Bufadienolides preferentially inhibit aminopeptidase N among mammalian metallo-aminopeptidases; relationship with effects on human melanoma MeWo cells.

Bufadienolides are steroids that inhibit Na+/K+-ATPase; recent evidence shows that bufalin inhibits the activity of porcine aminopeptidase N (pAPN). We evaluated the selectivity of some bufadienolides on metallo-aminopeptidases. Among the enzymes of the M1 and M17 families, pAPN and porcine aminopeptidase A (pAPA) were the only targets of some bufadienolides. ѱ-bufarenogin, telocinobufagin, marinobufagin, bufalin, cinobufagin, and bufogenin inhibited the activity of pAPN in a dose-dependent manner in the range of 10-7-10-6 M. The inhibition mechanism was classical reversible noncompetitive for telocinobufagin, bufalin and cinobufagin. Bufogenin had the lowest Ki value and a non-competitive behavior. pAPA activity was inhibited by ѱ-bufarenogin, cinobufagin, and bufogenin, with a classical competitive type of inhibition. The models of enzyme-inhibitor complexes agreed with the non-competitive type of inhibition of pAPN by telocinobufagin, bufalin, cinobufagin, and bufogenin. Since APN is a target in cancer therapy, we tested the effect of bufadienolides on the MeWo APN+ human melanoma cell line; they induced cell death, but we obtained scant evidence that inhibition of APN contributed to their effect. Thus, APN is a selective target of some bufadienolides, and we suggest that inhibition of APN activity by bufadienolides is not a major contributor to their antiproliferative properties in MeWo cells.

In Vitro Pharmacological Screening of Essential Oils from Baccharis parvidentata and Lippia origanoides Growing in Brazil.

In this study, the in vitro antimicrobial, antiparasitic, antiproliferative and cytotoxic activities of essential oil from Baccharis parvidentata Malag. (EO-Bp) and Lippia origanoides Kunth (EO-Lo) were explored. The relevant effects were observed against the parasitic protozoans Plasmodium falciparum, Trypanosoma cruzi, Trypanosoma brucei and Leishmania amazonensis (ranging 0.6 to 39.7 µg/mL) and malignant MCF-7, MCF-7/HT, 22Rv1, and A431 cell lines (ranging 6.1 to 31.5 µg/mL). In parallel, EO-Bp showed better selective indexes in comparison with EO-Lo against peritoneal macrophages from BALB/c mice and MRC-5 cell line. In conclusion, EO-Lo is known to show a wide range of health benefits that could be added as another potential use of this oil with the current study. In the case of EO-Bp, the wide spectrum of its activities against protozoal parasites and malignant cells, as well as its selectivity in comparison with non-malignant cells, could suggest an interesting candidate for further tests as a new therapeutic alternative.

Cucurbitane-type compounds from Momordica charantia: Isolation, in vitro antidiabetic, anti-inflammatory activities and in silico modeling approaches.

Momordica charantia L., commonly known as bitter melon, belongs to the Cucurbitaceae family. Various in vitro and in vivo studies have indicated that extracts of bitter melons have anti-diabetic properties. However, very little is known about the specific purified compounds responsible for these antidiabetic properties. In the present study, 3ß,7ß,25-trihydroxycucurbita-5,23(E)-dien-19-al, charantal, charantoside XI, and 25ξ-isopropenylchole-5, 6-ene-3-O-d-glucopyranoside were isolated from bitter melon fruit. The structures of the purified compounds were elucidated by HR-ESIMS, 1D, and 2D NMR experiments. All compounds exhibited significant inhibition of α-amylase and α-glucosidase comparable to acarbose. Molecular docking studies demonstrated that purified compounds were able to bind to the active sites of proteins. Additionally, the purified compounds showed significant anti-inflammatory activity, downregulating the expression of NF-κB, iNOS, IL-6, IL-1ß, TNF-α, and Cox-2 in lipopolysaccharide-activated macrophage RAW 264.7 cells. Our findings suggest that the purified compounds have potential anti-diabetic and anti-inflammatory activities and therefore hold promise for the development of plant-based management for diabetic and inflammatory conditions.

In vitro and in vivo activity of major constituents from Pluchea carolinensis against Leishmania amazonensis.

The search for new therapeutic agents from natural sources has been a constant for the treatment of diseases such as leishmaniasis. Herein, in vitro and in vivo pharmacological activities of pure major phenolic constituents (caffeic acid, chlorogenic acid, ferulic acid, quercetin, and rosmarinic acid) from Pluchea carolinensis against Leishmania amazonensis are presented. Pure compounds showed inhibitory activity against promastigotes (IC50 = 0.2-0.9 µg/mL) and intracellular amastigotes (IC50 = 1.3-2.9 µg/mL). Four of them were selected after testing against macrophages of BALB/c mice: caffeic acid, ferulic acid, quercetin, and rosmarinic acid, with selective indices of 11, 17, 10, and 20, respectively. Ferulic acid, rosmarinic acid, and caffeic acid controlled lesion size development and parasite burden in footpads from BALB/c experimentally infected mice, after five injections of compounds by intralesional route at 30 mg/kg every 4 days. Pure compounds from P. carolinensis demonstrated antileishmanial properties.