Peanut roots

R. L. Rittenhouse and M. G. Hale, Loss of organic compounds from roots. II. Effect of O, and CO, tension on release of sugars from peanut roots under axenic conditions. Plant Soil. 15 311 (1971). 

The acetone extracts were diluted 2 1 with water and partitioned against methylene chloride. The methylene chloride-soluble extracts were analyzed by comparative TLC (X). The aqueous phases were concentrated to dryness and dissolved in water that contained 5% acetonitrile and 0.2> acetic acid. These solutions were applied to SEP-PAK cartridges (Waters Associates) and the cartridges were washed with 5-10 ml of water and eluted with 5 ml of 50t acetonitrile. From 90 to 95% of the 1 C was recovered from the cartridges in the 50% acetonitrile eluate. The eluates were concentrated to dryness and dissolved in 18% acetonitrile/1% acetic acid and subjected to HPLC as previously described for PCNB metabolism in peanut roots (6). 

Insoluble residues have been reported as important end-products in the metabolism of other pesticides known to be metabolized by GSH conjugation in higher plants (, 6, 2ii 15). Some insight into the mechanisms of insoluble residue formation was obtained by comparing the metabolism of [ ClPCNB, S-[() C)PCP]Cys and pentachlorothiophenol-UL- C (t" C]PCTP) in peanut root and peanut cell culture (Figure 12). 

Methylene chloride-soluble residues. Methylene chloride-or chloroform-soluble C-labeled products were major residues in all of the plant tissues examined except peanut cell ciiltures (Figure 3). Chloroform-soluble C accounted for 59.2 of the radioactivity isolated from peanut roots 48 hr after treatment with [ C]PCNB. The radioactivity was in the form of PCNB (28.7 ), pentachloroaniline (22.5 ), pentachlorothiophenol (2.6 ) pentachlorothloanlsole (3.1 ) pentachlorothloanlsole sulfoxide (0.5 ) S-(pentachlorophenyl)-2-thioaoetic acid [(S-(PCP)ThioAcetate] (0.5 ) and S-(pentachlorophenyl)-3-thio-2-hydroxypropionic acid [S-(PCP)ThioLactate] (0.2 ) and S-(PCP)Cys (trace) (J), The structures of these compounds are shown in Figure 13. Based on TLC, the last three compounds in this list were classified as polar chloroform- or methylene chloride-soluble residues and the remaining compounds were classified as nonpolar residues. 

Figure 13. Structures of chloroform-soluble residues isolated from peanut roots treated with [ C] PCNB. Chloroform-soluble accounted for 59.2% of the in peanut roots.

S-(Pentachlorophenyl)-2-thioacetic acid and S-(PCP)Thio-Lactate were thought to be produced from S-(PCP)Cys by a transamination reaction. S-(Pentachlorophenyl)-2-thioacetic acid accounted for 7.3J of the in peanut roots treated with S-(PCP)Cys. S-(Pentachlorophenyl)-2-hydroxy-3-thiol-propionic acid and S-(PCP)ThioAcetate were minor metabolites and their presence was not definitively established in tissues other than peanut root. 

The metabolism of PCNB to S-(TCNP)GSH ultimately gave rise to S-(TCNP)MalCys in a manner that no doubt paralleled the metabolism of S-(PCP)GSH. The corresponding minor products of metabolism of S-(PCP)GSH were not observed with S-(TCNP)GSH. Several disubstltuted metabolites were Identified in peanut root. These were thought to be produced by a second reaction of glutathione with S-(TCNP)GSH or some metabolite derived from S-(TCNP)GSH. 

Chen RS, Wu PL, Chiou RY. Peanut roots as a source of resveratrol. J Agric Food Chem 2002 50 1665-1667. 

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