O extrato metanólico bruto (EMeOH) das partes aéreas da Herissantia crispa (L.) Brizicky, planta rica em flavonóides e que não possui estudos farmacológicos, foi testada para avaliar sua atividade sob os parâmetros comportamentais e determinar a dose letal 50 (DL50) em camundongos; atividade antimicrobiana e antiulcerogênica. O EMeOH (5000 mg/kg, v.o. ou 2000 mg/kg i.p.) não alterou os parâmetros comportamentais e não causou mortes nos animais. A amostra vegetal em estudo inibiu o crescimento bacteriano. O EMeOH (750 mg/kg) apresentou atividade anti-diarréica. O EMeOH (250, 500 e 750 mg/kg) foi capaz de inibir as lesões gástricas induzidas pelo 0,3 M HCl/etanol 60% em camundongos. Desta forma, pode-se concluir que a planta em estudo apresenta atividade antiulcerogênica, entretanto, se faz necessário avaliar tal atividade através de modelos mais específicos e estudar o mecanismo de ação pelo qual a amostra vegetal protege a mucosa gástrica.

The crude methanol extract (EMeOH) of the aerial parts of Herissantia crispa (L.) Brizicky, plant riches in flavonoids and without pharmacological studies, was tested to value its activity under the behaviour parameters and to determine the lethal dose (LD50) in mice; antimicrobial and antiulcerogenic activities. The EMeOH (5,000 mg/kg, v.o. or 2,000 mg/kg i.p.) did not alter the behaviour parameters and there were not mice deaths. The extract inhibited the bacterial growth. The EMeOH (750 mg/kg) showed anti-diarroeal activity. The EMeOH (250, 500 and 750 mg/kg) decreased the gastric lesions induced by 0.3 M HCl/ethanol 60% in mice. In conclusion, the EMeOH presents anti-ulcerogenic activity;, however it is necessary to value the antiulcerogenic activity in more specific models and to study the action mechanism by which the vegetable sample protects the gastric mucosa.

The phytochemical investigation of Herissantia crispa led to the isolation of seven compounds, identified as: sitosterol 3-O-β-D-glucopyranoside, stigmasterol 3-O-β-D-glucopyranoside, 3,5,7,4'-tetrahydroxyflavone (kaempferol), 3,5,7,3',4'-pentahydroxyflavone (quercetin), unpublished in the genus Herissantia, besides β-sitosterol, kaempferol 3-O-β-D-(6''-E-p-coumaroil) (tiliroside) glucopyranoside and kaempferol 3,7-di-O-α-L-ramnopyranoside (lespedin), described for the first time in the species. The structural determination of the compounds was made by means of spectroscopy methods such as Infrared Spectroscopy, ¹H and 13C Nuclear Magnetic Resonance, with the aid of two dimensional techniques, and by comparison with literature data. The toxicity activity of the MeOH extract and lespedin on Artemia salina Leach. was also carried out.

The phytochemical investigation of Sida galheirensis led to the isolation of 5,4'-dihydroxy-3,7,3´-trimethoxyflavone, 17³-ethoxyphaeoforbide, a rare natural product, 6,7-dimethoxycoumarin, ortho-hydroxybenzoic acid, sitosterol-3-O-beta-D-glucopyranoside, stigmasterol-3-O-beta-D-glucopyranoside, 5,7,4'-trihydroxyflavone, 5,7,3',4'-tetrahydroxyflavone, kaempferol-3-O-beta-D-(6"-E-p-coumaroyl) glucopyranoside and luteolin 7-O-beta-D-glucopyranoside. Their structures were assigned based on spectroscopic analyses, including two-dimensional NMR techniques. Antioxidant activities of hexane, CHCl3, EtOAc, BuOH and EtOH extracts of Sida galheirensis were measured using the 1,2-diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging assay. This is also the first work reporting the chemical investigation of Sida galheirensis.