Antioxidative catechol lignans/neolignans isolated from defatted kernel of Jatropha curcas

Abstract

Jatropha curcas L. has been cultivated in many countries for biodiesel production, and defatted kernel is generated in huge quantities as a by-product in the production. This study investigated the phenolic content and antioxidative activity of the defatted kernel of Jatropha. Four extracts, EtOAc-organic, EtOAc-water, MeOH-organic, and MeOH-water fractions, were tested for phenolic content and antioxidative activity using the Folin-Ciocalteu method and the DPPH (2, 2-diphenyl-1-picrylhydrazyl) method, respectively. The MeOH-organic fraction showed a high content of phenolic compounds and exhibited a relatively strong antioxidative activity. Eight compounds were isolated from the MeOH-organic fraction, and identified as a catechol-type lignan (3,3 0 -bisdemethylpinoresinol), five neolignans (isoamericanol A, americanol A, 9 0 -O-methylisoamericanol A, 9 0 -O-methylamericanol A, and isoamericanin A), and two sesquineolignans (isoprincepin, princepin). The antioxidative activities of 3,3 0 -bisdemethylpinoresinol (IC 50 : 16.0 lL), isoprincepin (9.12 lL), and princepin (11.7 lL), which have two catechol groups were higher than that of Trolox (21.5 lL). The isoamericanol A inhibited the oxidation of biodiesel. These results indicate that the defatted kernel of Jatropha is a source of natural antioxidants that would applicable for stabilizers in Jatropha biodiesel industries.

A catechol-type lignan and neolignans are specifically present in the seed coat of tung trees

“…Isoamericanol A, as a standard compound, was synthesized from the radical coupling reaction of caffeyl alcohol [6]. Caffeyl alcohol (892 mg, 5.37 mmol) was dissolved in an acetone-toluene mixture (50 mL, 1:2, v/v) and Ag 2 CO 3 (1.427 g) was added to the solution at room temperature.…”

“…The injection volume of the samples and standards was 10 μL each. Standards of isoamericanol A, americanol A, and (+)-3,3′-bisdemethylpinoresinol were obtained from defatted tung tree seeds [5]. A calibration curve was constructed by plotting the peak area versus the concentration of the synthesized isoamericanol A (0.02-0.4 μg/μL).…”

“…Therefore, we expect that the tung seed contains strong antioxidative compounds to protect the oil. Previously, we isolated and identified a catechol-type lignan and six neolignans from the seeds of tung trees that exhibited strong antioxidative activity like that of Trolox [5,6]. The lignans, which may have been generated from the oxidative coupling of caffeyl alcohol or caffeic acid, have shown interesting physiological activities.…”

“…Extracting the bioactive compounds from these residues contributes to the added value of these wastes. Using the antioxidants obtained from tung oil residues to stabilize edible fats and oil products may be difficult; however, the catechol-type lignans isolated from tung seeds could stabilize biodiesel [6]. To promote the utilization of the antioxidants in tung seeds, it is important to thoroughly analyse their amount present during the different developmental stages.…”

High Anticancer Properties of Defatted Jatropha Curcus Seed Residue and its Active Compound, Isoamericanol A

“…As all cells are exposed to free radicals, oxidation may be the major cause of carcinogenesis at tumor sites for several forms of cancer [9]. Suzuki et al examined the total phenolic content (TPC) and antioxidant activity of the four fractions (organic and water fractions of both EtOAc and MeOH) of the defatted Jatropha seed residue, using the Folin-Ciocalteu method and the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging method, respectively [10]. The MeOH-organic fraction was found to show the highest TPC and antioxidant activity among the fractions.…”