J. P. Parente

NEUTRALIZATION OF LETHAL AND MYOTOXIC ACTIVITIES OF SOUTH AMERICAN RATTLESNAKE VENOM BY EXTRACTS AND CONSTITUENTS OF THE PLANT ECLIPTA PROSTRATA (ASTERACEAE)

Ethanolic extracts of the aerial parts of Eclipta prostrata L. (Asteraceae) neutralized the lethal activity of the venom of South American rattlesnake (Crotalus durissus terrificus) when mixed in vitro before i.p. injection into adult Swiss mice. Samples of ethanolic extract corresponding to 1.8 mg of dry extract per animal neutralized up to four lethal doses of the venom (LD50 = 0.08 micrograms venom/g animal). Three substances isolated from the plant--wedelolactone (0.54 mg/animal), sitosterol (2.3 mg/animal) and stigmasterol (2.3 mg/animal)--were able to neutralize three lethal doses of the venom. Aqueous extracts of the plant inhibited the release of creatine kinase from isolated rat muscle exposed to the crude venom. The protection conferred against the myotoxic effects of the venom could be demonstrated also in vivo, when the venom was preincubated with the extract prior to injection into mice.

Haemolytic activities of plant saponins and adjuvants. Effect of Periandra mediterranea saponin on the humoral response to the FML antigen of Leishmania donovani

An 87.7% (P < 0.01) and 84% (P < 0.001) of protection against visceral leishmaniasis was achieved in CB hamsters and Balb/c mice, respectively, with saponin combined to the fucose-mannose ligand of Leishmania donovani (FML). However, an undesirable haemolytic effect was described for several saponins. Aiming to improve the formulation with FML/saponin, we comparatively analysed the haemolytic potential of recently characterized plant saponins and currently used adjuvants. The haemolytic activity of steroidic saponins from Agave sisalana; Smilax officinalis as well as commercial saponin (Riedel De Haëns), was higher than that of triterpenoid ones (Bredemeyera floribunda; Periandra mediterranea) and the Freunds complete adjuvant. The concentration resulting in 50% haemolysis was 500 micrograms ml-1 for aluminum hydroxide. The low haemolytic effect of P. mediterranea saponin was abolished by removal of its glycidic moiety and its sapogenin fraction as well as the Freunds Incomplete Adjuvant were non-haemolytic within this range. Furthermore, the adjuvant effect of three doses of P. mediterranea saponin injected with the FML antigen of L. donovani, was assayed in mice, either by the intraperitoneal (i.p.) or the subcutaneous (s.c.) route. The anti-FML IgG antibody levels increased and detectable levels were observed up to 3 months in the s.c. group. The response was expanded in both groups after an injection with a fourth vaccine dose. The IgG response showed increased levels of IgG2a only in the i.p. group, while IgG2b and IgG1 but not IgG3 antibodies were higher than controls in both groups. In conclusion, the results suggest that the recently described triterpenoid fractions of P. mediterranea can be safely used as adjuvant with low or non-haemolytic effect.

Steroidal saponins from Smilax officinalis

Three new steroidal saponins were isolated from the rhizomes of Smilax officinalis. The structures of these saponins were established by extensive spectral data, hydrolysis and chemical correlation as sarsasapogenin 3-O-beta-D-glucopyranosyl-(1-->4)-[alpha-L-arabinopyranosyl-(1-->6 )-beta- D-glucopyranoside, neotigogenin 3-O-beta-D-glucopyranosyl-(1-->4)-[alpha-L-arabinopyranosyl-(1-->6 )]-beta- D-glucopyranoside and 25S-spirostan-6 beta-ol 3-O-beta-D-glucopyranosyl-(1-->4)-[alpha-L-arabinopyranosyl-(1-->6 )]-beta- D-glucopyranoside. Acid hydrolysis of the latter compound gave a sapogenin which has a new orientation of an hydroxyl on the steroidal skeleton. A route is proposed for the biogenesis of the latter sapogenin which is an uncommon steroidal aglycone.

Constituents from the roots of Bowdichia virgilioides

Abstract The isolation and 13 C-NMR data of isoflavone derivatives from Bowdichia virgilioides roots are reported.

Biochanin A triglycoside from Andira inermis

A new isoflavonol triglycoside, biochanin A 7-O-beta-D-apiofuranosyl-(1-->5)-beta-D-apiofuranosyl-(1-->6 )-beta-D- glucopyranoside (1), was isolated from Andira inermis roots in addition to the known compounds genistein 7-O-beta-D-apiofuranosyl-(1-->6)-beta-D-glucopyranoside and lanceolarin.