavone, 3,5,7,8,3′,4′-hexamethoxyflavone, 5-hydroxy-3,7,8,3′,4′-pentamethoxyflavone, 5-hydroxy-3,6,7,8,3′,4′-hexamethoxyflavone, 5,7,8,4′-tetramethoxyflavone and 5,7,8,3′,4′-pentamethoxyflavone. The latter three flavonoids are reported for the first time as natural products. A method is described for readily obtaining small quantities of 5,7,8,4′-tetramethoxy and 5,7,8,3′,4′-pentamethoxyflavones from their 5,6,7-trimethoxy analogs.

Novel Anthraquinones from Stationary Cultures of Fusarium oxysporum

Abstract Two new anthraquinones are described which were produced by stationary cultures of Fusarium oxysporum isolated from the roots of diseased citrus trees. They are 2-acetyl-3,8-dihydroxy- or 3-acetyl-2,8-dihydroxy-6-methoxy-anthraquinone and 2-(1-hydroxyethyl)-3,8-dihydroxy- or 3-(1-hydroxyethyl)-2,8-dihydroxy-6-methoxy-anthraquinone. These compounds differ from most other microbial anthraquinones in that they lack hydroxyl substituents at the 1,4 positions, and have an acetyl or 1-hydroxyethyl group at the 2 or 3 positions. This is the first report of anthraquinone metabolites produced by F. oxysporum .

Naphthoquinones produced by Fusarium solani isolated from citrus

Abstract Eleven naphthoquinone pigments are described which were produced by F. solani isolates obtained from roots of diseased citrus trees. One of these pigments was shown to be the precursor for six of the isolated compounds.

Coumarins and psoralens in grapefruit peel oil

Abstract Four coumarins, four psoralens and two methoxyflavones were isolated and identified from the peel oil of grapefruit. Five of these compounds are reported as constituents of grapefruit oil for the first time, one of which, 5[(3,7-dimethyl-6-epoxy-2-octenyl) oxy]psoralen is a new natural product.

Antimicrobial activity of naphthoquinones from Fusaria

Twenty-two naphthoquinone compounds isolated or derived synthetically from culture extracts ofFusarium solani andF. oxysporum were examined for antimicrobial activity. Fifteen exhibited antibiotic activity againstStaphylococcus aureus, and 12 were active againstStreptococcus pyogenes, but none were active at the highest rate of 128 μg/ml againstEscherichia coli, Klebsiella pneumoniae, Salmonella typhi, Proteus vulgaris, Serratia marcescens, orPseudomonas aeruginosa. Of 8 plant pathogenic bacteria tested against 11 naphthoquinones,Corynebacterium poinsettiae was inhibited by 6 compounds, andPseudomonas viridiflava was weakly inhibited by one. Only one of a group of 6 fluorescent soil pseudomonads was inhibited by one naphthoquinone. Antifungal activity of 10 compounds against 8 fungal plant pathogens was limited to inhibition ofPhytophthora parasitica by one naphthopyran.

Degradation of d-glucose with acetic acid and methylamine☆

Abstract Thirteen products have been isolated from degradation of d -glucose with methylamine and acetic acid. Two compounds are responsible for the caramel odor observed in this degradation and have been identified as acetylformoin and 4-hydroxy-2,5-dimethyl-3(2 H )-furanone. Two new compounds, 2-(2-hydroxyacetyl)-1-methylpyrrole and 5-hydroxymethyl-1-methylpyrrole-2-carboxaldehyde are reported for the first time. Eleven of the 13 compounds isolated are derivatives of furan or pyrrole.

Naphthoquinones produced by Fusarium oxysporum isolated from citrus

Abstract Six naphthoquinone pigments are described which were produced by Fusarium oxysporum isolates obtained from roots of diseased citrus trees. These were 8-O-methylbostrycoidin, 9-O-methylfusarubin, 9-O-methylanhydro-fusarubin, 5-O-methyljavanicin, 5-O-methylsolaniol and 1,4-naphthalenedione-3,8-dihydroxy-5,7-dimethoxy-2-(2-oxopropyl). These naphthoquinones had not been previously identified from F. oxysporum isolates.

2,3-Dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one, a degradation product of a hexose

Abstract Evidence is presented to support 2,3-dlhydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one as the structure of a previously isolated, hexose degradation-pr

Toxicity of dihydrofusarubin and isomarticin from Fusarium solani to citrus seedlings

Abstract Rough lemon rootstock seedlings were held in 14-l. plastic tanks containing solutions of the pigments dihydrofusarubin (DHF), isomarticin and a mixture (T-79; 80% DHF and 20% isomarticin) of the two extracted from cultures of Fusarium solani . Both pigments, together or alone, caused initial leaf roll and wilt symptoms within 48–72 h after exposure. The T-79 mixture was effective at the lowest rate, 25 μgl −1 , causing wilt, a reduction in growth, a depression of solution uptake and veinal chlorotic patterns in leaves. Chlorosis was ascribed only to DHF in later tests, and it caused this symptom at the lowest rate tested, 10μgl −1 . At 50μgl −1 , each pigment had similar effects, but DHF increased vessel plugging in stems more than isomarticin. Both pigments caused a loss of water and electrolytes from leaves, indicating that they affected membrane integrity. Isomarticin and fusarubin, the oxidation products of DHF, were visually detected in stems and leaves. Of nine rootstocks tested with DHF, rough lemon appeared to be the most sensitive.

Flavonoids of the citrus cultivar calamondin and synthetic 2′β-dihydroxychalcones

Abstract Eight methoxyflavones were isolated and identified from the peel of calamondin. Citromitin and 5- O -desmethylcitromitin are actually nobiletin and 5- O -desmethylnobiletin, respectively. 5,6,7,8,3′,4′-Hexamethoxyflavanone and 5-hydroxy-6,7,8,3′,4′-pentamethoxyflavanone are not constituents of calamondin, although previously reported.