Guilherme V. Símaro

In vitro antiparasitic activity and chemical composition of the essential oil obtained from the fruits of Piper cubeba.

Protozoans of the trypanosomatid family cause the neglected tropical diseases leishmaniasis and trypanosomiasis, for which few drugs are available. In this context our group has recently reported that the essential oil obtained by steam distillation of the fruits of Piper cubeba is active against Schistosoma mansoni. Therefore, we have investigated the in vitro effects of the essential oil against the trypomastigote and amastigote forms of Trypanosoma cruzi isolated from an LLCMK₂ cell line culture and the promastigote forms of Leishmania amazonensis. The in vitro activity of the essential oil against trypomastigotes of T. cruzi increased upon rising concentrations, giving IC₅₀ values of 45.5 and 87.9 µg · mL⁻¹ against trypomastigotes and amastigotes, respectively. The essential oil was not active against L. amazonensis, since it displayed lyses of only 24 % at 400 µg · mL⁻¹, and an IC₅₀ of 326.5 µg · mL⁻¹. Therefore, the essential oil should be further investigated to determine the compounds responsible for the observed activities, as well as its mechanism of action.

In vivo and in silico anti-inflammatory mechanism of action of the semisynthetic (-)-cubebin derivatives (-)-hinokinin and (-)-O-benzylcubebin

(-)-Cubebin (CUB), isolated from seeds of Piper cubeba, was used as starting material to obtain the derivatives (-)-hinokinin (HK) and (-)-O-benzyl cubebin (OBZ). Using paw edema as the experimental model and different chemical mediators (prostaglandin and dextran), it was observed that both derivatives were active in comparison with both negative (5% Tween® 80 in saline) and positive (indomethacin) controls. The highest reduction in the prostaglandin-induced edema was achieved by OBZ (66.0%), while HK caused a 59.2% reduction. Nonetheless, the dextran-induced paw edema was not significantly reduced by either of the derivatives (HK or OBZ), which inhibited edema formation by 18.3% and 3.5%, respectively, in contrast with the positive control, cyproheptadine, which reduced the edema by 56.0%. The docking analysis showed that OBZ presented the most stable ligand-receptor (COX-2 - cyclooxygenase-2) interaction in comparison with CUB and HK.

(-)-Hinokinin Induces G2/M Arrest and Contributes to the Antiproliferative Effects of Doxorubicin in Breast Cancer Cells

Breast cancer incidence rises worldwide and new chemotherapeutical strategies have been investigated to overcome chemoresistance. (-)-Hinokinin is a dibenzylbutyrolactone lignan derived from the partial synthesis of (-)-cubebin extracted from Piper cubeba seeds. Biological effects of dibenzylbutyrolactone lignans include antiviral, antitumor, anti-inflammatory, and trypanocidal activities. In the present study, we evaluated the ability of (-)-hinokinin to modulate the antiproliferative effects of doxorubicin intumoral (MCF-7 and SKBR-3) and normal (MCF-10 A) breast cell lines. Treatment with (-)-hinokinin did not affect the cellular proliferation or contribute to the antitproliferative effects of doxorubicin in MCF-10 A cells. After 24 and 48 hours of treatment with (-)-hinokinin, MCF-7 and SKBR-3 were accumulated in G2/M and, when combined with doxorubicin, (-)-hinokinin contributed to the antiproliferative effects of this chemotherapic by modulation of the cyclin-dependent kinase inhibitor 1. Apoptotic cell death was observed in response to (-)-hinokinin alone in MCF-7, but not in SKBR-3 even 72 hours after treatment. In MCF-7, doxorubicin-induced apoptosis was not increased by (-)-hinokinin. The findings of the present study suggest (-)-hinokinin as an antiproliferative agent that contributes to the effects of doxorubicin. (-)-Hinokinin modulates apoptotic cell death via the molecular regulation of the cell cycle and apoptotic control genes, but the cellular genetic background directly affects the cell fate decision in response to treatment.

