Occular and dermal toxicity of Jatropha curcas phorbol esters.

Jatropha curcas seeds are a promising feedstock for biodiesel production. However, Jatropha seed oil and other plant parts are toxic due to the presence of phorbol esters (PEs). The ever-increasing cultivation of toxic genotype of J. curcas runs the risk of increased human exposure to Jatropha products. In the present study, effects of J. curcas oil (from both toxic and nontoxic genotypes), purified PEs-rich extract and purified PEs (factors C1, C2, C(3mixture), (C4+C5)) on reconstituted human epithelium (RHE) and human corneal epithelium (HCE) were evaluated in vitro. The PEs were purified from toxic Jatropha oil. In both RHE and HCE, the topical application of PEs containing samples produced severe cellular alterations such as marked oedema, presence of less viable cell layers, necrosis and/or partial tissue disintegration in epithelium and increased inflammatory response (interleukin-1α and prostaglandin E2). When compared to toxic oil, histological alterations and inflammatory response were less evident (P<0.05) in nontoxic oil indicating the severity of toxicity was due to PEs. Conclusively, topical applications of Jatropha PEs are toxic towards RHE and HCE models, which represents dermal and occular toxicity respectively. Data obtained from this study would aid in the development of safety procedures for Jatropha biodiesel industries. It is advised to use protective gloves and glasses when handling PEs containing Jatropha products.

Characterization of a Dispiroketal Spirolide Subclass from Alexandrium ostenfeldii.

A new subclass of spirolide marine toxins, represented by spirolides H (1) and I (2), were isolated from the marine dinoflagellate Alexandrium ostenfeldii. Spirolides H and I are structurally distinct from other spirolides in that they contain a 5:6 dispiroketal ring system rather than the trispiroketal ring system characteristic of previously isolated spirolides. The structures were assigned using a combination of spectrometric and spectroscopic techniques. Previously isolated spirolides containing a cyclic imine moiety showed toxicity in the mouse bioassay. Spirolide H contains this cyclic imine moiety but does not show toxicity in the mouse assay, suggesting that the presence of the cyclic imine moiety is not the only structural requirement for toxicity.

Review of ß-carboline alkaloids from the genus Aspidosperma.

Plants belonging to the genus Aspidosperma, a member of the family Apocynaceae, provide a rich source of ß-carboline alkaloids, which makes them potentially poisonous. However, some of these alkaloids possess antitumor and antimicrobial activity. The present review is a survey of the ß-carboline alkaloids and shows that they comprise of a diverse array of structural modifications.

Isolation, stability and bioactivity of Jatropha curcas phorbol esters.

Jatropha curcas seed oil, which can be utilized for biodiesel production upon transesterification, is also rich in phorbol esters (PEs). In this study, PEs from J. curcas oil (Jatropha factors C1 and C2 (purified to homogeneity), Jatropha factors C3 and (C4+C5) (obtained as mixtures) and PE-rich extract (containing all the above stated Jatropha factors) were investigated. The concentrations of Jatropha PEs were expressed equivalent to Jatropha factor C1. In the snail (Physa fontinalis) bioassay, the order of potency (EC50, µg/L) was: PE-rich extract

Cassane diterpenoids of Caesalpinia pulcherrima.

Five new cassane diterpenoids (1-5) were isolated from the roots of Caesalpinia pulcherrima, along with the known isovouacapenol C (6), pulcherrimin A (11), and 6beta-cinnamoyl-7beta-hydroxyvouacapen-5alpha-ol (12). Compounds 3-5 possess the alpha,beta-butenolide moiety, whereas compounds 1 and 2 contain a more usual 2,3-disubstituted furan unit. Compounds 7 and 8 were derived from hydrolysis of 6, while 9 and 10 were derived from acetylation and oxidation of 6, respectively. The (1)H and (13)C NMR spectra of all compounds were completely assigned using a combination of 2D NMR experiments, including (1)H-(1)H COSY, HSQC, HMBC, and T-ROESY sequences.