Semisynthesis, cytotoxicity, antimalarial evaluation and structure-activity relationship of two series of triterpene derivatives.

In this report, we describe the semisynthesis of two series of ursolic and betulinic acid derivatives through designed by modifications at the C-3 and C-28 positions and demonstrate their antimalarial activity against chloroquine-resistant P. falciparum (W2 strain). Structural modifications at C-3 were more advantageous to antimalarial activity than simultaneous modifications at C-3 and C-28 positions. The ester derivative, 3ß-butanoyl betulinic acid (7b), was the most active compound (IC50 = 3.4 µM) and it did not exhibit cytotoxicity against VERO nor HepG2 cells (CC50 > 400 µM), showing selectivity towards parasites (selectivity index > 117.47). In combination with artemisinin, compound 7b showed an additive effect (CI = 1.14). While docking analysis showed a possible interaction of 7b with the Plasmodium protease PfSUB1, with an optimum binding affinity of -7.02 kcal/mol, the rather low inhibition displayed on a Bacillus licheniformis subtilisin A protease activity assay (IC50 = 93 µM) and the observed accumulation of ring forms together with a delay of appearance of trophozoites in vitro suggests that the main target of 3ß-butanoyl betulinic acid on Plasmodium may be related to other molecules and processes pertaining to the ring stage. Therefore, compound 7b is the most promising compound for further studies on antimalarial chemotherapy. The results obtained in this study provide suitable information about scaffolds to develop novel antimalarials from natural sources.

Effect of storage time and conditions on the diene valepotriates content of the extract of Valeriana glechomifolia obtained by supercritical carbon dioxide.

INTRODUCTION: Valepotriates (epoxy iridoid esters) represent an important group of constituents that contribute to pharmacological effects for the genus Valeriana. Storage and extraction of valepotriates is a demanding task, as these compounds are thermolabile and unstable: even when decomposition products are not formed, isovaleric acid liberation from the iridoid nucleus originate compounds with less complex substituents. OBJECTIVE: To study the influence of time and storage conditions on the diene valepotriates (valtrate, isovaltrate, acevaltrate, 1-ß-acevaltrate, 1-ß-aceacevaltrate) content of the Valeriana glechomifolia (native to southern Brazil), extract was obtained by supercritical fluid extraction using CO2 as the fluid (SF-CO2). METHODOLOGY: Above-ground and below-ground material of V. glechomifolia was extracted by SF-CO2 (40 °C, 90 bar). The extract was stored under nitrogen atmosphere or solubilised in methanol. Valepotriates stability was accessed during storage at -20 °C over 8 months through reverse-phase HPLC (mobile phase acetonitrile:water 50:50 (v/v); 254 nm). RESULTS: A gradual increase in valtrate levels and decrease in acevaltrate, 1-ß-acevaltrate and 1-ß-aceacevaltrate, concentration were observed from the first month of storage for the dry extract. However, for the methanol solubilised extract these changes occurred only after the third month and were accompanied by reduction in isovaltrate levels and formation of decomposition products. CONCLUSION: SF-CO2 showed high selectivity for valepotriates extraction. This is the first report on valepotriates molecular conversion, which was less accelerated when the extract was stored in methanol, but under this condition degradation products are also present, probably baldrinals, that are not observed in the dry extract.

Healing of dermal wounds property of Caryocar brasiliense oil loaded polymeric lipid-core nanocapsules: formulation and in vivo evaluation.

Cutaneous lesions lead to complications in patients, since they may be recurrent and also represent risk of progression to infection and/or amputation. Therefore, effective, protective, and topical treatments of easy application and removal need to be developed to provide effective alternatives to patients. The Caryocar brasiliense Cambess (CBC) presents important pharmacological activities and proved in the healing process. This paper reports the improvement of the CBC nanostructured (LNCCBC and LNCCBC+) activity in dermal wounds in vivo. The oil was physico-chemically characterized and used in the development of lipid-core nanocapsules (LNCs), coated (LNCCBC+) or without chitosan (LNCCBC), in concentration of 1.0 mg mL-1. Hydrogel (HG) was tested in vivo on lesions in the back of male Wistar rats for 14 days. The oil presented appropriate physico-chemical characteristics for its use, such as moisture 0.76 %, acidity 0.85 % and oleic acid 25.90 %. The LNCs showed nanometric size (around 200 nm), monomodal distribution, slight acid pH and zeta potential of + 22.1 mV in accordance with the composition. The nanostructured oil induced dermal healing in vivo showing significantly better improvement than free oil. LNCCBC+ showed best results showing the higher increase of the production of type 1 collagen, an important protein to the healing repair. These results suggest that development of formulations LNCCBC and LNCCBC+ are promising and important alternative for the treatment of dermal wounds, avoiding complications related to cutaneous lesions.

Ursolic acid from apple pomace and traditional plants: A valuable triterpenoid with functional properties.

