RESUMEN
Castor oil contains approximately 90% ricinoleic acid (RA) which is stored mainly in the form of tri-ricinoleic acid containing triacylglycerols (TAG). Ricinoleate is synthesized from oleate (18:1n-9) esterified to the sn-2 position of phosphatidylcholine (PtdCho) catalyzed by oleoyl-12-hydroxylase. PtdCho-derived diacylglycerol (DAG) is an important substrate pool for TAG synthesis, and the interconversion between PtdCho and DAG has been shown to play a critical role in channeling hydroxy fatty acids (HFA) to TAG. Although phospholipase D (PLD) has been reported to catalyze the hydrolysis of PtdCho to produce phosphatidic acid which can then be converted to DAG, its potential functions in the channeling of RA from PtdCho to DAG and the assembly of RA on TAG is largely unknown. In the present study, 11 PLD genes were identified from the Castor Bean Genome Database. Gene expression analysis indicated that RcPLD9 is expressed at relatively high levels in developing seeds compared to other plant tissues. Sequence and phylogenetic analyses revealed that RcPLD9 is a homolog of Arabidopsis PLDζ2. Overexpression of RcPLD9 in the Arabidopsis CL7 line producing C18-HFA resulted in RA content reductions in the polar lipid fraction (mainly PtdCho) and mono-HFA-TAG, but increased RA content in di-HFA-TAG. Since part of RA in di-HFA-TAG is derived from HFA-DAG, the results indicated that RcPLD9 facilitates the channeling of RA from PtdCho to DAG for its assembly on TAG in developing seeds.
Asunto(s)
Proteínas de Arabidopsis/genética , Fosfolipasa D/genética , Ácidos Ricinoleicos/metabolismo , Ricinus communis/genética , Triglicéridos/metabolismo , Arabidopsis/genética , Ricinus communis/metabolismo , Aceite de Ricino/química , Aceite de Ricino/genética , Aceite de Ricino/metabolismo , Endospermo/genética , Endospermo/metabolismo , Ácidos Grasos/genética , Ácidos Grasos/metabolismo , Plantas Modificadas Genéticamente/genética , Plantas Modificadas Genéticamente/metabolismo , Ácidos Ricinoleicos/química , Semillas/genética , Semillas/metabolismo , Triglicéridos/genéticaRESUMEN
OBJECTIVES: In China, Oldenlandia diffusa (OD) is a natural herb that is widely used and has been proven to be effective in the treatment of rheumatoid arthritis (RA). This study aimed to preliminarily reveal the mechanism by which OD exerts its beneficial effect. METHODS: Ultra-performance liquid chromatography photodiode array was applied to identify the absorbable compounds in the plasma of collagen-induced arthritis (CIA) model rats. After 2 weeks, an OD decoction or the identified absorbable compound was administered to CIA rats. Morphology, X-ray images of the joints, pathological images, arthritis index, and cytokine (TNF-α and IL-6) levels were evaluated. RESULTS: p-Coumaric acid (p-CA) was identified as the absorbed compound in plasma. After administration of p-CA solution or the OD decoction, symptoms in the treated rats were alleviated as compared to the untreated model rats, and inflammatory cell infiltration was suppressed. The arthritis index and serum levels of TNF-α and IL-6 were decreased as compared to the control group. CONCLUSIONS: OD may exert its anti-inflammatory effect on RA via its active ingredient, p-CA. This information sheds light on the mechanism by which OD exerts its anti-inflammatory effort in RA and forms the basis for further development of therapeutic agents for RA.