Apoptosis Caused by Triterpenes and Phytosterols and Antioxidant Activity of an Enriched Flavonoid Extract from Passiflora mucronata.

BACKGROUND: P. mucronata (Pm) comes from South America, Brazil and is characterized as "Maracujá de Restinga". It is used in folk medicine for its soothing properties and in treating insomnia. OBJECTIVE: The present study for the first time analyzed the antioxidant and cytotoxicity of the hydroalcoholic leaves extract and fractions from Pm. METHOD: The cytotoxicity test will be evaluated by different assays (MTT and CV) against human prostate cancer (PC3) and mouse malignant melanoma (B16F10) cell lines, and the antioxidant test by DPPH method. RESULTS: ß-Amyrin, oleanolic acid, ß-sitosterol and stigmasterol were isolated of the most active, hexane fraction. These substances were tested against the tumor cell lines: ß-sitosterol and stigmasterol showed the most relevant activity to PC3 in CV assay and, oleanolic acid to B16F10 by the MTT assay. In addition, it was possible to indicate that the mode of cell death for stigmasterol, presumably is apoptosis. In terms of antioxidant activity, the hydroalcoholic leaves extract presented higher activity (EC50 133.3 µg/mL) compared to the flower (EC50 152.3 µg/mL) and fruit (EC50 207.9 µg/mL) extracts. By the HPLC-MS, it was possible to identify the presence of flavones in the leaf extract (isoschaftoside, schaftoside, isovitexin, vitexin, isoorientin, orientin). CONCLUSIONS: P. mucronata hexane fraction showed promising cytotoxic effect against cancer cell lines, and stigmasterol contributes to this activity, inducing apoptosis of these cells. Furthermore, as other Passiflora species, Pm extract showed antioxidant activity and flavones are its major phenolic compounds.

Biological activities and phytochemical profile of Passiflora mucronata from the Brazilian restinga

ABSTRACT In general, Passiflora species have been reported for their folk medicinal use as sedative and anti-inflammatory. However, P. caerulea has already been reported to treat pulmonary diseases. Severe pulmonary tuberculosis, generally caused by Mycobacterium tuberculosis strains resistant to multiple drugs, can lead to deleterious inflammation and high mortality, encouraging new approaches in drug discovery. Thus, the aim of this work was to evaluate the Passiflora mucronata Lam., Passifloraceae, potential for tuberculosis treatment. Specifically, related to antimycobacterial activity and anti-inflammatory related effects (based on inhibition of nitric oxide, tumor necrosis factor-alpha production and antioxidant potential), as well as the chemical profile of P. mucronata. High performance liquid chromatography coupled with diode-array ultraviolet and mass spectrometer analyses of crude hydroalcoholic extract and ethyl acetate fraction showed the presence of flavonoids. Ethyl acetate fraction showed to be as antioxidant as Ginkgo biloba standard extract with EC50 of 14.61 ± 1.25 µg/ml. One major flavonoid isolated from ethyl acetate fraction was characterized as isoorientin. The hexane fraction and its main isolated compound, the triterpene β-amyrin, exhibited significant growth inhibitory activity against Mycobacterium bovis BCG (MIC50 1.61 ± 1.43 and 3.93 ± 1.05 µg/ml, respectively). In addition, Passiflora mucronata samples, specially hexane and dichloromethane fractions, as well as pure β-amyrin, showed a dose-related inhibition of lipopolysaccharide (LPS)-induced nitric oxide production. In conclusion, Passiflora mucronata presented relevant biological potential and should be considered for further studies using in vivo pulmonary tuberculosis model.

Phytochemical Study of Tapirira guianensis Leaves Guided by Vasodilatory and Antioxidant Activities.

The aim of this research was to perform a phytochemical study of the methanol leaves extract of T. guianensis (MET) guided by vasodilatory and antioxidant activities. The chemical profile of MET and the ethyl acetate fraction (EA fraction) was determined by HPLC-UV-MS and EA fraction guided fractionation by reverse-phase chromatography. The vasorelaxant effects of MET, fractions, sub-fractions and constituents were assessed on rat aorta pre-contracted with phenylephrine. Antioxidant activity was evaluated by using a DPPH assay. The results show that MET-induced vasodilation was dependent on NO/cGMP; and that the PI3K/Akt pathway seems to be the main route involved in eNOS activation. The EA fraction showed greater vasodilatory and antioxidant potency and was submitted to further fractionation. This allowed the isolation and characterization of quercetin, quercetin 3-O-(6″-O-galloyl)-ß-d-galactopyranoside and 1,4,6-tri-O-galloyl-ß-d-glucose. Also, galloyl-HHDP-hexoside and myricetin deoxyhexoside were identified by HPLC-UV-MS. These compounds are being described for the first time for T. guianensis. 1,4,6-tri-O-galloyl-ß-d-glucose and quercetin 3-O-(6″-O-galloyl)-ß-d-galactopyranoside showed no vasodilatory activity. Quercetin and myricetin glycoside seems to contribute to the MET activity, since they have been reported as vasodilatory flavonoids. MET-induced vasodilation could contribute to the hypotensive effect of T. guianensis previously reported.

Tannin composition of barbatimão species.

A comparative study of tannin composition of three species known as barbatimão (Stryphnodendron adstringens, Stryphnodendron polyphyllum and Dimorphandra mollis) was developed by TLC, hydrolysis followed by PC, and colorimetry. Principal component analysis of the data obtained showed strong differentiation between the genus Dimorphandra and Stryphnodendron. Additionally, barks from the two Stryphnodendron sp. also presented considerable differences in the tannin structure.