Henry Yokoyama

Lycopene Accumulation Induced by 2-(4-Chlorophenylthio)-Triethylamine Hydrochloride

After fruits, roots, or the mycelium of certain plants were treated with 2-(4-chlorophenylthio)-triethylamine hydrochloride, lycopene was detected in the tissue. This is the first known success in causing lycopene to accumulate in a wide range of carotenogenic tissues that normally do not accumulate the pigment at some stage of development. The response should be of value in the study of carotenoid biosynthetic pathways and gene control mechanisms.

Carotenoid biosynthesis in Blakeslea trispora

Abstract 2-(4-Chlorophenylthio)triethylamine hydrochloride (CPTA) has a profound effect on the carotenogenesis in Blakeslea trispora . When cultures were treated with CPTA, lycopene accumulated as the principle pigment with the concomitant increase in γ-carotene. CPTA is suggested to have multiple functions in carotenogenesis. It might act as an inhibitor of the cyclase(s) and additionally act as a derepressor of a gene regulating the synthesis of a specific enzyme(s) in the lycopene pathway.

Induced color changes in grapefruit and orange

Abstract The fruits of Marsh seedless grapefruit and navel orange do not normally accumulate lycopene. After treatment with 2-(4-chlorophenylthio)triethylamine hydrochloride (CPTA) both fruits accumulate large amounts of lycopene. CPTA appears to stimulate the lycopene pathway. It does not, however, appear to influence the terpenoid flavoring constituents present in the peel oil.

Structure--activity relationships of chemical inducers of carotenoid biosynthesis☆

Abstract Fifteen amines having a profound effect on carotenogenesis in Marsh seedless grapefruit are reported. The compounds fall into three series: Et2N(CH2)nMe (n = 4–8), Et2N(CH2)nPh (n = 1–5), and Et2NCH2CH2OC6H4R (R=H, p-Me, p-Et, p-iso-Pr, p-tert-Bu), There was up to an 11-fold increase in the total carotene content. Lycopene, not normally accumulated, became a major pigment. The inducing ability of the amines on carotenoid biosynthesis is correlated with the octanol-water partition coefficient. The mode of action appears to be similar to that of 2-(4-chlorophenylthio)triethylamine hydrochloride.

Citrus carotenoids—VI.: Carotenoid pigments in the flavedo of Sinton citrangequat

Abstract The flavedo of the fruit of the trigeneric hybrid Sinton citrangequat contains new and unusual carotenoid ketones (apo-carotenones). These pigments are unique in the carotenoid series in that they contain the terminal methyl ketone group in the side chain. Thus far, the methyl ketone carotenoids with nonaeneone and decaeneone chromophores have been isolated and characterized. They are sintaxanthin, citranaxanthin and reticulataxanthin. A minor carotenoid ketone, probably 3-OH-sintaxanthin, was also present. A methyl ketone carotenoid containing an in-chain hydroxyl group, 8′-OH-7′8′-dihydrocitranaxanthin, was also isolated. The remainder of the carbonyl carotenoids consisted of β-apo-10′-carotenal, β-apo-8′carotenal, β-citraurin, and probably 3-OH-β-apo-10′-carotenal. β-Zeacarotene was isolated for the first time from citrus. Neurosporene, γ-carotene and β-carotene in minor amounts were also detected. The rich red color of the flavedo is due mainly to the methyl ketone carotenoids.

The effect of 2-(4-chlorophenylthio)-triethylamine hydrochloride on the formation of carotenoids in citrus

Abstract 2-(4-Chlorophenylthio)triethylamine hydrochloride (CPTA) has a profound effect on the formation of carotenoids in the fruit of the trigeneric citrus hybrid Sinton citrangequat . When CPTA is applied to the immature green fruit and the fruit is allowed to ripen to full maturity and color, lycopene accumulates as the main pigment and is responsible for the rich color in the flavedo. Synthesis of methylketone carotenoids which normally produce the red color in the flavedo is inhibited. Treatment with CPTA after the fruits had attained near full maturity and color results in the accumulation of lycopene as a major pigment; no response is apparent in the previously formed methylketone carotenoids. Treatment with CPTA at immature green, mature green or nearly mature stages of fruit development, stimulates the synthesis of lycopene as the principal pigment or as a major pigment depending on stage of development.

Effects of amines on the carotenogenesis in Blakeslea trispora

Abstract Six amines profoundly affected carotenogenesis in Blakeslea trispora . When cultures were treated with the amines, namely 4-[β-(diethylamino)-ethoxy]-benzaldehyde, 4-[β-(diethylamino)-ethoxy]-acetophenone hydrochloride, 4-β-(diethylamino)-ethoxy]-benzophenone hydrochloride, triethylamine hydrochloride, α-diethylaminopropiophenone hydrochloride and tributylamine hydrochloride, an increase in the lycopene accumulation was observed. The modes of action of these amines appear to be similar to that of 2-(4-chlorophenylthio)triethylamine hydrochloride (CPTA); however, they difrer in relative effectiveness.

New chemical inducers of carotenoid biosynthesis

Abstract Five compounds having a striking effect on the color of Marsh seedless grapefruit are reported. The compounds, namely [β-(diethylamino)-ethoxy]-benzene, [γ-(diethylamino)-propoxy]-benzene, [δ-(diethylamino)-butoxy]-benzene, 4-[β-(diethylamino)-ethoxy]-benzaldehyde, and diethylaminoethyl anisolate caused a 5- to 12-fold increase in the carotene content. Lycopene, not normally accumulated, became the major pigment. The mode of action appears to be similar to that of CPTA.

Citrus carotenoids-VIII. : The isolation of semi-β-carotenone and β-carotenone from Citrus relatives

Abstract Two new naturally occurring carotenoid ketones have been isolated from the Citrus relatives, Murraya exotica Linn. and Triphasia trifolia (Burm. f.) P. Wils. These pigments were structurally identified as semi-β-carotenone and β-carotenone.

Enhanced yield of tomato in response to 2-(3,4-dichlorophenoxy)triethylamine (DCPTA)

Application of the bioregulator, 2-(3,4-dichlorophenoxy)triethylamine (DCPTA) to tomato (Lycopersicon esculentum Mill. cv. Pixie) significantly increased the vegetative growth and fruit-yield productivities of mature plants. Compared with controls, application of 30 μM (10 ppm) DCPTA as a pre-germination seed treatment increased the mean relative growth rates of leaves, stems, and roots, 37%, 16%, and 20%, respectively, during exponential growth. At fruit harvest, the dry weights of leaves, stems, and roots, and the harvestable yield of 30 μM DCPTA-treated plants were doubled when compared with controls. Increases in both the total fruit number per plant and the size of individual fruits contributed to the improved yield of 30 μM DCPTA-treated plants. The total soluble solids contents of mature fruits harvested from 30 μM DCPTA-treated plants were increased 24%, and the lycopene and beta-carotene contents were doubled as compared with controls. These results indicate that DCPTA treatment does not adversely affect the balanced partitioning of photoassimilate to vegetative and reproductive sinks in tomato.