Apple juice production generates a large amount of residue comprising mainly peels, seeds, and pulp, known as apple pomace. In the global context, Brazil ranks 11th in apple production and thousands of tons of apple pomace are produced every year. This by-product is little explored, since it is a rich and heterogeneous mixture, containing interesting phytochemical groups. Among them, ursolic acid (UA) has attracted attention because of its therapeutic potential. UA is a pentacyclic triterpene found too in several traditional plants, and has shown several functional properties such as antibacterial, antiprotozoal, anti-inflammatory and antitumor. Therefore, this review attempts to shed some light on the economical viability of apple and apple pomace as sources of bioactive compounds, highlighting the UA extraction, and its main functional properties published in the last 5years (2010-2015).

Evaluation of triterpenes derivatives in the viability of Leishmania amazonensis and Trichomonas vaginalis

Trichomonas vaginalis and Leishmania spp. are protozoal species responsible for millions of cases of parasitic diseases worldwide. Considering the potential of natural products and the need for more effective and less toxic alternatives to treat trichomoniasis and leishmaniasis, this study aimed to evaluate the effect of two series of triterpenes derivatives with different modifications at C-3 and C-28 positions of the ursolic acid (UA) and betulinic acid (BA) against trophozoites of Trichomonas vaginalis and promastigotes forms of Leishmania (L.) amazonensis. The compounds modified just at C-3 were the most active. The 3β-acetyl betulinic acid (1b) reduced the trophozoites viability of T. vaginalis at 74%, followed by the 3-oxo ursolic acid and 3-oxo betulinic acid (3a and 3b) compounds (55% of reduction). The compound 3β-isobutyl ursolic acid (7a) inhibited the viability of L. amazonensis promastigotes by 55%. Therefore, analyzing the structure-activity relationship and the data of literature, it is possible to suppose that the inclusion of polar groups in the skeletons could improve the antiprotozoal activity. Overall, further studies are necessary to develop triterpenic derivatives with more powerful trichomonicidal and leishmanicidal properties.

Anti-Trichomonas vaginalis activity of Hypericum polyanthemum extract obtained by supercritical fluid extraction and isolated compounds.

The anti-Trichomonas vaginalis activity of Hypericum polyanthemum extract obtained by supercritical fluid extraction (50°C, 150bar) and the chemical compounds isolated and purified from this extract (benzopyrans HP1, HP2, HP3, and phloroglucinol derivative uliginosin B) were assessed. All samples had anti-T. vaginalis activity; however, HP1 demonstrated the best selectivity against this protozoan (metronidazole-resistant and susceptible isolates), with no cytotoxicity on mammalian cells (selectivity index of 73.97). Moreover, HP1 had activity against a metronidazole-resistant isolate (52% of viable trophozoites), and this effect was higher when tested with a low concentration of metronidazole (23% of viable trophozoites). Experiments demonstrated that all isolated compounds caused damage to the parasites' membrane (>90% of LDH release) and do not present a notable hemolytic effect, although HP2 and uliginosin B exhibited cytotoxicity against mammalian cells. Therefore, the analyzed molecules are promising prototypes for new antiprotozoal drugs, especially HP1, which seems to improve metronidazole's effect on a resistant T. vaginalis isolate.

Comparison between spontaneous sedimentation method and Paratest® for the diagnosis of intestinal parasitic infections.

Correct diagnosis of parasitic infections is essential for the treatment of individuals avoiding indiscriminate use of anthelmintics which increases drug resistance. In a comparative study between the spontaneous sedimentation technique and Paratest(®), 140 stool samples were analyzed for the detection of parasites. The prevalence was 12.7% obtained by the spontaneous sedimentation method but only 5.7% using Paratest(®). Paratest(®) has shown a high proportion of false-negative results, lower sensitivity and negative predictive values compared with the spontaneous sedimentation method. Further optimization and studies of the Paratest(®) method are necessary for wider use in clinical diagnosis.

Supercritical fluid extraction and high performance liquid chromatographic determination of benzopyrans and phloroglucinol derivative in Hypericum polyanthemum.

The aerial parts of Hypericum polyanthemum Klotzsch ex Reichardt (Guttiferae) were successively extracted with supercritical carbon dioxide (SC CO(2)) under pressures of 90, 120, 150 and 200 bar at different temperatures (40, 50 and 60 degrees C), and compared with the n-hexane extract obtained by ultrasound-assisted extraction. The samples obtained were examined regarding extraction yield and HPLC quantification of the main secondary metabolites, the benzopyrans HP1 (6-isobutyryl-5,7-dimethoxy-2,2-dimethylbenzopyran), HP2 (7-hydroxy-6-isobutyryl-5-methoxy-2,2-dimethyl-benzopyran) and HP3 (5-hydroxy-6-isobutyryl-7-methoxy-2,2-dimethyl) and the phloroglucinol derivative, uliginosin B. SFE presented higher selectivity than the n-hexane maceration, and the best condition to extract the target metabolites has been determined to be at 50 degrees C and for the high molecular-weight compound, uliginosin B, higher pressures were required.