Biotransformation of (-)-cubebin by Aspergillus spp. into (-)-hinokinin and (-)-parabenzlactone, and their evaluation against oral pathogenic bacteria

Abstract The biotransformation of the lignan (-)-cubebin by filamentous fungi Aspergillus terreus and Aspergillus niger is an efficient bioprocess for obtaining (-)-hinokinin and (-)-parabenzlactone. The relevance of getting (-)-hinokinin is due to its promising effect against oral pathogens, especially S. sanguinis (both MIC and MBC 12.5 μg/mL), and other previous reported effects against Chagas disease and as anti-inflammatory. The advantage of using fungal transformation is the use of non-toxic and/or non-pollutant reagents and/or solvents in comparison with semi-synthesis. Microbial transformation of (-)-cubebin is also important to evaluate its human metabolism, since Aspergillus species are capable of mimicking P450 reactions, providing possible products of the metabolism, which is important in the assessment of its efficacy and safety. Furthermore, the present study describes a reliable RP-HPLC method to perform quantification of (-)-hinokinin in fungal extracts. It is simple, fast, selective, linear, precise, accurate and robust according to validation guidelines.

Evaluation of lignans from Piper cubeba against Schistosoma mansoni adult worms: A combined experimental and theoretical study

Six dibenzylbutyrolactonic lignans ((−)‐hinokinin (1), (−)‐cubebin (2), (−)‐yatein (3), (−)‐5‐methoxyyatein (4), dihydrocubebin (5) and dihydroclusin (6)) were isolated from Piper cubeba seed extract and evaluated against Schistosoma mansoni. All lignans, except 5, were able to separate the adult worm pairs and reduce the egg numbers during 24 h of incubation. Lignans 1, 3 and 4 (containing a lactone ring) were the most efficient concerning antiparasitary activity. Comparing structures 3 and 4, the presence of the methoxy group at position 5 appears to be important for this activity. Considering 1 and 3, it is possible to see that the substitution pattern change (methylenedioxy or methoxy groups) in positions 3′ and 4′ alter the biological response, with 1 being the second most active compound. Computational calculations suggest that the activity of compound 4 can be correlated with the largest lipophilicity value.

In vitro Activities of Pfaffia glomerata Root Extract, Its Hydrolyzed Fractions and Pfaffic Acid Against Trypanosoma cruzi Trypomastigotes

This article reports on the in vitro activity of the hydroalcoholic extract of Pfaffia glomerata roots, its hydrolyzed fractions, and pfaffic acid against Trypanosoma cruzi. The hydroalcoholic extract obtained from dried, milled P. glomerata roots was submitted to acid hydrolysis followed by partition with CHCl3. The concentrated CHCl3 fraction was suspended in MeOH/H2O and partitioned with hexane (F1), CHCl3 (F2), and AcOEt (F3), in this sequence. The trypanocidal activity of the hydrolyzed extract and its fractions was evaluated in vitro. The hydroalcoholic extract displayed low activity, but fraction F1 was active against trypomastigotes of the Y strain of T. cruzi, with IC50 = 47.89 μg/ml. The steroids campesterol (7.7%), stigmasterol (18.7%), β‐sitosterol (16.8%), Δ7‐stigmastenol (4.6%), and Δ7‐spinasterol (7.5%) were the major constituents of F1, along with fatty acid esters (7.6%) and eight aliphatic hydrocarbons (30.1%). Fractions F2 and F3 exhibited moderate activity, and pfaffic acid, one of the main chemical constituents of these fractions, displayed IC50 = 44.78 μm (21.06 μg/ml). On the other hand, the hydroalcoholic extract of P. glomerata roots, which is rich in pfaffosides, was inactive. Therefore, the main aglycone of pfaffosides, pfaffic acid, is much more active against trypomastigotes of the Y strain of T. cruzi than its corresponding glycosides and should be further investigated.