Two new pterocarpans and a new pyrone derivative with cytotoxic activities from Ptycholobium contortum (N.E.Br.) Brummitt (Leguminosae): revised NMR assignment of mundulea lactone

Abstract

Background Ptycholobium is a genus related to Tephrosia which comprises only three species. Compared to Tephrosia, which has been phytochemically and pharmacologically studied, Ptycholobium species have only few or no reports on their chemical constituents. Moreover, no studies on the cytotoxic activities of its secondary metabolites have been previously documented.ResultsFrom the non polar fractions of the roots bark of Ptycholobium contortum (syn Tephrosia contorta), two new pterocarpans: seputhecarpan C 1 and seputhecarpan D 2 and a new pyrone derivative, ptycholopyrone A 3 were isolated. Alongside, five known compounds identified as 3-α,α-dimethylallyl-4-methoxy-6-styryl-α-pyrone or mundulea lactone 4, glyasperin F 5, seputhecarpan A 6, seputheisoflavone 7 and 5-O-methyl-myo-inositol or sequoyitol 8 were also obtained. Their structures were established by the mean means of spectroscopic data in conjunction to those reported in literature. The NMR assignment of the major compound mundulea lactone 4 is revised in this paper. In addition, the cytotoxicity of the isolated metabolites was evaluated on two lung cancer cell lines A549 and SPC212. 8 was not active while compounds 1, 2, 4–7 displayed antiproliferative effects against the two carcinoma cell lines with IC50 values below 75 µM. IC50 values below 10 µM were obtained for 4, 6 and 7 on SPC212 cells.ConclusionBased on the obtained results, Ptycholobium contortum turns to be a rich source of phenolic metabolites among them some bearing prenyl moieties. This study reports for the first time the isolation of pyrone derivatives 3 and 4 from Ptycholobium genus. The cytotoxicity observed for the isolate is also reported for the first time and shows that 4, 6 and 7 could be chemically explored in order to develop a hit candidate against lung cancer.Graphical abstractTwo new pterocarpans and a new pyrone derivative with cytotoxic activities from ptycholobium contortum (N.E.Br.) Brummitt (Leguminosae): revised NMR assignment of mundulea lactone.Electronic supplementary materialThe online version of this article (doi:10.1186/s13065-016-0204-x) contains supplementary material, which is available to authorized users.

Cytotoxicity of seputhecarpan D, thonningiol and 12 other phytochemicals from African flora towards human carcinoma cells

“…1 ) were five terpenoids including one steroid: β -spinasterol ( 1 ) and 4 triterpenoids: friedelanone ( 2 ), 16 β -hydroxylupeol ( 3 ), β-amyrin acetate ( 4 ) and lupeol acetate ( 5 ), one cyclitol: 5- O -methyl-myo-inositol or sequoyitol ( 6 ), 3 flavonoids: rhamnitrin or 7- O -methylquercetin 3- O -rhamnoside ( 7 ) and europetin 3- O -rhamnoside or 7- O -methylmyricetin 3- O -rhamnoside ( 8 ) and thonningiol ( 9 ); one isoflavonid: glyasperin F ( 10 ), three pterocarpan isoflavonoids: seputhecarpan B ( 11 ), seputhecarpan C C 21 H 20 O 5 ( 12 ) and seputhecarpan D ( 13 ) and one xanthone: rheediaxanthone A ( 14 ). The isolation and identification of compounds 2 , 3 and 14 from Garcinia epunctata [ 10 ] and 5, 9–13 from Ptycholobium contortum [ 11 , 12 ] were previously reported. Compounds 1, 4, 6, 7 and 8 were isolated from the bark, leaves and roots of Synsepalum zenkeri (Sapotaceae).…”

“…The cytotoxicity of compound 3 is therefore in accordance with published literature and this work provides more information on the activity of lupeol derivatives. The cytotoxicity of compounds 10, 12 and 13 was reported against A549 and SPC-212 lung cancer cells [ 12 ]. The present work brings additional data on the cytotoxic potential of these compounds.…”

“…The isolation and identification of compounds 2 , 3 and 14 from the Cameroonian medicinal plant Garcinia epunctata Stapf (Guttiferae) [ 10 ] and compounds 5, 9–13 from Ptycholobium contortum ( N.E.Br .) Brummitt (Leguminosae) from Botswana [ 11 , 12 ] were previously reported. Garcinia epunctata Stapf (Guttiferae) was collected in July 2011 at Eloumden inYaoundé (Centre Region of Cameroon) and identified by Mr. Victor Nana at the National Herbarium where a voucher specimen (19,534/SRFCam) was deposited [ 10 ].…”

“…Garcinia epunctata Stapf (Guttiferae) was collected in July 2011 at Eloumden inYaoundé (Centre Region of Cameroon) and identified by Mr. Victor Nana at the National Herbarium where a voucher specimen (19,534/SRFCam) was deposited [ 10 ]. Ptycholobium contortum was harvested around Maun, Ngamiland District in North-Western Botswana and identified by Joseph Madome of the Okavango Research Institute (ORI) Herbarium; voucher specimen (KM-2-Maun-2014) is available at at ORI Herbarium, respectively [ 11 , 12 ]. Compounds 1, 4, 6, 7 and 8 were isolated from the bark, leaves and roots of Synsepalum zenkeri Engl.…”

“…Within our drug discovery research program, the present study was planned to investigate the cytotoxicity of a panel of 14 natural products previously isolated from the Cameroonian medicinal plant Garcinia epunctata Stapf (Guttiferae) [ 10 ], Ptycholobium contortum ( N.E.Br .) Brummitt (Leguminosae) from Botswana [ 11 , 12 ], and freshly isolated from Synsepalum zenkeri Engl. ex Aubrév.…”